Patrol Car Antennas
- Thread starter wcrock01
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Those would be for the Lo-Jack system. http://www.specialservicemustang.net/images/FHPfederal2.jpg
Those would be for the Lo-Jack system. http://www.specialservicemustang.net/images/FHPfederal2.jpg
LoJack - Wikipedia, the free encyclopedia
LoJack - Wikipedia, the free encyclopedia
JLM7424
Member
If all Four are Equaly Spaced and are Identical they Definetley Lo-Jack
These Pictures were found On : http://www.freqofnature.com/frequencies/common/lojack.shtml
These Pictures were found On : http://www.freqofnature.com/frequencies/common/lojack.shtml
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1radicalman
Newbie
2 part question related to LoJack Mobile Antennas - Police Vehicles
1) Does anyone know the brand and model of the 4 roof mounted antennas on police vehicle equipped LoJack Locators?
2) If I install 4 of those antennas in the same fashion as patrol vehicles, in your opinion, would I be able to tie the 4 cables into one terminated with a BNC connector to use it with my BCD536HP Uniden Scanner?
1) Does anyone know the brand and model of the 4 roof mounted antennas on police vehicle equipped LoJack Locators?
2) If I install 4 of those antennas in the same fashion as patrol vehicles, in your opinion, would I be able to tie the 4 cables into one terminated with a BNC connector to use it with my BCD536HP Uniden Scanner?
nd5y
Member
I have seen different kinds.
You could but it most likely would not work well. That isn't how the antennas are connected on a Lojack or other doppler direction finder.
mmckenna
I ♥ Ø
Varies, depends on who did the install.
LoJack uses 173.075MHz., so a 1/4 wave whip cut for something near that frequency would be used. Since they do not transmit, exact length isn't critical.
It wouldn't be directional, and unless all 4 antennas were phased together properly, it'd probably have a funky effect on the reception.
If you just want to listen for LoJack signals, you don't need all 4 antennas, just one will work fine.
If you are going for the "look", then install 4 antennas, but only hook one up to your scanner.
To make the array directional sensing.
Why would you want to do that?
NO!! They're not always Lo-Jack antennae. Some police cars use a locating system for bank robberies. Instead of dye packs, some banks use dummy packs of money that have transmitters. This allows officers to follow the suspects even while several blocks apart. It works.
1radicalman
Newbie
I was going for the looks (4 antennas) but also thinking that I can maximize the antenna reception capabilities. Kind of like fishing with 4 hooks in a line.
1radicalman
Newbie
You hit right on I was going for the looks and hoping also that I could maximize on the reception part, but I will likely follow your advice and install 4 but connect one. I don't know of any 4 into 1 splitter for this application anyways. Thanks for the response.
mmckenna
I ♥ Ø
If it's just for receiving, you can use a receive multicoupler. If you want to transmit, then you get into phasing harnesses.
n5ims
Member
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- Jul 25, 2004
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Generally the 4 square antennas are for Lojack. The bank money tracking system generally use 3 antennas in a triangle configuration. They're two different systems on different frequencies and some departments have both installed in the same vehicles (gives a real porcupine look). There are also fixed location devices that work on those systems as well. The antenna is a single mount with the three or four antennas on that mount with the hardware located in the antenna's base and feeds a box that transmits the direction and strength back to the local PD. Often there are at least three of these fixed locations in an area to help triangulate the location for the mobile units to do the fine tracking.
jim202
Member
Nope.
Project25_MASTR
Millennial Graying OBT Guy
Called pseudo-doppler. The array spins (electronically by switching antennas) and the receiver then measures the doppler shift for each antenna. Once that is known, a bearing relative to the cruiser can be ascertained with a bit of computing.
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