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Fred McKenzie · October 11th 07, 04:50 AM posted to rec.radio.amateur.homebrew

In article .com,
wrote:

I am trying to establish a wireless network for Internet Access, Video
Conferencing and Intranet Applications, I though to use either a
2.4GHz Sector or Omni Directional Antenna would do the job but I can
find any product that goes as far the distance I am trying to cover (a
radius of 20Km). My idea is to use a powerful radio with the Antenna
monted on a tall mast at the location of the internet feed (via VSAT),
this location is idea for LOS at the other locations.

Does anybody has experience/advise with this ?

As I understand the problem, the network would cover an area with a 20Km
RADIUS. You include a reference to an omnidirectional antenna and a
"powerful" radio, with the base station antenna mounted sufficiently
high to be line-of-sight from the end-users.

My thought is that you are a bit naive, describing a one-way system
similar to a Television or FM Broadcast Station. There are existing
systems used for providing community internet access, and I don't think
that is how they work!

While I'm not familiar with the community systems, there are technical
problems with your proposal. For one, it is a two-way system. If high
power is required at either end, it is required at both ends. Even with
a high gain antenna at the remote end, the gain works on both
transmitting and receiving.

For another, by using a single base station site to cover such a wide
area, the base station receiver will be exposed to various noise sources
over that entire area. The total interference from these sources will
reduce data rates for all users' transmissions toward the base station.

Perhaps Geoff's MESH Network or Bruce's WiFi Network would be a good
approach, but breaking the coverage area down into a more manageable
size and using multiple sites.

Fred
K4DII