K3S and K3 Firmware Information

NOTE: Beginning with revision 5.26, the K3 and K3S transceivers share the same firmware. Both use K3 Utility for firmware loading. 
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K3 MCU 5.67 / DSP 2.88 / FPF 1.26, 1-22-2019

* 6 M GAIN REDUCTION (FOR USE WITH KPA3A):  In some cases the KPA3A may have more gain than necessary on 6 meters. As a precaution, all radios using a KPA3A (instead of the older KPA3) should be configured to insert some attenuation. See instructions below. No hardware modifications are required.

INSTRUCTIONS:  [Do this only on a K3S, or a K3 that has a KPA3A installed.] 
1. Select the 6 meter band. 
2. Connect a dummy load rated at 50 W (or higher) to the transceiver.
3. Set the PWR control to 50 watts. 
4. Place the ATU in bypass mode.
5. Locate the CONFIG:TUN PWR menu entry. Set the value to NOR using VFO A.
6. Locate the CONFIG:TXGN HP menu entry. 
7. Tap the '8' switch (NR) once to add "ATN6" to the parameter display on VFO A. 
    (Tapping it a second time would return to the original non-attenuated setting.)
8. Exit the menu.
9. Hold TUNE to do automatic power calibration on 6 meters at the 50 W level. After a few seconds, tap XMIT to terminate the TUNE operation.

NOTE: If you have difficulty reaching full power on 6 meters after making this change, it could be because your PA module is actually a KPA3, not a KPA3A. In this case, re-do the above procedure, changing the TXGN HP menu setting back to the original (i.e., without "ATN6" showing). (Max. power output at 50 MHz is specified at 100 W +/- 1 dB, typical. 1 dB below 100 W is approx. 90 W. See Specifications for max output at 51 MHz and higher.)

* T/R TIMING IMPROVED. Adds more margin during KPA3A TX sequencing.

K3 MCU 5.66 / DSP 2.88 / FPF 1.26, 11-28-2018

* ADDED SWR READ COMMAND:  "SW;" returns the most recent SWR reading in transmit or TUNE mode, e.g. "SW023;" for an SWR of 2.3:1. Max value returned is "SW99;" (SWR = 99.9:1).

K3 MCU 5.64 / DSP 2.88 / FPF 1.26, 2-22-2018

* RCV MODE "HI CUR" THRESHOLD CHANGED:  The threshold at which "HI CUR" (excessive current drain) warnings appear in receive mode has been increased. Some users with all options enabled (including the sub receiver, internal transverter, and K-Pod) were seeing spurious HI-CUR warnings and disabling of one speaker channel.

K3 MCU 5.63 / DSP 2.88 / FPF 1.26, 11-22-2017

* KPA1500 ATU TUNE INTEGRATION:  When used with a K3/K3S and the ACC cable, the KPA1500 completely controls ATU TUNE, requiring just a single switch tap. The amplifier automatically starts/stops TUNE mode at the K3. 

K3 MCU 5.62 / DSP 2.88 / FPF 1.26, 11-16-2017

* NEW CONTROL COMMAND ("TM"):  The TM command sets or reads the transmit metering mode on the LCD. TM0; sets the bar graph for SWR/RF, while TM1; sets the bar graph for CMP/ALC. The TX metering mode also determines what is read by the BG (bar graph read) command during transmit. With TM0 in effect, BG reads the power level. If TM1 is in effect, BG reads the ALC level.

K3 MCU 5.61 / DSP 2.88 / FPF 1.26, 6-5-2017

* HOST & P3 UPDATED ON MODE CHANGES due to A/B swap, REV, ALT, etc.). 

K3 MCU 5.60 / DSP 2.88 / FPF 1.26, 5-15-2017

* K-POD AND MACRO BUG FIX: Fixed bug that was causing occasional loss of macro commands, activated either with a K3 front-panel switch or the K-Pod.

* NEW CONTROL COMMAND (DE): The DE remote-control command inserts a command processing delay of about 10 to 2550 ms. This is useful in switch or K-pod macros, where a delay may be desired to allow the radio to complete a previous operation (such as band change or CW message send) before the next command is processed. The format of the command is   DEnnn;  where <nnn> can be 001-255. This value represents the delay in 10 ms increments. Note: A value of 001 may result in a delay shorter than 10 ms, while 002 is guaranteed to provide a delay between 10 and 20 ms, etc.

K3 MCU 5.59 / DSP 2.88 / FPF 1.26, 5-11-2017

* POWER CONTROL BUG FIX: PWR control adjustment was sometimes enabling the TX carrier, so that tapping XMIT afterward would result in unexpected RF output. (Any subsequent transmit operation, e.g. another tap of XMIT, would clear the condition. For this reason the problem was rarely observed.) 

K3 MCU 5.58 / DSP 2.88 / FPF 1.26, 3-16-2017

* PREAMP 2 (ON KXV3B) NOW USABLE ON 15 AND 17 M: PREAMP 2 improves noise figure by about 6 dB on 15 m and 3 dB on 17 m relative to PREAMP 1.

* TX LINE OUT (MONITOR) LEVEL NOW ADJUSTABLE: In CONFIG:LIN OUT menu entry, tap '2'  (REV switch) to set the "T=" level (TX monitor). Tap '2' again to return to the RX LINE OUT setting.

* K-POD SWITCHES WORK CORRECTLY FOR MESSAGE PLAY: K-Pod switch tap and hold can now be used to play, chain, or repeat messages programmed into the K3's M1-M4 message buffers. For example, if macros 9 and 10 were set up as "SWT21;" and "SWT31;" using K3 Utility, then tapping K-Pod switches F1 and F2 would trigger messages M1 and M2, respectively. 

* AM SYNC BUG DURING MEMORY RECALL/STORE FIXED: Previously, recalling or storing a memory with AM-S/TRACK selected could cause the displayed memory number to change on VFO B.

* QSK/VOX DELAY NOT APPLIED IN VOX MODE IF TX START/STOP IS VIA PTT OR XMIT SWITCH: When VOX is selected for any operating mode, the selected delay (set by the DELAY control) is applied on exit from transmit. Now, if the operator starts/stops transmit via PTT or the transmit switch with VOX selected, no delay is applied.

For software developers: 

* VOX SET HOST COMMAND ADDED:  VXn where n = 0 for OFF, n = 1 for ON. CW VX setting is separate from voice/data modes.

* RX ANTENNA HOST COMMAND ADDED:  ARn where n = 0 for RXANT OFF, n = 1 for ON. 

K3 MCU 5.57 / DSP 2.88 / FPF 1.26, 2-16-2017

* FASTER RESPONSE TO HIGH REFLECTED POWER: The transceiver will now reduce drive more quickly when transient conditions cause excessive reflected power. This roll-back response does not change the set power level (PWR knob); instead, it reduces the drive to get below the reflected power limit. This means that once a better match is restored (such as when using an antenna tuner), the set power level will automatically be restored.

K3 MCU 5.56 / DSP 2.88 / FPF 1.26, 10-26-2016

* SCANNING WORKS WITH FREQUENCIES BELOW 1.0 MHz: Previously, scanning would stall in this case.

* REDUCED K-POD MACRO FLASH TIME:  If text decode is enabled, then the length of time that K-Pod macro names are flashed is greatly reduced. This reduces the obstruction of text shown on VFO B.

* DT, FR, and FT HOST COMMANDS DISALLOWED IN TX MODE: Previously, these commands could be sent to the K3 during transmit from some software applications. This could cause side effects such as muting of transmit audio in DATA modes.

K3 MCU 5.55 / DSP 2.88 / FPF 1.26, 10-20-2016

* KPOD WORKS IN REMOTE-RIG TERMINAL MODE:  The K-Pod will now function correctly with a K3 or K3/0-mini being used as a remote-rig terminal. Basic functions of the K-Pod can be used, including switch tap / hold and VFO A/B/offset control. LEDs and AUX outputs of the terminal K-Pod are not yet supported. Note:  At present, when switches on the terminal K-Pod are used, they will execute macros stored at the remote K3. This will be apparent when macro names are flashed on VFO B. 

K3 MCU 5.54 / DSP 2.88 / FPF 1.26, 9-24-2016

* FLASH MEMORY INTERFACE UPDATED:  Improved robustness of read/verify operations between the MCU and flash IC.

* POWER-ON CHECK OF ADC REF MENU PARAMTER:  If the value of CONFIG:ADC REF is out of range, it is reset to 5.00 V to ensure useful accuracy of voltage and current displays, etc.

K3 MCU 5.53 / DSP 2.88 / FPF 1.26, 8-24-2016

* VFO B TUNE VIA K-POD OVERRIDES K3 ALTERNATE DISPLAYS:  If you use the VFO B tuning function of the K-Pod while the K3 has an alternate display showing (via the DISP switch), the VFO B frequency will be displayed instead, as long as you keep tuning it. This is especially useful for operators who keep a VFO B alternate display showing at all times, such as RIT/XIT offset, time, date, supply voltage, etc.

K3 MCU 5.52 / DSP 2.88 / FPF 1.26, 8-11-2016

* K-POD LED AND AUX OUTPUT CONTROL:  K-Pod LEDs and AUX outputs can now be controlled directly from K3 macros using the KPLEDnON|OFF and KPOUTnON|OFF commands. See examples in latest K-Pod owner's manual.

K3 MCU 5.51 / DSP 2.88, 7-16-2016

* TX MONITOR to LINE OUT:  Transmit monitor audio (voice or sidetone) is now available at LINE OUT. At present the level is fixed. A future release will allow adjustment.

K3 MCU 5.50 / DSP 2.87, 5-17-2016

* K-POD BUG FIX:  Eliminated "ERR KP1" messages (K-Pod parity errors) that were occurring when the K-Pod knob was spun at the same time the P3 was used, along with heavy external polling from HRD, etc. 

K3 MCU 5.49 / DSP 2.87, 4-10-2016

* K-POD SUPPORT:  Reads switch and encoder events from an Elecraft K-Pod attached to the RJ12 jack under the K3/K3S front panel. F1-F8 tap on the K-Pod execute macros 9-16; F1-F8 hold execute macros 1-8. Use the latest K3 Utility to set up macros and write them to the K3/K3S. 
  
K3 MCU 5.47 / DSP 2.87 / FPF 1.25, 3-1-2016

* 15/17 M POWER OUTPUT FIXED: No longer limited to 95 W on these bands. 

* DSP LINE OUT CONTROLS: Further description TBD. 

K3 MCU 5.46 / DSP 2.86 / FPF 1.25, 1-8-2016

* IMPROVED T/R CONTROL FROM SOFTWARE APPLICATIONS: Some computer logging/contesting applications send an "RX;" command to exit transmit mode (e.g. N1MM, when ESC is pressed). This now works reliably even if transmit was initiated via PTT or any other method. Note: If an application sends "RX;" substantially before dropping the PTT line, the radio will still return to receive, but the user will see ERR PTT on VFO B and further transmit will be locked out until PTT is released. Similarly, if "RX;" is sent while external KEY input is still present, ERR KEY will be shown on VFO B, and transmit locked out until KEY in is released.

* KRX3 support: Firmware detects latest KRX3 PCB (rev. C), which uses a different type of IC for selecting crystal filters. (No performance difference from older revisions.)

K3 MCU 5.40 / DSP 2.86 / FPF 1.25, 11-11-2015

* PA TEMP MENU FUNCTION CHANGE:  Tapping '1' in CONFIG:PA TEMP selects one of two PA temperature-sensing algorithms for use on 12 and 10 m: "T AND R" or "R ONLY". The default is "T AND R" (normal 12/10 m PA temp sensing in both TX and RX modes). The "R ONLY" selection should be used if PA temperature sensing on these higher bands may be affected by higher load SWR, poor grounding, or supply voltage drop. In this case, normal temp sensing is done only in RX mode, while in TX mode, sensing is done in a way that minimizes sensor error due to RFI. 6 meters always uses the R ONLY method. 

K3 MCU 5.38 / DSP 2.86 / FPF 1.25, 10-3-2015

* CR & LF NOW HANDLED IN FSK-D and PSK-D MODES: Carriage return (CR) and line feed (LF) characters are now correctly handled in FSK-D and PSK-D modes, for both receive and transmit. These are used by computer applications (such as the K3 Utility Terminal screen) for screen formatting, etc. FSK-D and PSK-D are the transceiver's built-in data modes, allowing the operator to send using a keyer paddle, a keyboard connected to the P3 panadapter, or a computer application. Decoded text is also scrolled on the radio's VFO B display.

* ELIMINATED UNEXPECTED ERR PTT/ERR KEY MESSAGES: Operators were finding that when they held the mic PTT switch, then tapped certain switches including A/B, they were seeing ERR PTT/ERR KEY messages. Such messages now appear only if the PTT/KEY inputs on the RS232 or USB connectors are in use (see CONFIG:PTT-KEY), and the user tries to exit a transmit condition by tapping XMIT. 

K3 MCU 5.35 / DSP 2.86 / FPF 1.24, 8-20-2015

* MAIN:ATTEN MENU ENTRY NO LONGER GETS SET TO 0 DB: This menu entry sets the per-band attenuator ON level (5, 10, or 15 dB for the K3S, 10 dB fixed for the K3). In the previous firmware release, MAIN:ATTEN could be set to 0 dB by computer logging/control applications. This is not a valid parameter value. Once the menu entry is set to the desired ON value, the attenuator itself is turned on/off by the ATT switch. (Holding ATT for 3 seconds is a shortcut into the menu entry.)

For Application Developers:

* "RA01" and "RA10" COMMANDS BOTH SELECT 10-dB RX ATTN VALUE:  The K3's RA set command for 10 dB Is RA01. The K3S uses actual dB values, so for 10 dB, RA10 is normally used. (The K3S can also accept RA05 and RA15.) To improve compatibility with unmodified K3 applications, the K3S now allows either RA01 or RA10 for 10 dB. The GET response uses whichever SET format was received last.

MCU 5.33 / DSP 2.86 / FPF 1.23, 8-3-2015

* DIVERSITY WORKS WITH MISMATCHED MAIN/SUB RX FILTERS:  Diversity mode in the K3S (or a K3 with the KSYN3A installed) now works with any combination of main/sub RX crystal filters. They can have different bandwidths or offsets, and it's not necessary to have an equal number of filters in each receiver. Note: Matched filters are optimal for diversity, but non-matched filters will still perform well.

* PTT/KEY USE WITH THE USB PORT IMPROVED:  PC applications can activate PTT and KEY at the K3S via the USB port's RTS/DTR signals. However, initial setup of the rig's USB port by the PC may cause pulsed or continuous activation of the transmitter. This can happen if the computer is turned on after the K3S, or if the USB cable is not connected. There is now a "Safe" mode (the default) which disables PTT-KEY transmit until the K3S receives a command via USB, such as a read of the rig's VFO frequency. To turn on safe mode on/off, go into CONFIG:PTT-KEY and tap '1' to select "USB SAFE" or "UNSAFE". Exit the menu and turn the K3S off/on. Applications that use PTT-KEY via USB but never send commands may require "UNSAFE" mode. In this case, unwanted transmit can be avoided by turning the PC on before the K3S.

* CANCELLING UNEXPECTED PTT-KEY ACTIVATION:  If an external source (usually a PC) activates PTT or KEY unexpectedly, you can cancel transmit by tapping the XMIT switch. This will show ERR KEY or ERR PTT on VFO B. Once the PTT or KEY source as been removed, transmit will be re-enabled. If the cause may be unneeded PTT-KEY activation via the USB port, go into the CONFIG:PTT-KEY menu entry and set the parameter to OFF-OFF.

For Application Developers (also see Programmer's Reference, rev. F2):

* PARAMETER ADJUSTMENT VIA "UP" and "DN" COMMANDS:  UP and DN now apply to all settings adjusted using VFO A/B, including: NB, NR, manual notch, pitch, and text decode . (It also still applies to the menu.) It does NOT apply to special displays controlled by VFO B (use DB), or to settings controlled by the small encoders.

* OM (OPTION MODULE) COMMAND CHANGES:  Three new single-letter fields have been added to the OM command:  'L' (low-noise amp/preamp2 available on present band), 'V' (KSYN3A installed, allowing the VFO to tune down to 100 kHz), and 'R' (K3S RF board in use; see impact on RA command, below). Note that 'L' (preamp 2) only applies on 12/10/6 meters. Preamp 2 is located on the new KXV3B module.

* RA (ATTENUATOR) COMMAND FORMAT CHANGE: If a K3S RF board is in use (determined using the OM command, above), the set/response format of the RA command uses dB values  (RA00/05/10/15). The K3 format is still RA00/01. Note:  5 and 15 dB attenuator settings only apply to the main RX. The sub RX attenuator is 10 dB, even in the K3S. But if a K3S RF board is detected, the sub RX RA format is RA00/10. 

MCU 5.29 / DSP 2.83 / FPF 1.22, 6-16-2015 

* EXTERNAL ALC DEFAULT FIXED: External ALC (CONFIG:EXT ALC menu entry) was being set to ON at first-time power-up. It now correctly defaults to OFF. Any K3S first powered-up with rev. 5.26 should be checked for the correct setting (normally done at the factory). Set to OFF unless external ALC is in use.

* ADC REFERENCE DEFAULT FIXED: The A-to-D converter reference setting (CONFIG:ADC REF menu entry) was left uninitialized at first power-up, possibly with a value that could adversely affect the accuracy of power, SWR, and other readings. Any K3S first powered-up with rev. 5.26 should have ADC REF recalibrated (normally done at the factory).

MCU 5.28 / DSP 2.83 / FPF 1.22, 5-27-2015 

* Manufacturing support changes.

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MCU 5.26 / DSP 2.83 / FPF 1.22, 5-8-2015 

(First Combined K3S/K3 Release)
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* USB COMPUTER PORT FOR COMBINED CONTROL and DIGITAL AUDIO (K3S, KIO3B):  If a KIO3B module is installed (standard with the K3S), the CONFIG:RS232 menu entry will have a "USB" setting. If this setting is used, then a single USB cable can be used between the K3S and a computer to provide remote control, digitized line-level audio in/out, and PTT/KEY (via equivalents to the "RTS" and "DTR" signals). All of these signals are usually recognized by computer applications that also support RS232. This eliminates the need for a sound card and associated analog line in/out cables, as well as any external converter units. Refer to the K3S owner's manual, pgs. 18-20, for details.

* NEW P3 PANADAPTER CABLE SUPPORT (K3S, KIO3B):  If a KIO3B module is installed, then the P3 Panadapter must be connected to the K3S at its RS232/P3 connector (RJ45). Two different special cables are available for this purpose, depending on whether a computer will be connected via USB or RS232 to the K3S and P3. Refer to the K3S owner's manual for details (pg. 18 and 19).  

* LINE IN/OUT AUDIO USE WITH USB PORT (K3S, KIO3B):  If a plug is inserted into the LINE IN jack on the K3S, this audio signal will override the digitized audio line-in data that is present in the USB cable. LINE OUT on the K3S, however, is always available even if the USB cable is being used for line-out.

* PREAMP 2 and CONFIG:PREAMP2 MENU ENTRY (KXV3B):  This menu entry is only applicable if a KXV3B module is installed (supplied with the K3S). It also only applies if the current band is 12, 10, or 6 meters. If PREAMP2 is set to ON, then the PRE switch rotates through settings of OFF, PRE 1, and PRE 2 on the applicable band. PRE 2 turns on the low-noise preamp on the KXV3B module (+20 dB, with a typical NF of -144 dBm on 12/10/6 meters). When PRE 2 is selected, the PRE icon will flash slowly. Note: Do not use an external preamplifier (such as an Elecraft PR6 or PR6-10) when using the built-in low-noise preamp (PRE 2). This would result in excessive gain.
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* MULTIPLE ATTENUATOR SETTINGS and MAIN:ATTEN MENU ENTRY (K3S RF BOARD): On a K3S, the MAIN:ATTEN menu entry is used to select the per-band attenuation level for the ATTN switch (5/10/15 dB). A shortcut method of accessing this menu entry is to hold the ATTN switch for about 3 seconds. (On a K3, the parameter is fixed at 10 dB.)

* LOW-LOSS ATU BYPASS SETTING (KAT3A): The upgraded internal ATU option, the KAT3A, includes a very low-loss bypass path via an additional relay. The bypass relay is engaged when the ATU switch is used to turn the ATU icon OFF. This setting can be used with closely matched antennas. ("Bypass" mode on the earlier model KAT3 ATU uses a minimum-L/minimum-C network setting rather than a relay, result in a small dissipation loss that varies with frequency.)

* 100-500 KHZ SENSITIVITY IMPROVEMENT (KBPF3A): The KBPF3A is an upgrade from the KBPF3. The lowest-frequency filter in the KBPF3A has a cutoff at 100 kHz rather than 500 kHz. This improves typical sensitivity at 137 kHz (2200 meters) to about -120 dBm, and at 472 kHz (600 meters), about -130 dBm.

* UPDATED "PA" (PREAMP) REMOTE-CONTROL COMMAND (KXV3B): The PA command now supports a SET/RESPONSE value of "PA2" whenever preamp 2 is available. This applies on 12/10/6 meters with a KXV3B module installed and preamp 2 enabled (see CONFIG:PREAMP2 description, above).

MCU 5.22 / DSP 2.83 / FPF 1.21, 4-9-2015

* Noise blanker driver optimization: no effect on normal operation.

MCU 5.20 / DSP 2.83 / FPF 1.21, 3-30-2015

* MENU IMPROVEMENTS:  (1) CONFIG:VFO LNK will now alternate between ON and OFF when assigned to a PFx or Mx switch. (2) The KNB3 is required for operating the radio, and there are no configuration settings, so this entry was removed. (3) Accessing menu entries via PFx/Mx switches now correctly restores the operator's last-used MAIN and CONFIG menu selections on exit. 

