WiFi Bridge

Perhaps hindsight? NLOS (non-line-o-sight) is the holy grail of wireless connectivity. Claims of amazing and miraculous connectivity through a variety of obstructions are rampant. My limited experience on 2.4Ghz is that you can usually achieve a connection, but staying connected 24x7 is almost always a marginal proposition. Therefore, I consider NLOS to be somewhat of a bad joke, along with "self configuring" and "self healing" networks.

The Pre-N (NINO) radios do a fairly good job of dealing with obstructions by bouncing signals all over the place and then attempting to put them all back together. It's sorta a statistical approach to redundant paths. However, they require 3 antennas at each and methinks such a derangement on a rooftop would not be aesthetically acceptable. (I said the same thing about pizza dish DBS antennas with 3ea LNB's and was proven wrong).

In general, the best advice is to find some line of sight. That could mean a taller mast, inconvenient radio location, creative antennas, or chain saw work.

However, all is not lost and there are some partial solutions. However, in all cases, you'll need to either spend some real money, or live with some performance losses.

  1. 900MHz radios. These will go through trees fairly well. However, they're slow. 115Kbit/sec to 750Kbit/sec is typical. 0 to 0 per radio. 2-4 mile range through a forest. 25 miles with line of sight. Bug me if you want vendors.
  2. Repeaters and WDS bridges. Instead of trying to get line-o-sight directly, you find a place to locate a repeater that both ends can see. Single radio (simplex) repeaters will cause a 50% loss of thruput. This may not be significant if you're sharing a DSL or cable mode. Dual radio (duplex) repeaters on different channels do not have this problem. However, now you need 4 radios total instead of two.
  3. Big ugly antennas. The rules for power output at 2.4Ghz are rather weird for point to point links. Legally, you can run a 24dBi dish antenna with a +24dBm (250milliwatt) transmitter. Given sufficient antenna gain (notice I didn't say sufficient xmit power as in a hang on power amplifier), you can sometime "drill" though a building or line of trees. If you can sorta see through the obstruction somewhat, you have a chance.
  4. Spatial diversity. Two radios at each end of a link. Each one has separate antennas. Multiport router (Freesco.org) with some sort of error detection script to optimize which link to use. With multilink, you also get twice the bandwidth through the link, but you don't need that. If one path goes down, the other one might be functional. One of my acquaintances did one of those with 4ea WRT54G boxes in bridge mode. When the trees sway one direction, one radio link works. When they sway the other direction, the other link is active. I've never seen the actual installation, but I've troubleshot the system remotely. It works. However, if you're gonna do this, make sure you have STP (spanning tree protocol) running and functional or you may create a loop.
Reply to
Jeff Liebermann
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Is there any alternative to line of sight?

Reply to
Phridge

for what? Please leave some context in your posts.

Reply to
Mark McIntyre

Maybe wire? ;-)

Reply to
Si Ballenger

braille?

Reply to
bryan

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