RadioBanter - View Single Post

October 8th 04, 05:39 AM

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.

--
Telamon
Ventura, California