* VCO CAL (FOR KSYN3) DISABLED IF KSYN3A DETECTED. 

* FA & FB REMOTE-CONTROL COMMANDS WORK DOWN TO 100 KHZ WITH KSYN3A. Note that a KBPF3 module is required to use the K3 below 160 meters. Sensitivity is then quite good (-125 dBm) down to about 400 kHz, although it falls off below that. For example, 250 kHz MDS is about -90 dBm. 

MCU 5.14 / DSP 2.83 / FPF 1.19, 2-26-2015

* VCO CAL FIXED (NOT APPLICABLE TO KSYN3A):  The original KSYN3 synthesizer must be calibrated at time of assembly using CONFIG:VCO MD. This is once again working correctly.

* DUAL PB CW FEATURE RESTORED:  The original DUAL PB (dual-passband) CW feature has been added back in. CONFIG:DUAL PB can be used to select either DUAL PB or APF (audio peaking filter). APF is the default. See manual for details.

* 50-WATT TX GAIN CALIBRATION REQURED (ONE TIME): The first time rev. 5.10 or later firmware is loaded into the K3, 50-watt TX gain calibration should be performed on all bands. This is fully automated by K3 Utility. This initializes transmit drive limit data that is now used to prevent overdrive of the KPA3 amplifier.

MCU 5.13 / DSP 2.83 / FPF 1.19, 2-24-2015

* KSYN3A CONTROL BUG FIXED:  On some K3s, a communications error would sometimes occur between the main MCU and KSYN3A, leading to either the main or sub receiver being off frequency. This has been corrected.

* TURNING DIVERSITY OFF DOESN’T TURN OFF THE SUB RX: This applies to both a hold of the SUB switch and the DV0 host command. The sub must be turned off by tapping SUB. (Also see next item.)

* NEW "DVS" HOST COMMAND: This variation of the DV command turns both diversity and the sub RX on/off at the same time. This is useful for operators who want a single switch macro to quickly alternate between sub with diversity ON and sub OFF. Use K3 Utility to create a switch macro, then assign it to a programmable switch using CONFIG:MACRO n.

* "DT" HOST COMMAND FIX (data sub-mode): The DT set command to select the DATA submode for VFO A now correctly sets the same submode for VFO B. 

* RF board device driver updates. No effect on normal operation.

MCU 5.10 / DSP 2.83, 2-2-2015

* EASIER DIVERSITY RECEIVE SELECTION: A regular hold of SUB now goes directly into diversity receive, without first having to go through "LINK". This should benefit most users of the KRX3 sub receiver, since few use the VFO linking function. Those who do use VFO linking can still turn it on by setting CONFIG:VFO LNK to ON. This menu entry can be assigned to a programmable function switch for easy selection if desired, eliminating the need to bring up the menu. Note: Remote-control command "LN" is another way to accomplish VFO linking.

* DIVERSITY-MODE FIX: Diversity mode with mis-matched crystal filters was in some cases resulting in the main and sub receivers being offset.

* PREAMP ICON FIX:  In some cases the "PRE" icon was left in the incorrect state.

* REMOVED CONFIG:DUAL PB MENU ENTRY: This menu entry isn't needed since the K3's original, idiosyncratic "DUAL PB" function for CW mode ("context/focus" filtering) is no longer supported. APF (audio peaking filter) was added later; it is far more effective and of greater utility. In conjunction with this, the DUAL PB front-panel switch now always selects APF in CW mode. (In AFSK-D and FSK-D modes, DUAL PB still turns the dual-peak audio filter on/off.)

MCU 5.09 / DSP 2.83, 1-25-2015

* KPA3 DRIVE LIMIT CHANGES: Per-band limits on KPA3 drive level were introduced in rev. 5.04. If a memory was recalled that had been programmed before the 50-W TX gain calibration was done on the current band, the drive limit would be lost. Also, the drive limit had been set too low. Those who loaded rev. 5.04 should load 5.09 and re-do the 50-Watt gain calibration, which is automated by K3 Utility.

* SYNTHESIZER TEST ON POWER-UP FIXED: The synthesizer presence check was not being done correctly in all cases.

MCU 5.04 / DSP 2.83, 1-14-2015

* KPA3 OVERDRIVE PROTECTION:  Power amplifier efficiency can be reduced if operated into certain reactive loads, or with reduced power supply voltage. Normally this will be revealed by TX current drain or reflected power measurements, allowing the firmware to quickly reduce power output to a safe level. The latest release provides an additional margin of safety by putting an upper limit on drive power into the KPA3. The maximum allowed is based on data obtained during TX GAIN calibration. How To Set Up Drive Limits: After loading rev. 5.03 firmware, re-do the 50-W calibration step on each band. This can be done manually, or via the automated TX GAIN procedure in K3 Utility. A 50-W capable dummy load is required, per the K3 owner's manual (pg. 49).

* NO CW QSK AUDIO ARTIFACTS IN PRESENCE OF QRM: In previous releases, CW QSK break-in speed was maximized by saving receive audio in the DSP "pipeline" on key-down, then inserting it back into audio stream on key-up. This resulted in audible artifacts when operating in the presence of heavy noise or QRN. The operator now has the option to clear the DSP pipeline on key-down, eliminating the artifacts. This provides much cleaner CW operation, at the expense of a slightly longer delay before receive audio recovers (we'll improve this in a future firmware release). To select the old or new QSK algorithm, tap '3' in the CW WGHT menu entry (CONFIG menu). "New QSK" clears the DSP pipeline; "Old QSK" saves it and inserts it back in on key-up. Historical note: The original "Old QSK," which used even shorter mute times, is no longer available. Some operators felt it provided somewhat better QSK (reduced artifacts). But the new algorithm (now "New QSK") is far superior in this regard.

* Fixed size of front-panel-flash file (hfpf0116.HEX): Eliminates firmware load error with older Mac versions of K3 Utility, and reduces flash file load time in all cases.

MCU 4.93 / DSP 2.83, 10-16-2014

* PSK63 MODE ADDED:  To select PSK31 or PSK63, first tap either end of the MODE switch to select DATA, then hold the DATA MD switch and use VFO A to select the PSK data rate.

* KAT500 POWER-ON REMINDER ON K3 DISPLAY: If a powered-off KAT500 is pulling the auxBus signal low when the K3 is first turned on, "TURN ON KAT500" is displayed. Previously this condition would lock up the K3 without explanation.

* K3/0-MINI TX NOISE REDUCTION:  Polling by Remote-Rig units is suspended during PTT use to reduce a "ticking" noise heard in some cases.

* Changes to synthesizer, KXV3, and KPA3 device drivers (no effect on normal operation).

MCU 4.86 / DSP 2.83, 6-9-2014

* REAR HEADPHONE JACK CONTROL: The rear headphone jack (on the KIO3) was recently changed to a different type whose speaker-cutout switch logic is inverted from the original. If speaker audio is missing even without phones plugged in, you'll need to change the setup. Locate CONFIG:SPKR+PH, then tap '1' to switch to "PH.R SW-" (inverted). Tapping a second time reverts back to the original setting, "PH.R SW+".

MCU 4.83 / DSP 2.82, 2-8-2014

* FSK-D (RTTY) POWER-CONTROL BUG FIX: Power output can now be increased while in transmit mode when using FSK-D.

* KAT500 ATU SUPPORT: Automatic retuning of KAT500 LC network as K3 VFO is moved. VFO frequency messages are sent via the auxBus. Sends VFO A frequency except in SPLIT mode, where VFO B frequency is sent.

MCU 4.81 / DSP 2.82, 1-25-2014

* XVTR IF BAND CAN NOW BE 10 OR 18 MHZ (in addition to the original selections).

MCU 4.80 / DSP 2.82, 1-13-2014

* RTTY BAUD RATE NO LONGER STORED PER-BAND/PER-MEMORY: The FSK-D/AFSK-A baud rate (45 or 75 baud) is now global, meaning that one setting applies in all cases. The baud rate is set by holding DATA MD, selecting FSK-D or AFSK-A using VFO B, then selecting the baud rate using VFO A.  

* FIXED MACRO EXECUTION BUG AFFECTING "SB", "MD", "DV", "BW" commands. These would sometimes not work correctly when used in macros.

* RTTY/FSK IMPROVEMENT:  In FSK-D mode using an PC-generated FSK input, the K3 no longer exhibits DSP errors (ERR DSE) or loss of communications. Previously, these may have occurred when the K3 was sent too many serial (RS232) commands.

MCU 4.77 / DSP 2.82, 12-30-2013

* NO LOSS OF RS232 DATA DURING BAND CHANGES: On any band change, the K3 sends band data to possibly-connected XV-series transverters and the KRC2. This takes 15 milliseconds, during which RS232 data (from PC applications) was locked out. RS232 data is now properly handled during this time, which could eliminate some K3-to-PC communications issues on band change.

MCU 4.76 / DSP 2.82, 12-11-2013

* LOGGING OF REMOTE-CONTROL COMMAND ERRORS (ERR DSE): Rapid polling of the K3 by a PC application program can in rare cases result in overflow of the K3's internal serial data buffer, leading to the execution of an invalid control command and a subsequent internal MCU-DSP communications error. When this occurs, the K3 will now send "E*DSEn;" to the attached host, where <n> is 0 if the error occurred when addressing the main DSP and 1 for the aux DSP. Application developers can then consult their communications log file to see what commands were being sent at the time.

MCU 4.74 / DSP 2.82, 11-16-2013

For those using PC software:

* BW and FW (BANDWIDTH) SET COMMANDS SENT DURING TX ARE REJECTED (K3 returns "?;"). This prevents a possible DSP error (ERR DSE). A future release will allow use of these commands, as well as the "WIDTH" control.
* DV and SB (DIVERSITY and SUB) SET COMMANDS SENT DURING TX ARE REJECTED (K3 returns "?;"). This avoids possible side-effects.

For those using Remote Rig mode: 

* REMOTE-RIG BUG FIXES: (1) speaker mute when entering TERM mode; (2) MODE display swap on PTT; (3) connection lost during PTT (when K3 was out of band before entering TERM mode); (4) encoder commands with VFO A/B locked before entering TERM mode; (5) VFO B lock now working in remote mode.

MCU 4.73 / DSP 2.82, 11-11-2013

* RIT CAN NOW BE TURNED ON/OFF DURING TX: This applies to both the RIT switch and the "RT" remote-control command. Note: If RIT is turned on or off during transmission of a CW character, the length of one code element may be affected. This will be corrected in a future release.

* CRYSTAL FILTER OFFSET ADJUSTABLE IN CW MODE:  You can now set the crystal filter lower edge in CW mode to 0.1, 0.2, or 0.3 kHz above zero beat. The default is 0.2 kHz. The 0.1-kHz selection provides enhanced bass response, but may allow you to hear a low-pitched opposite-sideband signal when tuned near very strong signals. The 0.3-kHz selection may be preferred by some operators in extremely strong-signal environments. To change the setting: Select CW mode, then go into MENU:RX EQ and tap '0' (CWT) to choose the desired XFIL LO value.

* A>B SWITCH TAP SENDS VFO UPDATE IN "AI2" MODE: This is useful for those writing computer-control applications.

MCU 4.67 / DSP 2.81, 4-16-2013  

* FIXED LCD ICONS FOR NOTCH, MANUAL NOTCH, and NORM "wings" on DSP graphic. Applies to version 'B' front panel hardware only. 

NOTE:  Tap '1' in the FW REVS menu entry to see the front panel hardware version. VER A and VER B differ only in the type of LCD driver IC used.

MCU 4.66 / DSP 2.81, 3-22-2013  

* FSK-D KEYING BANDWIDTH GREATLY REDUCED: This change reduces the amplitude of the FSK-D keying sidebands by 25-30 dB at a 500-Hz offset, giving the K3 one of the cleanest FSK signals available.

* K3/0 (REMOTE-RIG) IMPROVEMENTS: (1) Supply voltage can go down to 7.6 V; (2) VFO lock works correctly; (3) TX LED no longer gets out of sync.

MCU 4.62 / DSP 2.80, 11-29-2012  

* IMPROVED HANDLING OF SERIAL I/O (RS232) ERROR CONDITIONS.

* SUPPORT ADDED FOR ALTERNATIVE LCD DRIVER IC. This has no effect on radio operation.

MCU 4.61 / DSP 2.80, 11-19-2012

* RIT AND XIT NO LONGER TURNED OFF UNINTENTIONALLY: In previous releases, changing bands via direct frequency entry (FREQ ENT) or remote-control band change commands (FA, FB, and BN) would turn off RIT and XIT. This was true even if CONFIG:SPLT SV was set to YES.

MCU 4.60 / DSP 2.80, 11-17-2012

* ESSB TRANSMIT CAN USE THE FM FILTER: The wide (FM) crystal filter can now be assigned to ESSB transmit as well as FM and AM. This can potentially free up a crystal filter slot for customers who were using the 6-kHz filter only for AM/ESSB. NOTE: The 6-kHz filter is still recommended for high-performance ESSB and AM receive, as it will provide significantly better close-in dynamic range than the FM filter.

* TRANSVERTER FREQUENCY ENTRY FIXED:  The previous release did not handle direct frequency entry to transverter bands correctly (e.g., 144 MHz came out as 180 MHz).

MCU 4.58 / DSP 2.80, 11-7-2012

* CW DECODE IMPROVED: The CW decode algorithm now includes its own AGC system, independent of regular AGC threshold/slope/decay settings. Decode of element spaces vs. word spaces adjust slightly to improve rate of copy on average code samples.

* KEYER PADDLE ENABLED IN FSK-D/PSK-D MODES ONLY IF TEXT DECODE IS ON: Those using FSK-D/PSK-D via with a computer requested that the paddles be disabled when the K3's internal text decode is OFF so that hitting the paddles accidentally doesn't interfere with PC-based transmission.

MCU 4.57 / DSP 2.79, 10-24-2012

* AM TRANSMIT CAN USE THE FM FILTER: The wide (FM) crystal filter can now be assigned to AM transmit as well as FM. This can potentially free up a crystal filter slot for customers who were using the 6-kHz filter only for AM.

* K3EXREF USERS MUST NOW ENABLE THE MODULE IN THE MENU: To do this, locate the CONFIG:REF CAL menu entry and tap 2 to change the setting; flashes XREF IN or XREFOUT. If you DO NOT have a K3EXREF module installed, use the XREFOUT setting (the default). If you use the XREF IN setting without a K3EXREF module installed, you may hear digital switching noise on the 6-meter band.

* REMOTE-RIG (K3/0) BUG FIX: The SUB RF GAIN control now works correctly.

* XVTR BAND DISPLAY FIXED FOR MICROWAVE BAND DISPLAYS: Previously, a band defined as 3400 MHz in CONFIG:XVn RF would not produce the correct display when the VFO was tuned below 3400 MHz.

* PSK-D/FSK-D PROSIGN TRANSMIT FIXED: Was sending "BB" for "BT", "AA" for "AR", etc., always duplicating the characters.

* VOX TRANSMIT TERMINATION VIA REMOTE CONTROL FIXED: The "RX;" remote control command will now properly terminate transmit when VOX is in use. Some customers who use VOX in audio data modes will find this useful. Previously the K3 would sometimes not exit transmit, requiring an additional "RX;" command.

* VFO A/B REV AND SWAP DE-GLITCHED: In rare cases, swapping VFOs would generate a loud audio artifact.

MCU 4.51 / DSP 2.76, 5-9-2012

* AGC IMPROVEMENTS: AGC threshold (CONFIG:AGC THR) can now be set much higher, and the AGC has better (more monotonic) response curves. Greatly improves signal clarity in pile-ups and other high-noise or dense-signal situations, especially with threshold set to 12 or higher. NR and autoNotch can be used at all threshold settings.

MCU 4.48, 1-13-2012

* K3/0 SUPPORT: If the unit is designated as a K3/0 (via an EEPROM 
ID value), power-on self-tests and run-time tests associated with non-
populated hardware are skipped. This allows the unit to power up
much more quickly for use with RemoteRig.

MCU 4.47 / DSP 2.73, 10-19-2011

* MORE ROBUST "GT" CONTROL COMMAND (AGC): Some PC
applications may accidentally turn AGC off, possibly due to
a buffer overflow. The GT command format is now verified more
rigorously, making this less likely. NOTE: PC applications should not
send too many K3 "get" commands simultaneously, especially if a P3
is also in the system. Ideally they should wait for a response to each
command before proceeding.

MCU 4.46 / DSP 2.73, 9-20-2011

* REMOTE-RIG SUPPORT: One K3 can now directly control
another, with one acting as nothing but a front panel. This 
"remote rig" mode provides a nearly perfect emulation of the 
remote K3's display and controls. (Previously, front panel
emulation was limited by the K3's legacy command set.) The 
simplest way to use this is to connect the two K3s together 
using a "null modem" cable at the RS232 ports. However, by using
a computer or a third-party hardware as an intermediary, it's possible
to control a K3 over the internet or even a wiFi connection. 

Note that the controlling K3 can have a totally different configuration
from the remote K3. It could be a K3/10 with no options, for 
example, yet it could still control a remote K3 with all options,
including sub receiver, KPA500, etc.

To use Remote-Rig mode, set both K3s to 38.4 kb and connect
them together via the RS232 ports (possibly using an intermediary
device). Next, at the local K3, hold CONFIG until you see
"TERM" on VFO B. If the remote K3 is listening, the TERM
message will be replaced with a display that looks exactly like the
remote K3's. From then on, the remote K3 can be controlled
by the local one (the remote K3 can still be controlled with its
own front panel, too). The local K3's audio will be muted. Both
receive and transmit audio must be handled by the intermediary
device.

To exit Remote-Rig mode, hold CONFIG on the local K3 until you 
see "NORM" flashed on VFO B. The local K3 will return to 
normal operation.

MCU 4.43 / DSP 2.73, 8-30-2011

* POWER CONTROL COMMAND WORKING WITH XVTRs: 
The "PC" remote control command now works correctly with transverters.
For example you can send "PC150;" to set I.F. output to 1.5 mW.
(This also applies to HF bands if CONFIG:KXV3 is set to TEST.)
Note that the upper bound on power output level is specified per-
transverter band using the CONFIG:XVn PWR menu entry.
Please review the K144XV manual when setting up the drive level
for the internal 2-meter module.

* PRELIMINARY SUPPORT FOR "REMOTE-RIG" MODE (details TBD).

MCU 4.42 / DSP 2.73, 8-24-2011

* 2-METER FREQUENCY LOCKING TO REF CAL & EXT. REF:
The K144XV RFLK option locks the K3's 2-meter module to the rig's 
master reference. Previously, users of this option had to enter offsets
in the CONFIG:XVn OFS menu entry based on how far off the
master reference was from 49380.000 kHz. These offsets can now
be calculated automatically based on the REF CAL menu entry.
If a K3EXREF module is also installed, then REF CAL itself 
is automatically calibrated based on an external 10-MHz reference
(see K3EXREF on 2 m, below).

To enable this, locate XVn OFS in the menu, then tap ‘0’ until you see
“REFLOCK”. This lets the K3 firmware know that the RFLK module is
installed. (If the RFLK option is not installed, then the K144XV’s 
oscillators are not locked to the K3’s master reference. The offsets 
should then be set according to the label on the transverter module.)
To see the automatically calculated offset value in the XVn OFS 
menu entry, the K3 should be switched to the 2-meter band. Otherwise,
the K144XV offset parameter may be initially displayed as "-0.00".

K3EXREF on 2 m: If a K3EXREF module is installed, REF CAL itself 
will be automatically calibrated based on an external 10-MHz reference.
In this case, selecting “REFLOCK” for XVn OFS will allow the K144XV 
frequency to track this external reference. 2-meter frequency accuracy will 
be about a factor of around two worse than on HF, due to the higher 
frequency of the 2-meter local oscillators.

* K3EXREF REF CAL VALUE SAVE: In REF CAL, tapping '1' will 
now save the K3EXREF-derived reference value as the manually
entered value. This is useful in the event that the K3 is ever 
disconnected from the 10-MHz reference, as it will revert to the 
manually entered value. Note: To use this feature, a K3EXREF 
module must be installed, a 10-MHz external reference connected, 
and an asterisk (*) be present in the menu entry name (“REF*CAL”).
You can then tap '1' to save the value.

MCU 4.40 / DSP 2.73, 7-11-2011

* NO ERROR TONE ON KPA500 OPERATE/STANDBY
SWITCHING, etc.: Previously, the K3 would emit an error
tone on any KPA500 switch event. Now such tones are
only emitted if the CONFIG:SW TONE menu entry is set
to ON, or on a hard fault.

MCU 4.39 / DSP 2.73, 6-15-2011

* NEW AF MIXER COMBINATIONS (CONFIG:L-MIX-R):    
Added AB A,   B BA,   B B,   B A,   A A. These may be useful for
“SO2V” operation and various DX/contest scenarios.

MCU 4.38 / DSP 2.73, 6-14-2011

* KAT3 IMPROVEMENTS: T/R timing and power thresholds 
changed to improve SWR measurement sensitivity. This 
should help on 6 meters in particular. 

* “BG” (BAR GRAPH) REMOTE CONTROL COMMAND: 
Added 'R' or 'T' at end of command to indicate RX (S units) or 
TX (watts).

MCU 4.37 / DSP 2.73, 4-30-2011

* ADDED "SMH" COMMAND (high-resolution S-meter): 
This is presently experimental; it is intended to work with 
W8WWV's “S-meter Lite” program. "SMH;" responds with
"SMHxxx;" where xxx is approx. 005 @ S-1, 040 @ S-9, 
and 100 @ S9+60. Resolution is approximately 1 dB.
NOTE: The value returned will probably be adjusted after
testing.

