I am not sure if this is when these devices debuted however I vividly recall them back in the 1970's when night clubs utilized them on FM frequency. The latter was user-set within a clean, blank area of local FM broadcast. It was fun sitting outside of a lounge listening to performers with a wireless system within range if you had the patience to manually locate and tune in your automobile's FM radio to the frequency that the group or club utilized. PS...For you reel-to-reel recorder enthusiasts, the background probably is what part of Heaven must look like. I have always loved physically wide recording tape. Although I never fiddled much with reel-to-reel recorders, I have utilized VHS HiFi recorders with an amazingly high level of quality since I bought my first one in 1985. In that day the quality of VHS HiFi was quoted to rival digital music of the time and I always believed that. VHS HiFi audio recordings always (and were) easy. And inexpensive, particularly nowadays when people just about give away these fine recording machines of a couple decades ago...