On 11/14/2010 4:22 PM, Dr. Gerald N. Johnson wrote:
>> There are two causes of feedline radiation/reception -- common mode
>> > current and conductor spacing. A common mode choke AT THE FEEDPOINT can
>> > essentially kill the radiation due to common mode current unless the
>> > feedline is some multiple of a half wave, in which case an additional
>> > choke placed along the line to act as an "egg insulator" to make it less
>> > than a half wave would kill the remaining current.
> Or if the feed line isn't perpendicular to the radiator and so gets
> coupled to the radiator beyond the choke.
That's the function of the additional choke as egg insulator -- to break
the feedline into lengths (from a common mode point of view) where very
little current can flow.
73, Jim K9YC
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