ftp://ftp.elecraft.com/KX3/firmware/beta/kx3fw1r61.zip AM TRANSMIT IMPROVED: Depth of modulation increased.
SSB SPEECH COMPRESSION IMPROVED: Significant cleanup of opposite-sideband intermodulation (IMD) products with speech compression turned on.
CURRENT DRAIN LIMITS ADJUSTED: Receive and transmit current drain limits were set a bit too low, occasionally causing an unexpected roll-back of power output or turn-off of the KX3. Note: If rollback of power output still occurs, it is probably because the supply voltage is dipping below 11 V on keydown, or because of excessive transmit current drain, possibly due to a low-impedance load.
ESSB MODE IMPROVED: Speech compression is now automatically disabled when ESSB mode is turned on. This completes the ESSB implementation. To turn on ESSB, use the TX ESSB menu entry. Tap ‘1’ to turn ESSB on/off; use VFO A to adjust the transmit bandwidth from 3.0 to 4.0 kHz. (These menu changes cannot be made while in transmit mode.)
KXPA100/KXAT100 SUPPORT: (1) Tapping ATU TUNE tunes the KXAT100 if applicable. KX3 power output is set to 5.0 watts during auto-tuning, then restored to the user’s selected level. (2) KXPA100 amp/tuner faults are displayed on the KX3 and can be cleared by any switch tap. (3) The FW REVS menu entry shows the KXPA100 firmware revision (rotate VFO A to see all firmware revisions – uC, DSP, PA). Note: All KXPA100 integration features require use of the KX3-to-KXPA100 control cable, and the PA.X MD menu entry must be set to ON.
ROOFING FILTER USE CONFIGURABLE IN SSB MODE: Roofing filter FL2 (3 kHz) can now be inserted when the upper edge of the receive passband is either 2.4 kHz (original value) or 2.9 kHz. When the passband edge is higher than this point, FL1 is used (wide filter). If the KXFL3 filter option is not installed, FL1 is always used.
If you frequently encounter QRM in SSB modes, use the 2.9 kHz selection; this will insert FL2 when normal passband settings are used. If QRM is less of an issue or you frequently use ESSB, use the 2.4 kHz selection (original value); this will insert FL1 for normal passband settings. The PBT knob can override either selection (see below).
To select the desired FL2 insertion point: Locate the PBT SSB menu entry. Tap ‘1’ to select either 2.4 or 2.9 kHz using the criteria above.
Impact of FL2 configuration on the NORM function: If 2.4 kHz is selected, NORMalizing the passband (by holding the PBT knob) will select FL1 (wide filter). If 2.9 kHz is selected, NORM selects FL2 (narrow). Impact of FL2 configuration on the PBT I/II functions: When LO-HI CUT is in effect for SSB, the FL2 setting determines when FL2 is inserted as HI CUT (PBT II) is adjusted (2.4 or 2.9 kHz). When WIDTH / SHIFT (NOR) is in effect, the FL2 setting affects both adjustments. For example, with the passband NORMalized, reducing WIDTH (PBT I) inserts FL2 at either 1.7 kHz or 2.8 kHz, for the 2.4 and 2.9 kHz FL2-insert selections, respectively. However, the insertion point for FL2 is also affected by the SHIFT setting (PBT II).
Note on SSB demodulation methods used for FL1 vs. FL2: When FL1 is in selected (wide filter), the KX3 uses conventional SSB demodulation, providing the best overall audio fidelity. When FL2 is selected (3 kHz filter), the KX3 uses “Weaver” SSB demodulation, which introduces a narrow 1.5 kHz notch into the receive passband as part of the DSP algorithm. This notch typically has no impact on speech intelligibility, but it can sound slightly different to an operator who is most concerned about fidelity.
12-kHz AUDIO SPUR ELIMINATED: Some operators reported hearing a very weak 12-kHz tone at the headphone jack, even with the volume turned all the way down. This tone has now been suppressed by an additional 20 dB (approx.).
“WEAVER MODE” SSB RECEIVE IMPROVED: When the high end of the KX3’s SSB receive passband is set below about 2.4 kHz using the PBT control, the DSP switches to “Weaver” demodulation mode. This allows roofing filter FL2 to be used. In previous releases, Weaver demodulation had poor opposite-sideband image rejection; this has been corrected.
Note: It is
not necessary to re-do RXSBNUL calibration.
ATU IMPROVEMENTS: Tapping ATU TUNE now recalls stored LC settings for the current VFO frequency prior to tuning, avoiding auto-tuning from scratch in most cases. Also, ATU settings are now reloaded (if necessary) when the A/B, A>B, REV, FREQ ENT, or SPLIT switches are used. This increases the likelihood that the ATU will be kept tuned during receive, improving sensitivity, without having to transmit first. Previously, only XMIT, TUNE and band changes would force an ATU settings reload.
Note: If you switch to a different antenna, such as when taking the KX3 into the field, you may want to clear old ATU LC settings for one or more bands prior to doing new auto-tunes. To do this, locate the ATU MD menu entry, then hold CLR (hold function of the OFS/B knob). You can change bands from within this menu entry using BAND +/-.
CW-IN-SSB TRANSMIT ADDED: This feature allows you to send CW while in SSB mode, which can be useful when your SSB signal cannot be copied due to poor conditions. The other station will hear a tone at your CW pitch.
To enable CW-in-SSB: Locate the CW WGHT menu entry, then tap ‘1’ (PRE) to alternate between “SSW +CW” (enabled) and “SSB –CW” (disabled). The default is disabled.
Important Notes: (1) CW-in-SSB does not yet apply in SPLIT mode. (2) When CW-in-SSB is enabled, tapping the KEYER/MIC knob toggles between
keyer speed and
mic gain rather than between the two transmit metering scales (CMP/ALC and SWR/RF). The CMP/ALC scale is still shown temporarily whenever CMP or mic gain are adjusted.
1-HZ TUNING PRESERVED AFTER APF-OFF: If you were using 1-Hz tuning prior to turning on APF (CW audio peaking filter), 1-Hz tuning will be restored when APF is turned off. Prior to this change, exiting APF would set the tuning rate to 10 Hz.
