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New Contributor

Electrical Interference on 7km bridge

I need to build a 7km bridge but there is a small electrical sub-station less than 500m from one of the end-points.  Is there any AP device that could successfully overcome electrical interference or do I need to build a secondary bridge to bypass the interference?

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MVP Guru

Re: Electrical Interference on 7km bridge

Did you experience of measure the influence of the sub station?

 

Will you be using WiFi? Which APs? Which antennas? Do you have free line-of sight? Enough height to account for your Fresnel zones?

 

A point-to-point link over 7km is not something obvious, and I'd estimate there are only a few people in the world who actually have experience with such links. I'd try to find a professional or company who has experience in similar projects.

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MVP Expert

Re: Electrical Interference on 7km bridge

7km with clear line of sight and clear fresnel zone, using the AP-374 with ANT-4x4-5314 antennas is doable so long as you are in a regulatory domain that allows maximum EIRP *and* the RF is clear. It also depends on what your bandwidth requirements are or what kind of traffic you are wanting to carry over it. Bandwidth will be determined by SNR and channel bandwidth. Multicast traffic of any kind of a non-starter.

 

Longest shot I have done is 12km/7mi with the AP-374/274 and out 30x30 14dBi antenna, in US at max power. While it worked, it was not super reliable. 7km is only a bit over 4mi, so barring 

 

In most cases, electricity generators and substations, if they generate any significant interference, usually does so in the 2.4Ghz band, which would would not want to run mesh over anyway. 5Ghz should be clearer, but you should validate that with a spectrum analyzer. No one will be able to answer that for you but you, on site with the tools.

 

What country/region is this for and I can look up regulatory. 


Jerrod Howard
Distinguished Technologist, TME
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New Contributor

Re: Electrical Interference on 7km bridge

I have a clear line of sight but on the side closest to the power station I am much lower and closer to their interference.  It was suggested that I might need to use lasers but I had hoped the WiFi solution would be resilient enough.  Anything not affected by electromagnetic interference is very pricey.

 

I could also run a second bridge to a tower 200m away and then from there run a bridge to the 7km distance bypassing the sub-station.  This would require two bridges and a tower to be constructed but might end up lower cost.

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New Contributor

Re: Electrical Interference on 7km bridge

Northern Alberta, Canada.

 

This is definitely all unicast... simple bridge from point a to point b and there is nothing significant in between except this power sub-station.  I attached a couple pics from the roof of the one building looking at the horizon 7km away

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