Maximum number of Repeater

[ajarina]

I want to connect 2 sites with an estimate distance of 38-40 kilometers. Based on physical obstruction like mountains in between them, we estimate that we need 4 repeaters for this connection. Whats the maximum number of repeater that we can install? How much bandwidth can be made available for the connection? Please advise...

[jaunger]

In general, when you use a single bridge as a repeater, your throughput is cut in half (actually,

you may only get 40-45%). If you use 4 repeaters you can see that 1/2 of 1/2 of 1/2 of 1/2 is

approximately 1/16. A better way is to use 2 bridges Ethernet connected back-to-back as

a repeater (although this requires twice as many bridges). With this configuration, your throughput may be 85% of normal. For maximum throughput, put

the back-to-back bridges on different frequencies so their packets do not collide.

Also try to get a little (10 feet, for example) of vertical separation between the antennas. Finally,

consider the latency of each repeater (could be 20 ms, for example) and the effect that this

will have on your applications running end-to-end. 4 repeaters may be stretching it a bit.

On the other hand, depending on your applications, it just might work out for you.

Good luck!

[blue.modal]

You might consider circular polarization to cut the number of repeater location. Especially if you can get on top of any of the mountains that you are trying to work around.

It's a 'don't try this at home' solution if you are not experienced in RF work.

[cheath]

Does this require modification of the feed? Can an off the shelf antenna be modified?

How about a Pringles Can? ;-)

[blue.modal]

I don't think I would suggest a Pringle can for Alann's 40km link, but any brave soul like yourself is free to try it!

Circular polarized antennas aren't easy to find, but the 'modification' should be the RP-TNC to N connector.