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October 8th 04, 05:41 PM

Telamon wrote in message ...
In article ,
(bpnjensen) wrote:

(RHF) wrote in message
. com...

BJ,

I would venture to say 'if' you are using the Loop Antenna for both
Receiving and Transmission then a 1:1 or 2:1 Balun would work well
with a Coax Cable Lead-in-Line. An Antenna Tuner would be required
for Multi-Band operation.

"IF" the Loop Antenna is going to be used as a Receive "Only"
Antenna with a Coax Cable Feed-in-Line; then a 4:1 or even a 9:1
Balun could be used with good Multi-Band results.

~ RHF

Thanks RHF, and everyone else too - these are great ideas and links.
I have managed to obtain quite good results on most of the bands from
6 MHz and up, and so I was going to concentrate my efforts with this
loop on the tropicals. I was going to start with about 220' of wire
in a loop around my rooftop and off into some backyard trees.

Based on what I've seen here and on the websites, it looks as though
a 2:1 balun might be perfect, but a 4:1 may work about as well for a
slightly broader frequency coverage on a receive-only antenna; so I
may try these two first and then compare. One website says not to
use a balun at all (why?), so maybe I'll try it unmatched too.

The impedance changes according to the length of the loop relative to
the wavelength received. A full wave length loop within a wavelength of
ground is around 100 ohms so you would want to use a 2:1 BALUN to 50
ohm coax. If the loop is closer to half wave length then it will be
closer to 50 ohms and you would want to use a 1:1 BALUN.

Thanks for this, Telamon - I intend to use this antenna for reception
only on several lower frequency HF bands (really about 3 through 6
MHz), so I'm not sure that I want or need a BALUN/transformer that
will match the impedance so closely. Ultimately, I may end up
extending the length of the wire up to 340 feet and making it's shape
weird so that it will fit in my limited space, just to see if I can
achieve better results on 90m...but it weould still be used on 49, 60
and 75.

Bruce Jensen