Antenna question

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tweekd
Posts: 5
Joined: Sun Feb 05, 2006 10:19 am

Antenna question

Post by tweekd »

Hey guys , new to the board here , & might I add this is a GREAT site that I wish I would have found it a bit sooner for other installs....!! lol
I have a bit of a petty antenna question actually .. I was inquiring upon where I could find the 4 LoJack antennas that are mounted on Police cruisers .... I have an Ex Highway Patrol cruiser that I am re-furbing for small car shows that I would like to keep true to form & such, but have not had any luck finding them .. If I am not mistaken , Antennex makes them but does not sell on their website ...

Any part numbers or info would be greatly appreciated..
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akardam
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Joined: Thu Mar 04, 2004 10:53 am

Post by akardam »

Well, since LoJack operates on 173.075, the dopplar antennas should be VHF high antennas. I've never got a super close look at them, but I know they're spring loaded at the base of the antenna. What kind of mount is in the car right now? NMO, LM, etc.
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tweekd
Posts: 5
Joined: Sun Feb 05, 2006 10:19 am

Post by tweekd »

Right now the holes mount a 3/4" NMO ... The only thing I can put together , is that they are the Antenex L8 stud mount with the shock spring & I believe 17 inch whip ... But I am not very sure ..
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007
Posts: 1546
Joined: Sat Nov 23, 2002 5:22 am
What radios do you own?: W7 FPP lowband MaraTrac w/AES

Post by 007 »

LoJack antennas can be any VHF antenna cut for 173 MHz.

Some agencies use 3/4" NMO mounts with generic whips, while others use Larsen 3/8" stud mounts with springs. If you have 3/4" holes, get 4 NMO mounts and some generic VHF whips.
Do not make Sig angry...he'll just keep ringing the bell.
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tweekd
Posts: 5
Joined: Sun Feb 05, 2006 10:19 am

Post by tweekd »

What would be the correct length for 173 mhz ..? About 17 - 18" ?
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Tom in D.C.
Posts: 3859
Joined: Tue Sep 04, 2001 4:00 pm
What radios do you own?: Progreso soup can with CRT

173 mHz quarter wave...

Post by Tom in D.C. »

About 16.25 inches. Or 16.231213 according to the formula.
Tom in D.C.
In 1920, the U.S. Post Office Department ruled
that children may not be sent by parcel post.
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tweekd
Posts: 5
Joined: Sun Feb 05, 2006 10:19 am

Post by tweekd »

THanks for the great info guys ... I found some Larsons that are almost identical to what I'm looking for ,, but they come with a 3/4 "LM" mount .. Or what looks to be a 5/16 stud mount .. I'm not familiar with this mount , is it similar to mounting & sealing like an NMO?
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