Coax and Dipole
 

I'm putting up an offset dipole. I'm attaching a 4:1 balun. I'm running
RG-8 to the balun. The dipole will be attached at 20' and the other end will
be about 40'. My question is can the coax be tie-straped to the short end
of the dipole antenna wire and run back with it toward the houes? This is
basically to keep a big loop from hanging down and also keeping the wife
happy since it would look much cleaner. I didn't know if this would have a
large impact on operation or not.

73
Doug / KC8YEC

A quick look in the Handbook will show you that the feed line is suppose to be perpendicular to the dipole
BUT,
I think you should put it up like you described and then report back on the kind of results you get.
73
Richard WB8KRN

"Doug Birky" wrote in message ...
I'm putting up an offset dipole. I'm attaching a 4:1 balun. I'm running
RG-8 to the balun. The dipole will be attached at 20' and the other end will
be about 40'. My question is can the coax be tie-straped to the short end
of the dipole antenna wire and run back with it toward the houes? This is
basically to keep a big loop from hanging down and also keeping the wife
happy since it would look much cleaner. I didn't know if this would have a
large impact on operation or not.

73
Doug / KC8YEC

"Richard Heindel" wrote in message
...
A quick look in the Handbook will show you that the feed line is suppose
to be perpendicular to the dipole
BUT,
I think you should put it up like you described and then report back on
the kind of results you get.
73
Richard WB8KRN

"Doug Birky" wrote in message
...
I'm putting up an offset dipole. I'm attaching a 4:1 balun. I'm running
RG-8 to the balun. The dipole will be attached at 20' and the other end
will
be about 40'. My question is can the coax be tie-straped to the short
end
of the dipole antenna wire and run back with it toward the houes? This
is
basically to keep a big loop from hanging down and also keeping the wife
happy since it would look much cleaner. I didn't know if this would have
a
large impact on operation or not.

73
Doug / KC8YEC


Hi Doug
If you're going to do that why not just make a coaxial antenna?
Peel back 20 feet of braid over the coax and add a 20 foot wire to the end
of the center conductor.
Forget the balun. Use a tuner.
I think dressing the feedline next to a radiator is problematic at best.
Just my 2 cents.......
73
H.
NQ5H

"Doug Birky" wrote in message
...
I'm putting up an offset dipole. I'm attaching a 4:1 balun. I'm running
RG-8 to the balun. The dipole will be attached at 20' and the other end
will
be about 40'. My question is can the coax be tie-straped to the short end
of the dipole antenna wire and run back with it toward the houes? This is
basically to keep a big loop from hanging down and also keeping the wife
happy since it would look much cleaner. I didn't know if this would have a
large impact on operation or not.

73
Doug / KC8YEC

I saw an artical in a magazine once about doing something similar. The coax
was suspended a few inches below the dipole. I think but not sure that
somekind of choke was used on the coax near the end past the dipole to keep
the current off the outer portion of the coax.

Doug Birky wrote:
My question is can the coax be tie-straped to the short end
of the dipole antenna wire and run back with it toward the houes?

My comments assume this is a transmitting antenna.

Doing such will essentially short out the balun - not a good idea
and virtually guaranteeing common-mode problems. It would essentially
turn the antenna into a horizontal sleeve antenna which is unbalanced.

Even with the coax hanging down, this antenna will be a poor
performer as the SWR on the coax will be high as reported by
EZNEC. 40m 5:1, 30m 9:1, 20m 14:1, 17m 8:1, 15m 15:1, 12m 22:1,
10m 21:1. The free demo version of EZNEC is available from

http://www.eznec.com

My advice is to feed this antenna with 300 ohm balanced feedline
through a 1:1 choke at the antenna tuner.
--
73, Cecil http://www.qsl.net/w5dxp



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Thanks for all the input. This is the antenna I was planning to put up:
http://www.packetradio.com/windom.htm


H. Adam Stevens, NQ5H wrote in message
...

"Richard Heindel" wrote in message
...
A quick look in the Handbook will show you that the feed line is suppose
to be perpendicular to the dipole
BUT,
I think you should put it up like you described and then report back on
the kind of results you get.
73
Richard WB8KRN

"Doug Birky" wrote in message
...
I'm putting up an offset dipole. I'm attaching a 4:1 balun. I'm
running
RG-8 to the balun. The dipole will be attached at 20' and the other
end
will
be about 40'. My question is can the coax be tie-straped to the short
end
of the dipole antenna wire and run back with it toward the houes?
This
is
basically to keep a big loop from hanging down and also keeping the
wife
happy since it would look much cleaner. I didn't know if this would
have
a
large impact on operation or not.

