I am attempting to assemble a wireless network in a wooded area
(campground aprox 1 mile radius) where campers would be able to have
internet access. I am looking for some possible solutions without
running any cabling. I also have a few buildings I would like to tie
into the system.
I currently have a cisco 350 access point, some workgroup bridges,
some 14dB gain amps, and a 15 dBi gain omni antenna.
What height would be optimal for the antenna? Am I going to need to
get more access points to use as repeaters or is there a better way of
Any suggestions would be greatly appreciated.
Such a high gain omni antenna will have a pretty flat "doughnut"
dispersion pattern, so if you mount it really high it will overshoot
everyone. If you can shoot under the trees you might be able to do some
good. But as Bob said, shooting through trees is usually a no-go. I've
had some luck up to a quarter mile or so shooting through a small amount
of trees, but I wouldn't start out designing a network to go through
trees unless you have 900MHz equipment.
Trees and 2.4Ghz do not mix. Broadleaf trees and trunks are like a
solid wall. Nothing gets through. Needles and light foliage might
You might wanna look into wireless repeaters and WDS (wireless
distribution something). They eliminate the wired backhauls, but cut
your effective bandwidth in half.
How far away?
Loose the amps. They cause more trouble than they're worth. Also,
you're going to be illegal if you use the amp with that setup.
Maximum into an omni is +30dBm (1 watt) into a 6dBi omni for a grand
total of +36dBm EIRP.
If you start with the +20dBm from the Cisco AP you'll be overdriving
the +14dB amplifier, which would allegedly be putting out +34dBm or
about 3 watts. My guess is your unspecified amplifier puts out no
more than 1 watt (+30dBm). Therefore, you'll need to add -4dB of
attenuation to use the amp effectively and limit your antenna gain to
6dBi. If you use the 15dBi omni antenna, you're way over the legal
With the +15dBi antenna and the +20dBm output Cisco 350, you're 1dB
below the absolute max EIRP limit.
Any reason why you didn't bother to specify the make and model so I
can lookup the vertical radiation angle and downtilt? This is a
serious problem with high gain vertical omni antennas. The vertical
radiation angle can easily be so narrow that if you mount the antenna
too high, you end up sending all the signal over everyone's head.
Even so, you will also have very little signal directly below the
for a decent 15dBi omni is 3 degree beamwidth (-3dB) and 3
degree downtilt. That's a mighty narrow beamwidth. You may have to
put it almost at ground level in order to make it work.
IMHO, repeaters and WDS doth suck. A better idea. Find a tree that
overlooks the campgrounds from the edge, not the center. Dump the
omni and replace it with a 8dBi panel or 120 degree sector antenna.
Point the panel antenna downward toward the campground. Keep the
antenna below the branch level to avoid tree cluttter. There's less
of that low to the ground. Use a 2nd radio, on a different channel,
to act as a transparent bridge to act as a backhaul to wherever.
A mesh network is perfect for your situation, there are a few companies that
make some great products, cant remember them all, one I think is Firetide.
Mesh is for those situations where the norm wont work