You speak a lot about VirtualWire, this is no longer used. It was been replaced with RadioHead. There are no significant feature differences, afaik.<p>I&#x27;ll try this out tomorrow, using say 5 Arduinos with 433 MHz radios.<p>What antennas do you use for the radio modules? We&#x27;ve used quarter-wave monopole of 17.3 cm on both the receiver and transmitter with some success.