With station automation so prevalent a good silence alarm is about mandatory. Broadcast tools VAD-2 fits the bill and its cheap. It is rather a pain to program but beyond that it dials a call list when silence is detected, ours is now set at 30seconds we had it at 1:30 but time is needed for corrective action.
In addition it has some status and relay commands that can be tripped by a cell phone. So if your remote does not have a cell phone call in… it would work… or for a very basic remote On/Off Power +/- and power normal.
There is an obscure FCC rule that you may have to shut the transmitter off within 3 min. (some say this for AM only?) The relay could go to beam off and in theory a person could do it from a cell phone in that time.
I hook the audio to our STL microwave as our Moseley 1620 will page if we are off the air, but it could be hooked to a cheap DTV converter box or FM radio to also tell you, off air. But normally in our case it indicates a programing error or satellite down.