On 10/22/15 6:42 AM, Paul Christensen wrote:
Paul,
I am looking into a high power Wi-Fi solution to get our remote site off
DSL. The footprint edge of the Jacksonville-Comcast Xfinity service area is
approximately 10-12 miles away. The idea is to install a wireless site at a
Comcast subscriber location.
Any idea of the maximum expected LOS distance when running these units at
full power? We can get the Wi-Fi antenna at the remote site as high as 140
ft. AGL. Possibly two units would be installed, one at a lower height for
"lightning damage diversity," then switch between the two on the ground.
Paul, W9AC
It's on a tower, and relevant to ham applications, so I suppose it's
legal grist for the list..
What kind of antenna are you thinking about for the WiFi? and What band?
29 dBi antennas for 5.8 GHz are about $70, same size antenna is about
24dBi for 2.4 GHz band. These are the "barbecue grill" looking ones.
Are you thinking about polarization diversity? There's a fair number of
dual pol antennas available, although you could just bolt two of the
cheap grid antennas on, 90 degrees rotated from each other.
A back of the envelope for 2.4 GHz seems to show that with 24 dBi
antennas on both ends of the link, and radiating 100mW, you've got about
-60 dBm into the receiver. That seems like a lot of margin for WiFi. I
didn't allow for cable loss, antenna mismatch, etc.
I also don't know if 100mW into a 24dBi antenna will be too high for
Part 15 EIRP limits.
You'll need to calculate Fresnel zone distances to make sure you don't
pick a "bad" height. Curvature of the earth means you'll need to be at
least 20 ft high.
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