* P3 and PC NOTIFIED ON RX ANT CHANGE: Switching 
RX ANT on/off now informs the P3 and a connected PC of 
possible changes to the preamp and attenuator settings. These
are stored separately for the RX ANT on and off cases.

* SUB RECEIVER ANTENNA MESSAGE: Suppose both main
and sub receivers are on 6 meters, with sub sharing the main 
antenna. If the main receiver is then switched to a transverter
band, “USE AUX” will flash on VFO B, along with the SUB icon,
for about 3 seconds. This alerts the operator that the sub 
will not have any incoming signal from the main antenna path. 
The user should switch to the sub receiver’s AUX antenna.
(This warning already appears if the main receiver is switched
to a band whose low-pass filter would attenuate signals on
the sub receiver band.)

* "ERR 12V" VERIFICATION: If the PA 12 volt input is found to
be missing, it is checked a second time (after a delay), to make
sure it wasn’t due to noise.

MCU 4.36 / DSP 2.73, 4-20-2011

* KPA500-TO-K3 BAND CHANGE, FAULT/STATUS, and POWER
CONTROL: If the KPA500 is connected to the K3 via the ACC cable
(including auxBus and band data lines), the following new features
will be available:

(1) the amp’s band switches can change the K3’s band
(2) amp faults and operate/standby changes will be reported on
    the K3 display
(3) if CONFIG:PWR SET = PER-BAND, the K3 will provide two
     separate sets of per-band power levels: one for use with the
     KPA500, one for barefoot use (amp in standby). If the amp
     power levels are in effect, an asterisk is added to the K3’s
     power control display (e.g. “30 W*”). This should eliminate the 
     need to adjust the K3’s power control when changing bands 
     or switching the amp between operate and standby.

* REF*CAL ASTERISK BLINKS DURING K3EXREF DATA 
RECEIPT.

* UP & DN REMOTE COMMANDS NOW UPDATE P3.

MCU 4.31 / DSP 2.72, 3-23-2011

* QRQ CW AUTO-OFF ON SPLIT/RIT/XIT:  QRQ CW is now 
automatically turned off whenever you turn on SPLIT, RIT, or XIT. 
You’ll see "QRQ OFF" flashed on VFO B. QRQ mode is restored if
you turn these off. (For QRQ CW details, see Rev. 4.03 notes.)

* REVERSE (REV) FOR FM/REPEAT IS PERMANENT: Pressing
REV when in FM mode with a repeater offset (+/-) selected now 
permanently swaps RX/TX frequencies and reverses the repeater 
offset direction. You do not have to continue to hold the REV switch.

* 2-METER MODULE “S9” METER LEVEL ADJUSTED: The “S9”
level on the K3’s S-meter now occurs with an input signal level of
-93 dBm when the K144XV is selected. (This is a recognized 
standard on bands from 2 meters up. On other bands, “S9” still
occurs at -73 dBm.) Notes: (1) The K3’s S-meter may not go all the
way to S0 on this band because of the high preamp gain on the
K144XV module. (2) If you have SMTR MD set to NOR, the S-meter
reading will vary with the settings of the PRE and ATTN controls.

* FRONT PANEL MIC PREAMP GAIN CONTROL: The front panel 
mic preamp has a high-gain setting that is now accessible. (This is 
independent the present “mic boost” DSP function.) If you use a 
low-output mic element, you may benefit from the high-gain setting.
In MIC SEL (MAIN menu), use VFO A to select the front-panel 
mic (FP), then tap ‘7’ on the keypad to select high preamp gain. 
A “high bar” symbol will appear to the right of the mic boost
character (L or H). As a reminder, DSP mic boost (H, or Hi) can be 
turned on/off by tapping ‘1’ on the keypad. Bias is controlled by ‘2’.

* EXTERNAL 10-MHZ REFERENCE SUPPORT (K3EXREF):
When the K3EXREF option is installed, the K3 will use it to 
automatically calibrate the internal 49.380 MHz reference oscillator. 
The user must provide a suitable 10-MHz input signal to the module.
Typical accuracy at the operating frequency, when locked, is +/- 1 Hz, 
(The K3EXREF uses frequency locking, not phase locking. See
K3EXREF installation manual for further details.)

Remote-Control/Switch Macro Command Changes:

* "AP" COMMAND TURNS APF ON/OFF: You can turn the CW 
audio peaking filter on/off by sending “AP1;” or “AP0;”, respectively.
Applies only in CW mode with CONFIG:DUAL PB set to APF. (Not
yet available for direct sub receiver control. Swap VFOs or do A>B
copy in order to set up sub receiver APF.) You can use this 
command to create a TAP function to turn APF on/off; use the Help 
function in K3 Utility for details on macros. 

* "BG" COMMAND USEABLE IN TX MODE: Reads PWR or ALC 
depending on METER setting. Note: In RX mode, BG returns up 
to 21 with CWT off, but only up to 09 with CWT on. Also, at 
present there is no way to read CWT, SWR, or CMP.

* CHANNEL HOPPING CANCELLED ON FA/FB BAND CHANGE.

MCU 4.25 / DSP 2.71 / FPF 1.14, 12-13-2010

* P3 FIXED-TUNE MODE SUPPORT: The P3 now has a 
“fixed-tune” mode, where the displayed range remains constant
as the VFO is turned. Requires P3 firmware rev 0.44 or later.

* FIXED A/B SWITCH PROBLEM DURING BAND CHANGE: 
CW or SSB filter setups were sometimes getting changed when 
a quick memory was recalled, followed by a quick tap of A/B.

For software developers:

* FW$ GET NOW WORKS. Was authorizing only BW$ GET.
* BN$ GET NOW WORKS. Intended to exclude only BN$ SET but excluded both.

MCU 4.22 / DSP 2.71 / FPF 1.14, 11-23-2010

NOTE: Be sure to install all firmware files for this release, 
including FPF 1.14. Otherwise your menu text will be incorrect.

* SSB Reduced Power Level Bug Fixed.  Error was introduced
in DSP 2.65.

* AutoNotch "stutter" on return to Tx to Rx transition Fixed. Error was
intrioduced in DSP 2.62.

* APF (AUDIO PEAKING FILTER) ADDED: APF provides enhanced
copy of weak signals in CW mode, and is especially useful when 
signals are at the noise level. The K3’s APF is patterned after
the most successful analog APF implementations, and is equally
effective in user tests. To use APF, make sure CONFIG:DUAL PB 
is set to APF. (This is the default. “NOR” restores the original DUAL PB
function.) Then hold DUAL PB to turn APF on/off. A special DSP
graphic display is used to show that APF is in effect. At the time 
APF is activated, the regular I.F. SHIFT setting, if any,  is “frozen,” 
and SHIFT then controls the center pitch of the APF filter in 5-Hz
steps. APF is independent for the main and sub receivers, as well
as for presets I and II. Switching between these two presets is a 
convenient way of turning APF on/off quickly.

* ADDED VOICE TX “FAST MONITOR”: Normally the voice 
monitor includes a ~20-ms delay, which is necessary to hear how your
on-air signal will sound (with compression, etc.). If you prefer to not
hear any delay in the voice monitor, set CONFIG:TX MON to FAST.
Note: You’ll still hear the delayed and processed monitor if you 
adjust the MIC, CMP, TX EQ or TX GATE settings while transmitting.

* TX NOISE GATE IMPROVEMENT: The Noise Gate/Downward
Expander for voice modes has smoother response and much
improved performance near the threshold.

* NARROW AF FILTER IMPROVEMENT: Adjusting SHIFT and
WIDTH when using very narrow DSP filters no longer causes
‘pop’ artifacts.

MCU 4.15, 10-14-2010

* MSG CHAIN BUG FIX, FSK-D MODE: Chaining was resulting in a 
  receive offset in some cases.

MCU 4.14 / DSP 2.60 / FPF 1.13, 10-6-2010

* ELIMINATED POWER-UP SELF-TEST ERRORS (ERR BP1, etc.):
On rare occasion, a K3 would display a series of error messages
on power-up. This has been corrected.

MCU 4.13 / DSP 2.60 / FPF 1.13, 9-23-2010

* P3 UPDATED CORRECTLY ON K3 A/B SWITCH PRESS.

* P3 FUNCTIONS CORRECTLY AFTER REV SWITCH PRESS:
Previously, holding REV at the K3 would cause the P3 to stop 
tracking K3 VFO movement. Note: At present, holding REV 
does not result in any change in the P3 display. This will be
corrected in a future revision of K3 firmware.

* BN REMOTE CONTROL COMMAND (BAND CHANGE):
This command now changes bands more quickly. 

MCU 4.12 / DSP 2.60 / FPF 1.13, 9-15-2010

* K3-to-P3 SERIAL COMMUNICATIONS: The K3/P3 RS232 
interface has been optimized to eliminate problems with VFO 
tuning and some third-party PC applications such as HRD.

* DVR TRANSMIT MONITOR SEPARATELY ADJUSTABLE:  Applies
to TX message play as well as transmit playback of the 90-second loop.
First, set CONFIG:TX DVR to IND (independent) and exit the menu. Next, 
hold in the CMP/PWR knob to select MON. Holding the knob in a 
second time alternates between MON xx and DVR xx. You can adjust 
MON or DVR level during transmit playback.

* NO GAP IN 6-METER POWER RANGE: The PA now kicks in 
at 9 W on 6 m, rather than 13 W as on the other bands. This 
eliminates the original gap from 9 to 12 W on 6 meters.

* 60-METER CHANNEL HOPPING DOWN TO 5.366.5 KHZ WORKS:
Previously, the PLL voltage would sometimes go to zero in this case.

* VFO B to A COPY NOW UPDATES THE P3. This is useful for 
re-centering the P3 at a desired center frequency. For example, you
could leave VFO B set to the center of a band segment. After tuning
VFO A around, use VFO B>A to go back to the  center. (To use 
VFO B>A, assign CONFIG:VFO B>A to a PFx or Mx switch.)

* K144XV S-METER CORRECTION: The S-meter is now properly
compensating for the added gain of the K144XV.

* K144XV BAND-DATA OUTPUT ADDRESS RANGE INCREASED: 
Originally, CONFIG:XVn ADR was always set to “INT TRN1” to enable
the K144XV. This set all band data outputs on the ACC jack to 0. Now, 
XVn ADR has of “INT TRN0” to “INT TRN9” for the K144XV. Band-data 
outputs are set accordingly. This may be useful when the K144XV is
used as an IF for higher-band external transverters. (If you have a 
K144XV, the original INT TRN1 will now be INT TRN0 in the menu.
This is the new recommended setting if you’re not using external
transverters in conjunction with the K144XV.)

NOTE: When using the K144XV, XVn RF can be set to the RF band 
of an external transverter that is using the K144XV as an I.F., rather
than at the 2-meter band edge (144).

MCU 4.06 / DSP 2.60, 8-19-2010

* DVR PLAY/RECORD FIX: The AF PLAY and AF REC positions 
within the DVR’s 90-second audio loop were not being setup correctly. 

MCU 4.05 / DSP 2.60, 7-20-2010

* Additional K3->P3 command responses, including BN.
This release required for production P3 users.

MCU 4.03 / DSP 2.60, 6-10-2010

* 75 BAUD (100 WPM) RTTY SUPPORT: The internal data
encoder/decoder now supports both 45 and 75 baud. To 
select the desired rate, use the DATA MD switch, then rotate
VFO A.

* ULTRA-FAST BREAK-IN AND QRQ CW (“CW+”):  
If you set CONFIG:CW QRQ to ON in the menu, the K3 will 
provide extremely fast break-in at all CW speeds. It will also
allow both the internal keyer and external keying to work
at up to 100 WPM. (Be sure to turn on both QSK and VOX.) 
The “+” mode icon turns on when CW+ is in effect. 

Tip: You may want to assign the CW QRQ menu entry to 
a programmable switch function (e.g., PF1) for quick access.
This can be done by locating the CW QRQ menu entry, then
holding PF1 until you see “PF1 SET”.

Note 1:  There are limitations to QRQ CW mode at present. 
You cannot use SHIFT, or turn on RIT, XIT, or SPLIT. However,
you can still use splits, in effect, if you have the sub receiver
installed: Turn the SUB on, and use VFO B as the receive VFO. 
(In a subsequent firmware release, RIT/XIT will be usable over
a small range in QRQ mode.)

Note 2:  If you use CONFIG:TX DLY to set external keying
delay, you may need to adjust its setting for QRQ CW use. Also,
any increase in the default (8 ms) may decrease the maximum
available CW speed.

* AF BALANCE CONTROL IMPROVED: The SUB AF control
can be used as a main/sub RX balance control (see CONFIG:
SUB AF). Previously, when the control was rotated fully 
clockwise, main receiver audio would not be fully turned off. 
This has been corrected.

* ADDED ERROR CODE “ERR RXF”. This message is flashed 
if you switch to a crystal filter that is too wide for the present 
settings. For example, ERR RXF will flash if you are in QRQ 
CW mode and select a filter wider than 2.8 kHz. To correct this,
you'll need to turn off wider-bandwidth crystal filters either 
manually (using CONFIG:FLx ON) or via K3 Utility.

* FIXED FSK-D STUCK TONE: Occasionally, sending RTTY
using the keyer paddle (FSK-D) would leave sidetone on.

MCU 3.97 / DSP 2.58, 5-9-2010

* TX INHIBIT IMPROVEMENT: If TX INH is active (see 
CONFIG:TX INH), voice monitor and CW/DATA tones are disabled,
giving the operator audible feedback about inhibited status to 
supplement the flashing “TX” icon.

* DSP NOISE BLANKER IMPROVED: A new algorithm has
been added that makes the DSP NB more effective on
some types of noise. Odd-numbered DSP NB levels (t1-1, 
t1-3, t1-5, etc.) apply the new algorithm, while even-numbered 
levels use the original. To avoid unwanted interaction between
the NB and on-air signals, always use the lowest effective setting.

* CW KEYING ARTIFACT WITH AFX/DELAY ELIMINATED:
The “DELAY” settings of AFX previously created a small audio
artifact when listening to CW keying in the presence of background 
noise or signals.

* AGC-OFF S-METER IMPROVEMENT: Turning AGC off no longer
results in a drop in the S-meter reading. This was most noticeable
in the presence of strong band noise. 

* K144XV S-METER NOW ACCURATE: The S-meter reading is
is now adjusted to account for RX gain when the K144XV is in use.

* TX NOISE GATE IMPROVED: The voice transmit noise gate
now uses a downward expander rather than simple gating.
See TX GATE menu entry for further details.

* MANUAL NOTCH: Pitch now defaults to 1000 rather than 2000 Hz.
This starting point is a better compromise between CW and SSB.

* ESSB ON/OFF COMMAND: The new “ES” control command
can be used to turn ESSB on/off via a switch macro or from a
software application. The K3 must also be in LSB or USB mode
before ESSB ON takes effect. (See K3 Programmer’s Reference.)

* BN REMOTE CONTROL COMMAND (BAND CHANGE):
Previously this command was “GET only”, returning the 
present band number (00-24). It can now be used as a SET
command to switch to the desired band. For example, BN00;
switches to the last-used frequency on 160 m. Note: VFO B 
will also be restored to its last frequency used on the new band,
except in the case where CONFIG:VFO IND is set to YES. 

MCU 3.94 / DSP 2.54, 4-17-2010

K3 Memory Editor:

* This revision of K3 firmware works with our new K3 Memory 
Editor (presently PC/Windows-only, but may eventually work on other
platforms). The memory editor allows you to edit frequency
memories 00-99 and, if desired, per-band quick memories (M1-M4).
Each memory includes a “QSY” button, providing convenient 
memory selection. Memory contents can be saved in a file
and shared with other K3 users. (Further details posted elsewhere.)

* MEMORY CHANNEL COMMAND (MC): This new remote-control
command was created in support of the K3 Memory Editor (see
above). Sending an MC command to the K3 loads VFOs from a 
memory (or “channel”), emulating M>V. It can be used in switch 
macros. Examples: “MC080;” loads memory #80. “MC100;” loads 
160-m quick-memory M1. (For details on creating macros, 
refer to K3 Utility Help or the K3 Programmer’s Reference.)

Other New Features:

* SEPARATE RECEIVE EQ FOR CW MODE: To set up CW RX EQ, 
select CW mode, then use MAIN:RX EQ. To set up voice-mode RX EQ, 
select any non-CW mode. (Mode can be changed while in the menu.)

* SEPARATE TRANSMIT EQ FOR SSB MODE:  The SSB transmit 
passband can now be set up differently from AM/FM/ESSB. To set up 
SSB TX EQ, select USB or LSB with ESSB off, then use MAIN:TX EQ. 
To set up AM/FM/ESSB TX EQ, select AM, FM, or USB/LSB with 
ESSB on.  (To turn ESSB on/off, tap ‘1’ in CONFIG:TX ESSB. When  
ON ,the “+” mode icon appears.)  Also see TE command, below.

* TRANSMIT EQ SETUP COMMAND (TE): Can be used 
in switch macros to quickly optimize TX EQ settings for different 
users or mics. For example, “TE-08+00+00+00+00+00+00+00;” 
cuts the 50-Hz EQ band by 8 dB.

* Full support for P3 Panadapter. Allows very fast K3-to-P3 response
during VFO movement, etc.

For software developers:

* See TE and MC commands, above.

* TEXT BUFFER COMMAND (TB): This is an improvement over the 
“TT1” method for implementing a CW/data terminal. Returns number of 
transmit characters from KY<text> packets remaining to be sent, as well 
as a string containing all available characters, and RX character count. 

* Fixed KY<text> problem in PSK-D/FSK-D modes: Sending packets 
during the 4-second idle time was delaying transmit until end of idle time.

* Now recognizing a slashed-zero character from the PC keyboard 
(0xD8) in KY<text> packets. Converted to regular zero.

* IC COMMAND: Added CONFIG:MEM 0-9 setting (byte a, bit 1).

MCU 3.84 / DSP 2.54, 3-22-2010

For software developers: 

* NOISE BLANKER LEVEL CONTROL:  Added NL and NL$
commands to remotely set DSP and IF blanker levels for main
and sub receivers. Refer to the K3 Programmer’s Reference,
revision C10 or later. 

Changes related to European FM and Repeater Operation: 

* 12.5 AND 25 KHZ VFO INCREMENTS (FOR EU REPEATERS) : 
Added 12.5 kHz and 25 kHz step sizes in FM mode. To specify step
size, select FM mode, then use the CONFIG:VFO CRS menu entry.

* SQUELCH-CONTROLLED 1750-HZ PL TONE: Some EU 
repeaters require a 1750-Hz PL tone burst to open. Previously, an 
0.5-second burst was generated at the start of each transmission. 
Now, this tone is only generated if squelch is not already open. 
The squelch-controlled PL tone feature can be turned off by
setting the PITCH parameter to PL OFF. With either the PL TONE
or PL OFF setting, the operator can still do manual PL tone
burst as described in the next item.

* MANUALLY CONTROLLED 1750-HZ PL TONE:
The operator can now generate a variable-length tone burst 
at any time while transmitting by holding PITCH switch. 

* PL TONE DEVIATION RANGE CHANGED: The deviation range 
for the 1750-Hz PL tone is now 1.5 to 6.0 kHz. The default, 3.6 kHz,
is about 70% of 5 kHz, as recommended for many EU repeaters. 
The deviation for sub-audible tones is now stored separately
and has a range of 150-600 Hz (default 360 Hz).

MCU 3.79 / DSP 2.54, 3-5-2010

* RX ANT SWITCH ALLOWED DURING TX. This is useful if you
need to compare signal strength of received signals while sending
a repeating CQ message in CW mode. 

* SPURIOUS ERR XXX MESSAGES ELIMINATED: On rare 
occasions operators have seen multiple error messages such as
ERR BP1, ERR LPF, etc. on power-up. This was caused by a 
timing error when communicating with SPI-bus devices, such as
the shift registers controlling band-pass and low-pass filters.

MCU 3.78 / DSP 2.54, 3-4-2010

* MENU ENTRY TEXT ON VFO B:  Eliminated occasional incorrect
text appearing on VFO B while scrolling through menu entries.

* AM MODE 9 KHZ TUNING (EU): Corrected occasional PLL errors
related to tuning in 9 kHz steps in AM broadcast band.

* AFX “BIN” MODE: Further stability improvement for the “BIN” 
audio effect (selected by MAIN:AFX). An audio artifact could 
occur under certain receive-signal circumstances.

MCU 3.77 / DSP 2.53, 2-27-2010

* DIVERSITY MODE MAIN/SUB RECEIVER OFFSET FIXED: 
In some cases a small frequency offset between the main and 
sub receiver could be introduced due to transmitting while 
moving VFO A or the RIT offset. This no longer occurs.

* SUB RECEIVER BAND-PASS FILTER SWITCHING FIXED:
If the main and sub receivers were configured for independent
band selection (CONFIG:VFO IND = YES), switching the main
receiver to any of 17-10 m may have caused an incorrect 
band-pass filter to be selected for the sub receiver.

* SYNTHESIZER PLL TABLES UPDATED: Reduces the
DDS tuning range slightly to minimize group delay through the 
DDS crystal filter. (These tables are located in the 
“HFPF0108” file, part of the firmware release package.)

* AFX “BIN” MODE FIX: Stability improvement for the “BIN” 
audio effect (selected by MAIN:AFX). Previously, a loud audio
artifact could occur under certain receive-signal circumstances.

