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Old January 6th 07, 06:49 AM posted to rec.radio.amateur.antenna
Jeffrey Herman Jeffrey Herman is offline
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First recorded activity by RadioBanter: Nov 2006
Posts: 20
Default Choke balun (was: Interesting 144 foot Dipole)

Cecil Moore wrote:
When one feeds the antenna system at a current maximum
point, the balun is non-critical. I am presently using
ten turns of RG-400 on an FT-240-61 toroid with no


Hi Cecil,
It seems like it's been a decade since we debated on RRAP. I hope all is
well with you.

I plan on erecting a multi-band inverted V with several insulators and
associated shorting connectors along each leg so that with all connectors
open, the antenna is resonant on 10m; with the first insulator on each leg
shorted, the antenna is resonant on 15m; with the first and second insulators
on each leg shorted the antenna is resonant on 20m; et cetera. Shorting and
opening insulators is easier than winding accurate chokes!

For a balun, I'm considering N4UJW's "Ugly Balun"
(see http://www.hamuniverse.com/balun.html).
UJW leaves the diameter of the coil form to the reader, only specifying that
18-21 feet of coax be used. Can you (or anyone else on RRAA) tell me if there
is an optimum diameter, considering that most of my operations will be on 20m?
(On that page, UJW has two balun projects -- see the first one.)

Warmest regards,
Jeff KH6O

Chief Petty Officer, U.S. Coast Guard
Mathematics Lecturer, University of Hawaii System
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