Lo-Jack

[gmclam]

What might be interesting is a description of how Lo-Jack direction finding works. Do all receive setups have 4 antennas? Do they use the same "receiver"? In my area there are "towers" that also detect signals - do these locations just detect signals or do they also report a direction?

[ecps92]

Yes to direction-find you need all 4 antennas.

Yes there are towers that just Detect

Yes there are towers that Direction-find and connect back
to a central facility that could Plot [Triangulate] on a Map.

Originally Posted by gmclam

What might be interesting is a description of how Lo-Jack direction finding works. Do all receive setups have 4 antennas? Do they use the same "receiver"? In my area there are "towers" that also detect signals - do these locations just detect signals or do they also report a direction?

[letarotor]

LoJack is an old and established company (20+) and I would have thought the product would have become much more widespread here in the north Texas area by now, but it simply hasn't. I have seen their recent advertisements for installation in laptop computers, but never see any advertisements for vehicle installations. And the car dealers I have delt with never mention LoJack; "Oh, we can give you a number to call if you want to have it installed," the last salesman I delt with told me. The salesman was more interested in giving me some stupid window etchings with a number different from the vehicle serial number (a stupid idea, but obviously they make a commission on that). I guess the greedy car dealers want more of a commission than LoJack wants to pay; but that is the place to get the customers. Very few people are going to go out an purchase a 20+K auto then fork out an extra $800 cash for something like LoJack (Dubs and Twanky Duces being another story of course!). That kind of thing needs to be rolled into the monthly payment.

There are no receiver towers I'm aware of in our area. The system here relies on individual receivers in squad cars and police helicopters. There are less and less receivers being installed in new cruisers as they cycle cars through the ready lot. Someone with a hot LoJack could drive right though our city (1+million) and most officers on the street without receivers wouldn't be the wiser! We might get one or two hits a week, and I have yet to be involved in a recovery of a knicked laptop with a LoJack. It's a good and inexpensive system to get your car back. I don't have it in my rides because quite frankly I'm not sure I want my ride back after some punk has done Lord knows what with it! I'd rather they crash the thing or burn it so I can get the insurance money and get a new car! The insurance company will give you a break on your insurance because the quicker your car is recovered the more money they save.

MC

[specman]

Frankly with the advent of cheap and reliable GPS setups I'm surprised that LoJack still operates in the manner it does. It would take nothing to design a transmitter that simply outputs the current GPS position of a vehicle on a "hot" car. No need to triangulate anything; a central monitoring center or whatever could simply tell the cops where the car is in terms of map co-ordinates.

[Astrak]

Originally Posted by specman

Frankly with the advent of cheap and reliable GPS setups I'm surprised that LoJack still operates in the manner it does. It would take nothing to design a transmitter that simply outputs the current GPS position of a vehicle on a "hot" car. No need to triangulate anything; a central monitoring center or whatever could simply tell the cops where the car is in terms of map co-ordinates.

The downside to GPS is it needs a clear view of the sky to get a location, with lojack the car can be parked in a garage and still be located.

[specman]

Originally Posted by Astrak

The downside to GPS is it needs a clear view of the sky to get a location, with lojack the car can be parked in a garage and still be located.

Ahhh, good point. I suggest however that a mix of the two technologies would work well. The car would have had to have been driven outdoors until it "lost lock"; the transmitter could simply repeat the last co-ordinates. Todays GPS receivers work surprisingly well compared to older models two; in tests the GPS "puck" that I use will easilly obtain a lock anywhere inside the car passenger area, not just in the window.

For the LoJack scenario you could still have the necessarily receiving equipment to DF the hot car. The advantage to my scenario is that it would not require the large investment in infrastructure that the current LoJack system seems to require.

[N_Jay]

"Work" and "work well" are very different things.

GPS even on the roof of a car is very unreliable in urban settings.

Most consumer GPS units hide a lot of GPS errors from the use by matching to a map.

