[Amps] SB-220

[R.Measures]

On Nov 4, 2004, at 9:39 AM, Bill Turner wrote:

> On Wed, 03 Nov 2004 13:58:51 -0500, Will Matney wrote:
>
>> Now to me, if the lead(s) length is correct, and the gain high enough,
>> the internal capacitance of the tube along with the inductance of the
>> lead(s) could make up a VHF oscillator.
>
> _________________________________________________________
>
> One other factor not mentioned is the Q of the VHF circuit, which has
> a great effect on gain.  If the VHF Q is very high, oscillations are
> almost guaranteed.

Indeed, Bill.  The higher the VHF Q at the anode circuit's resonance, 
the higher the gain at that frequency, and the greater the chance of 
regeneration.  The relationship between VHF-Rp, VHF-Q, and VHF gain is 
that all are proportional.

> VHF Q is usually not known in most amplifier
> circuits, and having a parasitic suppressor circuit is just added
> insurance.  I wouldn't be without one.
>
> --
> Bill W6WRT
>
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>

Richard L. Measures, AG6K, 805.386.3734.  www.somis.org