PaulS:
I will slowly try and implement a signal strength indicator.
And then you'll discover that it's mostly useless information. It is not going to tell you anything about distance.
You're probably right on this, maybe the most important info to be gleamed is if
you're close to the signal dropout point. RSSI will probably be very nonlinear falloff.
However, now that I went to the trouble to write the code, it might be interesting
to measure RSSI vs range, JFTHOI. I have tried so many different kinds of modules
now, might be interesting to compare them all.
Xbee = about 30 foot usable range.
nRF24L01+ = about 25 feet.
XBee Pro = 300 feet L.O.S.
RFM12 [1 mW, 433 Mhz] = about 120 feet -(frequency matters)