[Heathkit] Re: parasitic suppression - Better Title

[rbethman]

Carl,

I submit that the 6146 *indeed* has required *both* low frequency *and* 
VHF parasitic suppression.  It is also a 6.3V filament tube that did 
*not* ever make it into automobiles without a HAM installing a radio for 
his/her use.

The 6146 *and* the sweep tubes used in Heath equipment, I.E., the HW-12, 
HW-16 as examples, have in their designs the cure for *BOTH* low 
frequency and VHF frequency parasitic resonance.  These are NOT some off 
the wall antique tubes, nor are they NON Heath radios.

In some instances, the neutralization was achieved by a simple aluminum 
rod in the RF PA enclosure bent as needed to resolve the problem, (DX-60 
and TX-1 Apache).  In other instances the problem was fixed by a 
capacitor, air variable, from plate back to grid.  (HW-101 - SB-102).

You and I have been around for some time.  We both know a fair bit of 
information.  Sometimes we overlook are forget things.  It does NOT take 
only a Triode, nor 250KW radios to deal with parasitic resonance.  It 
can even be a TPS-1D radar system!

Bob - N0DGN
> The low frequency parasitic in vacuum tube ham equipment went out with 
> 6V electrical systems in cars. Handbooks like to repeat themselves for 
> several generations before some one catches on and edits. Some of 
> those antique tubes even took off at audio.
>
> And yes, some SS stages can have LF parasitics.
>
> Since this IS a Heathkit reflector I am sticking to the tubes they 
> use; they do not lend themselves to LF parasitics.
>
> If you wish to discuss how to tame a 250KW SWBC amp that is a 
> different story.
>
> Carl
> KM1H