I'm not near a General Aviation airport anymore but when I was younger and worked at a FBO that had a busy flight school, we'd have every now and then a pilot have a hard landing and set off his ELT (emergency locator beacon, set off by high g-force) without it being known. Sometimes the mechanics would do so inadvertently. Our unicom was close enough to hear it if it was on our ramp, but sometimes the only warning would be seeing the FAA car with the 4 antennas on the roof go by on the ramps. We'd usually tip off the competition and the ramp rats and CFI's would scurry around with handhelds trying to find the culprit. I taught them the trick of using attenuation (dropping it a tube o' tin foil, removing the whip) to find it on a crowded ramp full of Pipers and Cessnas. If he found it first, there would be hell to pay but if we got to it then it was ok.
Avionic techs were permitted to briefly test them at a certain part of the hour, and no more than 3 whoops. One shop used to use one to announce to their techs on the ramp the coffee truck/roach coach had arrived. It didn't take long for the folks in the tower to pick up wrong time "tests" when that bunch would hurry into their building and the next time the FAA was waiting for them at the truck. They had to get pizza for everyone in the Tower, office and FSS, or eat the fine, and they gladly paid it, LOL.
At some point they were supposed to phase out the 121.5 ELT's and go to 406 MHz, but I don't know if they did that yet.