Lojack close call hit

dlwtrunked

Member
Premium Subscriber
Joined
Dec 19, 2002
Messages
708
Decoding the signal will only yield an unusable multi-digit reference code.

No specific user info.
That is not entirely true. Some analysis has been done. One can extract the transmitting base station identifier and other things. Google sdrtrunk and LoJack. Yes, sdrtrunk has a choice to decode LoJack although the documentation is incomplete and there are some errors.
 

dlwtrunked

Member
Premium Subscriber
Joined
Dec 19, 2002
Messages
708
I'm just put in the 173.075 frequency on my SDS200 and I get a squawk about every 10 seconds or so. It will squawk a few times and then maybe be silent for 1 minute. Sometimes I get what sounds

Brian (COMMSCAN)
Typically each base station transmits every 64 seconds at the start of an 8 second window (so there are 8 transmitting windows normally possibly limiting one to hearing 64/8 = 8 base stations. In my area, there are a lot of base stations meaning a transmission every 8 seconds can be heard from a base station with each base station heard again 64 seconds later. Any replying mobile unit will be heard between these.
 

letarotor

Member
Premium Subscriber
Joined
Dec 19, 2002
Messages
751
Location
Arlington, TX
Not quite right. There are 8 8-second windows in each 64 second period that can be used by different base stations. Stolen articles replay between those transmissions.
Yeah I think this kind of sounded like what I was hearing on Saturday or Sunday when I shot the video. It seemed like there would be a period of time every so often where you would hear no signals whatsoever for about one minute and then the cycle would start over again that sounded a little bit more like what you're describing in this example.

I do live near a lake where I am sure there may be boats on the lake that would also have LoJack installed on them. And like I mentioned earlier there's a highway that comes through my town that I've heard pursuits of stolen vehicles on numerous times through the years as well as some construction of roads in the area where they have a lot of machinery that might have LoJack installed . I really don't know how much it gets used anymore and I plan on doing a little research just to see if people are still buying it nowadays.

This is all fascinating to me because it's just not a signal I really had ever thought about being able to receive or decode and now I'm realizing a little bit of both can be done.

It sounds like NFM is the right mode to be using. Just really surprised that with all of the various band and frequency range searches I do, one being the 162. 6 - 174.0 + MHz range, that I have not been landing on this signal or did I even have it locked out or temporarily locked out on my SDS200 I've been using to search with a whole lot and also checking the LoJack frequency with the last few days. It's like I just missed the correct timing to be able to come across the signal and until I saw what the frequency was and manually put it in the radio I don't think I ever heard the LoJack transmitted data.

Since it's not really a signal you want to listen to all day, I think I'm going to put it in one of my older analog scanners and maybe even my old Yupiterru MVT-9000M that has a band scope where I can turn the signal down real low or even where it's not audible at all but where I can look over and see if anything changes with the signals being received.

I've never had anything like a LoJack installed and now that I am legally blind and have not been able to drive for a number of years, I really doubt I'll ever have a need for anything like that. But I guess the signal on the vehicle gets activated by the company when a vehicle or item is stolen. Obviously the GPS tracking is probably a lot more useful and helpful nowadays to vehicle owners. But then there's always the people that don't really know what they are buying and they just buy something because of a name they've heard of and I guess that keeps LoJack in business? I'm sure I can find this information if I do some searching but I figured I'd just ask and see if anybody can help me save time. How is the LoJack signal activated after something is stolen? Or is this a signal that is constantly going on a vehicle? I don't think it would be that last options since I have heard the police helicopter as well as the DPS helicopter searching for stolen vehicles with LoJack "activated" a number of times over the years. And even from the helicopters they seem to sometimes have a hard time narrowing down the signal location. But I have heard some successful cars recaptured and criminals arrested also from the use of LoJack even as recent as last year in one incident I can recall.

Since this is something I had never tried monitoring before and it has peaked my interest, I'm going to do some research and just learn what I can about how all of this works. It's always fun to find something new you can do with your radio hobby and passion :)

Thanks for the helpful information and details...

Sent from my SAMSUNG-SM-G930A using Tapatalk

Sent using Google Voice to Text. Please excuse any errors I could not see or catch.

Brian (COMMSCAN)
 

dlwtrunked

Member
Premium Subscriber
Joined
Dec 19, 2002
Messages
708
Decoding the signal will only yield an unusable multi-digit reference code.

No specific user info.
Decoding the base station will tell you the base station site number and what it is telling some (unidentifiable to us) asset what to do (slow down or speed up or turn off repetition of its transmissions, etc.)
sdr-trunk can do this but does things wrong...for example, you have to re-arrange the bits to get the right site ID.
Here are for example, the correct decoded site numbers for all of the MD base stations (not including 4-2,in Bethesda, that is part of the DC region):
10-1WPLP844ClarksvilleMD
10-2WPLP844BaltimoreMD
10-3WPLP844FrederickMD
10-4WPLP844Prince FrederickMD
10-5WPLP844HillsvilleMD
 

Dispatrick

Member
Premium Subscriber
Joined
May 17, 2004
Messages
468
Location
Bergen County, New Jersey
Sound clip is from Summer 2017 of a LoJack hit on my scanner while monitoring 173.075MHz

I was driving down the Parkway near the Driscoll Bridge at the time. Tracker signal went weak-strong-weak, obviously a vehicle going the opposite direction on the highway.

Can anyone figure out the vehicle lo-hi blip sounds (both the lower and higher sounds) in Hz?
 

Attachments

IC-R20

Member
Joined
Nov 19, 2018
Messages
130
64 seconds is the tower
10 seconds is the stolen article.
10 seconds is normal vehicle chirp rate. Actual Stolen vehicles are 1 second intervals. There's already tons of info on this on the RR and various other wikis as well as an RR forum thread about decoding it.
 

tvengr

Active Member
Joined
Feb 10, 2019
Messages
2,507
Location
Baltimore County, MD
If you hear a data burst once every second, that is a LoJack unit that has been activated. If you have ever seen 4 VHF antennas arranged in a square on the roof of a police car, they are used for the direction display on the LoJack receiver.
 

KK4JUG

Member
Premium Subscriber
Joined
Dec 13, 2014
Messages
3,060
Location
GA, AL, TX, OK, KS, AR, NC, or MI
If you hear a data burst once every second, that is a LoJack unit that has been activated. If you have ever seen 4 VHF antennas arranged in a square on the roof of a police car, they are used for the directional display on the LoJack receiver.
Not always. Local banks don't use dye packs. They use radio transmitters and several patrol vehicles have the necessary triangulation equipment to track the bait money.
 

IAmSixNine

Member
Feed Provider
Joined
Dec 19, 2002
Messages
1,871
Location
Dallas, TX
Lo Jack uses 4 antennas and ETS trackers (going of memory so i think thats what they called them) used 3 antennas. I have not heard a bank robbery tracking in over a year. So not sure they are still in use.
 
  • Like
Reactions: wtp

KK4JUG

Member
Premium Subscriber
Joined
Dec 13, 2014
Messages
3,060
Location
GA, AL, TX, OK, KS, AR, NC, or MI
You may be right. I've been retired from the PD for several years. While there have been some bank robberies, the ETS isn't something that's talked about out loud so I'm not sure they still use it. I'll ask or begin looking at the trunks of police cars.
 
Top