Hi Amos

From memory the Cisco 5.6GHz box had a path prediction sensitivy number
of about -87dBm. ie full speed with that input to the RX. I suspect that
at a lower data rates and extra 10dB might be a good number to use. I
have seen that larger microwave system manufacturers do publish their
specs so look it up for the equipment that is going to be used.

FM rcvs on 2M can often go to about -117dBm. An SSB rcvr on 2m with a
preamp hits thermal noise at about -141dBm. This also needs a good human
ear.

Cheers Bob VK2YQA

Amos Keag wrote:
Receiver sensitivity is unknown. I regularly communicate 20+ miles with
500 milliwatts from a ham radio walkie talkie. [the receiver is located
on top of a mountain] Most communiation grade radios can receive a
signal as small as 0.000000000000002 watts. [one millionth of a volt].
So, you can see why I say 400 milliwatts is plenty. So, the receiver you
use should have a moderately good sensitivity 5 microvolts or smaller.