Alpha fm 433mhz keyfob transmitter module smd rf solutions alpha tx433s the alpha fm 433mhz keyfob transmitter module smd alpha tx433s is an extremely cost effective but high performance radio module supplied in a miniature surface mount package these modules can transmitreceive at up to 115kbps at up to 300m range operating at 2 5v both transmitter and receiver monitor their battery voltage and can sleep with very low standby current the modules can wake intermittently and provide