[Elecraft] Measuring power output of an SSB transmitter

[Stewart Baker]

I have now repeated the test with my 2 tone external source, and 
get similar results to the microphone "Wurlo" test. The PEAK 
signal amplitude is influenced by the Compression (Clipping ?)....

Approaching the anniversary of the product release, it's 'bout 
time the SSB transmit side of the K3 was sorted out.
Brings back memories of the KSB2 saga !

73
Stewart G3RXQ
On Tue, 29 Apr 2008 03:46:46 -0700 (PDT), G4ILO wrote:
>
>
> Stewart G3RXQ wrote:
>
>> My PEAK  power is down by about 50% as measured on an 200MHz
>> oscilloscope when the COMP is set to 0. This can't be right..
>>
> I don't have your measuring equipment, Stewart, but something 
doesn't seem
> right to me either.
>
> The power output doesn't seem consistent even when you don't 
change the
> settings. With MIC=60 CMP=0 and PWR=12.0 if I "aaalo" into the 
mic, my
> average reading power meter normally shows about 1W. But 
sometimes it holds
> at 2W or even 3W and sometimes a bit less. I have also observed 
the meter
> steady at say 2W then after about a second drop back to 1W, even 
though I
> haven't changed the pitch or tone of my "aaaa...". I realize 
this is not a
> scientific test, but I don't believe that there is that much 
difference
> between my consecutive repetitions of "aaalo."
>
> I need CMP=20 to get a reasonable average level on speech. 
Without any
> compression the talk power is too low. Even my FT-817 with 5W 
pep output can
> manage an average of 1W on speech and it doesn't have a speech 
compressor.
>
> After doing these tests I connected the antenna again and the 
power meter on
> the MFJ tuner was showing a low reading. I put the PM20 back and 
sure
> enough, the power was low. No control on the radio was changed. 
I twiddled
> the power control down and then back up to 12.0 and full power 
was restored.
> Go figure.
>
> -----
> Julian, G4ILO  K3 s/n: 222 K2 s/n: 392
> G4ILO's Shack: www.g4ilo.com
> Zerobeat Ham Forums: www.zerobeat.net/smf