2,4Ghz - 5Ghz bands versus Powerlines.

[WirelessRudy]

Does anyone have experiance with radio links where the LOS crosses high powerlines. What is best to use, 2,4Ghz, 5Ghz or even other frequencies?

The powerlines cross straight througth the middle of the LOS on a almost 90 degree angle.

[M/Q]

I do not have any firm research on this subject. But, I suspect that since 802.11 is in the microwave frequency range it will not be affected by the power lines in the same way as it affects lower frequencies. In fact many BPL trials are using wireless equipment on the poles to provide Internet access to the local clients.

Again I have no proof, but I suspect that since you are at 90deg to the powerlines, that will be a huge plus. It is SOP to run any data cabling at 90deg to any power lines, so as to null out EMI (I think).

I would appreciate it if you kept us informed with your findings.

[WirelessRudy]

Thnks, Althoug I don't quite understand all your terms (BPL, SOP) I can see what you mean.
Actually the difference in wavelenght is huge so interference won't be the issue. It's more is it not blocking any pass through just because of the sheer power of the power lines. I mean, they act like huge antenna's with several MegaWatts of energie running.

But on the other hand, we all know the old Medium Wave or Long wave bandt car radios always had problems with powerlines while nowaday's FM is hardly affected.
But may be it has someting to do with modulation techniques. I don't know. I think we just need to try.

[M/Q]

BPL is Broadband over Powerlines and most likely will be the next big broadband technology. SOP is Standard Operating Procedures. WaveLength difference is not really as you suggested, as there are an infinite number of harmonics.

Also it is not the power per se, it is the EMI produced by the current flowing through the lines. And as I mentioned you are supposedly 90deg to that, it has to do with the RH or Faraday rule I believe. Forgive me, my EE was a long time ago.

http://en.wikipedia.org/wiki/Faraday_paradox

You are correct in that it is the modulation techniques that make the designs more interference proof, if you will. I also must admit that I am more of a IT type and an amateur radio operator, not a RF engineer

[WirelessRudy]

I think we are going to invest into two 5,x Ghz radio's with antenna's. We are not talking hell lot of money here and this way we will find out. I've got no other alternatives anyway. We will let you know the outcome when it is in the air. It might take some weeks, even months. I run a small amateur WISP and have other work to do actually bringing the cash to have the WISP set up. But I will come back on it.

Thnks.

[M/Q]

Great, I would appreciate that. Also, could you publish all of the details of the link setup if you have the time. Good experiment.

[FlaWireless]

I just installed a ptmp link using Cisco 1400s 5ghz.........the links are very near and some cross the power lines with no problems what so ever. 2 links at almost 4mi running strong at 54mbs.