Tilt on APs

I would like some input on how much tilt, if any, should be applied to 5.7Ghz Advantage APs, and what experiences people have had with using tilt on their APs.

We currently have a tower with a few customers at 8.5 and 10.5 miles out. Their service seems to drop-out at times. If I did my calculation correctly, even 1 degree of downward tilt on a 350 ft tower has the signal going into the ground at 20054 ft (~4 miles) (based on triangle math: hypotenuse = 350ft / cos 89 degrees). We have played with tilt and have improved the signal strength for those customers in the mid-range 2 - 5 miles out, but we may have adversely affected those customers further out.

Thoughts - experiences?

Moto provides a M$ Spreadsheet to aid in this very decision.

http://www.canopywireless.com/click.php?code=1040

I’m also serving a mirror of some wireless tools (including an antenna tilt calculator) from the Green Bay Professional Packet Radio (gbppr.org). They help me quite a lot, feel free to use them.

http://lagasse.racc2000.com/wireless/

We use 900MHz mostly, and don’t have it nearly as high. That said, we mostly use 85 degrees (or 5 deg down tilt) on our towers

The 2.4, 5.2, 5.7 APs have a 3 dB antenna beam width of 60 degrees for vertical and horizontal. I can’t imagine a few degress (1-5) making a diffrence. If any one has experience with downtilt making a difference for the AP’s please let me know.

The tilt is very important to SM with a passive dish that has a 3 db beam width of only 6 degrees (horz and vert) for 5.7 Ghz (17 deg. for 2.4 Ghz SM with reflector).