K3 Power problems

[PD2R]

Hello,

 

I'm having problems with my power out put. I have followed the calibration procedure and the K3 more or less puts out the desired power on all bands. (I'm not sure how accurate my PWR meter is)
The problem occurs in SSB when I'm using a microphone (Heil pro set plus or a Kenwood MC-43S, that doesn't matter). When I have set the power to 100W and I yell "Oooolaaa" (into a dummy load off course) into the mic, the PA puts out full power en after a couple off seconds it drops to the set power.
When I do the same with the power set 50 W, it produces around 70 W and again, after a few seconds the power drops to 50 W.

 

After the initial power drop it pretty much stays at the pre set power but when I rotate the PWR knob and set the power to a different level, the same thing happens again.

 

This only happens when using microphones. When using the TUNE button this doesn't happen.

 

What is wrong?

 

73, Maarten

PD2R

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[Julian, G4ILO]

Maarten van Rossum wrote

Hello,

I'm having problems with my power out put. I have followed the calibration
procedure and the K3 more or less puts out the desired power on all bands.
(I'm not sure how accurate my PWR meter is)
The problem occurs in SSB when I'm using a microphone (Heil pro set plus or
a Kenwood MC-43S, that doesn't matter). When I have set the power to 100W
and I yell "Oooolaaa" (into a dummy load off course) into the mic, the PA
puts out full power en after a couple off seconds it drops to the set power.
When I do the same with the power set 50 W, it produces around 70 W and
again, after a few seconds the power drops to 50 W.

After the initial power drop it pretty much stays at the pre set power but
when I rotate the PWR knob and set the power to a different level, the same
thing happens again.

This only happens when using microphones. When using the TUNE button this
doesn't happen.

What is wrong?

I don't know, Maarten, but I think there is something fundamentally wrong with the K3 ALC at the moment. I don't use SSB much and don't have a peak reading meter. Like you on TUNE and in CW I get exactly the requested power, but when I feed audio in to operate data modes I don't get the power I requested. The difference in my case is that I get almost twice the requested power, and it never backs down to the requested power so I have to use the audio drive level to regulate the output, which is not very convenient. In SSB I cannot be confident that when I select 100W the peak output is really being limited to that power.

I have re-done the power calibration and I have the TX Gain setting at zero. I cannot see any reason why the radio should produce more power than that selected with the power control. This was not a problem with earlier firmware releases. It has reached the point that I am losing confidence in the whole concept of software defined radios. Working with computers, I have probably wasted many days of my life on problems that were caused by bugs, and now it seems there is no escape from them in my hobby either.

[KK7P]

Hello Maarten!

> The problem occurs in SSB when I'm using a microphone (Heil pro set plus
> or a Kenwood MC-43S, that doesn't matter). When I have set the power to
> 100W and I yell "Oooolaaa" (into a dummy load off course) into the mic,
> the PA puts out full power en after a couple off seconds it drops to the
> set power...

If this is happening consistently, please go to CONFIG:TX VCE and change
the setting from 0.0 to something less, perhaps -1.5 or so, and try
again.  I think you'll find a setting that works well with your
particular voice, Tx EQ amd CMP settings.

73,

Lyle KK7P
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[PD2R]

Thank you all for the great response.

 

I think I got the problem solved by setting the TXO VCE to -3 dB. I still has a slightly higher power out put in the first couple of seconds when transmitting for the first time after setting the power level.

For instance, when I set the power to 100 W. it first puts out 110 W and after a couple of seconds it will remain at approximately 100 W.

When te power level is set to 50 W, the first couple of seconds the meter tells me it puts out 60 W and then it drops to 50 W.

It slightly varies on other bands. To me that sounds acceptabel.

 

On the other hand, what is the down side of having to set te TXO VCE to -3 dB (that is the minimum)?

 

If I use the TUNE button, it will put out 100 W, now problem. It only happens on SSB when using a microphone

 

The MIC GAIN and the COMPRESSION levels are set correctly, I get good audio reports so there is no reason to question that. I haven't used the TX EQ for now, I will experiment with that later.

 

I have also loaded the latest firmware, 2.46 if I´m not mistaken.

 

Thanks again for the great help!

 

73, Maarten

PD2R

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