[Elecraft] K3: Output power on PSK31 and AFSK

[Don Wilhelm]

Jerry,

I am confused about your saying "before ALC kicks in", and it makes me 
wonder if you are using enough audio gain.

The latest recommendation from Lyle is to increase the line-in gain (or 
the soundcard gain) until you have 4 to 5 bars indicated on the 'ALC' 
bargraph.  At that level, Lyle assures us that we are not driving the K3 
into ALC compression and that is the designed operating point for the 
K3. See below.

If you do not adjust the gain to give 4 to 5 bars of indication on the 
"ALC" bargraph, you will not have full power output.  But please, use 
the lowest power to maintain your QSO on PSK31 - other operators will 
appreciate it because you will not be wiping out their QSO on a nearby 
frequency.

73,
Don W3FPR

If I may quote part of his reflector post dated 4/06/2008:
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In this case, the ALC meter display is acting as a "VU Meter" and is 
being used to help you set the Tx audio path gain correctly.  It is not 
showing you how much you are over-driving the PA.  This is why you can 
set it up in Tx test mode, when you are not transmitting any RF at all.

If you have a little too much drive, the DSP will scale things back at 
the output of the mic amp.  Thus at the 5th ALC bar, the DSP is at the 
threshold of gain compression.  At the 6th bar, it is cutting back gain 
by 6 dB or so.
--------------------------------------------------------------------

Jerry T. Dowell wrote:
> I am running beta 2.63/1.95 firmware. Although power output is normal in CW,
> USB and LSB modes (setting SSB to operate with several bars of ALC), I can
> only get about 10-20W out on PSK31 and 50-60W out on AFSK before ALC kicks
> in. This is the case whether I use LINE IN or FP/RP MIC connections for the
> input. It seems to me that I was able to comfortably get at least 50W out in
> these modes when I first tried them several months ago, although I am not
> sure of that. The low power also occurs if I use USB instead of DATA A for
> the digital signals.
>
> Has anyone else run into this problem? Am I forgetting something?
>
> Jerry  AI6L
>   
>