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Would a discone cover all the US TV broadcast Freqs?
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December 18th 08, 06:47 AM posted to rec.radio.amateur.antenna
Richard Clark
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First recorded activity by RadioBanter: Jul 2006
Posts: 2,951
Would a discone cover all the US TV broadcast Freqs?
On Wed, 17 Dec 2008 18:36:49 -0800,
(Dave Platt)
wrote:
If you want a truly-omnidirectional (or close to it) antenna, with no
significant pattern variation or serious sensitivity variation in
frequency over the TV band, horizontally polarized, with no
requirement for electronic switching of elements and no mechanical
rotator... I sure don't. I skimmed through the antenna designs given
in Bailey's "Television and other Receiving Antennas" book a few days
ago, and didn't see any which come close to this.
A closer reading (skimming) would reveal:
Data sheet 10-15 Biconical Full Wave Antenna
Data sheet 10-30 Crossed Dipoles (Turnstile)
Data sheet 10-32 Slot Antenna
Data sheet 10-33 Slotted Cylinder Antenna
Basically, the take-home for widebandedness is a thick antenna (or its
skeletal equivalent). Many are vertical designs, but you simply build
the mirrored half and turn the assembly 90 degrees.
Although not the widest of designs (but wider than most), I would add
the Inverted F, example to be found at:
http://www.qsl.net/kb7qhc/antenna/In...%20F/index.htm
Make it thicker to make it wider (or fan out the segments). This is a
very low profile antenna by the way.
As for Ed's repeated advice for paint it black (Rolling Stones?), no.
Paint it off-white or a paler shade of blue (Procol Harumish). In
experiments during WWII, they discovered that lighting targets against
the sky made them disappear - not darkening them which offered
contrast. Oxidized aluminum is probably the best coloration.
73's
Richard Clark, KB7QHC
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