In article ,
Cecil Moore wrote:

Does anybody have a copy of K1BQT's article from the Summer 1997 issue
of Communications Quarterly, on a method for constructing a 2-meter
extended double zepp antenna with a novel feed/matching arrangement?

Is it better than just feeding it with about 15 inches of ladder-line?

Better? Dunno - maybe so, maybe no.

The K1BQT design creates an EDZ using a pair of 38"-or-so rods or
whips, and two just-under-10" lengths of RG-58 solid-core coax
(conductor and braid shorted at the outer end, braid left open at the
center where the antenna connects to the feedline). The lengths of
RG-58 act as inductive stubs, cancelling out the capacitive reactance
of the radiators; the lengths of the rods/whips are adjusted to yield
a 50-ohm-per-side resistive impedancea at the feedpoint. The
resulting 100-ohm impedance is matched to the feedline by a 3/4-
wavelength piece of RG-59 75-ohm coax which is coiled around the
center support... it serves both as an impedance transformer and a
choke balun.

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.




--
Dave Platt AE6EO
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