GPS is almost useless in any covered parking.

[specman]

Originally Posted by N_Jay

"Work" and "work well" are very different things.
GPS even on the roof of a car is very unreliable in urban settings.
Most consumer GPS units hide a lot of GPS errors from the use by matching to a map.
GPS is almost useless in any covered parking.

You need to get with the times N_Jay. Modern GPS receivers are getting over some of the obstacles you describe (other than a parking garage of course). For instance I have used a "hiking" type GPS unit in several urban excursions and have not exerienced any of the troubles you speak of. This type of GPS receiver does not rely on a map BTW.

Read my reply to the other poster for a "hybrid" type Lo-Jack that would use both technologies.

I apologize for steering this thread in a different direction.. just wanted to throw in some different ideas.

[specman]

duplicate post - please ignore

[ecps92]

And Shipping Containers at the PORT

Originally Posted by Astrak

The downside to GPS is it needs a clear view of the sky to get a location, with lojack the car can be parked in a garage and still be located.

[mancow]

Very true. Some of the newer generation covert tracking devices are down right amazing. They are designed to nav under the car with the antenna facing down toward the pavement. I guess they pick up the scatter of the GPS signals off the pavement. I don't see how it words but it does and it's not uncommon to get well over three satellites at a time, usually around 5-7. That's more than enough for very accurate tracking.

Originally Posted by specman

You need to get with the times N_Jay. Modern GPS receivers are getting over some of the obstacles you describe (other than a parking garage of course). For instance I have used a "hiking" type GPS unit in several urban excursions and have not exerienced any of the troubles you speak of. This type of GPS receiver does not rely on a map BTW.

Read my reply to the other poster for a "hybrid" type Lo-Jack that would use both technologies.

I apologize for steering this thread in a different direction.. just wanted to throw in some different ideas.

[Astrak]

Originally Posted by mancow

Very true. Some of the newer generation covert tracking devices are down right amazing. They are designed to nav under the car with the antenna facing down toward the pavement. I guess they pick up the scatter of the GPS signals off the pavement. I don't see how it words but it does and it's not uncommon to get well over three satellites at a time, usually around 5-7. That's more than enough for very accurate tracking.

Just from experience with survey grade GPS I know I could turn the receiver upside down about a half a foot from the ground and it would hold about 8 satellites but the received signal wasn't good enough to accurately survey, I know vehicle tracking doesn't have to be as accurate as surveying. I would imagine a consumer grade GPS only receiving L1 signals would be accurate to a few hundred feet if placed under a vehicle that might be good enough to locate a stolen vehicle.

[Hooligan]

It's nice to argue about how GPS would be better than Lo/Jack, but the people that are doing so aren't addressing other aspects of the LoJack system -- the activation of the transponder, transmitting the ID/location data stream to law enforcement vehicles in real-time, covert placement of the device, coverage inside enclosed areas/urban canyons, etc. Sophisticated crooks can detect the LoJack transmissions emanating from something they've stolen, then either ditch the item, try to mask the signal, or disable it.

I heard a story about a violent thug who went by the street-name "Wayniac" that stole a Jeep once & used a low-power transmitter keyed up on the LoJack frequency to block the Lojack-equipped Jeep from receiving the signal to activate it's LoJack transponder for a couple hours until he was able to strip the Jeep & locate the LoJack device & remove the battery for it.


GM's Onstar & some of the advanced features it offers (remote engine shutoff) is probably better than LoJack in many ways.

Back around the time LoJack was first introduced, there was a competing system called Teletrac which used 900MHz spread-spectrum. This was before GPS was cost-effective, so Teletrac used something like TDOA & a network of towers set up in & around urban areas. Teletrac could also be set up to remotely disable the vehicle, and an optional feature was to have audio from within the vehicle (presumably only when it'd been reported stolen) be monitored from the Teletrac network ops center.


