Probably it's just the general stability of the oscillator circuit. It seems to drift around 300 kHz around its center frequency of 340 MHz, so about +/-1‰. For

Probably it's just the general stability of the oscillator circuit. It seems to drift around 300 kHz around its center frequency of 340 MHz, so about +/-1‰. For such a very simple transmitter that's likely demodulated with an equally simple LC-filter and an envelope detector, it could just be be right "up to spec": http://imgur.com/l47Nm4B http://imgur.com/l47Nm4B Edit: % -> ‰