Today you see four antennas on police cars for digital diversity reception, originally desirable for minimizing multipath issues but today just about required f

Today you see four antennas on police cars for digital diversity reception, originally desirable for minimizing multipath issues but today just about required for P25 "phase II" operation of multiple repeaters on the same channel. These are usually 900MHz radios, one of the factors in the decline of traditional Lojack was many police departments shifting to 900MHz for P25 and no longer equipping all vehicles with VHF radios. Depending on the department, vehicles may not have any radio capable of receiving Lojack transponders. Whether or not they're programmed for it is also a question. When direction finding was used Doppler DF based on multiple antennas was rare due to the high cost of the electronics package, which also consumed a lot of trunk space. Most police departments did it the old fashioned way with a handheld log periodic they waved around. Another part of the decline of the original Lojack system was the high price of providing good DF receivers to police departments, so not many had them. LoJack never got big into having their own DF "hunters" on staff like other companies using transponders did.