Here in Northern California, the best anti-theft feature I could have on my vehicle are small signs on all sides reading "ATTENTION LAW ENFORCEMENT: IF YOU OBSERVE ANYONE OTHER THAN A WHITE MALE OPERATING THIS VEHICLE, PLEASE MAKE A FELONY-STOP ON IT" but I expect politically-correct people would vandalize the vehicle to punish me for perceived 'intolerance.'

[MGBGTRacer]

I found a Teletrac in a Range Rover I bought used- that thing was HELL to remove. It was tied into the ignition, fuel and several other circuits with miles of wires.

I used to get LoJack in all my new vehicles- they gave huge law enforcement discounts. Problem is that when I moved to the country from D.C. it rendered the lojack useless. I went all through the last car I had with one and never found it.

[letarotor]

No question, if you want your car back, get LoJack. Problem I've seen is it takes too long to activate. Police have to come to your location, take the report, call or type it into the report system, then a clerk somewhere has to get the report then enter the stolen vehicle into the NCIC system, then LoJack will activate the system. That can take close to two hours in my experience. Bad news for a vic in our area since that's about 1/3 of the way to Mexico! On-Star is better in that it can get activated quicker and doesn't require independent receivers in squad cars to pick it up. The problem with On-Star is most people do not renew the initial one-year trial subscription and when they get jacked or their car is stolen, they are SOL! That's when you tell the complainant, "Hope you don't owe more on the car than its worth."

Correct me if I'm wrong however, but systems like On-Star require a cell subscription and thus a cell antenna somewhere on the outside of the vehicle to transmit the GPS coordinates to the dispatch center? If the perp breaks off the cell antenna, will that render the system useless?

[n1das]

Anybody here keep the Lo-Jack transponder frequency in their scanners?

173.075 MHz

If my car were to get stolen, I pray that I DON'T get it back because of the condition it likely will be in.

[ecps92]

Depends, many have been recovered with minimal Damage, just due to the fact the theives will let it cool-down and see if it has Lo/Jack.

Actually found one wrapped in Aluminum Foil, in an attempt to block the signal

Originally Posted by n1das

Anybody here keep the Lo-Jack transponder frequency in their scanners?

173.075 MHz

If my car were to get stolen, I pray that I DON'T get it back because of the condition it likely will be in.

[jwb8734]

Originally Posted by ecps92

Actually found one wrapped in Aluminum Foil, in an attempt to block the signal

Are you kidding me Bill. Where was this? I want the pictures of this.

[ecps92]

I wish I had some. This was 15 yrs ago ! Amazing the tricks.

We also took the old WX Cubes and used them for DF'n [not as sensitive as a scanner] in parking garages etc.

Originally Posted by jwb8734

Are you kidding me Bill. Where was this? I want the pictures of this.

[Hooligan]

Originally Posted by letarotor

Correct me if I'm wrong however, but systems like On-Star require a cell subscription and thus a cell antenna somewhere on the outside of the vehicle to transmit the GPS coordinates to the dispatch center? If the perp breaks off the cell antenna, will that render the system useless?

The cellular/PCS connection is included in the basic service plan for OnStar. I certainly think you're right about a thief breaking off the antenna being possible, but I think that as OnStar has migrated up to PCS from the older 800MHz cellular system, they're integrating the PCS antenna into a combined PCS/GPS/FM radio receiver (& maybe also Sirius/XM!) antenna mounted on the roof, as opposed to the stand-alone 800MHz cellular system on-glass antenna that older OnStar-equipped vehicles have.

Just putting a tin can on it might be enough to degrade received GPS & tx'ed/RX'ed PCS signals enough so that the OnStar network can't be connected to, or at least doesn't get an accurate fix as to the car's location.

For the older OnStar 800MHz on-glass antennas, even if a bad-guy were to break off the 800MHz radiator, the coax & mount might be enough to act as an antenna with a nearby cell site.


I don't have OnStar, but I did peruse OnStar By GM | OnStar.com, Car Safety Device and Vehicle Security System before making this pontification.