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Old January 11th 07, 12:36 AM posted to rec.radio.amateur.antenna
John John is offline
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First recorded activity by RadioBanter: Jan 2007
Posts: 1
Default Coax choke balun

Jeffrey Herman wrote:
(I posted the msg below last week but never saw it appear.)

I plan on erecting a multi-band inverted V with several insulators and
associated shorting jumpers along each leg so that with all jumpers 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 with the jumpers across the insulators is easier than winding accurate
traps (as in the trap dipole thread).

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 anyone tell me if there is an optimum
diameter, considering that most of my operations will be on 20m and 40m?
(On that page, UJW has two balun projects -- see the first one.)

73, Jeff KH6O

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



G4FGQ, Reg Edwards, made lots of DOS programs. One was SELFRES3. Go for it
at http://www.btinternet.com/~g4fgq.regp/ by clicking on "DOWNLOAD PROGRAMS
FROM HERE". Then look for SELFRES3 (Performance of solenoid-wound choke
coils, particularly coaxial chokes in antenna feedlines).

I'll bet it will make Reg happy if it is of use to you.

73,
John