MCU 3.76 / DSP 2.52, 1-23-2010

Changes related to K144XV, transverters, FM, and repeaters:

* REPEATER REVerse: If a repeater offset is in use (+/-), 
holding REV switches VFO A to the repeater's input frequency. 

* RF POWER BARGRAPH: Now shows *tenths of a milliwatt* when
using low-level transverter I/O (applies to both the K144XV and 
external transverters). 10 bars = about 1.00 mW at the IF. This 
corresponds to about 10 W output when using the K144XV.

* COARSE TUNING WITH XVTR OFFSETS:  Fixed problem with
VFO display when using COARSE tuning steps in combination 
with a non-zero transverter frequency offset (CONFIG:XVn OFS).

* IMPROVED FM RECEIVE: FM demodulation algorithm
refined to reduce signal distortion.

* FM SQUELCH: No longer opens briefly during memory recall.

* "ANT3" REMINDER WHEN K144XV SELECTED: If you switch 
to a band configured for use with the Elecraft K144XV internal 2-m
module, “ANT3” is flashed to remind you to use the separate 
BNC antenna jack provided on the fan panel, rather than ANT1/2.

Other new features and improvements:

* NR (NOISE REDUCTION) ON/OFF: This is now saved
on a per-band/per-receiver basis (same as NB). NR ADJ 
(noise reduction setting) is stored independently for each mode.

* TX MESSAGE MEMORY ERASE:  To completely erase a 
transmit message buffer, tap REC, then M1-M4, then CLR. 
Note that erasing a CW/DATA memory will not erase a DVR 
Message assigned to the same M1-M4 switch, and vice-versa. 

* ERR PTT & ERR KEY (rig keyed at power-up): These error 
conditions no longer lock out the POWER switch.

* DELAYED MEMORY RECALL (M>V): In CONFIG:MEM 0-9, 
tap '1' to select "M>V NOR" or "M>V DLY". NOR is the default,
resulting in “live” memory recall as you rotate VFO A. In the "DLY" 
case, the receiver is not updated until you tap M>V a second 
time to exit memory recall. You may prefer “DLY” if you have 
external gear that switches as the K3 changes bands.

* 40-M TX RANGE EXTENDED TO 7.650 MHz (12 W MAX): TX
near the first I.F. has always been disabled from 7.550 to 8.990
MHz to protect the 8.21 MHz trap on the KAT3 or KANT3 module.
At power settings of 12 W or lower, the upper limit is now 7.650 
MHz, allowing use of some additional MARS channels.

Remote Control Command Changes: 

* XF/XF$ COMMAND ADDED: Returns crystal filter number (1-5)
presently selected for main (XF) and sub receiver (XF$). GET only. 
Not usable during BSET or REVerse.

* SQUELCH STATUS ADDED TO IC COMMAND: Byte e, 
bits 4 (main RX) and 3 (sub RX). 1 = squelched. (Works for both 
FM and non-FM squelch.)

* SUB RX NR STATUS ADDED TO IC COMMAND: Byte e, bit 2.

EEINIT (EEPROM Initialization) Changes: 

   - PL deviation (FM) set to 0.36 kHz (was 0.00)
   - Power output set to 5/50 W (was 0)
   - CONFIG:SPLT SV set to YES
   - RTTY mark tone set to 2125 Hz (was 1275)

MCU 3.68 / DSP 2.49, 12-11-2009

* AF OUTPUT PROTECTION IN AGC-OFF CASE: Moved 
threshold up to prevent false triggering on moderate signals.

* The CONFIG:AF LIM menu entry is now visible without setting
TECH MD to ON. The AF LIM entry menu sets up an AF output 
max level that only applies when AGC is OFF. Recommended
value is 18-24. Lower levels provide better protection but 
clip sooner. Adjust RF GAIN downward to eliminate clipping
on individual signals. Narrow-band filtering can also help.

* Synthesizer parameters updated on 6 m to eliminate 
possible PLL unlock when tuning in vicinity of 52 MHz. 

MCU 3.66 / DSP 2.48, 12-4-2009

* AF OUTPUT PROTECTION: The DSP now automatically 
senses when AF output would be so strong as to drive the 
speaker or headphone amplifier into the clipping range. If
this happens, AF is muted until you reduce signal levels.
(One possible source of excessive audio was a DSP internal
overrange, which could result in a very loud audio burst. 
DSP code has been changed to eliminate such cases.)

* Increased VCO settling time by 1 ms to eliminate a slight 
chirp noted by some operators (extremely rare).

* Increased SPI bus timing delays on power-up. May eliminate
spurious error messages (such as “ERR AT3”) that could 
occur due to SPI bus loading by multiple option modules.

MCU 3.63, 11-20-2009

* PTT USE WITH DVR: If the KDVR3 menu entry ‘1’ tap option
is set to AUTOPTT (the default), then PTT behaves as follows:

  - If you start DVR message play first (by tapping M1-M4), then 
    assert PTT during the message, DVR play will be cancelled.

  - If you assert PTT first, then play a DVR message, it will
    play normally, and will complete even if you let go of PTT.

You can also cancel DVR message play by tapping REC, as usual, 
whether PTT is asserted or not. (Or cancel from a computer
using the “RX;” command – see below.)

Note: If the KDVR3 menu entry ‘1’ tap option is set to
USE PTT, then PTT is required as a qualifier for DVR 
message play. In this case, releasing PTT in the middle
of a DVR message will cancel it.

Remote Control Command Changes:

* DVR MSG PLAY CANCEL: You can now use the “RX”
command to cleanly cancel DVR message play (as well
as any other transmit or message-play function, in any mode).

* CONFIG:DIGOUT1 MENU PARAMETER is now accessible 
with the “MP" command. Values 000 and 001 only; get/set.

MCU 3.59 / DSP 2.46, 11-18-2009

* FSK-D WAS CHANGING TO AFSK-A ON A/B or REV: Fixed.

* AM SYNC VFO TRACKING ACCURACY IMPROVED (DSP 2.46).

* SWR INDICATOR TONES AFTER ATU TUNE: If switch tones
are enabled, a second tone will be emitted following an ATU TUNE.
This tone provides a rough idea of the SWR that the KAT3 was 
able to obtain:

  Lower pitch than 1st tone: Unknown SWR (ant. may be shorted)
  Same pitch as 1st tone: SWR <= 2.0:1
  Medium-high pitch: SWR <= 3.0:1
  High pitch: SWR > 3.0:1.

This feature was added primarily for our blind customers, but it’s useful
whenever you tap ATU TUNE without looking at the final SWR reading.

Remote Control Command Changes: 

* IC COMMAND (ICON status): Now returning correct message 
bank in voice modes (byte a, bit 3).

MCU 3.57 / DSP 2.45, 11-7-2009

Misc. Improvements:

* TUNE SWITCH:  “Double beep” with NR on eliminated.

* DATA A: Loss of power when using TUNE corrected.

New Feature: Synchronous AM Receive

* SYNCHRONOUS AM: Outperforms regular AM during selective fading.
Provides optional automatic VFO tracking of AM signals up to +/- 2.5 kHz. 

Select AM mode, then hold ALT to select AM-S. The -S icon flashes 
slowly if the signal is noisy. Select AM-S LSB or USB using SHIFT; 
one of the two sidebands may reduce QRM. Sync AM also works with 
diversity receive. (Note: Some AM broadcast stations encode their 
carrier, resulting in a low-pitched noise when Sync AM is turned on.)

With Sync AM you can tune manually, or use automatic VFO tracking:

-- If tuning manually, you need to tune to within +/- 10 Hz of the actual 
   carrier frequency, at which point the K3 will phase-lock to the carrier.

-- To enable VFO tracking, tap CWT, which turns on the T icon. Or, 
   tap SPOT to engage VFO tracking just long enough to lock. When
   tracking is on, the VFO may “hunt” slowly across a span of several Hz. 

IMPORTANT:  For AM QSOs, use SPLIT mode when VFO tracking is 
turned on. VFO B (TX) will remain fixed while VFO A tracks RX signals. 

Limitations: At present, VFO B cannot auto-tune in AM-S. Also, both
VFOs will always be in the same mode (AM-S LSB or USB).

Remote Control Command Changes: 

* UP0/DN0/UP$0/DN$0 moves VFOs 1 Hz. Similarly, UP8 and UP9 
move the VFOs by 100 and 200 Hz, respectively.

MCU 3.52 / DSP 2.43 / K3 Utility 1.2.10.27, 10-28-2009

Misc. Improvements:

* Eliminated some audio artifacts noted during control changes.

* Eliminated interruption of transmitted CW signal when certain switches 
were tapped, including RIT, during external keying.

* VFO LOCK PREVENTS COARSE STEPS VIA OFFSET CONTROL: 
Normally, you can use the RIT/XIT offset control to move VFO A in coarse
steps if (1) RIT and XIT are both turned off, and (2) CONFIG:VFO OFS 
is set to ON. Now, these conditions are overridden if the VFO is locked.

* AUTO-NOTCH IN SSB MODE EASIER TO TURN ON/OFF: The NTCH
switch now behaves differently in SSB mode. Tapping it turns auto notch
on-off, rather than cycling through off-auto-manual notch. (To turn on
manual notch in SSB mode, hold the NTCH/MANUAL switch.)

New Feature: Main/Sub AF Mixing Menu Entry

* AUDIO MIXING CONTROL ADDED: Normally, main receiver audio is 
heard in the left audio channel, and sub in the right. Using the CONFIG:L-MIX-R
menu entry, you can now put main in both channels while leaving sub in only 
one (or vice-versa, or even put both receivers in both channels). Another
benefit of this change is that AFX (audio effects) can be used even while the
sub receiver is turned on. (AFX, if turned on, will apply to any receiver whose
audio is mapped both left and right.)

Notes:  Applies only to non-diversity mode use of the sub receiver. (In 
diversity mode, left/right differentiation is maximized for best results.)
You’ll need stereo headphones or speakers to listen to stereo 
separation and audio effects. Set CONFIG:SPKRS to 2 if using stereo
speakers. (Headphones will always work with stereo material unless
SPKRS is set to 1 *and* CONFIG:SPKR+PH is set to ON.)

New Feature: User-Defined Switch Functions (e.g., “SPLIT+2”)

* SWITCH MACROS: You can now program the K3’s PF1-2 and M1-M4
switches to execute K3 remote control sequences, or “macros.” They
are created and tested using K3 Utility (rev. 1.2.10.26 or later). Once
macros are finished, you can send them to the K3, where they
can be assigned to any programmable function switch. The K3 
Programmer’s Reference, revision C6, has a number of sample macros 
and further details.

Example: A>B, A>B, SPLIT, VFO B up 2 kHz, RIT/XIT off, assigned to PF1

To create a macro and assign it to a K3 front panel switch, you’ll 
need to complete steps 1-8 below. Once you’ve been through the 
process one time, you’ll find creating or modifying macros very easy.

1. Run K3 Utility.
2. Click on the Command Tester/K3 Macros tab.
3. Click on the Edit Macros button. This pops up the macro edit window.
4. In MACRO 1’s Macro Label  field, enter the label “SPLIT+2”.
5. In the Macro Commands  field, enter:

    SWT13;SWT13;FT1;UPB5;RT0;XT0;

(The number 5 in the “UPB5” command is not a value in kHz;
it is an index into a table of step sizes. UPB5 moves VFO B up 2 kHz,
DNB5 moves it down 2 kHz, etc. There are similar commands for
VFO A. For the full list, see the “DN” (down) command in the 
Programmer’s Reference.)

6. Click on Send Macros 1-8 To K3.
7. At the K3, locate CONFIG:MACRO x menu entry, and tap ‘1’ if
   the menu entry label is not already “MACRO 1”.
8. Hold PF1 to assign PF1 to MACRO 1. Exit the menu.

From then on, PF1 will flash “SPLIT+2” and execute the above sequence.

Note:  M1-M4 cannot be used simultaneously for both message play
and macros. To revert an Mx switch back to message play, first
switch to CW mode, then tap Mx, tap REC, and tap  Mx again. This
will also restore message play for DVR purposes (voice modes). 

Remote Control Command Changes: 

* MP COMMAND ACCESS ADDED TO: LCD ADJ, LCD BRT, LED BRT. 
This allows creation of a switch macro that does LCD DIM/BRT, for example.
You can also use MP to control the new Main/Sub Mix menu entry.
See K3 Programmer’s Reference, revision C6 or later.

* Switch- and menu-emulation commands now run to completion
before subsequent commands in the buffer are handled. This means
that applications and macros using these emulation commands no
longer have to insert delays (such as dummy ‘;’) commands. 

* “BW” (BANDWIDTH) REMOTE CONTROL COMMAND ADDED: This is a 
non-modal version of FW (it work with either the K30 or K31
meta-command in effect). 

* “SB” REMOTE CONTROL COMMAND ADDED (sub receiver on/off).

* “LN” REMOTE CONTROL COMMAND ADDED (link/unlink VFOs).

* “KYW” VARIATION OF “KY<MSG>” COMMAND ADDED:  Waits until 
the current message has been sent before processing other host commands.
This is useful if the “KY<MSG>” command is followed by other 
commands, such as “KS” (keyer speed control). See examples in 
Programmer’s Reference.

* “SWT” / “SWH” COMMAND IMPROVEMENT: These switch emulation
commands are now non-modal (they will work with either the K30 or K31
meta-command in effect). 

* “DN” / “UP” COMMANDS IMPROVED: These VFO movement commands
have extended functionality and are now non-modal (they will work with
any of the K2x meta commands in effect).

MCU 3.44 / DSP 2.38, 10-14-2009

* TUNE & ATU TUNE NOW WORK IN DATA A MODE/SPLIT:
TUNE and ATU TUNE were producing no power output in DATA A
/SPLIT, even though normal transmit worked correctly.

* NON-FM SQUELCH WORKING ON A/B VFO SWAP:  In some
cases in SSB or CW mode, squelch could end up permanently
closed when swapping VFOs and listening to strong signals.

* NOISE REDUCTION CONTROL: Internal self-tests added to 
further reduce the likelihood of AF artifacts or continuous switch 
feedback tones when turning NR on/off, changing bands, etc.

MCU 3.42 / DSP 2.37, 10-06-2009

* POLLING PROBLEM WITH HRD FIXED: With no sub receiver
installed, HRD (Ham Radio Deluxe) was still able to poll for its
revision number, causing a timeout.  

* SQUELCH CAN BE SET FULLY CLOCKWISE: In some cases
rotating the squelch pot fully clockwise would open the squelch.

MCU 3.41 / DSP 2.37, 10-02-2009

* IMPROVED RX LOW-FREQUENCY RESPONSE in AM/SSB/CW MODES: 
Most noticeable with hi-fidelity headphones or large speakers. NORMalizing 
the DSP passband still sets the cutoff to about 100 Hz, but DSP controls can
be adjusted to provide a lower response. RX EQ can enhance bass further. 

* NO RX EQ OR TX EQ IN DATA MODES: That is, the response is flat.
The RX EQ and TX EQ menu entries now affect only the other modes.

* "LIVE" MEMORY RECALL (M>V):  If you tap M>V, then start rotating
VFO A to select a memory, the K3 will now switch to the band/mode 
of each memory. Exit memory recall by tapping M>V a second time.

* VFO COARSE STEP ROUNDING: Tap '1' in the VFO CRS menu entry 
to select RND=NO or YES. If YES, the VFO frequency will be rounded off
during COARSE tuning. This menu entry also sets the per-mode COARSE 
step size. Note: The RIT/XIT control moves the VFO in coarse steps if 
RIT and XIT are not in use (use CONFIG:VFO OFS to turn this on/off).

* SSB COARSE STEP SIZE OPTIONS NOW 0.1, 0.5, 1.0, and 2.5 kHz:
Replaced 5.0 kHz with 0.5 kHz.

* CWT (TUNING AID) NOW INDEPENDENT FOR CW & DATA.

* RF GAIN CALIBRATION PROCEDURE UPDATED:  You’ll need the 
latest revision of K3 Utility and a 50-microvolt signal source (e.g., an XG2).

* SUB RX NOISE BLANKER NOW FULLY INDEPENDENT OF MAIN:
This includes the on/off state and NB LEVEL settings. Note: Set
CONFIG:NB SAVE to YES to preserve your per-band NB on/off settings.

* DSP INTERNAL STATUS MONITORING: In the TECH MD menu entry,
tapping 1 (main) or 2 (sub) displays DSP status information. If it is “FFFF”, 
no error has been detected. Tapping CLR resets the data to “FFFF”.

* CHANNEL HOPPING IN FM MODE LOADS REPEATER SETTINGS: 
Repeater offsets and PL tones are now loaded during scanning/hopping.

* PL TONE DEVIATION ADJUSTABLE: Tapping '1' in CONFIG:FM DEV 
allows setting PL tone deviation (300-600 Hz in 30-Hz steps; default, 360 Hz).

* EU REPEATER 1750 HZ PL TONE BURST:  If a 1750 Hz PL TONE is
selected, a 500 ms tone burst will be sent on each PTT activation.

* EXTENDED 6-METER TUNING RANGE: The VFO can now be tuned 
down to 44 MHz to monitor signals that may be correlated with 6-meter 
band openings. Loss increases rapidly below 49 MHz (-34 dB at 45 MHz),
so a preamp (e.g., the Elecraft PR6) may be needed to obtain a useful NF.

MCU 3.30 / DSP 2.27, 9-2-2009

* RF Gain control now smoother if RF Gain Calibration has been
performed.  See K3 Utility Help for details.

* FIXED NOISE BLANKER SWITCHING IN BSET MODE: You can
now independently turn the noise blanker (NB) on/off for the sub
receiver in all cases. Previously, the NB switch was locked out
in some cases in BSET mode.

* DVR TRANSMIT WITH MANUAL PTT: Normally, playing a DVR 
TX message (M1-M4) automatically asserts PTT and goes into 
transmit mode. Now, you can manually assert PTT prior to playing
DVR messages, if necessary. (This might be required to meet external 
equipment switching requirements at some stations.) To do this: in the 
CONFIG:KDVR3 menu entry, tap ‘1’ until you see “USE PTT”. 
(This setting is ignored in VOX mode.)

* ELIMINATED AUDIO NOISE BURST WITH NR + AUTONOTCH:
Very rarely, the combination of NR and autonotch, in the presence of
a strong signal, could result in a loud audio artifact.

* MORE NR (DENOISER) SETTINGS:  There are now 32 NR settings.
F1-x to F4-x originally appeared in firmware revision 3.27, and are 
recommended for most applications. F5-x to F8-x are the same as
F1-x to F4-x from firmware revision 3.25. They provide a varying mix 
between processed (“wet”) and unprocessed (“dry”) audio. When x is 1, 
the mix is mostly "dry"; when x is 4, it's 100% "wet". A small letter “m” 
(e.g. "NR m F5-1") reminds you that "mixed" settings are in use.

Note 1: When you’re experimenting with different NR ADJ settings, allow 
1 to 3 seconds for the DSP to fully adapt to present signal conditions. 

Note 2: F5-x and higher NR settings may alter the amplitude of 
single-tone (CW) signals somewhat, depending on the pitch. Voice 
signals are less affected.

MCU 3.27 / DSP 2.24, 8-21-2009

* AUTONOTCH improved.

* SHIFT=.01 BUG FIXED W/LOW SIDETONE PITCH (300 Hz).

* VFOS TUNE DOWN TO 490 KHZ.

For Software Developers:

* "IS" COMMAND BUG IN 10-HZ MODE FIXED.

* FINE SHIFT BIT ADDED TO "IC" COMMAND: Byte e, bit 6.

* "MN" GET COMMAND IMPLEMENTED.

MCU 3.25 / DSP 2.21, 8-11-2009

New Features:

* NOISE REDUCTION (NR) IMPROVEMENTS: Our new NR
algorithm has less impact on signal strength, and should no 
longer make some weak signals “disappear” due to over-processing.
We may fine-tune the algorithm in future releases, based on
operator evaluation, but we’ve have good reports from early testers.

* VFO TUNING NOISE REDUCTION: Some operators have reported
hearing noise on 60, 10, or 6 meters when tuning the VFO under
very quiet conditions. If you experience this, try the following:
In the CONFIG:VCO MD menu entry, tap ‘1’ until you see “SPI 2”
(the default is “SPI 1”). This alters the timing of data sent to the 
synthesizer, which in turn changes the spectrum of SPI-bus
signal noise. It has no impact on performance. You will also need to
add two resistors and two diodes to the bottom of the RF board
(see application note on our K3 modifications web page).

* AUTOMATIC RECEIVER FRONT END PROTECTION:  If the K3 is
operated too close to high-power transmitters, it’s possible to damage 
some receiver components. While this rarely happens, we’ve taken
steps to prevent it by sensing a high-current condition at the mixer
post-amplifier (Q8/Q9) and automatically turning off the preamp and,
if necessary, turning on the attenuator. You will need to add one 
jumper wire on the bottom of the RF board (see application note 
on our K3 modifications web page). If you don’t add the jumper, 
operation will be unchanged; firmware can sense whether or not 
you’ve installed the jumper.

* 10-HZ PASSBAND SHIFT STEPS (EXPERIMENTAL):
If CONFIG:PB CTRL is set to SHIFT=.01 for a given operating mode, 
the SHIFT control will provide .01 kHz (10 Hz) steps rather than the 
original .05 kHz (50 Hz). Especially useful with narrow filter bandwidths.
This feature is experimental and has some limitations at present:
Applies to CW and DATA only; LOCUT/HICUT cannot be used when
10-Hz SHIFT steps are in effect; WIDTH steps remain 50 Hz in all cases. 
Not compatible with spur removal function yet (CONFIG: SIG RMV); 
signals mapped out may reappear.

