When you buy a car nowadays, along with the undercoating and satellite radio, the dealer often tries to sell a theft-recovery system called LoJack. This works via a two-way data radio installed out of sight in the car. If the owner reports the car as having stolen, the police broadcast a signal at 173.075 MHz with that car unit's serial number. The targeted unit answers on the same frequency, telling police the vehicle's make, model and registration, and letting them home in on the source of the transmission.
More advanced models don't wait for the owner's theft report. If the on-board system detects the car is being towed or started without a key, it sends an alarm to the LoJack headquarters, which notifies the owner that the vehicle might be in the process of being stolen.
The former rules were very limited as to permitted applications ("recovering stolen vehicles," period) and greatly restricted the duration of transmissions and how often they could occur. Licensees also had to show they caused little or no interference to TV channel 7, which lies close to 173.075 MHz (Although
other companies are eligible to use the frequency, so far only LoJack has applied.)
Now, at LoJack's request, the FCC has adopted several rule changes:
- roughly doubled the permitted power for both base stations and car-mounted units;
- allowed more frequent and longer transmissions;
- allowed more flexibility as to modulation; and
- greatly broadened the allowable uses. In addition to tracking and recovering vehicles, the system can also be used to track stolen or missing cargo and hazardous materials, missing or wanted persons, individuals at risk, and individuals "of interest to law enforcement." Car-mounted units can also transmit automatic notifications of collisions and vehicle fires, and can send carjacking alerts.
The technical changes permit car-mounted units to provide data such as GPS locations for stolen vehicles, and hazardous-material information on highjacked trucks.
Several broadcast interests opposed the changes, fearing increased interference to channel 7. The FCC retained the requirement for channel 7 interference studies, over LoJack's objection, but otherwise gave the broadcasters' concerns little heed