I have just started to put together a QRSS beacon transmitter, from some parts i had in my workshop. The transmitter is supposed to fit nicely into a junction box, for mounting outdoors. The size wasnt an issue as i thirst thought, i solderd together a colpits oscillator with a simple class A amplifier circuit, and with 13V it outputs about 50-60mW of RF into a 50ohm dummy load. Current draw is about 50mA, about 600mW, so effiency isnt that good, just about 10%. At the moment the circuit is equippped with a 7030kHz crystal, i will try to find a 30m one. Power supply will come from a battery, probalby solar charged. The circuit will be controlled by a AVR microprocessor, ATTINY25 or something like that. Does anyone know if 50mW is OK for QRSS? Or should i put a PA on the board and get 500mW instead? And what kind of speed would be good to start with? QRSS10?