* CW SPEED DISPLAYED WITH DECODED CW TEXT: If the TEXT 
DEC switch parameter is set to WPM CHK (using VFO B), the speed of 
on-air CW signals will be shown, along with a small window of CW text. 
You might see “18w.  CQ…”, where “18w.” means 18 WPM. Both text 
decode and WPM display accuracy can be improved by using narrow 
filtering and by careful adjustment of the “THR” (threshold) parameter 
(set with VFO A when the TEXT DEC switch is pressed).

* RF GAIN CALIBRATION: The K3’s hardware AGC circuitry can now be 
calibrated. This may improve both S-meter and RF GAIN control accuracy. 
To do RF GAIN calibration, use revision 1.2.7.24 or later of K3 Utility (use the 
RF GAIN calibration function, under Configuration). This procedure calibrates
both main and sub receivers. A signal source is required. Future firmware 
revisions will further improve accuracy, using the calibration data stored
by this procedure.

Misc. Improvements:

* "SK" IS NO LONGER DISPLAYED IN RESPONSE TO NOISE 
DURING CW DECODE. Incorrect characters are now displayed as ‘*’.

* 6 METER SCANNING NO LONGER PROHIBITED. Scanning is limited 
to the 6-m U.S. ham band (50-54). Exception: In some countries the K3 won’t
operate on 6 m at all.

* TTY CENTER FREQ NOW DISPLAYED CORRECTLY: In FSK-D
and AFSK-A modes, rotating SHIFT now shows the exact center
pitch (when indicated by an asterisk). The four available center
pitches are 1000, 1360, 1530, and 2210 Hz. Previously the pitch was
rounded down to the nearest 50 Hz.

For Software Developers:

* "RO" COMMAND (RIT/XIT OFFSET READ/SET) ADDED. This
command provides a more direct way to set up the RIT/XIT offset,
as an alternative to “RU” and “RD”. Set/Response format: 
ROsxxxx; where s is +/-, and xxxx is 0000-9999.

Troubleshooting Aid:

* KAT3 “NOT INST” setting is now global. If you set CONFIG:KAT3 to 
NOT INST for the present band/antenna, it applies to all bands/antennas.
Similarly, if you change the setting from NOT INST to any other setting,
all per-band/per-antenna ATU mode data is restored. This change is
useful if you need to remove a KAT3 module for troubleshooting.

MCU 3.19 / DSP 2.17, 6-14-2009

* POWER-RELATED CONTROL LOCK: The PWR, MIC, and CMP controls
can be locked by tapping '1' in CONFIG:PWR_SET. This is useful in 
some contests, such as Field Day, where a carefully-set up K3 might be
used by multiple operators. Accessing a locked control flashes "LOCKED". SPD/DELAY/MON functions are still accessible. Tapping a locked knob still 
displays the current parameter value, even though you can't change it.

* AUTOMATIC CW VFO OFFSET ON MODE CHANGE: Allows switching 
quickly between SSB and CW mode without either you or the other station 
having to re-tune the VFO (often done on 6 meters and transverter bands). 
First, locate CONFIG:CW WGHT and tap ‘5’ on the keypad until you see
“VFO OFS”. From then on, when switching to CW mode from any other 
mode, the VFO will be offset by an amount equal to your sidetone pitch 
(as set using the PITCH switch in CW mode). If the sideband most recently 
used on this band is USB, the VFO will be shifted UP; if it was LSB, the 
VFO will be shifted DOWN.

Note: If you make frequent use of this feature, you may want to
use CW reverse on bands where you use USB, and CW normal
on bands where you use LSB. This results in perfect pitch matching
when listening to a CW signal and switching from SSB to CW. 

* GHZ TRANSVERTER DIGITS are now shown for two seconds on any 
band change, if applicable (i.e. if transverter frequency is set for > 999 
MHz in menu entry CONFIG:XVn RF). This serves as a reminder of
the actual band in use, since the MHz digits alone can be ambiguous.

* AM MODULATION: Now closer to 100%.

* TUNING VFO FROM ONE BAND TO ANOTHER WITH BANDS 
MAPPED OUT: This no longer alters CONFIG:BND MAP settings.

* SYNTH UNLOCK WHEN USING PTT/CW: When using PTT, cancelling 
CW message play by tapping the key or keyer was sometimes causing the
synthesizer to unlock.

* CW SIDETONE STUCK WITH PTT: When using PTT, cancelling CW 
message play during a CW element was sometimes leaving sidetone on. 

* 6M CAN BE PERMANENTLY DISABLED: This is required for some 
countries. This would normally be done at the factory, but can also be
done in the field with a PC program (contact customer support if
interested).

* MAX POWER LEVEL NOW 110 W (was 120 W): This is intended
to reduce the possibility of excess KPA3 operating current on some 
bands. This might have occurred when using a high power setting 
along with low power supply voltage and/or a high load SWR. 
(Note: The recommended maximum power setting is still 100 W.)

For Software Developers:
 
* MONITOR LEVEL (ML) COMMAND: MLxxx (000-060 where 000 is 
OFF, in effect). Applied per-mode.

* IC COMMAND NOW HAS A "TX MSG PLAYING" FLAG. Byte "a" bit B2.

MCU 3.14 / DSP 2.16, 5-9-2009

* SPEAKER PROTECTION: If you’re set up for stereo speakers
(CONFIG:SPKRS = 2), but insert a mono speaker plug, the right speaker
output will be shorted to ground. This can cause excess current drain 
if you turn volume up to high levels. The K3 now detects this condition, 
automatically turning off the right channel (SPRKS = 1). If the left
channel is shorted, the K3 will reduce AF gain and flash “HI CUR”.

* CONFIG:XVn RF parameter can now be set up to 24999 MHz (24.9 GHz). 
Application programmers: FA & FB get/set can also how handle up to 24999 MHz.
This appears to work with N1MM all the way up. HRD tops out at 4 GHz, but 
Simon may be working on this.

MCU 3.11 / DSP 2.15, 4-18-2009

* DATA SUBMODE NOW SAVED/RESTORED CORRECTLY: On power 
up and on some band changes, the  correct data sub-mode was getting lost. 

* ERROR TONE PITCH PROBLEMS FIXED: The sidetone pitch was getting
changed by certain error conditions and when doing TUNE.

* SWITCH TONES NO LONGER GETTING STUCK ON: In AM mode
with wide AM bandwidths selected, tapping HI/WIDTH or LO/SHIFT could 
leave the switch feedback tones on, or omit the second switch tone entirely. 

* BALANCE CONTROL MOVEMENT JUST AFTER POWER-UP NOW OK: 
Someone noticed that if you power up the rig with the sub turned on, then 
moved BALANCE (SUB AF) before moving AF GAIN, the main receiver AF 
would be lost temporarily.

MCU 3.10 / DSP 2.15, 4-15-2009

* FASTER EXTERNAL CW KEYING SPEEDS : When transmit is
pre-enabled using PTT (i.e., with a footswitch or with PTT under computer
control), external keying speeds up to 100 WPM are now possible. (When
using CW with VOX, the recommended maximum is still 60 WPM.) 
Notes: (1) If you use a computer to control PTT, and wish to do this via
the K3’s serial I/O jack, refer to the CONFIG:PTT-KEY menu entry. 
(2) The maximum attainable CW speed may be lower during heavy
use of RS232 polling. Also, higher settings of the transmit delay menu
parameter (CONFIG:TX DLY) will also reduce maximum CW speeds.

* TRANSVERTER BAND DECODE CHANGE: The K3 can control up to
9 transverter bands via either a serial output (auxBus) or parallel 
(BAND0-3). The parallel outputs can select all 9 transverter bands, but the
auxBus is now limited to addresses 1-7, matching Elecraft’s XV-series
transverters. (In all cases, use CONFIG:XVn ADR to specify the address.)

MCU 3.09 / DSP 2.14, 4-9-2009

Misc. Improvements:

* NO AFX KEYING ARTIFACT IN RIGHT AUDIO CHANNEL:
Previously, a short burst of audio might be heard in the right audio
channel when keying the transmitter with MAIN:AFX MD set to DELAY x.
This was most likely with a strong signal or noise in the passband. 

* CW VOX OFF BY DEFAULT ON POWER-UP: Some stations using PC 
control may inadvertently key the K3 in CW mode on power-up if VOX CW 
is in effect. If this is an issue at your station, locate the CONFIG:CW WGHT
menu entry and tap '4', changing VOX NOR to AUTO OFF. This will make
CW VOX default to OFF when the K3 is turned on.

* SQUELCH CONTROL MORE RESPONSIVE: When rotating the RF/SQL
pot or changing SQ MAIN/SUB menu entries, squelch updates more quickly.

* PER-BAND POWER SAVED ON VFO A/B SWAP: Per-band power
settings (CONFIG:PWR SET=PER BAND) are now preserved if 
an A/B swap is done with the two VFOs set to different bands.

* RIT OFFSET PRESERVED ON BAND CHANGE: If CONFIG:SPLT SV
is set to YES, both the state of RIT/XIT and the present offset will be
saved on any band change. (Previously, the offset was set to 0 on band
change, which was inconvenient when alternating between two different
bands and using RIT or XIT.)

* SPURIOUS SIGNAL REMOVAL AND SUB-RX FREQ SHIFT: The use
of spurious signal removal (CONFIG:SIG RMV) for the main receiver no
longer causes a small shift in frequency of the sub receiver when a 
mapped-out spur segment is encountered.

* COARSE TUNING EFFECT ON VFO COUNTS/TURN: On exit from 
COARSE tuning, the normal VFO counts per turn value (CONFIG:VFO 
CTS) is now correctly restored.

For Software Developers:

* SQ$ ADDED (sub-RX squelch control). SQ and SQ$ work for both FM 
and non-FM squelch. Squelch control range via CAT or pot is now 0-29. 
This is different from the K2’s SQ control range.

MCU 3.06 / DSP 2.12, 4-1-2009

* SSB POWER CONTROL: Decreased time that SSB power output takes
to reach target when PWR control adjusted. Also eliminated drive level
change when ATU TUNE is used.

New Feature: All-mode squelch:

* SQUELCH IN ALL MODES:  Locate CONFIG:SQ MAIN, then tap '1' 
until you see "ALL". To use the SUB RF/SQL pot to control both main and 
sub squelch, set CONFIG:SQ MAIN to =SUB POT. (In this case, MAIN RF
will control both main and sub RF GAIN.)  If you want independent control 
of main and sub squelch, set SQ MAIN to a numeric value (0 opens the 
squelch all the way). SQ MAIN and SQ SUB will then be fully independent.
(They can be assigned to programmable function switches if you use them
frequently.) In this case MAIN RF GAIN and SUB RF GAIN are independent, 
using the two RF/SQL pots. 

MCU 3.04 / DSP 2.11, 3-25-2009

Misc. Improvements:

* DSP AGC FIXED: You can now use the original fast and slow AGC
decay setting (CONFIG:AGC DCY = NOR) if desired. In pileups or when
listening to voice signals, try setting AGC DCY to SOFT. This can reduce 
in-band IMD by 15-25 dB. Also see release notes for rev 3.03/2.10
concerning AGC HLD and overall AGC options.

* TUNING JUMPS DUE TO SPURIOUS SIGNAL REMOVAL: The use of 
CONFIG:SIG RMV no longer causes frequency tuning errors in USB and 
CW REV modes.

* MEMORY RECALL: This now preserves all settings that should be 
per-band (not per-memory), including PRE/ATTN and sub antenna selection.

* BSET INTERACTION WITH RIT/XIT: Using BSET no longer causes an 
unwanted change in RIT/XIT settings.

* FIXED FA/FB COMMANDS AND 1-HZ TUNING: Non-zero 1-Hz digits are 
now preserved when FA/FB commands are received and FINE tuning is
in effect.

* ANT NAME FLASH: The antenna name is no longer flashed when A/B 
or REV are used. It is still flashed on any band or antenna change.

MCU 3.03 / DSP 2.10, 3-17-2009

This is a major firmware release with a number of new features, including:

- Band independence for the sub receiver
- New AGC features especially for use in pileups
- ATU storage of multiple settings on each band, and per-antenna auto/bypass
- “Birdie” removal menu entry
- Improve behavior of PTT and the TX LED
- Extended transverter frequency coverage with a 10-m I.F.

Details appear below.

New Feature: Band Independence for the Sub Receiver

* MAIN/SUB RECEIVER BAND INDEPENDENCE. If CONFIG:VFO IND 
is set to YES, then VFO A and B can be set to different bands. In this case
BAND UP/BAND DN will only move VFO A, but in BSET mode, they will apply
to VFO B. VFO B can also have a different mode from VFO A. Some RX
parameters can be set differently for the sub receiver when in BSET mode,
including PRE, ATTN, all DSP controls, and NB (noise blanker) settings.

Limitations: For now, NR, notch, and some other controls remain common 
to both receivers. Internal text decode (CW, FSK-D, PSK-D) is available 
only for the main receiver. Scanning still must be set up using both VFO A 
and B on the same band. Memory recall only updates VFO A if VFO B is
on a different band. (Most restrictions will be removed in future revisions.)

New AGC Features

Introduction: All AGC systems modulate in-band signals to some degree, 
creating IMD if multiple signals are present. But you now have several choices 
when conditions are difficult: (1) AGC OFF, which eliminates virtually all 
in-band IMD, but requires “riding” of the RF GAIN control. (2) Slow AGC 
(AGC-S) with a nonzero hold time, typically 0.2 seconds or more (see 
CONFIG:AGC HLD below). This is nearly as clean as AGC OFF, but the AGC 
will charge on strong signals, reducing gain for the duration of the AGC HLD
amount. This can be distracting. (3) Soft-decay AGC (see CONFIG:AGC DCY,
below, which applies to AGC-S/-F). This recovers much faster than AGC-S with 
a long hold applied, and produces only a little more IMD. In the case of AGC-F 
(fast), soft decay will result in slower recovery time between code elements
than normal decay (nor), but it will still be much faster than AGC-S with a
hold time applied. (4) Normal-decay AGC. This is the traditional DSP-based
AGC decay characteristic, and it will create a lot more IMD than the 
other alternatives. (An application note showing the effect on actual signals
is pending.)

* AGC DCY MENU ENTRY (AGC decay type): Allows you to select "Soft" 
or normal AGC decay characteristic. When AGC DCY is set to “Soft,” both 
slow and fast AGC will create less in-band IMD (intermodulation distortion)
in multi-signal situations (e.g., pileups). You can assign AGC DCY to a
programmable function switch (PF1/2 hold, or M1-4 tap or hold) if you
need to turn it on/off quickly.

* AGC HLD MENU ENTRY (slow AGC hold time): AGC HLD now
applies to CW mode (originally it applied only to voice/data). AGC HLD 
may reduce receive IMD caused by normal AGC-S/AGC-F decay times.
Settings of about 0.3-1.0 seconds should improve copy when many 
closely spaced signals are present, as in a CW pileup. No effect on 
AGC-F.

New ATU (KAT3) Features

* MULTIPLE KAT3 ATU DATA SEGMENTS PER BAND/PER-ANT.: 10 kHz 
per segment on 160 m; 20 kHz on 80-12 m; 50 kHz on 10 m; 200 kHz
on 6 m. This keeps narrowband antennas in tune across the full ham
band. Note 1: You do not have to go through each band and do ATU TUNE
on every segment. The K3 will use the saved LC data segment closest
to your present VFO location. Note 2: You can erase all of the stored LC
data for a given band by tapping CLR in the CONFIG:KAT3 menu entry.

* AUTOMATIC KAT3 LC NETWORK UPDATE ON TRANSMIT: Each time
you transmit, the K3 first determines whether you’ve moved the VFO 
closer to another stored ATU data segment. If so, it will re-load the KAT3 with
this data, and flash the “ATU” icon twice, briefly. You’ll hear one or more
relays on the KAT3 change state. This will not interrupt transmit.

* ATU MODE STORED PER-BAND, PER-ANTENNA: You can now set
up the KAT3’s mode (AUTO, BYPASS, etc.) on a per-band/per-antenna (1/2)
basis. This is very useful if you have well-matched antennas on some bands,
or a dummy load connected to one of the ANT jacks.

New Feature: Spurious Signal Removal

* SPURIOUS SIGNAL REMOVAL: Fast-tuning “birdies” can in some cases
be eliminated using the new “Signal Removal” feature (CONFIG:SIG RMV).
We recommend that this be attempted only on birdies that can be heard
with an antenna connected. STEPS:  (1) Set up the receiver for a desired
band, and select the mode you’d normally use in the target band segment.
(2) Locate a birdie to be removed. A birdie is considered “fast-tuning” if a
small change in the SHIFT control (e.g. 50 Hz) moves the birdie about 500 
Hz or more (sometimes this small shift will move it completely out of the 
passband). Such birdies result from UHF harmonics of the VFO. If you do
test a birdie using SHIFT, be sure to return SHIFT to its normal setting before
continuing, because the value of SHIFT affects the birdie frequency.
(3) Locate the CONFIG:SIG RMV menu entry, and change the parameter 
from NOR to 0. This will save necessary information about the birdie,
including the present VFO frequency, mode, filter, and SHIFT value. 
(4) Try different values of SIG RMV, starting with -1 or 1, to see if the birdie 
can be removed. Greater values (- or +) will move the birdie farther out of 
the passband, but will also result in a greater change in the background noise 
as you tune across it. IMPORTANT: Each time you change SIG RMV,
exit the menu and see if the birdie has disappeared. Each SIG RMV value
applies to a 100-Hz VFO segment, e.g. from 28135.30 to 28135.39, so
you’ll have to tune slowly through that 100-Hz range using 10-Hz steps to
make sure the birdie has been completely removed. Once you’re finished,
you may still hear a slightly tuning artifact as you tune through this range.
NOTE: In most cases, you’ll need to apply SIG RMV to at least two adjacent
100-Hz VFO segments. Also, if you use more than one filter or SHIFT 
setting in the present operating mode, you’ll probably need to map out the
birdie more than one time. TO UNDO SIG RMV: If you tap CLR while
you’re in the SIG RMV menu entry, all birdie information for the present
band will be permanently deleted. SSB MODE ALTERNATIVE: In SSB
modes, simply leaving AUTO NOTCH on may be effective.

Limitations: SIG RMV is experimental. It applies only to the main receiver,
at present, and only in CW/SSB/DATA modes. Do not attempt to remove
birdies on transverter bands; instead, remove them on the I.F. band used.
On each band from 160-6 m, up to 60 birdies can be removed. But as 
mentioned above, each one may have to be mapped out from adjacent
VFO segments as well as for different filter and SHIFT settings. So the 
practical number of birdies that can be removed is more like 5 to 20 per
band. A small audible tuning artifact may remain after removing strong birdies.
Changing REF CAL or your sidetone pitch may make birdies re-appear.
In this case, you might want to tap CLR within SIG RMV to delete the data
for the present band, then start over.

Misc. improvements

* SSB/DATA POWER OUTPUT CONTROL: Power-setting accuracy has 
been significantly improved over previous releases.

* AFSK A TRANSMIT NOISE ELIMINATED: Under certain circumstances, 
such as with DUAL PB turned on, the AFSK A transmit signal could be 
modulated by low-level audio noise. This has now been eliminated.

* PTT-CW RELEASE FIXED: When PTT is used to “arm” CW transmit, e.g. with
a footswitch, releasing PTT in the middle of keying now disables transmit.
Note: This does not apply if VOX is turned on in CW mode. In this case, the
keying inputs are always “live,” i.e. you can hit the key to transmit whether
PTT was used or not.

* TX LED: This LED now only turns on if power output is actually enabled. 

* EXTENDED TRANSVERTER BAND COVERAGE: When 10 meters is used
as a transverter-band I.F., the upper end is no longer limited to 30 MHz. In the
case of a transverter band set up for 2 meters (nominally 144-146 MHz), this
allows tuning a bit higher than 146 MHz, if desired. The 10-meter
band-pass filter falls off pretty quickly above 30 MHz. But the extended range 
may be useful for hitting repeaters with in/out in the 146 to 147 MHz range.

For software developers

* IC COMMAND SHOWS SUB ON/OFF STATUS: Byte b, bit 0. This is 
more reliable than the SUB ON bit in the DS response. “IC” also as the 
advantage that "K31" mode need not be in effect.

MCU 2.82 / DSP 2.00, 2-9-2009

Data Mode Changes:

* AFSK MODE TRANSMIT FILTERING: Some K3 owners have reported 
hearing noise on their RTTY transmit signal when using AFSK-A mode. Possible 
sources of noise include RFI, ground loops, low AF level, or poor mark/space 
transition shaping by software. The effects of noise from many sources can
be eliminated by using a narrow, constant-delay transmit filter (DSP).
To enable this filter, set CONFIG:AFSK TX, to FIL ON (default is OFF).

* SSB/DATA-A/AFSK-A TRANSMIT POWER LEVEL: Power output in these
modes now more closely the requested power. Because of this, we recommend 
setting CONFIG:TXG VCE to 0.0 dB after loading this release, then adjusting
the value only if necessary.

* DATA MODE ALC METERING: ALC metering for DATA-A and AFSK-A 
modes has been adjusted to make the transmit audio level easier to adjust.
As before, the recommended audio level for transmission is 4 to 5 bars. 
3 bars will appear as soon the minimum required level for good S/N ratio 
has been reached.

* FSK POLARITY MENU ENTRY: Setting CONFIG:FSK POL to 0 reverses 
RTTY data polarity (applies only to FSK-D mode transmit) . Note: If you use
the ALT switch to select DATA REV mode, this reverses both RX and TX
tones, in both AFSK-A and FSK-D modes. This should rarely be required.
FSK POL can be used by itself or in combination with DATA REV.

