[Elecraft] K3 MCU 4.17 (APF beta) kills SSB output?

[Don Wilhelm]

  Phillippe,

You state the mic gain setting and the compression, but for the K3, the 
most important setting is to obtain 5 to 7 bars on the ALC meter with 
the compression turned to zero.  If that is not done as the first step, 
then the K3 cannot properly control its power output.

After setting the mic gain level for those 5 to 7 bars, then increase 
the compression to whatever you want.  You may want to recheck to be 
sure your mic gain is set correctly (even though an SSB bug apparently 
came along with 4.17.  BTW, thank you for trying the beta firmware - it 
is good to give Elecraft feedback on problems like this one.

While I am not saying this is your problem, we need frequent reminders 
of this initial requirement because many instructions for amplifiers and 
for digital interface boxes (use 4 to 5 bars for digital) will lead you 
to believe that you should control power output with the mic gain 
setting.  While that is true for many transceivers, it is not good 
advice for the K3.

 From the many posts on the reflector, there was a problem for SSB power 
output (bug) that happened in MCU 4.17, and Wayne has said he is working 
on it.

73,
Don W3FPR

On 11/5/2010 1:45 PM, Philippe Trottet wrote:
> After many tries, on Dummy load first then with distant Ham friends, conclusion was to re-installed MCU 4.14.
> Instead of giving the same dynamic with the MH2 microphone, with my Amp on, using 12w drive, using Mic=2 COMP=20, pronouncing the number 6 slowly, I have seen immediately the difference.
> For me, using a Amp w/GU84B tetrode, 12w drive on ssb give 500~600w on normal voice operation.
> With MCU 4.17 it gave only 300~400w and the power increase with difficulty on a single whistle to 500w. and when I pushed to maxi drive 65~70w I was unable to achieve the normal 64dBm+ of the Amp with normal voice.
> Normal cw tune procedure seems not affected and I can achieve the maxi as normal.
>
> The most important:
> It has been reported to me during the test on the air, some alteration of the modulation, like a RFI ground phenomena on the microphone or like a under voltage problem during transmitting.
> I've checked all connections from A to Z and no problem founded. re-load 4.17, installed it 2 times, with no changes.
> When re-installing the MCU 4.14 everything is back to normal with the very clear voice provided by the K3.
> Sure Wayne will share with us what's happened, .APF is a so great add-up in weak signal environment !
> Bst 73's
> Philippe A65BI
>