Telemax wrote:
"And would you guys say my 400 mw radio is overkill for 4 - 10 mile
shot?"

Depends on the whole system. The gains and losses must be totalled to
check for satisfaction.

Industrial microwave I put in almost 50 years ago was limited by the
klystrons available at reasonable cost at the time. As I recall, the
power was 1-watt or +30 dBm. At 6 GHz, the wavelength is only about 1
inch, so plenty of antenna gain was readily available. 6-ft parabolas
were common then and may have been a good cost to benefit trade off.
Their gain was near 38 dB at 6 GHz. We tried to limit our path to about
25 miles for reliability and the cost of radio towers. Here is how our
path might add up:

Free space loss: -140 dB
Antenna Gain (2ea): + 77 dB
Transmit power: + 30 dBm
Misc. loss (2 ea): - 5 dB

Received carrier pwr: - 38 dBm

A receiver sensitivity
for a multichannel RCVR: -80 dBm
would give us a fade margin of: 42 dB.

How would your system add up?

Best regards, Richard Harrison, KB5WZI