I worked for IDOT 1978 2002 We had old Motorola and a few old ISPERN radios that were changed to our frequencies on low band VHF. In the early 80's we got new low band radios that when the mic was keyed the dispatcher at the District HQ could see who was transmitting even if no audio was used, This really cleaned up the radio traffic, Especially on night time snow removal operations! The Motorola Motracs and the long whip antennas were the best! Truck to truck with easily a range of 40 to 50 miles. They were tube type radios that would really buzz when you keyed them up! The good ole days