Hello we plan to set up 4 routerboards on some mast for p2p links on diferent directions. what is recomendet distance betwen routerboards when it works on 5ghz band on diferent frequencies?what is recomended space betwen frequencies?
That involves a lot of factors especially what antennas you are using.
A “top tip” for P2P links converging on a mast is to try to design for the received power levels being similar. If you do that, you can get the frequencies and separations a lot closer.
Note that isn’t practical for the P2MP case where the subscribers are pretty well everywhere in terms of distance, and hence received power. But you said P2P so the above is really worth considering.
The parameters you have to juggle are
- received power levels (as above) - choose appropriate antnena gains
- antenna type (buy the best for front/back ratio and sidelobes)
- spatial separation (vertical on a mast, horizontally on a rooftop)
- angular separation (constrained by the directions the P2Ps are going)
- polarisation separation
- frequency separation.
Try and optimise all of the above.
Don’t use adjacent frequencies on adjacent antennas both linear and angular sense.
Using atheros cards, narrow channel width modes mean you can put the frequencies closer together.
I think that’s it - though I’m sure other users will comment more.
We did do some lab tests on this using 24dBi mesh parabolics to see how close we could get them. The results (at 20MHz, 54Mbps modulation) were amazingly good, i.e. they could be very close up providing the RX power level rule was followed, even on adjacent channels. But it was not “real life”, so I would hesitate making any recommendations from that.
Regards
CableFree Solutions