On Wed, 4 Mar 2009 10:35:09 -0800 (PST), Michael Germino wrote:
>I suspect under certain conditions the cage antenna, with a voice
>mode, will hear better than a regular dipole.
>Under rapid fading the extra wire may act like "diversity
>reception" even though the wires are not separated by much.
Your suspicions have no basis in science -- they fall apart as
soon as you plug actual numbers into the equations that describe
how they work.
A so-called cage dipole consisting of multiple wires of the same
length as an ordinary half wave dipole have three advantages.
1) The SWR bandwidth is significantly greater. This is measurable,
and can be of significant benefit if you're trying to make the
antenna work over a relatively wide ham band like 160M (10%),
80/75M (13%), and 10M (6%) without having to retune a matching
network.
2) The efficiency is VERY SLIGHTLY greater -- perhaps 0.1 dB. This
is real, but NOT measurable by most hams.
3) The antenna fits in SLIGHTLY less space -- perhaps 1% for 2-3
wires.
Bottom line -- #1 is a VERY good reason to use a so-called "cage
dipole," but it is also the ONLY good reason.
73,
Jim Brown K9YC
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