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Author Topic: Home brew 2 meter antenna info needed  (Read 736 times)
KD5OAU-911
Member

Posts: 3




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« on: June 19, 2001, 10:39:07 PM »

I want to make a 2 meter antenna out of a steel whip that has been cut down to size but I belive it will need some kind of coil. If anyone has plans or info on how I could do this it would be of great help

73s
kd5oau
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KC8AXJ
Member

Posts: 303




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« Reply #1 on: June 21, 2001, 05:23:10 PM »

Well, with out more info on what you have there,
I'll take a stab at it.

If what you are using to mount it to the vehicle is
just a straight feed from the coax to the element,
you could use 19.25" of element length and it would
be a 1/4 wave. That is if your mag mount or direct
mno, or 3/8 thread base (whatever) has no coil in it.
The other part of the antenna (reflection) would
use your vehicle body as a ground plane to "work"
against. If said area is steel that is.
Going any longer with the "whip" gets quite tricky
as that's when you start making 5/8 wave elements
and they require coils to make the match for 50 ohlms.
SOOOOOOO many factors there to get the correct impedence I don't know how a person could homebrew such
a thing. Some people on bikes make 1/2 wave antennas but I think for that to work you need to feed it with a
1/2 wave of coax length.

Well that's my 2 cents,

73      Steve  kc8axj@arrl.net

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KL7IPV
Member

Posts: 984




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« Reply #2 on: June 22, 2001, 12:53:09 AM »

And here is my 2 cents...... get an old CB antenna with a magnetic coil base. Cut the antenna down to 39" and remove the cover on the coil. Short out the coil by soldering a piece of wire from the bottom to the top of the coil. Adjust the whip until you get the SWR right. Go mobile. I have done that and it works well. Cheap too!
73,
Frank
KL7IPV
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