KPA 500: Does yours need time to warm up?

[tomb18]

I noticed that my KPA500 does not always give the full power that it is set for.  For example, if I turn it on,put it in operate and then transmit my call sign (in a pile up), the first few transmits are lower in power (around 50-100 watts) and it takes 7 or 8 of these before the power gets to 500W.
If I then continue for a while searching for another station, the same thing can occur.

Has anyone seen the same thing?
Thanks, Tom VA2FSQ

[Tony Estep]

On Sun, Nov 6, 2011 at 8:20 AM, tomb18 <[hidden email]> wrote:

> ....the first few transmits are lower in power...

============
Tom, I believe that someone mentioned in an earlier thread that symptoms
like this can be cured by doing the TX Gain calibration with the K3 utility
program.

Tony KT0NY

--
http://www.isb.edu/faculty/facultydir.aspx?ddlFaculty=352
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[Don Wilhelm-4]

Tom,

I believe the source of that situation is in the K3.  Run the TX gain
calibration to see if that helps.
There will always be some remnant of that behavior because of the way
the K3 controls power output, but the time for it to come up to full
power should be relatively short - a few seconds at most.

73,
Don W3FPR

On 11/6/2011 9:20 AM, tomb18 wrote:

> I noticed that my KPA500 does not always give the full power that it is set
> for.  For example, if I turn it on,put it in operate and then transmit my
> call sign (in a pile up), the first few transmits are lower in power (around
> 50-100 watts) and it takes 7 or 8 of these before the power gets to 500W.
> If I then continue for a while searching for another station, the same thing
> can occur.
>
> Has anyone seen the same thing?
> Thanks, Tom VA2FSQ
>
>
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/KPA-500-Does-yours-need-time-to-warm-up-tp6967951p6967951.html
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[k6dgw]

Hmmm ... mine is set on peak-hold 500W, and on the first dit on a new
band, it usually lights the first yellow LED.  After that, it just goes
to 500.

Fred K6DGW
TDY Sparks NV

On 11/6/2011 2:20 PM, tomb18 wrote:
> I noticed that my KPA500 does not always give the full power that it is set
> for.  For example, if I turn it on,put it in operate and then transmit my
> call sign (in a pile up), the first few transmits are lower in power (around
> 50-100 watts) and it takes 7 or 8 of these before the power gets to 500W.
> If I then continue for a while searching for another station, the same thing
> can occur.
>
>

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[tomb18]

Thanks for the info.  I will try the tx gain calibration.

[tomb18]

Well I did the TX gain calibration.  Any other ideas?  It can take 10-15 seconds to get the full power out.  I thought solid state amps were immediate?

[Don Wilhelm-4]

Do you have the mic gain set so it provides 5 to 7 bars on the ALC
meter?  If not, you are not driving the audio hard enough and the "power
creep" you are experiencing is normal for that situation - with low
audio, the K3 will "power hunt" to try to bring the power output up to
whatever was requested.

73,
Don W3FPR

On 11/20/2011 8:40 PM, tomb18 wrote:
> Well I did the TX gain calibration.  Any other ideas?  It can take 10-15
> seconds to get the full power out.  I thought solid state amps were
> immediate?
>
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[tomb18]

Hi,
I check that tonight.

[tomb18]

Well after a couple of days of making sure the ALC is 5-7 bars, I still have significant power creep especially on 12 meters.
I can take several CQ sequences before the power gets to the rated value.
Are there any other ideas?

[WE5ST]

Was there a satisfactory answer given for this issue? I don't notice the problem of limited power on 10-20 meters but on 40 it shows up. Several "kick starts" are required to see full power then it's smooth sailing.
I see adequate ALC and am driving the amp with ~25 watts from my K3. Kicking up K3 output or mic gain doesn't seem to matter in the first few transmissions.

'

tomb18 wrote

......, if I turn it on,put it in operate and then transmit my call sign (in a pile up), the first few transmits are lower in power (around 50-100 watts) and it takes 7 or 8 of these before the power gets to 500W.
If I then continue for a while searching for another station, the same thing can occur.

Has anyone seen the same thing?
Thanks, Tom VA2FSQ

Thanks!
Jack - WE5ST

[k6dgw]

I don't recall seeing an answer go by.  I don't observe this anomaly,
however I'm pretty much a CW operator.  I do notice that, if I've had
the power set to just light up the 500W LED and then turn the entire rig
off, when I turn it back on, the 550W LED will light up when I first
touch the paddle.  Before I get more than a letter or two out, it's back
to 500W.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2012 Cal QSO Party 6-7 Oct 2012
- www.cqp.org

On 6/5/2012 2:00 PM, WE5ST wrote:

> Was there a satisfactory answer given for this issue? I don't notice the
> problem of limited power on 10-20 meters but on 40 it shows up. Several
> "kick starts" are required to see full power then it's smooth sailing.
> I see adequate ALC and am driving the amp with ~25 watts from my K3. Kicking
> up K3 output or mic gain doesn't seem to matter in the first few
> transmissions.
>
> '
> tomb18 wrote
>>
>> ......, if I turn it on,put it in operate and then transmit my call sign
>> (in a pile up), the first few transmits are lower in power (around 50-100
>> watts) and it takes 7 or 8 of these before the power gets to 500W.
>> If I then continue for a while searching for another station, the same
>> thing can occur.
>>
>> Has anyone seen the same thing?
>> Thanks, Tom VA2FSQ
>>
>
>
> Thanks!
> Jack - WE5ST
>
> -----
> Jack - WE5ST
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[Mike K2MK]

Hi Fred,

The situation you are describing (first touch of the paddle) is an indicator that the K3 TX Gain might need to be touched up on one or more bands. Do the calibration from the K3 Utility and if that doesn't do the trick look at the fine tune instructions on the top of page 62 in the K3 manual in the CONFIG:TXGN area.

73,
Mike K2MK

k6dgw wrote

I don't recall seeing an answer go by.  I don't observe this anomaly,
however I'm pretty much a CW operator.  I do notice that, if I've had
the power set to just light up the 500W LED and then turn the entire rig
off, when I turn it back on, the 550W LED will light up when I first
touch the paddle.  Before I get more than a letter or two out, it's back
to 500W.

73,

Fred K6DGW

[WE5ST]

As Mike suggested in his response, the transmit calibration did the trick for me. The K3 Utility makes it super easy too.

Thanks for your help!

Jack - WE5ST