[Elecraft] [KX3] Re: Can't believe my Chameleon Antenna!
Ron D'Eau Claire
ron at cobi.biz
Tue Nov 20 11:55:13 EST 2012
That's an old and valid technique for broad banding an antenna. Throw away 3
dB of power and you can avoid ever seeing an SWR over 2:1 across a huge
frequency range. Sure, 3 dB may sound like a lot, but for applications such
as the military where simple, broadband antennas are a must it's a
worthwhile tradeoff. After all, they are not trying to bust a pileup halfway
around the world with a QRP signal.
I believe B&W still sells their 90 foot "folded dipole" that features just
such a broad banding technique to cover 1.8 to 30 MHz. The US Army uses a
lot of them.
The laws of physics still hold. A small, efficient antenna will be a narrow
band antenna requiring adjustment of a matching network over relatively
small frequency excursions.
73, Ron AC7AC
-----Original Message-----
Another two cents worth ...
A few years ago there was a dipole advertised in QST and other places that
claimed to be "broadband with a very low SWR on all bands". Turns out an
XRAY of the junction box / center insulator revealed a resistor (50 ohms?)
in parallel with the coax connector and the dipole. (;-)
73!
Ken - K0PP
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Excuse me for being ignorant...
Cut and paste from the Chameleon web page "antenna base has an integral
broadband impedance matching network allowing broadband antenna tuning.
An external antenna tuner is required to provide a low VSWR."
I see very little difference between this antenna, a PAR EFHW or any other
EFHW that uses an impedance matching unit.
Just my 2 cents worth
Flame suit is ON.!!
--
Dave G KK7SS
Richland, WA
'59 Morris Minor 1000 - working on it :|
'65 Sprite - running :)
'76 Midget - co-owned with #4 Son :)
'06 Honda Civic Hybrid
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