[AMPS] Parasitic suppressors/another question,

[Rich Measures]

>
>
>-----Original Message-----
>From:	Rich Measures [SMTP:measures@vc.net]
>Sent:	Friday, April 09, 1999 1:43 AM
>To:	Amps Reflector
>Subject:	Re: [AMPS] Parasitic suppressors/another question,
>
>
>
>
>>
>>>>Agreed. Still you can design an HF amp to be unconditionally stable and
>>>>test for that condition as well.
>>>
>>>?  Tuning the HF tank circuit and disconnecting the hf load have
>>>virtually nothing to do with what is happening in the anode-resonant
>>>circuit where the parasitic oscillations take place.
>>
>>Ah contrair!  You yourself have said that the anode-resonant circuit is
>>composed of Ctune.  Is not Ctune in the tank circuit???
>>Sooooooo.......tuning the tank circuit DOES make a difference.
>>
>?  Adjusting C-tune makes little difference in the anode resonance since
>C-tune is effectively in series with C-anode, which is much smaller.
>
>[Richard W. Ehrhorn]  <<< A sweeping generalization which is not 
>necessarily true. In many cases - such as big tetrodes tuned by vacuum 
>variables - Tune Cmin may be considerably smaller than tube Cout... right?
>
€  Surely.  The 8973 has 160pF of C-anode.  At 29.5MHz, C-tune would 
probably be around 100pF.    However, in a SB-220 the measured anode 
resonant freq. changes little between 80m and 10m operation.  



Rich...

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


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