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[AMPS] Re:

To: <amps@contesting.com>
Subject: [AMPS] Re:
From: measures@vc.net (Rich Measures)
Date: Wed, 17 Jun 98 10:08:36 -0800
>
>> >>No.  The two anode-circuit resonances have nothing to do with the 
>> >>self-resonance of Lsup. 
>> >
>> >What two anode-circuit resonances? I'm still  not following.
>> 
>> I think the two anode circuit resonances that Rich is trying to
>> explain 
>> are:
>> 
>> 1.) The resonance created by the parasitic supressor inductor
>> 2.) The resonance created by the parasitic supressor resistor
>> 
>Resistors don't create resonances
>
I agree, Gerard.  In this case, the suppressor resistor is connected in 
series with an existing resonant circuit -- i.e., the anode-C, the anode 
lead's total L plus the net X of the Tune-C, plus the chassis-L between 
the Tune-C gnd and the grid or screen gnd.  .  For a 3-500Z, typical 
values are 5pF  and c. 300nH.  Typical resonances are 100 - 150 MHz.  

>> I think he is saying that since both have different inductance values,
>> 
>> there will be two self resonance points in the anode circuit if both
>> have 
>> the same Impredance at the parasitic frequency.
>> 
>> Make sense?
>> 
>No, suppressors are there to prevent resonances, not to create them.  

The vhf resonance exists without a suppressor.  The suppressor is added 
to dampen the resonance and hopefully reduce the tube's amplification at 
the frequency of resonance - without substantially affecting performance 
at 29MHz.    
>
>> Note, I am not saying I necessarily agree with Rich's theory, but I
>> think 
>> this is what he is trying to say.
>> 
>Some of us wonder if Rich understands himself what he is trying to say
>
>Cheers
>
>Gerard
>M0AIU / AA3ES


Rich...

R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures  


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