Hmmm, not the range I was hoping for, I had a LED toggle on and off when a valid length message arrived ( sent every 500ms )
I got 150m solid signal, but after that it would skip a flash, but never actually stopped receiving even up to 250m, it just missed flashes more often.
OK I will be using a yagi at the TX, and perhaps a dipole at the RX, so it could work, but its got to be reliable.
The fact that it still received at over 250m seems to suggest that the RF strength isn't the problem, perhaps its a signal/noise bandwidth issue ( I hate RF , even when I was a radio ham 50 years ago ! )
The fact that the range went from 7 meters to 150 just with my library pot luck twiddles makes me think that perhaps I am a quarter of the way to the answer, but don't know enough about the software.
I used SIM20 modules last year on a project, but the documentation is atricious, so I dont think I can get that working in a semi-duplex mode.
I got 500m range with them, also with a 170mm antenna wire.
These RFM22Bs are a third of the price, so I would like to get them going properly, and perhaps use the diversity combiner mode with 2 antennas to avoid dead spots.
I have just found this on a picaxe forum
"I was just doing some long range LOS tests with the 434Mhz tuned RRM22, I got 100% reception reliability at 4.3Km with 25mW output, 50% reliability at 12mW. This was using 5khz deviation and 250bps data rate with Manchester enabled. "
Anyone know how to set these parameters ( OK perhaps not that slow ) up with the RFM22B , there is a spreadsheet thing to calculate it, but as I said it doesn't work on my Openoffice :-
http://www.hoperf.com/upload/rf/RF22B%2023B%2031B%2042B%2043B%20Register%20Settings_RevB1-v5.xls
I basically want to send 10 bytes every half second, and receive similar from the robot, so its not a lot of data.