[Elecraft] K2/100

[W3FPR]

Andrew,

If you are using a dummy load that is not frequency sensitive, you will 
not see an SWR increase even in the presence of an oscillation, but a 
rise in SWR may be an indication of a problem in the KPA100 SWR 
detection circuit and the follow-on circuits.

However, if you are using a resonant antenna (or circuit such as an 
antenna tuner) feeding the dummy load, then your assumptions may be correct.

In any case, the voltage tests that I listed are not frequency 
sensitive.  They will show that proper voltage is getting to the base K2 
VRFDET circuits to maintain power control.

73,
Don W3FPR

On 7/29/2026 4:23 AM, Andrew Lenton wrote:
> I want to what is coming out, as the SWR rises too, I suspect it 
> booting on a different crew, ie self oscillating
>
>
> KR
>
> Andrew
>
> Get BlueMail for Mobile <https://bluemail.me/download/>
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> On July 29, 2026, at 01:38, W3FPR <w3fpr111 at gmail.com> wrote:
>
>
>> Andrew,
>>
>> Your first problem is power control, that will not be seen with a
>> Spectrum Analyzer.
>> Do the voltage tests that I recommended first.  After you get power
>> level control, then you can proceed to a Spectrum Analyzer if you want.
>>
>> 73,
>> Don W3FPR
>>
>>