Given a distance (in miles) and the antenna gain of each end (in dBi), this will predict theoretical success rates. These numbers are based on publically available specs for power output and receiver sensitivity. You can view the source here.
We'll assume you're using one meter of LMR-400 and a lightning arrestor on each side, allowing 0.25dB loss for each connector, and 1dB for each pigtail.
A more detailed worksheet can be found at: http://www.gbonline.com/~multiplx/wireless/wireless.main.cgi
| 11Mbps | |
| 5.5Mbps | |
| 2Mbps | |
| 1Mbps |