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Author Topic: LoJack T Hunt  (Read 1905 times)

W0RW

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LoJack T Hunt
« on: January 31, 2019, 01:36:59 PM »

I was checking around the shack for noises and came across a big data burst on the LoJack frequency (173.075). It was swamping my HT receiver. I have a tin coffee can that I use as a shield for really strong signals to prevent overloading. My FT-411 and Baofeng UV-5R are both poorly shielded so I put the UV-5R into the can and attached a 60 dB variable attenuator and went out side hunting.
I didn't use my beam because it is now tuned to 146 MHz.
The UV-5R doesn't have an S meter, so I just opened the squelch and had lots of hiss noise to
detect the signal. The LoJack is a data burst (1-2 seconds every 65 seconds).
You have probably seen the police cars with the 4 - 17 inch meter whips on the roof. They do T Hunts automatically. I don't have one of those.
Well, I walked up and down the block switching from 30 to 40dB attenuation and the LoJack signal
was really strong. There was only one car around that is a spare car parked next door.
I was able to click in 55dB attenuation and still strong at the car. I went over to the passengers side rear window and got 60 dB and could still hear it. Then I saw the antenna. 2 little black vertical black stripes on the window, It is a FORD.  The police probably get a lot of these false signals. Distance from my shack was 50 feet. Real DX T Hunting.
The owner didn't even know what LoJack was. I told him to take it to the dealer and reset it.
It is like Probable Cause for any Police T Hunter to stop you, (Felony Stop with pistols).

Paul   w0rw

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WB5WPA

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RE: LoJack T Hunt
« Reply #1 on: January 31, 2019, 02:23:37 PM »

I think I've had VHF broadcast TV affected by LoJack equipped vehicles driving by ... with practically no antenna on a RS Pro-2006 I can receive databursts - those things must be everywhere!

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W0RW

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RE: LoJack T Hunt
« Reply #2 on: February 02, 2019, 10:03:10 AM »

VERY IMPORTANT:
I forgot to mention that real 'LoJack' signals come from Hijacked (Stolen) cars.
Many car thieves are armed and if you come around with a DF system, you will look like a cop,
So Don't Do This at Home.
Paul   w0rw
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KD6VXI

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Re: LoJack T Hunt
« Reply #3 on: November 02, 2022, 12:39:00 PM »

I was checking around the shack for noises and came across a big data burst on the LoJack frequency (173.075). It was swamping my HT receiver. I have a tin coffee can that I use as a shield for really strong signals to prevent overloading. My FT-411 and Baofeng UV-5R are both poorly shielded so I put the UV-5R into the can and attached a 60 dB variable attenuator and went out side hunting.
I didn't use my beam because it is now tuned to 146 MHz.
The UV-5R doesn't have an S meter, so I just opened the squelch and had lots of hiss noise to
detect the signal. The LoJack is a data burst (1-2 seconds every 65 seconds).
You have probably seen the police cars with the 4 - 17 inch meter whips on the roof. They do T Hunts automatically. I don't have one of those.
Well, I walked up and down the block switching from 30 to 40dB attenuation and the LoJack signal
was really strong. There was only one car around that is a spare car parked next door.
I was able to click in 55dB attenuation and still strong at the car. I went over to the passengers side rear window and got 60 dB and could still hear it. Then I saw the antenna. 2 little black vertical black stripes on the window, It is a FORD.  The police probably get a lot of these false signals. Distance from my shack was 50 feet. Real DX T Hunting.
The owner didn't even know what LoJack was. I told him to take it to the dealer and reset it.
It is like Probable Cause for any Police T Hunter to stop you, (Felony Stop with pistols).

Paul   w0rw

Get a copy of SDRTRUNK.  It decodes LoJack.

--Shane
WP2ASS / ex KD6VXI
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KD6VXI

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Re: RE: LoJack T Hunt
« Reply #4 on: November 02, 2022, 12:39:58 PM »

VERY IMPORTANT:
I forgot to mention that real 'LoJack' signals come from Hijacked (Stolen) cars.
Many car thieves are armed and if you come around with a DF system, you will look like a cop,
So Don't Do This at Home.
Paul   w0rw

While I agree don't go up to the car, most car thieves aren't going to shoot a cop.  They are going to do everything they can to get away without being caught.

--Shane
WP2ASS / ex KD6VXI
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