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Old August 5th 08, 08:04 PM posted to rec.radio.amateur.antenna
Roy Lewallen Roy Lewallen is offline
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First recorded activity by RadioBanter: Jun 2006
Posts: 1,374
Default Help me buy VHF/UHF television antenna? Can't decide!

JB wrote:

While the 1080 UHF is fairly sharp with some potential gain, the VHF
elements seem to be little more than "rabbit ears" - In fact it is a swept
dipole, so will be bi-directional and easily pick up reflections from behind
and around you.. Sweeping the elements has the effect of allowing the
elements to be better matched at odd multiples. . .


What the bending of elements does is to align the lobes broadside at the
frequencies at which the elements are approximately 3/2 wavelengths long
(that is, at about three times the fundamental half wavelength
frequency). Without bending, a 3/2 wave element has lobes which aren't
broadside. Bending it brings these to point broadside, resulting in a an
approximately bidirectional pattern. It's the shortest "vee beam" type
antenna, which extends this idea by decreasing the angle to maintain
alignment as the dipoles get longer.

The bending used in TV antennas has little effect on the impedance match.

Roy Lewallen, W7EL