On Sat, 04 Jul 2009 10:16:23 -0400, Pete Smith wrote:
>Take a look, and tell me what you think!
Good work! Several comments. First, since your primary interest is
HF, you'll get FAR more bang for the buck with WOUND chokes, as
opposed to a string of beads. The reasons why are well documented in
my tutorial, so I won't go into it here. Second, although the #73
beads have relatively low choking impedance as compared to a wound
choke, you make them do more by turning the common mode circuit into
a sort of voltage divider by taking it to ground. Third, for even
more noise suppression (if you haven't already hit the limit), I
suggest the same centertapped configuration combined with wound
chokes using the guidelines in my Cookbook. It's simply "if a
little;s good, more's better." Fourth, if you are going to use
beads, #73 is a good choice, since they are primarily resistive, not
inductive, at HF, which means that their interaction with feedline
length is minimal.
If you're going to do a wound choke, I'd suggest 7 turns of the coax
through the "big #31 clamp-on" specified in my Cookbook.
73,
Jim Brown K9YC
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