Dave -
I thought it was clear too, an SB200 (with 572Bs).
The conversion is mostly done with an easy 600W out on 6M. It's
single band. However, I'm still trying to find the optimum
anti-parasitic chokes, I started with a 50 Ohm 2W resistor with about
a 1" hairpin, and the resistor immediately caught fire. I tried a few
different coil resistor combination and actually finished up so far
using the SB200's original 3 turn on a 2W Carbon Comp resistor - its
not flaming but it is very hot so I need to use a higher wattage
combination. That's why I was interested in what other's were using
with these 572Bs. It does seem to be stable with this configuration.
- Paul
At 07:01 AM 6/3/2013, David Craig wrote:
Paul, your question is certainly clear enough here in reference to
"tube geometry & circuit layout". Unless of course you've decided to play
"blocks" with the SB200 internals. With that said, I did presuppose one
thing about your project: That it is a monoband conversion & not a band
switch mod. Presuming it is monoband I'd use the L / R combo I mentioned
before. If it isn't however, then check your wallet before you begin. You
can play all the theoretic mind games you want and it won't change the fact
a monoband conversion has one and only one value you need to worry about for
our purposes. Remember, NASA still uses Newtonian physics for calculating
orbits, even though Einstein proved him wrong. If you plan on utilizing the
band switch it still won't matter, but in that case because it won't survive
for very long.
Dave N3DB
-----Original Message-----
From: Carl [mailto:km1h@jeremy.mv.com]
Sent: Sunday, June 02, 2013 8:53 PM
To: David Craig; 'Paul Baldock'; 'Amps'
Subject: Re: [Amps] SB200 on 6M
There is no such thing as a one size fits all suppressor as tubes have a
wide range of parasitic frequencies controlled by tube geometry and circuit
layout. A 3-500Z suppressor, for instance, rarely does a good job on a 572B.
The 572B works fine on 6M but takes a deeper understanding of layout,
components, and having suitable test equipment.
Carl
KM1H
----- Original Message -----
From: "David Craig" <davidhcraig@verizon.net>
To: "'Paul Baldock'" <paul@paulbaldock.com>; "'Amps'" <amps@contesting.com>
Sent: Sunday, June 02, 2013 7:31 PM
Subject: Re: [Amps] SB200 on 6M
> I'd go with 1/4" flat strap in a "U" with a pair of 100 ohm 5w MOX
> in parallel. But, FWIW, I wouldn't use 572Bs either, though I am positive
> the latter comment will draw fire.
>
> 73 N3DB Dave
>
> -----Original Message-----
> From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Paul Baldock
> Sent: Sunday, June 02, 2013 7:17 PM
> To: Amps
> Subject: [Amps] SB200 on 6M
>
> I'm converting a SB200 for 6M. What's the best configuration for the
> Anti-Parasitic Choke?
>
> Thanks
>
> - Paul
> \
>
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