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lookng for ideas- coaxial VHF ant. covert application

Posted: Fri Jul 01, 2005 5:28 am
by jrm5265
I work for a regional drug task force and were trying to improve the tx of our repeater for the bug unit, anybody know a source for a "coaxial" antenna thats proffesionally done and cut to the freq professioanlly (so I know it right" need it to be about 10' long has to be hidden in random vehicles, the vehicles dont belong to us so not an option to permanently fix antennas hidden in vehicle its sorta jerk and run application/installs

would be at 167mhz

Thanks
Joe Mobley

Posted: Fri Jul 01, 2005 6:08 am
by mancow
Have you seen the coat hanger or kleenex box antennas?
Several companies offer them for around $100 but you can make one very easily.

Inside they are simply RG174 coax with the braid and hot separated in the proper length for the frequency to form a dipole.

They work surprisingly well.


mancow

re temp antenna

Posted: Fri Jul 01, 2005 8:42 am
by jhook
a friend of mine years ago built me i guess what they call a portable throw up antenna for my portable basiclly the same thing as above ,it's made out of a piece of coax and some of the old tv lead in wire i believe they called it ladder wire its that flat 2 wire cable for old style tv antenna . i still use it off and on still today and it does seem to work pretty good maybe try a google search for portable throw up antenna i know he got the instructions off the web probbally a ham radio site good luck Jhook

antenna

Posted: Fri Nov 11, 2005 5:11 pm
by jrm5265
will Casey Crane please contact me I want you to make me another one of those antennas

Joe

Posted: Fri Nov 11, 2005 7:17 pm
by kb0nly
By the sound of it you guys are talking about a J-Pole antenna.

Easy to make with some 300ohm tv twinlead from rat shack. The other style that Mancow described is also easy to make. Basically your folding back the shield to allow the center conductor to become the radiating element, the whip, of the antenna. The shield folded back becomes the radials, or ground plane. It's a very simple design, and if your not looking for super range it works great.

A J-Pole is also easy to make and tune for any band. There is plenty of sites out there with J-Pole calculators on them, just type in your frequency, or the center of a range that you need, and it gives you all the dimensions to build it in one click.

What type of antenna was it that Casey made you? Post a pic of it maybe? If you can't get a hold of the guy i could help out with another source or even help you build one.

Posted: Sat Nov 12, 2005 12:19 pm
by paramedic218
wouldn't a small vhf portable radio with a magnet or some type of hanger work. just a thought ???

ant

Posted: Sat Nov 12, 2005 3:51 pm
by jrm5265
what we ended up doing was taking a dipole (coaxial) antenna and arranging it in or on a coathanger and then put something over it worked good

Posted: Sat Nov 12, 2005 7:49 pm
by mancow
Yep, and the LEA body wire company wants $100 for that exact thing.

:lol:


crazy