[Elecraft] K3 Beta Firmware Rev. 3.66: AF output protection

[Wayne Burdick]

K3 beta-test firmware revision 3.66 (with DSP rev. 2.48) is now  
available.

AF Output Protection: The DSP now 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, protecting your ears (and transducers).

Normally, this will only happen if you turn off AGC while an extremely  
strong signal is present. If you hear the receiver mute under these  
circumstances, simply reduce gain by some means (back down RF GAIN,  
turn off the preamp, turn on the attenuator, or turn AGC ON).

Another possible source of excessive audio is a DSP numeric overrange.  
DSP code has been changed to eliminate such cases, and we've had over  
100 K3 users field-testing this new code with no reported AF  
anomalies. But the new AF output protection is always in effect, so it  
acts as a backup.

Please send any questions to k3support at elecraft.com. For instructions  
on how to load beta firmware, see:

      http://www.elecraft.com/K3/k3_software.htm

73,
Wayne
N6KR