Currently have database polling every 60 days, inventory is showing data that has been out of service for over a year, how can this data be removed and why does it think it is still seeing hardware?

Deploying 1400 Bridges in a line of site type of configuration. The distance is right at 200 meters between building, am looking for any suggestions in regards to what type of antennas to deploy to get best bandwidth and narrowest beam, since this i...