[Amps] Parasitics & Filament Sag

[Steve Thompson]

R L Measures wrote:
> 
> On Sep 1, 2006, at 7:06 AM, Steve Thompson wrote:
> 
>>
>>
>> R L Measures wrote:
>>
>>>> I hope not, I looked from 1MHz up to around 300MHz, in both full   and
>>>> part band sweeps. Around the tuned frequency was the only place  I
>>>> found repeatable signals. It's a laborious process as a spectrum
>>>> analyser (at least the ones I have) is unsuited to catching a short
>>>> duration signal.
>>>
>>>
>>>
>>> Switching the amp between Tx and Rx at a 5Hz rate
> 
> 
>> If/when I ever look again, I'll try that.
>>
>> and disconnecting  the
>>
>>> RF input coax might help.
>>
>> I didn't have anything connected to the input for any of the tests.
> 
> 
> And you were able to see the HF fundamental signal at the anodes.

I saw brief glimpses of a signal somewhere close to the tuned frequency 
(7MHz), which I assume was ringing in the whole tank circuit.

Steve