[Elecraft] KX3 Production Firmware (rev 1.10) -- Adds Noise Reduction (NR) and Autonotch

[Wayne Burdick]

KX3 production firmware rev 1.10 (with DSP rev 0.94) is now available.  
This release includes noise reduction (NR) and autonotch. NR  
parameters are fully adjustable per-mode (using the RX NR menu entry)  
to allow for experimentation, though the defaults are generally  
recommended. See full release notes below. This update is appropriate  
for all KX3 owners.

You'll need our KX3 Utility application to download and install  
firmware. For full instructions, refer to our KX3 software page:

    http://www.elecraft.com/KX3/KX3_software.htm

Thanks,
Wayne
N6KR

* * *

MCU 1.10 / DSP 0.94, 7-11-2012

* AUTO-NOTCH (AN) ADDED:  Auto-notch can be used to automatically  
reject interfering constant carriers in SSB and AM modes. (In all  
other modes, manual notch is available.) To turn auto-notch on/off,  
hold the NTCH switch. Note: Auto-notch is not available when AGC is  
turned off.

* NOISE REDUCTION (NR) ADDED:  Receive noise reduction reduces the  
amplitude of random noise while preserving desired signals. (RX NR is  
different from the VFO NR menu setting, which can be used to reduce  
VFO tuning noise on the higher bands.) NR works in CW, SSB, and AM  
modes. NR has a characteristic “hollow” sound. To turn NR on/off, hold  
the NR switch. Also see RX NR x menu entry, below. Note: NR is not  
available when AGC is turned off.

* RX NR x MENU ENTRY ADDED: Allows the user to customize receive noise  
reduction (NR). The letter appearing at ‘x’ in the menu entry name  
shows which parameter is being adjusted: "Beta" (B; tap ‘1’),  
"Decay" (D; tap ‘2’), or wet/dry "Mix" (M; tap ‘3’). The defaults are  
recommended, and this menu entry is locked to prevent accidental  
changes. The NR settings for CW are separate from those for voice modes.

Using the RX NR menu entry:  Unlock the parameter by holding KHZ for  
about 3 seconds; the VFO A lock icon will disappear. Then tap ‘1’,  
‘2’, or ‘3’ to select a parameter to change. You can turn NR on/off  
while in the menu to test its effectiveness.

The default beta is 5 for CW and 10 for voice modes. A lower beta will  
further reduce noise, but may attenuate weak signals. The default  
decay is 240. A much lower decay value will allow NR to track fading  
signals better, at the expense of somewhat worse noise rejection. The  
mix value determines how much of the signal is “dry” (unprocessed) vs.  
“wet” (processed). The default is 220 in CW mode and 250 in voice  
modes (this is essentially “all wet”). You might want to use a lower  
mix number to reduce the hollow sound or to minimize the effect of NR  
on weak signals.

* KXBC3 BATTERY CHARGER/RTC SUPPORT (BAT CHG MENU ENTRY): To use this  
menu entry, you must have a KXBC3 module and a set of internal  
batteries installed. ONLY NiMH BATTERIES CAN BE CHARGED. Other battery  
types can be installed to use the real-time clock and power the radio,  
but attempting to charge them could damage your KX3, cause a fire or  
acid leak, or other hazard. This will also void your warranty. Refer  
to the KXBC3 instruction manual for further details.