Elecraft KX3 firmware v0.78

MCU 00.78 / DSP 00.75

• MENU HELP-TEXT ACCESS CHANGE: To see the “help” information for a menu entry, do a 2-second hold​ of MENU. Tapping DISP or doing a regular hold of MENU now exits menu.
• 2-TONE GENERATOR WORKING. This is used for transmit IMD testing at the factory.
• DUAL-WATCH REMINDER: If you turn on DUAL RX while using the internal speaker, "USE PHONES JACK” is displayed on VFO B as a reminder that you must use either headphones or external speakers. (The SUB icon flashes when DUAL RX is in AUTO mode but is disabled either because the VFOs are out of range or because the internal speaker is in use.)
• NO TRANSMIT BELOW 1.7 MHz (for now).
• PSK-D TX IMPROVED: PSK-D is now generated in such a way that there is no opposite sideband signal.
• PSK-D/FSK-D PROSIGN TRANSMIT FIXED: When a prosign was sent in PSK-D/FSK-D mode using the keyer paddle, the actual on-air transmission was incorrect. “BT” was getting sent as “BB”, “SK” sent as “SS”, etc., always duplicating the first character.
• MAJOR CHANGE IN TRANSMIT CALIBRATION PROCEDURES: The TXSBNUL and TXCRNUL menu entries must now be set up per-band. This will be done at the factory for both kit and assembled units. Field-Test KX3s will need to be recalibrated, which requires a 160-6 meter receiver with a narrow crystal filter (or a spectrum analyzer such as the P3). Instructions will be provided in the revision XK owners manual.
• PC-BASED CALIBRATION IMPROVEMENTS (for Elecraft manufacturing engineers): (1) TXCRNULs 16-bit parameters can be accessed using the MQ host command (similar to MP, but 5 digits). (2) TXSBNUL and RXSBNUL parameters can be accessed using MP. (3) TXSBNUL and TXCRNUL now have an "parameter inheritance" feature during calibration. Start new-radio calibration at 160 meters. After each band is calibrated, send a BAND UP command within the menu entry (SWT19) to get to the next band. The new band inherits the settings of the previous band as a starting point for calibration. (4) BAND UP/DN is now possible from within all menu entries. The band in MHz is flashed on VFO A.

MCU 00.77, DSP 00.74, 3-6-2012

• DUAL WATCH added. In menu, set DUAL RX to AUTO. The SUB icon will come on. The VFO B control will be enabled (“B” LED). If dual watch is allowed, SUB will remain on. If dual watch is not allowed, SUB will flash slowly (you could set DUAL RX to OFF at this point if you dont need it). Here are the conditions required for DUAL R​X: CW, SSB, or DATA modes; PHONES jack in use (either with headphones or external speakers); VFO A and B separated by no more than 15 kHz.

IMPORTANT SUGGESTION REGARDING DUAL WATCH IN SPLIT PILEUPS: You can do this in two ways.

Either (1) listen to the DX station on VFO B and transmit on VFO A (i.e., non-SPLIT), or (2) listen to the DX station on VFO A and transmit on VFO B (i.e., SPLIT).

Non-SPLIT (1) makes more sense for callers, because youll be tuning your TX frequency (VFO A in this case), looking for a clear spot to call.

Its a lot easier to tune VFO Abigger knob, more encoder resolution.

SPLIT (2) makes more sense if YOU are the DX station.

• CW QSK IMPROVED. CW DLY switch settings as low as 0.04 now produce very good results. We have further work to do on this.
• HI CUT (PBT II) is default in SSB mode.
• SSB RX IMPROVED. Now uses conventional demodulation, with reduced in-band IMD, until you get to < 2.4 kHz HI-CUT. At that pointif the KXFL3 is installedwe switch to Weaver demodulation (slightly higher in-band IMD) and drop in FL2. (Weaver is what we had been using all along for SSB.) Reasoning: If the op reduces HI-CUT below 2.4 kHz, theyre more interested in QRM rejection than the ultimate in fidelity.
• ATU TUNE USES 2 W if Vbat < 9 V. (Normally uses 3 W.)
• BROADCAST BAND PRESELECTOR: We now make use of the ATU's broadcast-band preselector capability. Between 500 and 1300 kHz, youll hear some ATU relays switch as you tune the VFO (about every 20-50 kHz). The relay noise will be reduced in a future release, but some relay switching is unavoidable if the preselector LC settings are used.