[Scan-DC] LoJack

[John Wilson]

  A LoJack transmitter is located in DC; in Virginia the locations are 
Fairfax, Fredericksburg, Richmond, Emporia and Hampton.  A new site is 
under construction on Bull Run Mtn.  With the exception of the Bull Run 
Mtn.site and Hampton site (I64), all other LoJack Virginia locations are 
near I95.  Base transmitters are 100 watts.  Vehicles are 2.5 watts.  So 
the lesson  learned for a thief is if he/she steals a LoJack equipped 
vehicle in order to reduce the risk of being detected, avoid NOVA, I95 
and I64.  In NOVA  west  he/she additionally is at risk of being 
detected by the Bull Run Mtn. site.  Additionally he/she has to fear a 
VSP or city/county LoJack equipped unit being in his/her immediate 
area.  Just a guess that the 2.5 watt input signal after factoring 
efficiency, antenna location, losses, etc., the output omni directional 
signal probably is much less than 1 watt on 173.0750 mhz.  Depending on 
the physical surroundings and terrain the mobile signal typically may be 
heard a less than a mile or two radius by a Lojack detection equipped 
vehicle.

Chris Smolinski wrote:

>> Does anyone monitor LoJack on 173.075? They send out a broadcast page on
>> this frequency when a car is reported stolen, then the car's LoJack 
>> system
>> starts sending out periodic pings on this frequency to be received by 
>> the
>> base station, and by direction finding equipment in some police cars. 
>> I used
>> to have this freq programmed in, but can't recall ever hearing anything.
>> This afternoon, the Arlington PD were getting a LoJack hit within two 
>> blocks
>> of my office, so I started listening. I never heard anything, and they
>> apparently lost the signal as well. Just curious if anyone has ever
>> encountered LoJack signals. I imagine they sound like brief bursts of 
>> data,
>> every 30 seconds or 1 minute or so (there's a rule about how often 
>> they can
>> transmit, but I forget what it is).
>>
>> DANG! Just as I was about to hit send, I heard a data ping. Maybe 
>> that's the
>> car they're looking for, or the base station? Nifty.
>>
>
> I 've heard pings on 173.075. I've never known if they were base 
> stations or cars. My understanding is that the cars ping at a slow 
> rate until the police get close, then they are instructed to ping at a 
> faster rate?
>
>