[Amps] parasitic suppressor voodoo

[RICHARD SOLOMON]

You may think it's "voodoo" on HF, but on 6 Meters it's more like "Alchemy" !!
But, at least on my SB-220 Conversion, the ones I made are still holding of 
the evil humors of oscillation.

73, Dick, W1KSZ

> Date: Fri, 16 Jul 2010 07:52:32 +0200
> From: sm2ekm at telia.com
> To: amps at contesting.com
> Subject: Re: [Amps] parasitic suppressor voodoo
> 
> On a 2 x 4-1000A I used approx 3 turns 1 inch dia
> and 1 inch long coil on each tube. However I newer
> could get Globars or any other good resistors and I
> was too cheap to order any from the US. Instead I
> took a ferrite rod and put that inside the
> coil. The amp was 160-10m and worked just fine.
> 
> Jim SM2EKM
> -------------------------
> On 2010-07-15 22:00, Carl wrote:
> > Agree with Dave. In the past I turned out many 1-2 holers grid or cathode
> > driven to order; most covered 160 or 80-10M. Then I used 20-25W Globars or
> > surplus 68 Ohm 50W Carborundums which I bought almost 100 in sealed packages
> > for real cheap.
> >
> > Stopped that when all the local AM stations used the tubes until they were
> > even almost dead as modulators or went SS. I did about 10 3CX3000A7's and a
> > few 4CX5000A's after that.
> >
> > Carl
> > KM1H
> >
> >
> >
> > ----- Original Message -----
> > From: "DAVE WHITE"<mausoptik at btinternet.com>
> > To:<amps at contesting.com>; "Rob Atkinson"<ranchorobbo at gmail.com>
> > Sent: Thursday, July 15, 2010 3:34 PM
> > Subject: Re: [Amps] parasitic suppressor voodoo
> >
> >
> > On a 2 times 4-1000A amp (5.5kv, grounded grid, cathode driven) I used two
> > separate parasitic suppressors, each with 3 paralleled 50 ohm carbon
> > resistors inside a 15mm diamater two-turn coil of 2mm copper wire over about
> > 10mm length. The amp has worked flawlessly (80 thru 10m) for many years.
> >
> > If yours is a low band amp, you could probably make REALLY certain by
> > increasing the number of turns on the coil. Initially with four turns the
> > resistors smoked a little on 10m. I guessed "too much L". There was no
> > science to building these suppressors - it was a case of looking at the
> > W6SAI "Radio Handbook" and seeing if it worked. Voodoo? Maybe.
> >
> > I didn't try the amp without parasitic chokes but it seemed to work and "if
> > it ain't broke, don't fix it"....
> >
> > Hope this helps
> > Dave G0OIL
> >
> > --- On Thu, 15/7/10, Rob Atkinson<ranchorobbo at gmail.com>  wrote:
> >
> > From: Rob Atkinson<ranchorobbo at gmail.com>
> > Subject: Re: [Amps] parasitic suppressor voodoo
> > To: amps at contesting.com
> > Date: Thursday, 15 July, 2010, 18:40
> >
> > I would love to know what if any p.s. is needed on a pair 4-1000A at
> > 4.5 KV triode connected cathode driven for 160, 75 and 40 m.
> >
> > rob
> > K5UJ
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