Misc. Changes:

* DVR MESSAGE CANCEL WITH PTT OR VOX: Both one-time and repeating
DVR transmit message play can now be cancelled cleanly with either
PTT or VOX.

* AM MODE SPEECH COMPRESSION: Speech compression is now
available in AM mode. This can add punch to your AM signal. As with any 
type of compression, it should be used only when necessary.

* FM TX DEVIATION: This is now more accurate. Previous versions could 
underdeviate by as much as 1 kHz. Setting is now accurate from 3.0 kHz to
5.0 kHz of deviation when modulated by 1 kHz tone with 5 bars of ALC
indicated.

For software developers:

* “BN” COMMAND ADDED (Band Number). GET only. This command returns 
the K3’s present band number (0-10 = 160 m - 6 m, 11-15 reserved for
future use, 16-24 = XVTR bands 1-9). It is useful for software applications
that need to know if the operator has tuned the VFO across a logical band 
boundary. This eliminates the need for applications to keep track of what the
K3’s internal band boundaries are.

MCU 2.80 / DSP 1.99, 1-23-2009

* AM POWER LEVEL NO LONGER DRIFTS: AM power setting is now more
accurate, and doesn’t change over time. 

* AM TRANSMIT SIGNAL NO LONGER OVERMODULATED: AM ALC and
audio signal levels have been adjusted to provide a very clean transmit signal. 

* DVR TERMINATION VIA PTT: Activating PTT will immediately stop DVR
transmit message playback.

* CWT (CW TUNING AID) ON/OFF STATE SAVED: If you turn CWT on, it will 
always turn on when you return to the applicable mode (e.g. CW).

* MANUAL ATU L/C CHANGES ARE SAVED (per-band, per-antenna, 
just like when doing an auto-tune). Manual ATU adjustment is possible when
CONFIG:KAT3 is set to LC SET (see owner’s manual). Previously, manual 
L/C changes were lost when the KAT3 mode was returned to AUTO or BYP.

* ALC METERING AVAILABLE IN FM MODE: Previously, in FM mode the
ALC meter scale was fixed at 7 bars. 

* CROSS-MODE SPLIT : When using cross-mode SPLIT (e.g. LSB/USB) with 
the sub-RX ON, the use of TUNE would sometimes result in an incorrect sub 
receiver synthesizer frequency.

* SPOT and PITCH switches work correctly with switch feedback tones enabled.
Switch feedback tones are not used for these switches since a tone is generated
anyway. Previously, the sidetone would sometimes not be heard.

* XVx MENU ENTRY BEHAVIOR CORRECTED:  Previously, adjusting these 
menu entries would sometimes change the mode or frequency of the VFOs.

* VFO CTS MENU ENTRY: A change in the VFO counts-per-turn setting now 
takes effect immediately, rather than requiring a mode change or power cycle.

MCU 2.78 / DSP 1.98, 1-8-2009

* SIGN-ON BANNER SUPPORT (for your callsign, etc.): If you specify a sign-on
message (using K3 Utility), it will be displayed when you turn your K3 on. This
might include your call sign, serial number, etc. K3 Utililty revision 1.1.12.29 or
later is required. Click on the Configuration tab, then click on Edit Sign-On 
Banner. Up to 22 characters can be entered. If you delete all characters from 
the message, no banner will be shown.

Misc. Changes:

* SSB SPLIT TX AUDIO PROBLEM CORRECTED: In certain cases (ESSB,
VFO A/B on different modes, or SUB turned on), going into SPLIT mode would
result in no SSB transmit audio, or an incorrect transmit audio passband.

* VFO COUNTS PER TURN CORRECT AFTER EXIT FROM COARSE TUNING:
Previously, if you had CONFIG:VFO CTS set to 400 or 200, selecting COARSE
tuning would leave VFO counts/turn at 100 even after switching to another tuning
rate. (100 counts per turn is used for coarse tuning due to the large step sizes.)

* SUB/MAIN AF BALANCE CONTROL: Main and sub RX audio are now correctly
restored when the sub is turned on/off, etc. Previously, either receiver might
have remained muted after sub on/off when SUB AF was set up as BALANCE.

* DVR WITH COMPUTER CONTROL (HRD, ETC.): Running HRD (and some 
other PC applications) no longer terminates DVR record/play. Some programs
were polling every second or so for the DVR’s firmware revision, which stops the
DVR. The K3 MCU now handles this command in all cases without DVR 
interruption.

* AM DSP BANDWIDTH DISPLAY NOW SHOWS *AF* BANDWIDTH, NOT IF. We 
originally showed the IF bandwidth in AM mode since some operators might be
thinking about the underlying AM-mode implementation (i.e., the IF bandwidth 
has to be twice the AF bandwidth in this mode). But this was causing a lot of 
confusion, and was inconsistent with the way the DSP bandwidth control works in 
other modes, where the *AF* bandwidth is displayed. Also, LO and HI CUT show 
AF cutoff points – not IF – even in AM mode. So we now consistently define the 
function of all DSP controls as showing AF frequencies/bandwidths. Note: In AM 
mode, tapping XFIL will still show the *crystal filter* bandwidth, not the DSP BW.
So if you select a 6-kHz crystal filter by tapping XFIL, you’ll see “FL2 6.00” displayed
(for example). But the DSP width control now be at a starting point of 3.00 kHz.
Also see related change to “FW” remote-control command.

For software developers:

* AM-MODE "FW" COMMAND CHANGE: The filter bandwidth command (“FW”)
was reporting the IF bandwidth in AM mode (multiplying by two) which was confusing
for users of some PC applications. It now reports the DSP (AF) bandwidth in AM 
mode. As with the manual WIDTH control, the IF bandwidth is set to approximately
twice the AF bandwidth when an “FW” set command is sent. (Note that “K31” mode
must be in effect in order to use “FW” to get/set actual bandwidths.)

* ENTERING SPLIT CROSS-MODE VIA "FT;": This no longer results in icon flash, 
so no dummy SWT command is needed to cancel it. (When split is turned on
using the K3’s SPLIT switch, the cross-mode warning flash is still present.)

K3 Factory Test Changes:

* LOST KPA3 12V SENSE THRESHOLD IS NOW 0.2 V: This allows for possible 
future changes to the 12V PA sense circuitry (diode, etc.).

* ADC REF MENU PARAMETER NOW SAVED ON MENU EXIT: Previously it
was saved only on power-down.

MCU 2.76 / DSP 1.98, 12-21-2008

* POWER-ON AF NOISE BURST:  This should now be eliminated.

* DIGIT 2 SWITCH TONE FEEDBACK RESTORED. The ‘2’ key on the numeric
keypad now provides tone feedback when used for numeric entry or within
menu entries. There’s no tone when it’s used as “REV” (temporary A/B VFO
reverse).

* SSB TX AFTER VFO A/B SWAP: Transmit filter settings are now correct
after any A/B swap, regardless of the modes of VFO A and B. This had been 
noted by some customers as a problem on power-up, but it could occur
anytime the VFOs were in different modes at the time of an A/B swap.

* INDEPENDENT PREAMP AND ATTN FOR SUB RECEIVER: The preamp 
and attenuator settings for the receiver are now independent of main. On each 
band, you can set up the sub’s preamp/attenuator as desired using BSET. The 
sub’s preamp/attenuator are separate even in diversity mode, where you’ll 
often be using a lower-gain antenna for the sub receiver.  Note: A second tap
of A>B within the 2-second window still copies all main receiver settings to
the sub, including preamp and attenuator.

For software developers:

* “FR0” COMMAND (SPLIT CANCEL): Now correctly restores the VFO A arrow icon.

* CONFIG:KPA3 MENU ENTRY: The parameter for this menu entry is now 
accessible via the “MP” command.
  
* “FA”/”FB” commands and loss of PLL lock: Large FA/FB frequency steps 
were, on rare occasion, causing loss of PLL lock. This has been corrected.

* Added "PA$" (sub RX preamp) and "RA$" (sub RX attenuator) commands.
This is in conjunction with the sub preamp and attenuator settings now being
Independent of main (see above). During BSET, both return “?;” at present.

MCU 2.73 / DSP 1.98, 12-9-2008

* RX EQ is now applied to both main and sub receivers.

* TUNE NO LONGER CANCELS AUTO-NOTCH.

* CONFIG:ADC REF MENU ENTRY:  This allows the operator to calibrate 
the voltage reference used by the K3 to measure and display certain values,
such as the rig’s supply voltage. ADC REF calibration is optional but 
recommended. First, disconnect anything attached to the ACC jack. Next,
locate the CONFIG:ADC REF menu entry. It will initially show 5.00 volts as
the reference voltage. Using a DMM set to DC volts, measure the actual
voltage at pin 2 of the ACC jack. This must be done while the ADC REF 
parameter is being displayed. (The (-) probe of the DMM should go to 
the K3’s chassis ground, e.g. at the GROUND lug.) Finally, use VFO A 
to set the ADC REF menu parameter to what you measure at pin 2. 

For software developers:

* “CP” COMMAND ADDED (speech compression setting).

* Auto-report (AI2 mode) added for the “MG” command (mic gain).

MCU 2.72 / DSP 1.98, 12-9-2008

Misc. Changes:

* LINE OUT INCLUDES TX AUDIO: LINE OUT (nor menu setting) now includes
transmit sidetone and speech/data monitor audio.

* IMPROVED TX PASSBAND FLATNESS FOR PSK31: When operating in PSK31
mode via a PC, high-pitched audio tones are no longer attenuated more than
low tones. 

Support for Digital Voice Recorder option (KDVR3):

Note: The following information is more accurate than the DVR instructions in the
K3 rev D owner’s manual.

* DVR ICON: The DVR icon (dual arrows--above the S-meter) turns on whenever 
the DVR is in use. The icon flashes slowly during all record operations, and quickly
during play.

* DVR TX MESSAGES: Message record, play and repeat are functional. (Message
chaining will be added in a subsequent release.) To start voice message record,
tap REC, then tap M1-M4. Record will start immediately. Tap M1-M4 again
to stop recording. To play a voice message, tap M1-M4. To repeat a voice message
(e.g., a CQ), *hold* M1-M4 rather than tap. Message play or repeat can be 
cancelled at any time by tapping REC.

* DVR RX LOOP:  Hold AF REC to start receive-audio recording. Hold AF REC
again to stop record. Up to 90 seconds of audio can be recorded; beyond this,
earlier audio will be overwritten. Hold AF PLAY to start playback; press any
switch to stop. VFO B will show the playback position in seconds, relative
to the most-recently recorded audio segment. During PLAY, you can move
forward/backward through RX audio loop buffer by rotating VFO B. An asterisk
(*) beside the seconds counter shows the extent  of the most recently recorded
segment. Note: It is OK to record received audio continuously; this might be 
useful as a way of catching audio events that you wish to examine later.
Record will continue even if you transmit. However, at present, silence is recorded 
for the duration of any transmission.

* DVR RX LOOP PLAY IN TX MODE. First, enter voice transmit mode by holding
PTT or tapping XMIT. Then hold AF PLAY to start playback, and press any switch
to stop. CMP (speech compression) is automatically disabled. Note: Playback 
volume of the RX loop buffer during TX mode is not yet adjustable. 

For software developers:

* VOX STATUS ADDED TO “IC” CMD (separate flags for CW keying ‘VOX’
and voice/data audio VOX).

MCU 2.67 / 1.96, 11-12-2008

* MAIN/SUB BALANCE CONTROL:  If CONFIG:SUB AF is set to BALANCE,
then the SUB AF GAIN control becomes a main/sub AF balance control when
the sub receiver is turned on (including diversity mode). In this case the MAIN
AF GAIN controls the AF gain level for both receivers. When SUB AF is at
12 o’ clock, both receivers will be at full volume (main left, sub right). If SUB AF
is rotated fully counter-clockwise, you’ll hear only the main receiver. If it’s 
rotated fully clockwise, you’ll hear only the sub receiver. At intermediate settings
you’ll hear both. A BALANCE control is very useful for contesting and split 
operation. But it can also save a lot of AF gain control tweaking (i.e., matching 
main and sub), since MAIN AF controls both main and sub receiver audio.

* AGC-OFF AF LIMITER: An adjustable AF output limiter has been added
for operators who turn AGC off. This can protect your ears if a large signal 
appears. Signals or noise above the threshold will sound highly distorted
due to the limiting action, reminding you to back down the AF or RF gain.
The associated menu entry, CONFIG:AF LIM, defaults to NOR. Typical 
settings for those who often turn AGC off are 17 to 23, but some experimentation
will be required.

* DIGOUT0 SIGNAL (ACC connector): This now behaves as described in the 
owner's manual. When a transverter band is selected that is configured for
low-power operation (i.e., .01-1.50 mW, and using the KXV3’s XVTR IN/OUT
jacks), DIGOUT0 provides a low-resistance path to ground that could be used to 
activate a small relay or other circuitry. At all other times the DIGOUT0 line 
will float (high-Z). If all transverter bands are configured for low power, then 
DIGOUT0 can be used as a “transverter band selected” signal.

* POWER LEVEL ON XVTR AND HF BANDS: Switching between HF and 
transverter bands no longer modifies the present HF band power setting.

MCU 2.64 / 1.96, 11-5-2008

* RX ANT HOLD = sub RX antenna switch (if sub is installed). Shows AUX or MAIN.

* SUB ANT SAVED SEPARATELY FOR DIVERSITY/NON-DIVERSITY.

* DVR TX MSG RECORD/PLAY (incomplete).

MCU 2.63 / DSP 1.95, 11-04-2008

* NORM SWITCH ALLOWED DURING TX: The “NORM” switch function (receive
passband normalization, e.g. 400 Hz in CW mode) can now be accessed during
transmit mode. It takes effect after the K3 returns to receive mode. This is 
especially useful for CW operation.
 
* AM COARSE VFO TUNING RATES: Now 1, 5, 9, and 10 kHz.

* AM TRANSMIT: CONFIG:TXG VCE no longer affects AM Tx Levels.

* SPLIT COMBINATIONS AVAILABLE: Cross-mode SPLIT operation is possible 
with any combination of CW and SSB for VFO A and B. Same-mode SPLIT is 
possible in all modes except PSK-D.

* CROSS-MODE SPLIT INDICATION: If you turn on SPLIT with VFO A and B in
different legal modes (e.g. CW and SSB), the K3 will remind you of
VFO B’s mode by flashing it (as well as the VFO B TX arrow). This reminder 
can be cancelled by tapping any switch, key, or PTT. The reason for the 
“reminder” is that operators usually enter cross-mode split by accident. If so, 
cancel the reminder flash, then use BSET to change VFO B’s mode, or tap
A>B to copy mode A to mode B.

* COMPRESSION RANGE: Some operators asked for a higher “CMP” (speech
compression) setting to add “punch” under certain conditions. It can now be
set from 0-40. We still recommend lower settings (0-20) for normal operation.

For software developers:

* “FW$” ADDED (direct sub/VFO B filter bandwidth).

* “SM$” ADDED (direct sub-receiver S-meter read).

* "DV" (DIVERSITY) COMMAND:  DV0 (off), DV1 (on). Also turns sub off/on. To turn
on the sub but not diversity, use an “SWT” command (verify SUB status with “DS”).

* COMMANDS AVAILBLE DURING BSET: "IF", "FA", "FB", "MD”, “MD$", and "DT"
(GET only). “FW” and “FW$” work in BSET except during diversity (TBD).

MCU 2.60 / DSP 1.94, 10-29-2008

* SPLIT operation is now allowed in FSK-D, PSK-D, and CW-in-SSB modes.

MCU 2.59 / DSP 1.94, 10-28-2008

* SWITCH TONES NOW AVAILABLE: If CONFIG:SW TONE is set to ON, tapping
or holding switches produces audio tones corresponding to the switch state. This
supplements the normal tactile feedback of the switches.

* DIVERSITY MODE: Corrected issues related to adjusting receive
controls during transmit. 

MCU 2.58 / DSP 1.94, 10-28-2008

New Features:

* FAST BAND SWITCHING USING KEYPAD:  We’ve added a “band select” 
mode for memories 0-9. First, set CONFIG:MEM 0-9 to BAND SEL.
You can then use V>M to assign individual bands to keypad switches 0-9.
For example, use BAND UP/DN to get to 160 m, tap V>M, then tap #1.
From then on, tapping M>V, then #1, will take you to your last-used frequency
on 160 m, just as if you had used the BAND switches. Up to 10 of your favorite
bands can be assigned to keypad switches, including transverter bands. 
The behavior of memories 10-99 and the per-band quick memories (M1-M4)
will be unchanged.

* MAPPING OUT SELECTED BANDS:  You can now remove one or more bands
from the BAND UP/DN rotation using the CONFIG:BND MAP menu entry. Once
you’ve located BND MAP, use BAND UP/DN to select bands, and set them to
IN or OUT using VFO A. (Works with transverter bands, too.) You can still 
get to mapped-out bands using memory recall, direct frequency entry, or 
computer-control commands (“FA” and “FB”).

Miscellaneous:

* VOX CAN BE TURNED OFF DURING VOICE TRANSMIT: This is useful
if you’re using VOX and have a sudden increase in shack noise that activates
transmit.

* MSG PLAY IN SSB MODE FIXED: In revision 2.57, tapping M1-M4 to play a
message in SSB modes was setting the CW pitch to 0 Hz. This has been 
corrected.

For software developers:

* "RX" COMMAND AND TUNE: “RX” will now exit either an XMIT or TUNE
condition.

* MANUAL BAND CHANGE IN AI1 and AI2 MODES: Multiple rapid presses of
BAND UP or BAND DN were sometimes inserting band-change response data
for intermediate bands into the outgoing host command buffer. Now only the
data for the final band is sent.

MCU 2.57 / DSP 1.94, 10-24-2008

Major changes and new features:

* SSB POWER CONTROL IMPROVEMENTS: (1) No jumps in power while 
rotating PWR control during transmit. (2) No upward spike when crossing 
QRP/QRO boundary. (3) No loss of SSB TX drive level when tapping A/B, 
changing modes, or doing an ATU TUNE. (4) These improvements may also
lessen the effect of “spiking” external amplifiers, but further work on the
ALC routine is planned.

Note: The SSB drive does still get reinitialized to match the CW level if you do 
a TUNE (this is desirable). But it also happens if you change bands or recall a 
memory (that will be fixed in a later release). 

* FIRST A>B TAP COPIES MODE (if VFO A and B modes are different). This
should greatly reduce the chance of having VFO B in the wrong mode when
the operator later goes into SPLIT. (Those who want to do cross-mode split
can still set up VFO B differently using BSET mode, and should avoid A>B.)
Once the VFO modes are the same, operation of A>B is the same as before:
A single tap copies only the frequency, while a second tap copies everything.

* SPLIT CAN BE USED IN DIVERSITY MODE: See details below.

* PSK31 (PSK D MODE) TRANSMIT IMPROVEMENTS:  Eliminated 
erroneous characters during CW-to-PSK31 transmit when using the keyer 
paddle. Also greatly improved PSK31 transmit speed by removing all
extraneous “zeros” from the data stream. 

* MARS operation now possible on 40 m up to 7550 kHz.

VFO Linking, Sub RX, Diversity Mode, and SPLIT:

* SPLIT CAN BE USED IN DIVERSITY MODE: During SPLIT, VFO B is only the
transmit frequency. VFO A controls both receivers. So you now have a choice when using SPLIT with the sub receiver: diversity receive, or listening to both your 
RX (main) and TX (sub) frequencies simultaneously. Also see BSET note below.

* VFO A-B LINKING: This is now indicated by slowly flashing the VFO B kHz 
decimal point.

* A/B and REV CAN NOW BE USED IN DIVERSITY MODE. In both cases, the
VFOs are swapped, allowing you to listen in diversity mode on VFO B’s frequency.

* BSET IN DIVERSITY MODE: If you use BSET in diversity mode, you’ll now
hear the main RX in the left ear and sub RX in the right. This is useful when using
SPLIT with diversity, as it allows you to override diversity mode temporarily and
listen to both your RX and TX frequencies.

* VFO B NOT LOCKED WHEN LINKED TO VFO A: This means the VFOs can
be linked but at different frequencies. A fixed offset can be established using
VFO B, and will be maintained as you tune VFO A.

* VFOs NOT LINKED IN DIVERSITY MODE: VFO A is used to update both
synthesizers (main and sub), but VFO B is now free to be used as a SPLIT TX 
frequency (see below). In DIVERSITY mode, the VFO A kHz decimal point slowly flashes, as before.

Miscellaneous:

* MESSAGE PLAY FIXES: There were a few issues with CW and DATA message
buffer playback, including occasional truncated characters when chaining in CW
mode, and inconsistent behavior when chaining.

* MORE ACCURATE AM-MODE POWER LEVEL. Also slightly higher modulation 
percentage.

* INTERNAL 2-TONE TEST GENERATOR now works with 2.7 as well as 2.8 
kHz crystal filters, and the tones are now correct when used with both LSB and USB. 

* KEY OUT disabled sooner on power-up: Previously, KEY OUT was active for 
about 3 to 4 seconds on power-up. This has been reduced to under one second.
In any case, no RF is present during this period.

For Software Developers (see K3 Programmer’s Reference, rev B14):

* “DS” (VFO A DISPLAY READ): This command now correctly handles all of the
RX EQ / TX EQ “mini-bar graph” levels as displayed in the main menu. The bar
graph level 1 character, if it appears in the “DS” response string, is now converted
to an underscore rather than a semicolon. This preserves the semicolon as 
strictly a command terminator.

