We are deploying ePMP 3000 with the 4x4 sectors. These have 2* downtilt built-in already. We are at 300 feet on this tower and need to go out about 10 miles. Using some online calculators, it appears we should have a total downtilt of roughly 3.2 or 3.3* including electrical. So this means 1.2 to 1.3* mechanical downtilt.
When I use LINKPlanner, it shows I need 2.5* mechanical which would be 4.5* total downtilt for about 9.5 miles.
Why the discrepancy or what do you recommend for optimal downtilt to prevent interference?
Use link planner, its down tilt calc is very good and fairly reliable with a properly selected antenna.
We use KP Performance antennas and for 10 miles (16km) we use 8 degree downtilt on a 150ft grain elevator. This was determined by using the antenna data sheets and a little geometry to calculate the down tilt for connections at 10 miles.
You can also use link planner, add a SM at 10 miles and then run the down tilt calc for that AP and antenna combo. This will be extremely close to what you actually need for just about any other antenna if not in link planner.