[Central-Electronics] Re: [Amps] Central Electronics 600L

[Kenneth D. Grimm, K4XL]

>Does anyone here know how the 600L broadband amp worked?  I don't mean
>"pretty good" or something like that.  I mean what was the theory of
>operation?  How did they get it to be broadband?

I've been reluctant to answer your question, hoping that someone who
really knew how to produce the broadband couplers that are used in the
600L would speak up.  Since no one has, I'll just say that the couplers
are the secret to the broadbanding of the 100V, 200V and 600L.  As I
understand it, the coils were wound in a "special" way and a patent was
issued covering the technique.  It was apparently more "art" than
"science," however, as I've heard that during production there was only
about a 50% success rate in getting the couplers to work to specs.
Katashi Nose, KH6IJ (SK), attempted to wind coils for the 100V exciter
and was unable to replicate the broadband characteristic of Joe
Batchelors "broadband couplers."

Central Electronics took their secret very seriously.  When the 100V
first came out,  there was considerable curiosity about the nature of
the coils.   They were potted and, it was said at the time, that if you
tried to disassemble and "reverse engineer" the coil you were certain to
destroy the coil.  You were then up the proverbial creek as it was also
said that CE would not sell you a new one!   The cost of a replacement
coupler was the cost of a new 100V!

In his article about the 100V and 200V transmitters published in
Electric Radio some time back, Charlie Talbott, K3ICH, indicated that he
had copies of the original patents and instructions on how to construct
the couplers and would make them available for $5.  If all else fails,
you can probably still get a copy from him.

If anyone else has anything to contribute, please speak up!

73,
Ken K4XL
k4xl@arrl.net
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