Antenna coils Traps

[Glen Zook]

Except he said that they were loading coils and not
traps.  Loading coils are just inductors (no
capacitors).  Although they are "self resonant" (with
"stray capacity") at some frequency, their primary
purpose in life is to lengthen the wire electrically
while maintaining a shorter physical length.

If truly a trap then the length of the 40 meter
antenna would probably be considerably longer than 38
feet.  Of course, due to the inductive effects of the
traps the total length would be different from the
"normal" length of a half-wave dipole for 40 meters. 
If they were traps for 20 meters or 10 meters (traps
would not be needed for 15 meters due to the 3/2
wavelength factor) then the proper place would be a
little over 8 feet out from the center insulator for
10 meters and a little over 16 feet out for 20 meters.

Glen, K9STH


--- "G. Lofstead" <jerrylofstead at BELLSOUTH.NET> wrote:

If they are Spiro's, send him an Email and ask. 
Otherwise, they normally would go out about 2/3 from
the center.   I use a trap dipole on 80 & 40 M. Your
traps may go at the 20M dipole end length... You get a
40 & 20 M dipole...









Glen, K9STH

Web sites

http://home.comcast.net/~k9sth
http://home.comcast.net/~zcomco

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