On Sun, 12 Mar 2000 12:50:22 -0600 "Phil Clements" <philk5pc@tyler.net>
writes:
>Hi Marv, and everybody,
Hi Phil,
>I ran this article by the reflector a couple of years ago. Very
interesting.
>I saw a 3-30 mhz Harris amp some years back with an unbelievably
>short plate choke in it. (about 2 1/2 inches long) Turns out, this choke
>had a ferrite rod inside the form also. B&W uses this technology in
their
>BBC model hi-power chokes.
Your posting likely predates my "membership" in this group. I was
aware of the B&W's but, cited the 73 article since it disclosed the
internal details.
>Mr. Measures quickly poo-poohed the usage of ferrite in an RF deck,
>but several commercial designs have been very successful with this.
>A caveat is that I have never seen a version of this choke work all the
>way from 1.8 to30 mhz. These appeared in articles and amps
>before 160 meters and the WARC bands were of concern.
>There must be a reason that nobody I know of picked up the ball and
>ran with it after Mr. Deane's article was published.
Maybe because Lafayette, the given source of the ferrite rod, went out
of biz? :-)
More likely, it didn't catch on back then because it wasn't really
necessary. Before the WARC bands, it was fairly easy to park the
unwanted resonance(s) somewhere. Nowadays, there isn't as much leeway.
73,
Marv WC6W
*
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