[Elecraft] KPA500 power output starts out low, then goes up

[Barthold Lichtenbelt]

> I didn't see anything in this thread that suggested that the problem
wasn't observed on all bands. Maybe I missed it?

I see it on 20m, 40m, 80m, on two different antennas. Haven't tried any
other bands.

> Also haven't noticed anyone suggest using the K3's "TUNE" function,
instead of SSB modulation, as a test.

Excellent idea! It does NOT happen when I use the TUNE function. Not with
the KPA500 in standby nor in operation. Tried 20m and 40m.

> If it doesn't, it might be an issue of insufficient audio input for SSB
modulation. (AFAIK) the K3 will automatically boost the audio input if it
detects that there's not enough (a feature that I'm not particularly fond
of).

I carefully tuned the Mic gain and Compression as per the manual. ALC goes
up to 5 or 6 bars, compression below 10 dB when I speak in my normal voice.
So that suggests input side is OK?

Barthold
AD0RM


-----Original Message-----
From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of iain
macdonnell - N6ML
Sent: Wednesday, November 16, 2016 11:12 AM
To: Jack Brindle
Cc: Elecraft Reflector
Subject: Re: [Elecraft] KPA500 power output starts out low, then goes up

I didn't see anything in this thread that suggested that the problem wasn't
observed on all bands. Maybe I missed it?

Also haven't noticed anyone suggest using the K3's "TUNE" function, instead
of SSB modulation, as a test. If the output ramps up with the TUNE function,
it's an output problem. If it doesn't, it might be an issue of insufficient
audio input for SSB modulation. (AFAIK) the K3 will automatically boost the
audio input if it detects that there's not enough (a feature that I'm not
particularly fond of).

73,

    ~iain / N6ML



On Wed, Nov 16, 2016 at 9:56 AM, Jack Brindle <jackbrindle at me.com> wrote:
> A TR switch failure would affect all bands. This one is a bit different.
It will be interesting to see the cause when we finish troubleshooting.
>
> Jack Brindle, W6FB
> Elecraft Engineering
>
> Sent from my iPhone
>
>> On Nov 16, 2016, at 12:04 PM, Arie Kleingeld PA3A <pa3a at xs4all.nl> wrote:
>>
>> This might be a problem with the pin diode T/R switching in the KPA500.
>>
>>
>> 73,
>>
>> Arie
>>
>>
>>
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net Please help support this 
>> email list: http://www.qsl.net/donate.html Message delivered to 
>> jackbrindle at me.com
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net Please help support this email 
> list: http://www.qsl.net/donate.html Message delivered to 
> ar at dseven.org
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message
delivered to bartholdl at yahoo.com