On Aug 31, 2006, at 2:51 PM, Steve Thompson wrote:
>
>
> R L Measures wrote:
>>
>> On Aug 30, 2006, at 1:17 PM, Steve Thompson wrote:
>>
>>>
>>>>>> Any change in current causes a resonant circuit to ring. Ringing
>>>>>> amplitude depends on how fast the current changes and on Q.
>>>>>> Faster
>>>>>> and
>>>>>> more Q =s more V. I have heard from more than a few TL-922
>>>>>> owners who
>>>>>> report that a big-bang, flashover, and damage occurred when
>>>>>> their 922
>>>>>> was un-keyed.
>>>>>
>>>>>
>>>>> Sure, but how fast does the current change? By the time the
>>>>> decoupling
>>>>> capacitors have charged to allow the tube to drift into cutoff, I
>>>>> doubt
>>>>> the rise time alone is going to make the anode ciruit ring at vhf.
>>>>
>>>>
>>>>
>>>> During the Grate Parasitics Debate in 1996, a member of the
>>>> audience
>>>> hauled his SB-220 to work and loosely coupled the anodes to a HP
>>>> spectrum analyzer. When the 220 was keyed, he observed damped-wave
>>>> ringing at 112MHz at on And at off.
>>>
>>> I wish I could reproduce that. I've tried repeatedly with spectrum
>>> analyser and 'scopes and only ever find operating frequency ringing,
>>> even with suppressors removed.
>>
>>
>> Apply no driving signal and rapidly key the T/R bias.
> Did that, no result. Hence my post.
¿You found the driving signal, but you applied no driving signal?
Please describe the coupling method to the S.A.
>
> Steve
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>
R L MEASURES, AG6K. 805-386-3734
r@somis.org
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