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Old September 19th 05, 08:36 AM
Buther Boy
 
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Default Base Antenna Suggestions for Attic

Is there a good base antenna that can be used in the attic? I have a
lot of room, but haven't measured my attic. I would say there is at
least 12 feet of free vertical space...maybe even enough for an Imax
or A-99. Any suggestions you have would be great....Thanks!

Buther Boy

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Old September 19th 05, 02:40 PM
Vinnie S.
 
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On Mon, 19 Sep 2005 02:36:46 -0500, Buther Boy wrote:

Is there a good base antenna that can be used in the attic? I have a
lot of room, but haven't measured my attic. I would say there is at
least 12 feet of free vertical space...maybe even enough for an Imax
or A-99. Any suggestions you have would be great....Thanks!

Buther Boy



The Imax is 24 feet. Forget it. The A-99 is 18 feet. You would have to out it at
a 45 degree angle. You best bet is a 1/2 wave dipole.

Forget the vertical in the attic idea. I tried it and there was a ton of noise.
I was able to shoot skip, but had little local communications.

Vinnie S.
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Old September 19th 05, 10:56 PM
Buther Boy
 
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On Mon, 19 Sep 2005 09:40:13 -0400, Vinnie S.
wrote:

On Mon, 19 Sep 2005 02:36:46 -0500, Buther Boy wrote:

Is there a good base antenna that can be used in the attic? I have a
lot of room, but haven't measured my attic. I would say there is at
least 12 feet of free vertical space...maybe even enough for an Imax
or A-99. Any suggestions you have would be great....Thanks!

Buther Boy



The Imax is 24 feet. Forget it. The A-99 is 18 feet. You would have to out it at
a 45 degree angle. You best bet is a 1/2 wave dipole.

Forget the vertical in the attic idea. I tried it and there was a ton of noise.
I was able to shoot skip, but had little local communications.

Vinnie S.


Do you think I would be able to shoot skip with a 1/2 wave dipole? And
can you recommend a manufacturer or model number?

Thanks.

Buther Boy

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Old September 20th 05, 03:17 PM
Vinnie S.
 
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On Mon, 19 Sep 2005 16:56:53 -0500, Buther Boy wrote:



The Imax is 24 feet. Forget it. The A-99 is 18 feet. You would have to out it at
a 45 degree angle. You best bet is a 1/2 wave dipole.

Forget the vertical in the attic idea. I tried it and there was a ton of noise.
I was able to shoot skip, but had little local communications.

Vinnie S.


Do you think I would be able to shoot skip with a 1/2 wave dipole? And
can you recommend a manufacturer or model number?


Easily shoot skip. You would have some local success. But you might run some
TVI. Hang it as high as you can get it, away from AC power wires.

http://www.geocities.com/Augusta/7117/antenna.html

Here is the formula for the antenna. You can easily make you own. Get some 14
gauge wire from Home Depot. Cut the 2 wires about 9 feet long per leg, solder
one wire to the center conductor, and one wire to the ground braid, and then
trim 1/2 inch at a time, to the SWR you need. Make sure you use electrical tape
or shrink tubing to insulate where you solder. When trimming, trim both ends the
same amount, each time you cut. They need to be equal. You will be closer to
about 8.66 feet when it's all set and done. Some people say to just make it out
of the coax, and use the center conductor as one leg, and the braid as another.
That is much harder and much more expensive. Use the 14 gauge wire instead.

Use a good shielded coax like Belden 9913. Also, some people here have suggested
to coil the coax at the feedpoint using 10 turns - 6 inches apart. The best
thing to do is find a can about 6 inches in diameter, and wrap 10 turns of coax
around it, tape it and remove the can. This would choke stray RF and keep the
coax from radiating. I am not the antenna guru of this group. There are plenty
of them. This info comes from them, and most of it very helpful.


Whatever you do, don't run power with this. You will most likely produce TVI.
Get yourself a good TVI low pass filter with the money you save.

Vinnie S.
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Old September 20th 05, 03:30 PM
Frank Gilliland
 
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On Mon, 19 Sep 2005 02:36:46 -0500, Buther Boy wrote
in :

Is there a good base antenna that can be used in the attic? I have a
lot of room, but haven't measured my attic. I would say there is at
least 12 feet of free vertical space...maybe even enough for an Imax
or A-99. Any suggestions you have would be great....Thanks!

Buther Boy



Just use a 9' whip. Find a sheet of copper, brass or aluminum for a
base, drill a hole through the center for the stud, and mount it near
the center of the attic. For the ground plane, scrounge a transformer
for the wire, cut several pieces to go from the base to as far as you
can stretch them, then attach them to the base. Works great. And yes,
it works great for local comm, too. Vinnie's problem is that he didn't
follow directions and tried to cut the ground radials to resonance.
They -should- be cut for as long as your space will allow, which is
hopefully a lot longer than 9'.








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Old September 21st 05, 06:27 PM
GHB
 
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You have enough room in your attic to construct yourself a quarter wave
ground plane using a 102 inch SS whip, the spring, the mount, a metal
mounting surface and several 108 inch long aluminum ground plane elements.
You should place the vertical element as close as possible to the roof
without touching it which would let you position the ground plane elements
at an angle toward the floor(ceiling joists). Your coax center conductor
would tie to the vertical element while the coax shield would tie to the
ground plane elements. the vertical element absolutely should not touch the
ground plane elements or the antenna will not work. I hope this gives you
the general idea.
"Buther Boy" wrote in message
...
Is there a good base antenna that can be used in the attic? I have a
lot of room, but haven't measured my attic. I would say there is at
least 12 feet of free vertical space...maybe even enough for an Imax
or A-99. Any suggestions you have would be great....Thanks!

Buther Boy

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Remove the word Spam from my e-mail to contact me...
http://www.PrivacySig.com/SIGbutherb...mail-black.png
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