# Antenna downtilt

I know this is not the first time the question came up, but I have a different question. If I have a 130 ft. tower and I need to cover 6 miles, What would be the antenna downtilt? i.e.: Should the upper portion of the vertical beamwidth hit the 6 mile mark, or should I aim to have the center of the antenna hit the 6 mile and let the upper portion of the beamwidth get lost in the air?

conectorized antenna?
standard Ap does not need downtilt.

yes, connectorized antenna, 7 degree vertical beamwidth

What brand of antenna?

Terrawave… but does it really matter?

Assuming the ground is flat this would put the center of the beam at the 6 mile mark.

So 6 miles = 31680 ft

A is the down tilt angle.

if tan(A) = 130/31680

arctan(130/31680) = A
A = 0.23 degrees

I would leave the down tilt at 0 degrees. Pretty hard to down tilt 0.23 degrees.

How close is the closest subscriber?

The closest subscriber would be around 1 to 2 miles

As reseibel said, go with the horizon or slightly below the horizon.

Too much downtilt and you will get ground bounce causing other issues.

So long story short, the center beam should be the one to hit the ground at 6 miles?

With your antenna, what everyone is saying is that you do not need to worry about adding downtilt.

Your subscribers are close enough that the antenna placed on the tower or AP site will provide more than enough signal to cover the area.

I was just thinking about purchasing a new antenna for our tower and had a similar question.

How do I determine if the vertical beam width is too low? My closest customer is about 9500ft away and our tower is 500ft. The antenna we we’re looking at has a 15 Degree vertical beam. Anyone know the formula?