Thread: Am reception
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Old November 12th 05, 11:31 PM
Cecil Moore
 
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Default Rick Littlefield K1BQT article on feeding extended double zepps

Dave Platt wrote:

Cecil Moore wrote:
Is it better than just feeding it with about 15 inches of ladder-line?


If I were going to feed a 5/4 with ladder line, for tower
side-mounting, I suppose I'd probably put the ladder line inside the
PVC support arm, and then connect it to some 50-ohm coax which was
wound around the outside of the arm to create a choke balun.


Cebik's stuff is probably for HF. EZNEC sez an 8 foot long, one
inch diameter dipole at 36 ft. height has a feedpoint impedance
of 86-j91 on 146 MHz. Heck, that's already better than some rubber
duckies. All it takes to resonate that impedance to a 50 ohm SWR
of about 1.6:1 is about 2.5 inches of 450 ohm ladder-line in
series. What could possibly be simpler than that?
--
73, Cecil http://www.qsl.net/w5dxp