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[Amps] Minimum Value of RF Plate Chokes

To: "Gary Schafer" <>, <>, "Paul Kelley N1BUG" <>
Subject: [Amps] Minimum Value of RF Plate Chokes
From: "Edward Swynar" <>
Date: Thu, 26 Feb 2009 13:12:12 -0500
List-post: <">>
Many thanks, Gary & Paul, for your very informative feedback to my original 
head-scratching here, Hi Hi.

Well, maybe I'm deluding myself here, but I like to at least *think* that I'm 
somewhat of a purist, too --- and when it comes to 160-meters, any residual 
effect(s) from less-than-stellar design / operating procedure of "linear" 
amplifiers can have unfortunate effects upon others using the band...and 
believe me, I KNOW what I'm talking about from first-hand experience here (I'm 
practise the old-school "...earn-as-you-learn" techniques, Hi).

To that end, I think what I'm going to consider doing here (once the "regular" 
160-meter season ebbs with QRN) is install TWO series chokes for my 813's, i.e. 
the big multi-pi National jobbie that's in there now, physically mounted below 
my 250-uh. solenoid choke: the tricky part will be devising some sort of a 
switch that would short-out the multi-pi choke for those bands other than 160.

(BTW Gary, you are right on the money re. series resonances: my 250-uh. 
solenoid coil shows a dip at around 24-MHz, just as your 200-uh. coil did.)

I think that a switchable choke arrangement is a FAR better option to consider, 
rather than building a separate, dedicated low-band amplifier...although if I 
could ever get my paws on a good 833A, or two, I just might eat those words! Hi 

The 250-uh. choke was the one that I originally used in the amplifier, and I 'd 
gallop merrily along literally all over the authorized SW spectrum with it, 
with narry a problem --- except on 160, where the amplifier just never quite 
seemed to tune-up properly (until I subbed-in the multi-pi National, that is).

The more I know, there more there is to learn, it seems --- but one thing is 
for certain: Ham radio, as in life itself, is FULL of compromises!

~73~ Eddy VE3CUI - VE3XZ
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