On Sep 1, 2006, at 11:46 PM, Steve Thompson wrote:
>
>
> 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 --- There are two resonant circuits in the output circuitry,
one HF and one VHF. The HF (near)*-resonant part has a broad, shallow
dip. The VHF part has a sharp, deep dip that can suck a dipmeter out
of osc. when coupled too close.
Does make sense that the HF one rings and the VHF one does not ring?
- note - In the (1996) case I cited, the coupling method was a probe
near the anodes. Nothing was directly connected to the anodes. cheerz
* near-resonant because a Pi-network is actually two L-networks in
series, and because L-networks are resonant only when they are doing
Infinite Z-transformations, I refer to them as near-resonant or semi-
resonant circuits.
CHEERZ
>
> Steve
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>
R L MEASURES, AG6K. 805-386-3734
r@somis.org
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