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

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 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

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.

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

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

= = = (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
..

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

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

That's what I had in mind but experiment. You never know.

CW
KC7NOD
"dxAce" wrote in message
...


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

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

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

bpnjensen wrote:

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.

It has been my experience in years past that horizontal loops are great for close in work, say on 160, 75 and 80 meters. However, they do not seem to
support long haul DX. And that is why many amateur users of those bands love them, makes for a great, close in range signal, firing up, and then down.

Yes, great for reducing QRM sources, but that is because they concentrate on vertically arriving signals, rather than the more commonly horizontally
polarized QRM.

Now, if you had the loop in the vertical plane, that would of course change things dramatically.

Just my opinion, of course.

dxAce
Michigan

"dxAce" wrote in message
...
|
|
| bpnjensen wrote:
|
| 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.
|
| It has been my experience in years past that horizontal loops are great
for close in work, say on 160, 75 and 80 meters. However, they do not seem
to
| support long haul DX. And that is why many amateur users of those bands
love them, makes for a great, close in range signal, firing up, and then
down.
|
| Yes, great for reducing QRM sources, but that is because they concentrate
on vertically arriving signals, rather than the more commonly horizontally
| polarized QRM.
|
| Now, if you had the loop in the vertical plane, that would of course
change things dramatically.
|
| Just my opinion, of course.
|
| dxAce
| Michigan

From the FWIW Department, John Devoldere believes higher - angle
angennas (esp. quarter - wave verticals) outperform low - angle antennas
for greyline work, on the lower HF bands. Of course, that's only 30
minutes of a given day.

73,

Steve Lawrence
KAØPMD
Burnsville, Minnesota

"If a man wants his dreams to come true then he must wake up."
- Anonymous


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Outgoing mail is certified Virus Free.
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In article , dxAce
wrote:

bpnjensen wrote:

Telamon wrote in
message

odigy.co m...
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.

It has been my experience in years past that horizontal loops are
great for close in work, say on 160, 75 and 80 meters. However, they
do not seem to support long haul DX. And that is why many amateur
users of those bands love them, makes for a great, close in range
signal, firing up, and then down.

Yes, great for reducing QRM sources, but that is because they
concentrate on vertically arriving signals, rather than the more
commonly horizontally polarized QRM.

Now, if you had the loop in the vertical plane, that would of course
change things dramatically.

Just my opinion, of course.

I generally agree with what you stated. My horizontal loops generally
seem to work better evenings as opposed to daytime where the lower
frequencies are favored. Generally, I get a stronger signal response
from a vertical loop daytime but they are directional where the
horizontal loop is not.

Remember that for a one-wavelength or more loop the response is in and
out of the loop so a horizontal loop is looking straight up. The pattern
changes, as the loop becomes half wave where the response is from the
edge. For a fixed horizontal loop then at high frequencies it looks up
and at low frequencies, it looks more toward the horizon in one
direction.

The BALUN will most likely only help you with local noise coming from
the AC power through your radio up the coax to the antenna and then back
to the radio input.

--
Telamon
Ventura, California

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

BJ,

If you are planning on using the Loop Antenna for transmitting
on one specific Amateur Band with a un-balanced or balance
feed-line; and have cut and trimmed the Wire Loop Antenna Element
for a very low SWR. Then a Balun would simply be source of power
loss, and have no added value in getting your signal out (ERP).

NOTE: These are sometimes called "SkyWire" Loop Antennas.
You may wish to check-out the SkyWire Loop Antennas eGroup on YAHOO!
SKYWIRE-LOOP= http://groups.yahoo.com/group/SkyWires/

iane ~ RHF
..
..

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

Thanks!
Bruce Jensen
..

"Mark Keith" wrote:

| Huh? A 1/4 wave vertical is a fairly low angle radiator. The better
| the ground radial system, the better the low angle performance. The
| max radiation of a 1/4 wave ground plane is under 5 degrees when it's
| over a 1/2 wave up and has 4 radials.
| If a 1/4 wave vertical is a higher angle radiator, what do you, or he,
| consider a low angle radiator? MK

A 1/2 wave vertical, or ideally, a 5/8 (.625) wavelength vertical, actually.
I wasn't disputing the fact that a 1/4 wave vertical works very well for DX
purposes, but was pointing out that there is an exception to every rule, and
I found this particular "Exception" quite interesting.

You can find a reference to the "high angle CAN be better for gray line
work" phenomenon in one of the Twin Cities DX Association's newsletters:

http://www.tcdxa.org/

The link appears under "TCDXA Info." Click on the "Gray Line Report."
There are 3 newsletters on that particular page, and it's in there
*somewhere*
or other.

VY 73,

Steve Lawrence
KAØPMD
Burnsville, Minnesota

"If a man wants his dreams to come true then he must wake up."
- Anonymous


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