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-   -   CW's Loop antenna and "balun" (https://www.radiobanter.com/shortwave/45029-cws-loop-antenna-%22balun%22.html)

bpnjensen October 5th 04 08:03 PM

CW's Loop antenna and "balun"
 
Hi, folks (and maybe CW) - on his helpful hints pages, CW (kc7nod)
recommends the possible use of a balun (which I take to mean a
transformer?) at the coax-antenna junction of a loop antenna...

http://www.kc7nod.20m.com/loop.htm

In this instance, can anyone advise what the ratio on this would be?
4:1? Another value? I'd like to try out this antenna design, and the
balun idea too.

Thanks,
Bruce Jensen

dxAce October 5th 04 08:07 PM



bpnjensen wrote:

Hi, folks (and maybe CW) - on his helpful hints pages, CW (kc7nod)
recommends the possible use of a balun (which I take to mean a
transformer?) at the coax-antenna junction of a loop antenna...

http://www.kc7nod.20m.com/loop.htm

In this instance, can anyone advise what the ratio on this would be?
4:1? Another value? I'd like to try out this antenna design, and the
balun idea too.


My guess would be a 1:1 balun.

( I hope this is not a quiz) ;-)

dxAce



dxAce October 5th 04 08:30 PM



dxAce wrote:

bpnjensen wrote:

Hi, folks (and maybe CW) - on his helpful hints pages, CW (kc7nod)
recommends the possible use of a balun (which I take to mean a
transformer?) at the coax-antenna junction of a loop antenna...

http://www.kc7nod.20m.com/loop.htm

In this instance, can anyone advise what the ratio on this would be?
4:1? Another value? I'd like to try out this antenna design, and the
balun idea too.


My guess would be a 1:1 balun.

( I hope this is not a quiz) ;-)


This site says either a 1:1 or 4:1 :

http://www.radioworks.com/nloop.html

Also there may be some other ideas there for you to try.



dxAce



Mark S. Holden October 5th 04 08:49 PM

bpnjensen wrote:

Hi, folks (and maybe CW) - on his helpful hints pages, CW (kc7nod)
recommends the possible use of a balun (which I take to mean a
transformer?) at the coax-antenna junction of a loop antenna...

http://www.kc7nod.20m.com/loop.htm

In this instance, can anyone advise what the ratio on this would be?
4:1? Another value? I'd like to try out this antenna design, and the
balun idea too.

Thanks,
Bruce Jensen


I use a 4:1 transformer on my horizontal loop.

Simon October 5th 04 08:52 PM

bpnjensen wrote:
Hi, folks (and maybe CW) - on his helpful hints pages, CW (kc7nod)
recommends the possible use of a balun (which I take to mean a
transformer?) at the coax-antenna junction of a loop antenna...

http://www.kc7nod.20m.com/loop.htm

In this instance, can anyone advise what the ratio on this would be?
4:1? Another value? I'd like to try out this antenna design, and the
balun idea too.

Thanks,
Bruce Jensen


Find out some more antenna loop ideas he

http://www.dxzone.com/catalog/Techni...op/index.shtml

El Conjeturar October 5th 04 09:08 PM

Assuming you are talking about a full wave loop antenna:

Maybe read the info at URL:
http://www.bloomington.in.us/~wh2t/loop.html
AND
http://hamgate.sunyerie.edu/~buffaloam/loop_antenna.htm

Depending on height above ground, a loop's impedance is nominally 100 ohms
So you can take it from there.

Baluns are described in detail at an ARRL site:
http://www.arrl.org/tis/info/pdf/8004019.pdf

More to them than just impedance matching -- such as common mode stuff

--
The generation of random numbers is too important to be left to chance.



"bpnjensen" wrote in message
om...
Hi, folks (and maybe CW) - on his helpful hints pages, CW (kc7nod)
recommends the possible use of a balun (which I take to mean a
transformer?) at the coax-antenna junction of a loop antenna...

http://www.kc7nod.20m.com/loop.htm

In this instance, can anyone advise what the ratio on this would be?
4:1? Another value? I'd like to try out this antenna design, and the
balun idea too.

Thanks,
Bruce Jensen




RHF October 6th 04 05:22 AM

= = = (bpnjensen) wrote in message
= = = . com...

Hi, folks (and maybe CW) - on his helpful hints pages, CW (kc7nod)
recommends the possible use of a balun (which I take to mean a
transformer?) at the coax-antenna junction of a loop antenna...

http://www.kc7nod.20m.com/loop.htm

In this instance, can anyone advise what the ratio on this would be?
4:1? Another value? I'd like to try out this antenna design, and the
balun idea too.

Thanks,
Bruce Jensen



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
..

JuLiE Dxer October 6th 04 10:39 AM


It seems a lot easier to just run ladder line to your loop and let a
balun equipped tuner deal with matter.

On 5 Oct 2004 12:03:29 -0700, (bpnjensen) wrote:

Hi, folks (and maybe CW) - on his helpful hints pages, CW (kc7nod)
recommends the possible use of a balun (which I take to mean a
transformer?) at the coax-antenna junction of a loop antenna...

http://www.kc7nod.20m.com/loop.htm

In this instance, can anyone advise what the ratio on this would be?
4:1? Another value? I'd like to try out this antenna design, and the
balun idea too.

Thanks,
Bruce Jensen



bpnjensen October 6th 04 04:29 PM

(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.

I will post some observations when I get this thing up and running.

Thanks!
Bruce Jensen

Terry October 6th 04 08:06 PM

JuLiE Dxer wrote in message . ..
It seems a lot easier to just run ladder line to your loop and let a
balun equipped tuner deal with matter.


It is very hard to get balanced RF transmission lines
that are anywhere near balanced. For transmitting, a little
imabalance only sprays RF all over the place, but any
imbalance on receive will let noise enter the system.

A friend has a cabin in an isolated location with no power,
telephone or cable TV. And a balanced line, even AC zip cord,
works great for receiving. But in every location with AC mains
power that I have tried to use balanced zip cord, 300 Ohm
(unsheilded) or 450 Ohm lader line, I have experienced lots of noise.
I have had good results with 300 Ohm shielded, but when compared
to 50 or 75 Ohm coax, there was no perceptable difference.

Local noise, generated in the SLWers home, is often the biggest
limitation and anything you can do to reduce it, either at the
source, or by keeping out of the feedline will help pull in those
weak signals.

A tuner mounted at the antenna, with a remote control would be nice
to play with. But a matching transformer is a lot easier and cheaper,
and for most of us is more then "good enough".

Terry


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