* "DT" COMMAND ADDED (VFO A DATA sub-mode read/set). "MD" is 
still used to set norm/rev.

* "IF" COMMAND INCLUDES DATA SUB-MODE (K31 must be in effect).

* "IC" COMMAND ADDED (ICON and MISC STATUS): Provides state information on many functions, including BSET, TX TEST, VFO linking, diversity mode, sub RX antenna, full/semi QSK, dual-passband CW, dual-tone FSK filtering, ESSB, nose gate, FM PL tone on/off, etc. 

* “LK$” COMMAND ADDED (VFO B LOCK).

* “TQ” (TRANSMIT STATUS QUERY) now returns 1 consistently when the K3 is in
transmit mode.

* MORE MENU ENTRIES ACCESSIBLE WITH “MP” COMMAND: KAT3, VCO MD, and AGC THR are now available. See MN command table for details.

* KY (keying) remote control command now handles CR, LF, TAB and other
ASCII characters including:   [ \ ] ^ _ `    All of these characters are useful in 
PSK D mode. They’re ignored in other modes, except that  '_' becomes an
"AA" prosign in CW mode. 

* Prosign mapping (e.g., “=” conversion to “BT”) is now disabled in PSK D 
and FSK D modes. This allows all ASCII characters to be transmitted normally.
(Prosigns can always be sent using the alphabetic characters themselves 
in these modes.)

MCU 2.46 / DSP 1.94, 10-3-2008

* 40 METER PA CURRENT REDUCTION:  This revision corrects the low-pass 
filter configuration used on 40 m. The 10/12 LPF, not the 6 m LPF, is now used
in-line with the 40 m LPF. This optimizes return loss, keeping current at the
target level at 100 W (about 20 A).

* NOTE ON AM COMPRESSION: Starting with MCU 2.45/DSP 1.92, speech
compression has been disabled in AM mode. We hope to create a more effective
compressor for AM in a future revision; the original was adding distortion
without increasing “punch”. On the other hand, the available AM modulation level 
has been increased, and we’re better utilizing the mic AGC system in this mode.

MCU 2.45 / DSP 1.92, 9-29-2008

* TRANSMIT NOISE GATE ADDED:  The TX noise gate can be used to suppress 
transmitted audio below a certain level, e.g. a noisy fan (not the one on the K3, of
course). To use the noise gate, locate CONFIG:TX GATE, tap ‘1’ to turn it ON,
then use VFO A to set the desired threshold. Since there’s no visual indication that 
transmit audio is below the threshold, you should adjust it using the transmit voice
monitor (MON), ideally using headphones. Set the threshold high enough to cut off 
transmit audio due to shack noise, but not so high that it causes your voice to drop
out too frequently. The TX GATE threshold can be adjusted in TX TEST mode.

* TRANSMIT INHIBIT (TX INH) FUNCTION IMPROVED: Activating the TX INH input 
on the ACC jack now asynchronously suspends RF output. It has no interaction
with transmit sequencing. When TX INH is active, the only indication is that the
“TX” LCD icon flashes, as in TX TEST mode. This should closely match the transmit
inhibit logic of other transceivers.

* COARSE TUNING CORRECTED: (1) Downward tuning with COARSE increments in 
effect occasionally resulted in the synthesizer unlocking, especially in AM mode with
9-kHz European broadcast band increments. (2) Tuning down to the low end of
the K3’s tuning range would cause quantization. For example, if you were at 505 kHz 
with 9 kHz steps selected and tuned downward one tic, the VFO would go to
500 kHz, and the next upward tic would be 509 kHz. Both of these problems
have been corrected.

* “VOX=OFF” REMINDER: Whenever you change the VOX setting from ON to OFF
in CW mode, then sometime later hit the key, you’ll see a one-time “VOX=OFF” 
message. This is a subtle reminder that VOX must be turned on in CW mode to
enable hit-the-key operation. Otherwise you have to “arm” the transmitter
by tapping XMIT or by using PTT. (This has always been the case for the K3, and 
most rigs behave in the same way.) We decided to add this reminder message because
operators not familiar with “VOX for CW” have occasionally turned it off, only to wonder
later why the rig won’t transmit in CW mode.

* TRANSMIT DISABLED DURING FIRMWARE LOADS:  You cannot key the 
transmitter during firmware loads, via KEY IN, PADDLE, PTT, XMIT, VOX, or 
computer commands. 

For Software Developers:

Note: Refer to the K3 Programmer’s reference, rev. B10 or later.

* "OM" COMMAND ADDED: Shows which K3 option modules are installed.

* "MP" COMMAND ADDED: Menu parameter direct read/set. Only applies to 
selected menu entries, as listed in the programmer’s reference. 

* "MG" COMMAND ADDED: Mic gain read/set.

* "MD$" COMMAND ADDED: Sub RX/VFO B mode read/set.

* "IS;" COMMAND ADDED (I.F. shift). Note: In diversity mode, an IS or FW command
will be sent to both main and sub. In AI2 mode, moving the SHIFT or WIDTH controls 
will generate both IS and FW responses.

* “FW0000x” form of the FW command can now handle x = 1 through 5 (requires
"K30" and "K22" be in effect; see programmer’s reference.

* Added the following AI2 responses:  PC, AG, AG$, RG, RG$, NB, NORM (FW).

MCU 2.38 / DSP 1.90, 9-7-2008

* RIT CLEAR COMMAND: The “RC” remote-control command now correctly
clears the RIT offset. It would sometimes do the equivalent of a “long-hold” 
of the CLR switch, copying the RIT offset to VFO A before clearing the offset.

MCU 2.37 / DSP 1.90, 9-2-2008

* FIRMWARE UPGRADE PROCESS IMPROVEMENT: When upgrading firmware, 
MCU and DSP code versions may temporarily become incompatible, resulting in
error messages during loads. These spurious errors are now suppressed, resulting
in a cleaner upgrade process, especially when upgrading from much older revisions.

MCU 2.36 / DSP 1.90, 9-1-2008

* SUB/MAIN AF GAIN EQUALIZED. 
  
* VCO CAL improved to make synthesizer alignment easier.

MCU 2.34, 8-29-08

* CORRECTED SHIFT CONTROL DISPLAY. Center frequency was 
Incorrect in some cases.

MCU 2.33, 8-28-08

* DSP FILTER POSITION CORRECTED: At some bandwidth and SHIFT settings,
the DSP IF was shifted downward. Especially noticeable in CW mode.

* SHIFT CONTROL CW CENTER FREQ DISPLAY: If you’re using a CW sidetone 
pitch that’s not at a 50-Hz boundary, it will now be displayed accurately when the
SHIFT control is centered (i.e., when the asterisk appears).

MCU 2.32, 8-28-08

* CORRECTED ESSB/SSB PASSBAND ERROR (introduced in MCU rev. 2.31).

MCU 2.31 / DSP 1.89, 8-28-08

New Features and Enhancements:

* CW SIDETONE INCREMENTS NOW 10 HZ (originally 50 Hz).

* RIT CLR switch now works during transmit in all modes and at any time.

* RIT CLR MENU ENTRY: You can use this menu entry to select “UNDO ON” or
“UNDO OFF”. OFF is the default. When “ON”, tapping CLR will alternate between
0.00 and the present RIT/XIT offset, if any.

* DIVERSITY RECEIVE MODE: If you have the sub receiver (KRX3 option) installed, 
you can take advantage of “diversity receive” by using two separate receiving antennas.
This can improve signal copy during fading, and adds a spatial (L/R) effect to signals.
DIVERSITY MODE further enhances this capability by slaving the sub receiver’s 
mode, filter settings, and VFO to the main receiver. To enter diversity mode, hold
SUB until you see “DIVRSTY” on VFO B (about 2 seconds). The kHz decimal point
of the VFO A display will flash slowly as a reminder that diversity mode is in effect.

Notes on Diversity Mode:

1. Entering diversity mode switches the sub receiver  to its AUX antenna
source. If you don’t hear any right-channel audio, you probably don’t have
an antenna connected to the sub’s AUX input. Refer to the owner’s manual
or KRX3 manual for information on sub receiver AUX antenna configuration.

2. If your main and sub receiver have 5-pole crystal filters with differing frequency 
offsets, you may hear a slow phase modulation in the received audio at some
VFO frequencies. The only way to eliminate this effect is to use 5-pole filters with
matched offsets (available on request; contact Elecraft) or use 8-pole filters,
which have no offset.

Miscellaneous changes:

* DUAL PB CW MIN CONTEXT BANDWIDTH NOW 400 Hz. In high-QRM situations,
a 400 Hz or 500 Hz crystal filter may be very useful as a limit to the context bandwidth.
Note that the “pedestal” effect (-24 dB context filter) becomes more of a sloped 
response as the context bandwidth is reduced.

* DATA TX ALC IMPROVEMENTS. PWR control is now more responsive during
transmit in all DATA modes.

* FM SQUELCH THRESHOLD: Closely matched between main and sub receivers.

* NOISE BLANKER ON/OFF ON BAND CHANGE: The DSP noise blanker 
wasn’t set up properly during band changes. It may have been left ON on the new
band in some cases.

* PA TEMP and FP TEMP are now "normal" VFO B alternate display modes, 
meaning that you don’t have to set TECH MD to ON in the config menu.

* DDS frequency shifting during T/R changed to eliminate a variation in CW 
keying duty cycle that was occurring only over specific, narrow frequency ranges
on each band. This also eliminated a related CW keying artifact.

For software developers:

* RG$ command implemented (sub receiver RF gain). 

* "FA", "UP" ,"DN", “RC”, “RU”, and “RD” COMMANDS UPDATE VFO B IF VFOS ARE LINKED (except in SPLIT). These commands can also be used in transmit mode.

MCU 2.23, 7-31-08

*LSB/USB TRANSMIT EQUALIZATION (experimental): Improved gain balance between LSB and USB. A 1 to 3 dB difference between the two had been reported with the 2.7 kHz (5-pole) filter. The passband should also be slightly flatter. 

* ESSB (EXTENDED SINGLE SIDEBAND) ADDED:  Allows the K3 to transmit in SSB modes at a bandwidth of up to about 4 kHz. Requires a 6 kHz crystal filter on the RF board. Note: ESSB receive is obtained just by adjusting the WIDTH control. 

To enable ESSB transmit: 

(1) Make sure the 6 kHz filter is configured correctly for AM transmit; switch to AM mode, then specify this filter using CONFIG:FLTX AM. (A future firmware release should allow use of the FM filter for SSB as well, pending lab tests.) 

(2) Locate CONFIG:TX ESSB. Select the desired extended bandwidth for SSB transmit (3.0 to 4.0 kHz) using VFO A. Then tap ‘1’ on the keypad to turn ESSB on/off. When on, the “+” icon in the mode area will turn on. (If you turn ESSB on/off frequently, you might want to assign the TX ESSB menu entry to a programmable function switch.)    

MCU 2.22, 7-29-08

* CHANNEL SCAN no longer locks out small encoders (during scan or after stopping it). 

* USER-DEFINED “NORM” VALUES are now referred to as NORM1/2 rather than ALT1/2
  to avoid confusion with the “ALT” switch, which is unrelated to NORM.

* FLASH MEMORY INITIALIZATION corrected to prevent spurious “FPF LOAD 
  PENDING” message. If this message does appear unexpectedly, tap any switch
  to see the flash read exception code, e.g. “FPF 1”. Report this to customer support.

MCU 2.20 / DSP1.88, 7-24-08

* AGC: Slope is now approximately linear in dB.  Threshold 
  moved about 10 dB lower, closely matching earlier DSP revisions.

* NR: Gain levels re-balanced to account for changes to AGC.

* USER INTERFACE: Minor clean-up of menu entry text and parameters,
  help text, error messages, etc., to make operation more intuitive.

* SUB RX ON/OFF now has no effect on SPLIT, RIT, or XIT.

* SUB RX SYNTHESIZER is no longer updated when sub RX is turned off,
  even with VFOs linked. This prevents an audio artifact when tuning. Also
  eliminated interaction between main and sub synthesizers during T-R 
  switching that was causing keying artifacts at very specific frequencies 
  on some bands.

* IIR DSP FILTER ON/OFF SELECTION now applies to both main and sub
  receivers. (IIR filter on/off is selected by tapping the ‘7’ switch while in the
  FLx BW menu entry. IIR filters apply only to 100 Hz and narrower DSP
  bandwidths. They have slightly more ringing than the default FIR filters.)

MCU 2.16, 7-9-08

* SUB RCVR AUX ANT SELECTIONS: The ANT=ATU and ANT=BNC selections were
  reversed. You may need to set this up again (CONFIG:KXV3).

* SUB RCVR CONTROLS LINKED TO MAIN RCVR WHEN VFO IND=NO: 
  BAND, PRE, ATTN, NB, NR, NOTCH. Attempting to change these (using BSET)
  results in "=MAIN" flashed on VFO B. Once we allow VFO IND=YES, these
  controls will have individual settings in BSET mode. 

* SUB RCVR NB/NR/NOTCH WORKING: Setting up any of these functions for
  the main receiver sets them up for the sub receiver as well.

* RIT/XIT OFFSET NOT CLEARED WHEN SUB RCVR TURNED ON.

MCU 2.15, 7-8-08

* SYNTH TUNING CORRECTED ON 80 M: Downward tuning was sometimes 
  leading to loss of receive and/or transmit at certain frequencies.

* SYNC DATA: Selecting sync data or “-S” (CONFIG:SYNC DT, used to minimize 
  the error rate of AMTOR, PACTOR, ARQ, and similar modes) now ensures that the 
  same crystal filter will be used for both RX and TX (either 2.7 or 2.8 kHz). While -S 
  is in effect, the receive crystal cannot be changed with XFIL, and SHIFT/LOCUT/HICUT
  are unavailable. WIDTH can still be changed, but it will affect only the DSP IF, not
  the crystal filter. The RX and TX 1st I.F.s will thus remain identical.

MCU 2.14, 7-4-08

* MEMORY RECALL ON 6 M (CW REV, etc.): Corrected problem with recall
  of CW normal/reverse and other parameters on 6 meters only.

* 50 AND 100 HZ bandwidths are now available in DATA A (for use 
  with PSK31 and other narrow modes).

MCU 2.13 / DSP 1.83, 7-3-08

New Features:

* MEMORY ERASE: During memory recall or store, tapping CLR erases 
  the present numbered memory (00-99) and flashes "ERASED". You can 
  rotate VFO A to select and then erase any number of memories.

* POWER-UP KEY/PTT PROTECTION: If any external device attempts to key
  the transmitter within 2 seconds of power-up, "ERR KEY" or "ERR PTT" 
  will be shown on the VFO B display, and transmit will be inhibited. This applies
  to KEY IN, DOT, DASH, PTT, vox, or computer-initiated transmit (TX or KY
  commands). It should prevent accidental transmit during power-on when
  a computer, keyer, or other device is powered-up at the same time as the K3.
  Once all keying/PTT/vox activity has stopped, the message disappears,
  and normal transmit activity can be resumed.

Miscellaneous:

* RATE, FINE, and COARSE VFO tuning controls are all now saved
  per-mode rather than per-band/per-memory.

* ANTENNA CONTROLS are all now saved per-band, not per-memory. These include:
    - Main RX/TX antenna selection (1 or 2) 
    - Sub RX antenna selection (MAIN or AUX)
    - RX ANT in/out selection
    - Preamp/attenuator settings for RX ANT ON and RX ANT OFF
    - DIGOUT1 menu parameter setting for ANT1 and ANT2

* PTT RLS MENU ENTRY (PTT release delay). This menu entry allows the
  the operator to specify a delay from release of PTT to exit from transmit 
  in voice and audio data modes. Not applicable to CW, FSK-D, or PSK-D.
  The default is 0. A higher value may be needed in ARQ and similar data modes,
  where the transmit DSP “pipeline” must be fully processed before the 
  carrier is dropped.
 
* NARROW CW/DATA FILTERS (100/50 Hz): Corrected distortion and loss issues.

* SYNTHESIZER: VCO CAL improvements related to “ERR VCO” and “ERR PL1” 
  error messages.

For software developers:

* '$' character in CAT commands targets the sub receiver. At present only the
  AG$ command is implemented (sub AF gain, e.g. AG$;  AG$050;).

* "FI" command provides last four digits of the K3’s exact I.F. center frequency, in Hz.
  For example, if the selected filter has an offset of 0.00 and is not shifted, the I.F.
  is exactly 8215000, and “FI;” will return “FI5000;”.

* "MD" COMMAND DURING “TUNE”: For the duration of TUNE, the MD command 
  will return the operating mode that was in effect at the time TUNE was activated,
  not CW mode. This should fix a problem with third-party panadapters
  that may have seen TUNE as a mode change to CW.

Sub receiver:

* KRX3 MENU ENTRY: Settings now include NOT INST, ANT=BNC, ANT=ATU. When
  the sub receiver is installed, the operator must select one of the two “ANT” settings based
  on what is connected to the KRX3’s “AUX RF” input: the KAT3’s non-transmit antenna
  (ANT=ATU) or the rear-panel AUX RF BNC jack (ANT=BNC).

* BSET-MODE ANT1/2 ICONS:  When the sub receiver turned on, you can use BSET mode
  to view or change the sub’s antenna assignment: MAIN (sharing the main receiver’s 
  antenna) or AUX (using the sub’s AUX RF input). When AUX is selected, the ANT1/2 icons
  will either turn off (if ANT=BNC was specified for in the KRX3 menu entry) or one of
  them will be on (if ANT=ATU was specified). 

* SUB RX FILTER SETUP: In menus, toggling between RF and SUB and switching 
   filters or modes now properly sets up sub if applicable. This allows the operator to hear
   the effect of any changes on the sub receiver’s own filters (if SUB AF GAIN is set
   so it can be heard). NOTE: You must turn the sub receiver ON before entering the
   menu if you want to listen to the sub during filter changes.

MCU 2.10 / DSP 1.81, 6-22-08

* SYNTHESIZER OCCASIONAL RX/TX DROP-OUTS FIXED.

* SYNTHESIZER BANDSWITCHING DELAY increased to allow VCO more time to lock.

* TX/RX switching time improvement in DATA-S mode.

* NARROW FIR FILTERS: Gain balanced (CW and data modes).

* NOISE BLANKER can now be used with AGC turned off in all modes. 

* DENOISER: Gain balance improved in SSB/AM modes. 

MCU 2.03 / DSP 1.78, 6-9-08

Misc:

* EXT ALC voltages adjusted to match resistors called out in EXT ALC mod document.
  
PC Control Command Changes (for application software developers):

* "PC" (PWR READ) IN K22 MODE now supplies correct value for QRO (KPA3) on/off.

* “FA/FB” BAND CHANGE now saves mode for old band before switching to new band. 
   This prevents problems with per-mode bandwidth, etc., following band changes.

* “MD” COMMAND FIXED:  On 6 m, CW norm/reverse were being reported backwards. 
  On all bands, DATA A and PSK-D were reversed for both get and set (AFSK A and 
  FSK-D were correct). NOTES: When an “MD” command is used to switch between 
  data normal and reverse, it applies to both DATA A and PSK-D (if either of these was
  in effect), or AFSK A and FSK-D (if either of these was in effect). To get/set data
  modes, use “SWH43;” to emulate pressing the DATA MD switch, then “DB” to retrieve
  the data mode text string from VFO B, and “UPB;” / “DNB;” to change the mode. 

MCU 2.02, 6-7-08

* VOX SWITCH NOW FUNCTIONS CORRECTLY IN CW MODE. When VOX is OFF in
  CW mode, transmit must be enabled via XMIT or PTT rather than just hitting the key.

* MEMORY-BASED CHANNEL HOPPING (for 60 m in particular):  This now works
  as described in the K3 Owner’s Manual (rev C., page 37). You can manually ‘hop’ 
  with VFO A, or scan channels. First, store the desired channels in adjacent memories. 
  For example, you might set up 60-m channels in memories 61-65 (5330.5 kHz, etc.).
  Next, change the first label character in each of these memories to an asterisk (*) as 
  described in the manual. (The first memory above and below your channel-hop group
  must either have no asterisk in their first label position, or be on different bands.) 
  Finally, tap M->V and select any one of these memories. Manual rotation of VFO A 
  and scanning will then use only the memories in the group. To return to normal operation, 
  use any of the VFO rate switches, or change bands. NOTE: A future revision will allow 
  FM channel hopping based on squelch activity.

  SCANNING TIP: On a noisy band, scanning may pause too often. Try using a narrower 
  filter, turning the preamp off, or backing down RF GAIN until the scan starts.

MCU 2.00 / DSP 1.77, 6-6-08

* BAND DATA FOR TRANSVERTERS: The BAND0-3 outputs on the 15-pin ACC jack
  can now be used to control transverters as described in the Owner’s Manual (revision
  C, page 18-19). To enable this feature, set CONFIG:KIO3 to HF-TRN (which outputs
  band decode data for both HF and transverter bands) or TRN (transverter band
  data only). The default is NOR (HF band decodes only).

* CW MODE SPEAKER ARTIFACT ELIMINATED: Some operators reported
  a periodic burst of noise coming from the speaker when headphones were
  used in CW mode. This has been corrected.

* MIC BUTTON FUNCTIONS DEFAULT TO OFF:  There’s now a menu entry for
  turning the mic up/down buttons on or off (CONFIG:MIC BTN). The default is OFF, 
  which makes these buttons inactive. You should turn it ON only if you have a
  mic whose up/down buttons provide contact closures to ground, with no resistors
  in series or in parallel (such as a Kenwood MC-43). Some mics have internal 
  resistors and are not compatible with the K3’s up/down feature. If you try to
  use such a mic (by setting CONFIG:MIC BTN to ON), VFO A may scan continuously.

