STAY WELL CLEAR OF AM TRANSMITTER MASTS, because the first warning you'll get that it's active could be your last. AM transmitter masts are very often electrically energised with a radio frequency (RF) high voltage, meaning that if you get too close to the base you will be rewarded with a very nasty RF burn. Or death. The entire mast is supported on a surprisingly small bearing point. Although the long-wave antenna at Droitwich is a T supported from two masts, this mast doubles as a medium-wave antenna.