Wireless over 10+ miles (Mr. Bandel?)

[Shawn Tayler]

On Thu, 12 Oct 2006 12:51:30 -0500 "David Bandel" <david.bandel at gmail.com>
exclaimed:

> 20db SNR is _great_ signal.  Most of my shots have only about 12-15
> max, some less.  If your noise floor rises above about -92, I'd try
> another freq.
> 
> I just know what works for me.  But, unless you have all pygmy trees,
> 30 foot won't get you over the trees.  The antennas must "see" each
> other directly.
> 
> FYI, 10 mi over "flat" terrain requires 50 towers each end due to
> earth curvature (and that's with no trees in the way).  Also note that
> while RF curves somewhat, it curves differently than your sight, but
> not significantly.
> 

One thing to remember is that coax cable has loss.  At 2.4Ghz its really
lousy.  So, unless you want to invest in some very large diameter heliax
say 1-1/4 or 1-5/8, LDF6 or 7 to get you losses down, I would suggest
putting your wireless bridge as close to the antenna as possible, in a
rain resistant shielded box.  Run power and the ethernet up to it, the
loss is markedly lower for these signal types.  I also recommend proper
grounding of the tower as well as the shields of the lines as they leave
the antenna, tower, and enter your building.  A good line surge
suppressor(s), Polyphaser has a good line, along with another low
impedance ground run to the suppressor, I mount mine on a 4in by 18in by
1/8" copper plate.  I use 02 copper or 3-6 in copper strap to the  single
point ground ring in the dirt outside.  

Works fine and lasts a long time.

Shawn