73
Doug / KC8YEC


Hi Doug
If you're going to do that why not just make a coaxial antenna?
Peel back 20 feet of braid over the coax and add a 20 foot wire to the end
of the center conductor.
Forget the balun. Use a tuner.
I think dressing the feedline next to a radiator is problematic at best.
Just my 2 cents.......
73
H.
NQ5H

Doug Birky wrote:
I'm putting up an offset dipole. I'm attaching a 4:1 balun. I'm running
RG-8 to the balun. The dipole will be attached at 20' and the other end will
be about 40'. My question is can the coax be tie-straped to the short end
of the dipole antenna wire and run back with it toward the houes? This is
basically to keep a big loop from hanging down and also keeping the wife
happy since it would look much cleaner. I didn't know if this would have a
large impact on operation or not.

73
Doug / KC8YEC


Hi Doug,

I'm Running the Windom ( OFCD) it identical to what your saying. but
you'll find that the coax needs to come off the antenna in pretty much a
90 degree angle. ohterwise you will end up with lots of fedline
radiation which will cause problems in the shack.
73 Dave kc1di

KC1DI wrote in message ...
Doug Birky wrote:
I'm putting up an offset dipole. I'm attaching a 4:1 balun. I'm running
RG-8 to the balun. The dipole will be attached at 20' and the other end will
be about 40'. My question is can the coax be tie-straped to the short end
of the dipole antenna wire and run back with it toward the houes? This is
basically to keep a big loop from hanging down and also keeping the wife
happy since it would look much cleaner. I didn't know if this would have a
large impact on operation or not.

73
Doug / KC8YEC


Hi Doug,

I'm Running the Windom ( OFCD) it identical to what your saying. but
you'll find that the coax needs to come off the antenna in pretty much a
90 degree angle. ohterwise you will end up with lots of fedline
radiation which will cause problems in the shack.
73 Dave kc1di

Can you give me an indication about how long a lead I need before
running the coax back toward the house and into the radio? I'm going
to run the coax up the house and out to the feedpoint.

Doug

"Doug" wrote in message
om...
KC1DI wrote in message
...
Doug Birky wrote:
I'm putting up an offset dipole. I'm attaching a 4:1 balun. I'm
running
RG-8 to the balun. The dipole will be attached at 20' and the other
end will
be about 40'. My question is can the coax be tie-straped to the short
end
of the dipole antenna wire and run back with it toward the houes?
This is
basically to keep a big loop from hanging down and also keeping the
wife
happy since it would look much cleaner. I didn't know if this would
have a
large impact on operation or not.

73
Doug / KC8YEC


Hi Doug,

I'm Running the Windom ( OFCD) it identical to what your saying. but
you'll find that the coax needs to come off the antenna in pretty much a
90 degree angle. ohterwise you will end up with lots of fedline
radiation which will cause problems in the shack.
73 Dave kc1di

Can you give me an indication about how long a lead I need before
running the coax back toward the house and into the radio? I'm going
to run the coax up the house and out to the feedpoint.

Doug

90 degrees under the antenna, not perpendicular at it's elevation. Get as
far away as possible, burying the feedline so your earlier dilemma will not
be worsened ;-)

I know my wife just _loves_ seeing that feedline "drop out of the sky" in
the middle of the lawn. But that's the way the antenna is designed. Suggest
you try that, determine it's efficiency by whatever means you can, then try
running it straight over to the house. I think we all agree it will lose
some output power back onto the feedline, but you could handle the safety
issue there, or try, with some RadioWorks line isolator products.

Jack

Hi Doug,

I'm Running the Windom ( OFCD) it identical to what your saying. but
you'll find that the coax needs to come off the antenna in pretty much a
90 degree angle. ohterwise you will end up with lots of fedline
radiation which will cause problems in the shack.
73 Dave kc1di


Can you give me an indication about how long a lead I need before
running the coax back toward the house and into the radio? I'm going
to run the coax up the house and out to the feedpoint.

Doug

Hi again Doug,

Was out of town so did not get your question for a few days.

You should run it away from the antenna at 90 degrees for about 1/4 wave
if possible. on 80M that would be about 66 ft. but as far as you can
in any event. some claim choke balun at 22' down the feedline works
well Mine is about 30' then a choke balun then about 75' to the shack
and it seem to work for me.
73 Dave