[Scan-DC] Arlington Police Locate Missing Elderly ManUsingLoJack

[Andrew Clegg]

Here's what that FCC R&O has to say about the periodic bursts. When a car is 
reported stolen, the base stations send activation pings every 15 minute for 
2 hours, then every hour after that. I guess that due to the number of 
LoJack-equipped cars reported stolen at any given time, the base stations do 
a lot of pinging. That might be what you are hearing.

>From FCC 08-186:

LoJack's stolen vehicle recovery network operates as follows.  LoJack and
the licensed law enforcement agency install in each LoJack-registered
vehicle a vehicle location unit (VLU) that remains dormant until the owner
reports a vehicle theft.    Once police receive a stolen vehicle report, the
officials send an electronic message to a central law enforcement computer,
which causes a network of radio base stations licensed to the police to
broadcast a message that instructs the particular VLU to begin transmitting
a brief "tracking" message.   The base stations transmit activation messages
every fifteen minutes for the first two hours, then once an hour thereafter
until the vehicle is recovered or thirty days have passed, whichever is
sooner.   The VLU tracking message contains a unique reply code that is
received by vehicle tracking units (VTUs) located in law enforcement
vehicles.   Police identify the vehicle make, model and registration from
the reply code, and then use that information to track and recover the
stolen vehicle.   LoJack currently uses an alternative, uplink duty cycle to
facilitate its "Early Warning Detector" (EWD) operations.   When activated,
the EWD detects external movements of the vehicle or determines that the
vehicle has been started without use of a key and, thereupon, instructs the
VLU to begin transmitting a brief periodic tracking message, which contains
a unique reply code.   The nearest base station processes and forwards the
message to the LoJack central control center, whereupon LoJack personnel
immediately alert the car owner that the vehicle is possibly being stolen.



--------------------------------------------------
From: "Doug Kitchener" <oldsdoug at hotmail.com>
Sent: Saturday, February 05, 2011 10:28 PM
To: <scan-dc at mailman.qth.net>
Subject: Re: [Scan-DC] Arlington Police Locate Missing Elderly 
ManUsingLoJack

>
> Thanks to all for the responses... I'll have to digest all this stuff over 
> a day or two.
>
> Dewey, I'm inclined to agree with what you've described below... I figured 
> it was probably the system identifying itself and maybe signaling any 
> wayward vehicles to "phone home" or something along those lines.
>
> By the way, I'm a dope... I went down to the Auto Show this afternoon and 
> never even thought to see if LJ had a booth there...
>
> DK
>
> ----------------------------------------
>> From: dewey3 at gmail.com
>> To: scan-dc at mailman.qth.net
>> Date: Sat, 5 Feb 2011 20:32:46 -0500
>> Subject: Re: [Scan-DC] Arlington Police Locate Missing Elderly Man Using 
>> LoJack
>>
>> I hear what Doug is hearing. It's a data burst as described by Doug and 
>> not
>> beeping, also, it is at regular intervals. Maybe it's a system 
>> transmitter
>> that sends out "Daddy" signals, I just don't know. I do believe that when 
>> a
>> car is reported stolen, it is the system transmitters that send a signal 
>> out
>> to cause the stolen car to go into the "alert" mode (for lack of a better
>> term). Is it possible that these regularly scheduled data bursts contain
>> "routine housekeeping" data and include freshly reported stolen vehicle 
>> data?
>>
>> Dewey
>>
>> -----Original Message-----
>> From: scan-dc-bounces at mailman.qth.net
>> [mailto:scan-dc-bounces at mailman.qth.net] On Behalf Of cohenner at gmail.com
>> Sent: Saturday, February 05, 2011 20:21
>> To: Doug Kitchener; scan-dc-bounces at mailman.qth.net; 
>> scan-dc at mailman.qth.net
>> Subject: Re: [Scan-DC] Arlington Police Locate Missing Elderly
>> Man UsingLoJack
>>
>> I can tell you, the range on the people transmitters are not much - if I
>> remember correctly, its about 1/2 a mile or so.
>>
>> The sounds you hear on the receiving device is a beeping. The beeping 
>> gets
>> faster or slower depending on how far away you are from the transmitter.
>> ------Original Message------
>> From: Doug Kitchener
>> Sender: scan-dc-bounces at mailman.qth.net
>> To: scan-dc at mailman.qth.net
>> Subject: Re: [Scan-DC] Arlington Police Locate Missing Elderly Man
>> Using LoJack
>> Sent: Feb 5, 2011 12:48
>>
>>
>> OK, so I've programmed in the LoJack frequency below, and it's doing
>> something, because at regular periodic intervals I'm getting a squelch 
>> break
>> - possibly a data burst, as it sounds similar to the MSP helos' locator
>> beacons.
>>
>> But, what kind of signal / modulation does it use if it spots something? 
>> In
>> other woids, what does it sound like?  Also, what's the range?
>>
>> Thanks!
>
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