[Elecraft] Power too high in PSK31 / SSB

[Joe Subich, W4TV]

> I am seeing is the power not being limited to what the power 
> control has set. For example, set 5W, key down in CW mode, 5W 
> is transmitted. Switch to data mode, send a pure tone, 12W is 
> transmitted. Something is wrong with the way the power 
> control is working.

Have you set a value for CONFIG:TXG VCE because you voice peaks 
were not coming up to the CW level?  Adding a dB or two there 
will cause PSK peak powers to run higher than the CW value. 
 
> In reply to Rob, if I reduce the audio input level so that no 
> ALC bars are shown, I can get the output power on a pure tone 
> to follow what is set on the power control.

Running "no bars" of ALC in PSK/AFSK causes the microphone gain 
to be increased to compensate for the insufficient drive.  This 
will result in added distortion (noise and IMD).  

73, 

   ... Joe, W4TV 
 




> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net 
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Julian, G4ILO
> Sent: Saturday, October 04, 2008 5:47 AM
> To: elecraft at mailman.qth.net
> Subject: RE: [Elecraft] Power too high in PSK31 / SSB
> 
> 
> 
> 
> 
> Rob May-2 wrote:
> > 
> > I worked some PSK today at 20 watts and it seems to be 
> fine.  Just a 
> > couple of bars on the RF meter when I have the power dialed to 20 
> > watts. I running the latest beta (2.45) but I didn't have 
> any problem 
> > with 2.38. No compression, mic gain turned down so that the 
> ALC just 
> > barely makes one bar.
> > 
> In reply to someone who responded off-list, I am aware that 
> the power when a pure tone is sent will be about twice the 
> power shown when the transmitter is modulated. However, what 
> I am seeing is the power not being limited to what the power 
> control has set. For example, set 5W, key down in CW mode, 5W 
> is transmitted. Switch to data mode, send a pure tone, 12W is 
> transmitted. Something is wrong with the way the power 
> control is working.
> 
> In reply to Rob, if I reduce the audio input level so that no 
> ALC bars are shown, I can get the output power on a pure tone 
> to follow what is set on the power control. However, this is 
> not how we have been told the K3 should be set up, and it was 
> not necessary to do this with previous versions of the 
> firmware. Lyle stated in a post some months ago, that the ALC 
> meter in data mode does not actually measure ALC, but signal 
> level, and should be adjusted to a steady 4 or 5 bars to 
> ensure adequate drive.
> 
> I will try the most recent release of the firmware to see if 
> it makes a difference.
> 
> -----
> Julian, G4ILO. K2 #392  K3 #222.
> http://www.g4ilo.com/ G4ILO's Shack   
> http://www.ham-directory.com/ Ham
> Directory    http://www.g4ilo.com/kcomm.html KComm for 
> Elecraft K2 and K3 
> -- 
> View this message in context: 
> http://n2.nabble.com/-K3--Power-too-high-in-PSK31---SSB-tp1143
050p1143674.html
Sent from the Elecraft mailing list archive at Nabble.com.

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