On Sun, 31 May 2009 01:46:54 -0500, Phil Clements wrote:
>The question is do they also need to be placed 15-30 feet away, or can they
>be closer to the feed point?
As the designer of the coax chokes using clamp-ons or toroids, I'll step up to
respond. They are a real "brute force" design, adding a VERY high impedance in
series with the common mode circuit. As a result, they do not require the
additional ground rods in the DXE design. Ideally, the choke should be very
close to where the coax terminates to the matching transformer.
Other chokes have significantly lower impedance than my designs, so they need
be be used with a "network" -- in this case, the path to ground via the rods to
provide sufficient isolation.
Note that there's nothing "magic" in my designs -- everything is documented in
the RFI tutorial that's on my website, and in the accompanying power point on
coax chokes.
73,
Jim K9YC
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