MCU 1.99 / DSP 1.76, 6-4-08   

New Features & Misc. Changes:

* POWER LOSS DURING TRANSMIT ON 6 M CORRECTED.

* RIT APPLIES TO BOTH VFOs WHEN LINKED. With the sub receiver installed,
   this allows diversity receive tuning via RIT while preserving a fixed transmit frequency.

* ANTIVOX GAIN increased. (Some antivox users may need to use a lower setting.)

* MIC UP/DOWN buttons, if provided on your mic, will move VFO A up or down one
  unit at the present tuning rate. Holding the UP or DOWN buttons for about 1 second
  will auto-repeat the VFO movement, allowing manual scanning of the current band.

* PER-BAND POWER CONTROL:  This feature is very useful with external amplifiers
  as well as transverters. To use it, change CONFIG:PWR SET to PER-BAND.

* RECEIVE RFI DETECTION: If the CONFIG:RFI DET menu entry is set to
  NOR (normal), the K3 will detect the presence of very large signals (about 2 watts or 
  higher) that appear at the ANT1/2 jacks in receive mode. “HI RFI” will be displayed 
  on VFO B. Try separating antennas, using single-band filters, or reducing power. 
  To disable RFI detection, set CONFIG:RFI DET to OFF (not recommended).

* EXTERNAL ALC:  We strongly recommend that external ALC only be used to protect 
  your amplifier during operation into a failed load or other serious condition. In fact, most 
  amplifiers have such protection built in, and do not need or specify the use of ALC. 
  ALC should not be used as a way to clip or compress fast voice peaks. The K3’s
  ALC uses a moderate attack time specifically to prevent signal distortion due to ALC
  action, so it is the responsibility of the operator to keep drive below this level.

  DO NOT SET THE K3’s POWER LEVEL TO MAX AND ADJUST AMP OUTPUT USING
  THE AMP’s ALC CONTROL. THIS WILL RESULT IN SPLATTER AND KEY CLICKS. 
  INSTEAD, ADJUST THE DRIVE ON EACH BAND SO IT’S JUST BELOW THE LEVEL 
  WHERE ALC STARTS TO ACTIVATE. (See Per-Band Power Control, above.)

  NOTE: You may need to make some simple modifications to the transceiver to use 
  external ALC. This information will be added to our K3 mods page. Information for 
  specific amplifiers will be made available when possible.

  Once the mods have been made, set CONFIG:EXT ALC to ON by tapping ‘1’. (6 m can be 
  turned on/off separately from HF.) The default external ALC threshold of -4.0V will work 
  in most cases, but can be changed if required. If your amplifier’s gain varies from band 
  to band, you may want to set CONFIG:PWR SET to PER-BAND. You can then adjust
  the drive ideally on each band to prevent external ALC activation during normal operation.
  If you select CMP/ALC metering, external ALC activity is indicated by 8 or more bars. 
  If you select SWR/RF metering, the CMP/ALC meter icons will flash during external ALC 
  activity to make you aware of the condition. Reduce the drive power if this occurs.

PC Control Command Changes (for application software developers):

* BAND CHANGES RESULTING FROM FA/FB commands now run to completion before 
  any additional commands are processed (such as MD or FW). This should prevent 
  errors in mode or filter settings which sometimes occurred with older K3 firmware.
  Band changes take approximately 0.5 seconds to complete.

* FA/FB COMMANDS TARGETING 6 METERS will select a 6 m transverter if available. 
  If not, these commands will select the K3’s internal 6 m band.

* FW (filter bandwidth) command fully implemented. If K3 extended command mode is
  in effect (“K31;”), FW sets or reads bandwidth in 10-Hz increments. 

* DS (VFO A/icon read) now reports a number of K3-specific icon states, including 
  RX ANT, SUB, etc. See K3 Programmer’s Reference, revision B2 or later.

MCU 1.96, 5-14-08

  * NEW VFO COARSE TUNING RATES: FM, 10 kHz; CW, 0.1 kHz; SSB, 0.1 kHz.

  * SQUELCH ASSIGNED TO SUB RF/SQL now persists across a power cycle.
     (This is done using CONFIG:SQ MAIN; set it to “=SUB POT”.)

  * XVn ON menu entry, when assigned to a programmable function switch, will
    will now alternate between YES and NO. This now applies to all 2-valued menu entries.

  * Flash and EEPROM memory read/write are now verified to improve reliability
    of parameter storage. This includes PLL data tables, frequency memories, etc.

MCU 1.94 / DSP 1.73, 5-12-08

  * VOX: Increased sensitivity. Typical VOX GN settings now ~30-50.

  * VOICE MONITOR: Eliminated “scratchy” artifacts with compression set to high levels.

  * FM DEVIATION ADJUSTABLE:  Use CONFIG:FM DEV menu entry (default: 5.0 kHz).

  * Flash memory driver improved to prevent occasional receive dropouts, “ERR PL1”, and
    “FPF LOAD PENDING” messages.

  * XMIT SWITCH IN MENU: Tapping XMIT while in menu correctly starts/ends transmit.

  * PASSBAND SHIFT BELOW “0.00” CORRECTED: The SHIFT control no longer allows
    continued rotation below 0.00. (This was occurring only with sidetone pitch < 500 Hz.)

  * SQUELCH/RF GAIN CONTROL CHANGES: By default, the RF/SQL concentric pots
    control main and subreceiver RF gain, and squelch is controlled by two CONFIG menu 
    entries (SQ MAIN and SQ SUB). But setting SQ MAIN to "=SUB POT" assigns 
    SUB RF/SQL pot to both main and sub squelch, and in this case, the main RF/SQL
    pot controls both main and sub RF gain. Setting SQ MAIN back to a numeric value 
    restores the default assignments. Note: Squelch applies only to FM mode at present.

  * USE LAST SEGMENT OF S-METER (S9+60) IF NOT IN SMTR PK MODE.

  * USE TEXT DEC THRESHOLD FOR AUTO-SPOT.

  * SMOOTHED OUT NOISY CWT REPRESENTATION DURING CW COPY.

MCU 1.88 / DSP 1.70, 5-4-08

  * CONFIG:XVn PWR menu entry now correctly sets the power range upper limit for
     the associated transverter band; the PWR control can be used to reduce this level. 
     Also, the max limit for each transverter band is now enforced on band change.

  * MIC AND LINE IN GAIN: Resolution improved; higher settings will be required as a result.

  * FM DEVIATION corrected (now 3 kHz). In DSP rev 1.69 it was set too high. 
     Eventually it will be adjustable.

  * AFX “BIN” mode no longer causes SSB TX distortion or CW RX distortion.

  * CONFIG:TXG VCE menu entry is now working. If your peak power in voice modes
     is too low compared to the PWR knob setting, use a higher TXG VCE value.
     However, if you have an amplifier connected, watch it’s meter for excessive
     voice peaks, and reduce the PWR setting accordingly. (Also see comments about
     SSB POWER CONTROL in previous firmware release.)

MCU 1.87 / DSP 1.69, 5-3-08

  This release includes improvements in all areas. Changes are categorized below.

  NEW FEATURES:

  * CW KEYING IN SSB MODES:  While in SSB modes, you can now send CW without
    changing modes or using an offset. The other station will hear the signal at your CW pitch.
    This is especially useful on VHF bands when SSB signals can’t be copied.
    To enable this feature, go into CONFIG:CW WGHT and tap ‘1’ until you see SSB +CW.

  * FM MODE ADDED: Requires FM filter installed in slot FL1. The bandwidth for FL1
    must be set to 13.0 kHz. FL1 must also be set to ON for FM mode. Those not needing 
    FM mode can set CONFIG:FM MODE to OFF. To set up a repeater offset: Use the
    CONFIG:RPT OFS menu entry, then hold ALT to select -/+/simplex (-/+ appear under
    the FM mode icon). To set up tone encode: hold PITCH, then rotate VFO B to select 
    PL TONE or PL OFF, and rotate VFO A to select the desired CTCSS tone. (When 
    PL TONE is on, a letter ‘T’ will appear near the FM mode icon.) Repeater offsets and
    PL tones are stored per-band/per-memory.

  * VARIABLE AMP KEYING DELAY: Added CONFIG:TX DLY menu entry, which
    sets the time from KEY OUT jack (active low) to first RF in 1-ms steps, from 8 to 20 ms. 
    To minimize loss of QSK speed, use the shortest delay that works with your amp.
    Most will work with the default (minimum) setting of 8 ms.
  
  * LINE OUT ALLOWS RX/TX AUDIO RECORDING: Normally, CONFIG:LIN OUT sets a 
    fixed-level, receive-only output for main/sub (L/R), compatible with digital modes. Tapping 
    '1' switches LIN OUT to =PHONES, where the line outputs match headphone audio, 
    audio level controlled by AF/SUB gain controls, and both RX and TX audio available.

  * SIMULTANEOUS USE OF MIC AND LINE IN:  If the MAIN:MIC+LIN menu entry is set to 
    ON, and MIC SEL = FP or RP, the present mic OR line in can be used for transmit audio. 
    NOTE: Setting MIC SEL to LINE overrides the MIC+LIN menu entry (its parameter 
    becomes "N-A").  When MIC+LIN is in effect, rotating the MIC control shows MIC GAIN. 
    The op has to set MIC SEL to LINE temporarily to set LINE IN gain. 

  * S-METER ABSOLUTE MODE: Use the CONFIG:SMTR MD menu entry. Set to ABS 
    (absolute) to have S-meter stay constant with preamp/atten settings. Default is NOR (where
    PRE/ATTN affect the S-meter). ABS mode requires recalibration (SMTR OF & SMTR SC).

  RECEIVE:

  * SSB RECEIVE PASSBAND EXTENDED AT LOW END (now 100 Hz; was 200 Hz).

  * AM RECEIVE WIDTH RANGE INCREASED:  The WIDTH control in AM mode now has
    a range of 2.8 to 10.0 kHz. Wider settings provide outstanding fidelity for hi-fi speech 
    and other wide-band signals. This is the *IF* filter bandwidth -- the traditional way to show 
    bandwidth for AM, because the required IF bandwidth is twice the modulation bandwidth.
    NORM selects an IF bandwidth of 6.0 kHz in this mode. WIDTH settings above 6.0 kHz
    will not be useful unless you have an FM-bandwidth crystal filter installed (at FL1).

  * IF A 2.8 KHZ FILTER IS INSTALLED, SSB "NORM" BW is 2.8 kHz (was fixed at 2.7 kHz).

  * AUTO-SPOT (SPOT with CWT ON) now works with both very weak and very strong signals.

  * PSK AUTOTUNE ACCURACY improved. You may still need to use RIT (FINE steps) to 
    tune in signals for best built-in text decode. (Also see CW-to-DATA in the Owner’s Manual.)

  TRANSMIT:

  * TRANSVERTER POWER CONTROL: The value set in CONFIG:XVn PWR now correctly
    sets a fixed power level on the associated transverter band (0-1.50 mW or 0-12W). 

  * POWER ROLLBACK BASED ON REFLECTED POWER:  Power rollback begins at about 
    2.5:1 at 100 W (and of course much higher SWRs are tolerated at lower power settings).
    Recovers to original target power level after mismatch is corrected.

  * CW QSK further refined, with smoother mute/unmute in the presence of QRN and QRM.

  * SSB TRANSMIT BANDPASS EXTENDED AT LOW END. Improvement is about 2 dB 
    at 300 Hz, 3 dB at 200 Hz, and 6 dB at 100 Hz. Additional improvement possible via TX EQ.

  * SSB TX POWER CONTROL improved. Set ALC for about 5 bars (rarely 6+) using MIC gain
    control, then set CMP and POWER as desired. The RF power bargraph shows approx.
    peak power when you whistle or shout, but will typically show well below peak power
    during normal speech. If you’re using an external peak-reading wattmeter or power 
    amplifier, adjust POWER as required while observing the effect of speech peaks.
    If you find that an SSB power setting higher or lower than for CW is often required,
    you may wish to compensate for this using the CONFIG:TXG VCE menu entry.

    Technical Note: Our latest MCU and DSP code uses minimal amounts of ALC, consistent 
    with analysis done by Leif Asbrink, SM5BSZ. (His findings and recommendations can be 
    found on his web site, www.nitehawk.com/sm5bsz.) The general idea is to keep 
    transmit drive just below where ALC can cause splatter on speech peaks, rather than 
    apply ALC heavily to achieve additional compression.

  CONTROLS:

  * A->B SWITCH: 1st tap copies frequency only; 2nd tap within 2 seconds copies mode 
    and filter settings.

  * VFO LOCK is no longer cancelled by VFO tuning controls (RATE, FINE, or COARSE).

  * TUNING EITHER VFO ACROSS MULTIPLE BANDS now brings the other VFO along 
    with it, so that both VFOs will always be on the same band. This eliminates the problem
    of bands getting out of sequence due to wide tuning excursions. (Later, we’ll allow the 
    subreceiver to be on a different band from main if CONFIG:VFO IND is enabled.)

MCU 1.78, 3-18-09

  * SPOT now usable in REF CAL menu entry.

MCU 1.77 / DSP 1.58, 3-12-08

  * SSB TX power overshoot corrected.
  * DUAL-PASSBAND CW now working correctly (was acting like a single-BW 150-Hz filter).
  
MCU 1.76 / DSP 1.58, 3-11-08

  * TX power output spikes eliminated (may still get slight overrange with high CMP 
    settings -- a fraction of a dB).
  * "Dead RX" on band change, etc., fixed (hopefully).
  * DUAL PB CW working (had been lost a few revisions back due to unrelated DSP change).
  * SQUELCH control added (SUB RF/SQL knob). Applies to both receivers.
  * RX/TX EQ bin 6 now labeled 1.6 kHz per spec (was incorrectly labeled 1.2 kHz).
  * MIC BIAS factory default is OFF.
     		
MCU 1.75 / DSP 1.57, 3-4-08

  * SSB TRANSMIT Improvements: 

    This is the first phase of our effort to make SSB transmit setup and use more consistent
    with operator expectaions. Changes so far include:

        - Higher signal-to-noise radio at both mic jacks, as well as LINE IN
        - Livelier and easier to use transmit-mode metering (CMP, ALC, SWR, POWER)
        - Better optimized TX EQ menu function
        - More effective compression (CMP)
        - Greatly reduced distortion with CMP set to 0 (for audio data modes, high-fidelity
          speech, and two-tone testing with an external audio generator)

    (Planned for next release:  Improved low-frequency response and adjustable TX passband.)
    
    Note on MIC gain setup:  To properly adjust MIC gain, first set CMP to 0, then adjust
    MIC gain for about 5 bars on the ALC meter (it should not hit 6 bars during normal speech).
    Then set CMP for the desired compression amount.

  * 2 USER-DEFINED "NORM" filter setups for each mode: 

    Now, in addition to the K3's "NORM" values, you can save two of your own often-used filter
    setups in each mode, and recall them using the NORM function. The new NORM values
    are named ALT1 and ALT2. To save a filter setup, hold NORM until you see "<- SAV ->"
    (3 seconds), then rotate the knob left or right to save it as ALT1 or ALT2. (The arrows to the
    left and right of "SAV" are a reminder that you can rotate the knob left or right go get to the
    "ALTernate" filter memories.) To recall, hold NORM until you see "<- NOR ->" (about 
    1/2 second), then rotate the knob left or right to recall ALT1 or ALT2. Note: Whenever
    you normalize the filter passband via NORM, ALT1, or ALT2, two "wings" appear on the 
    DSP filter passband graphic. Moving any DSP control makes the wings disappear, as a 
    reminder that the passband is no longer normlized.

  * DUAL PASSBAND Bandwidth Restore: On exit from DUAL PB, the previous CW bandwidth 
    is restored.

MCU 1.73 / DSP 1.56, 3-1-08

  * BETTER MIC JACK S/N RATIO:  This is the first of several changes intended to
    improve voice transmit performance. (Other changes are still in the works.) This change
    increases the gain ahead of the transmit A/D converter, which should result in lower 
    quantization noise, especially with mics that have low output. Still experimental.
                              
  * SPEAKER "popping" eliminated when using headphones and certain combinations of
    features (such as NR).  
 
  * VFO LINKING: Holding the "SUB" switch links/unlinks the two VFOs. When linked,
    VFO A is the master; turning it moves both VFOs the same amount. VFO B can be 
    set to the same frequency by tapping A>B, or it can be offset a fixed amount from VFO A.
    Setting them to the same frequency will permit diversity receive with the subreceiver.

  * LOCUT/HICUT CONTROL RANGE: DSP controls are better behaved, preventing 
    "wrap-around" and other reported anomalies.

  * Tapping A>B in SPLIT mode now updates the filter settings correctly.

MCU 1.70, 2-20-08

  * [#94] ATU MATCHING IMPROVED: If operator taps ATU TUNE a second time on the same 
    band/antenna within 5 seconds, a more extensive search is used. Dramatically improved 
    performance in tests with some high-Q (narrow-band) loads. Original (fast) algorithm 
    is unchanged. 

  * [#243] RIT/XIT OFFSET DISPLAY MODE ADDED (right after date, before voltage). This is 
    especially useful with CW-to-PSK31, where the operator may be quite conscious of the 
    required RIT offset, or for those using RIT during contesting.

  * [#322] RTTY CWT INDICATOR UNSTUCK (was getting stuck when PITCH was accessed).

  * [#275] Tapping XMIT during CW message playback both stops the message *and* exits 
    transmit mode.

  * [#199] SSB filter BW steps now 100 Hz up to 3 kHz, then 200 Hz.

  * [#292] NON-VOX CW no longer has any delay after transmit termination (i.e., release of 
    PTT or exit from XMIT).

  * [#236] Switching of antennas during tune is not allowed (this was fixed some time ago).

  * [#285] Tapping transmit-related multifunction encoders briefly displays the present parameter 
    value (SPEED/MIC/CMP/PWR). Double-tap to display the existing parameter (since this
    switches first to the alternate, then back).

  * [#305] Tapping filter-related multifunction function encoders briefly displays the present
    parameter value (SHIFT/LOCUT/HICUT/WIDTH). Double-tap to display the existing parameter.

  * TRANSMIT BLOCKED from 7.500 to 8.999 MHz (to prevent possible damage to the 
    KAT3/KANT3 traps). This range is blocked even if the customer has unblocked transmit using
    our software "MARS enable" utility. It is only usable in milliwatt-power mode (KXV3).

MCU 1.69, 2-18-08

  * Fixed problem with CW transmit via the KEY jack, where short-duration noise pulses
    or very fast CW could result an incorrect synthesizer frequency on return to receive.

MCU 1.68/DSP 1.53/DTBL0008, 1-30-08

  * CW-to-PSK transmit added. It works, but now that QSOs are possible in this mode, 
    we need to look into the +10 to +16 Hz receive offset reported by users.  
  * "UP" and "DN" remote control commands now work for parameter setup, such as NB, 
    TEXT DEC, DATA MD, NR ADJ, etc. Adding 'B' (e.g., "UPB;", "DNB;") controls the 
    VFO B parameter; otherwise, the VFO A parameter is controlled. 
  * DATA MODE selection is now stored per-band, per-memory.
  * MIC Source is now independent for voice/data modes. See micCtrlVoice, micCtrlData.
  * Milliwatt power display now correctly shows "-9.0" dB between -8 and -10.
  * Synthesizer control improvements (eliminated some ERR VCO cases during VCO CAL,
    as well as 30-m transmit problems).
            
MCU 1.66, 1-29-08

  * CORRECTED ATU TUNE PROBLEM: In version 1.65, tapping ATU TUN would use the value
    set in the new TUN PWR menu entry, and afterward set the power knob to the TUN PWR value.
    The ATU TUNE power level is supposed to be fixed (5W and 10W, automatically controlled).
    It should not be affected by either the TUN PWR menu entry or the power knob.

MCU 1.65 and DSP 1.52, 1-28-08

  * TUNE POWER level menu entry (TUN PWR). This determines the power level used 
    when the TUNE switch is pressed. The default, "NOR", uses the power knob setting.
    Alternatively, the value can be set to any power level from 0.1-120 W.

  * REAL-TIME-CLOCK display now keeps accurate time. The RTC IC itself was running
    accurately, but the VFO B time display was running about 9% slow.

  * MODE SWITCH now only cycles thorugh one sideband (LSB or USB) on each band -- 
    not both. Saves time when switching modes, especially useful in contest situations.
    Use the ALT switch (hold the left end of MODE) to switch between LSB and USB (per-band).
    NOTE: As a result of this change, you may need to re-select the desired sideband on 
    some bands. You'll only have to do this once.

  * S-METER ACCURACY Improved. Suggest using SMTR SC=14 and SMTR OF=24 
    (these are the normal defaults).

  * EXTERNAL CW TIMING IMPROVED: Corrected rise/fall time assymmetry. Internal
    and external keyers should now be closely matched in weighting.
    NOTE: You may need to reduce the weight of external keying, if you had increased
    it to compensate.

  * AMTOR RX/TX turnaround times improved. To do this, we've created a variation of
    SSB and DATA modes called SYNC DATA. It should only be used with modes like
    AMTOR that require the fastest possible turnaround time. To turn on SYNC DATA, first
    locate the SYNC DT menu entry (SYNC DATA), and assign it to any programmable
    function switch (PF1, PF2, M1 tap or hold, M2 tap or hold, etc.). Then use this 
    programmable switch to enable SYNC DATA. The -S mode icon appears. This setup
    can be enabled separately for SSB or DATA modes. (The actual turnaround times will
    vary with crystal filter selection. Further improvements may be possible and are being
    explored.)