if you need just a PtP for .8 mi why not take a look at the highgainantenna PtP 5.x radios. You can use them in the 5.8 ghz range for o/s use . They have a 40db eirp with a 23db built-in flat panel antenna. This would make the radio about 17-20 db.
this should give you 100 link quality with 30-50mb bandwidith for about 400.00.
You could also do this with the tranzeo 5.8ghz flat panel radios also
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Bob smith Robert Smith Consulting