advice on interference with another canopy WISP

Hello all -
Need some advice, please. My main tower has 3 900MHz APs on it with 3 sector antennas. I have the freqs set at 906,915,924 just like the moto docs says to do. Now there is another WISP about 18-20 miles away who is using an omni that was originally set to 906. His tower is almost straight north from mine. I have 2 sectors pointing his way- one at NEE, the other at NWW. The last one is direct south (they are 120 degrees apart).

He is saying that one of my APs is interfering with his single AP. He has suggested that we put all of our APs on the same freq to avoid problems.
It is my understanding that if you are using 2 or 3 sectors, they all have to be on different freqs. If you are using 4, then you can use the same freq on NS or EW, etc…

Am I correct?

By the way, my furthest customer is at 13 miles, and it is not in his direction. I have my max distance set at 14 miles.

He is also telling me to upgrade all my SMs to 8.2.2 and turn on schedule whitening and set the right country code. That setting has nothing do with 900MHz, from my reading.

Any advice would be wonderful. Please correct me if I’m wrong.

Above all else, are you both using GPS Sync? That far away should not be too big a problem IF you are both using GPS sync. Everything else is way down the list.

Yes, we are.

Neglected to put that in first post…

Whitening isn’t used for 900Mhz. It does nothing.

If you are both GPs synced, Make sure that you Distance settings, Downlink ratio and control slots are all the same on all the AP’s.

So maybe set all AP’s with the following:

Distance: 15miles
Control Slots: 2
Downlink: 75%
(This is just an example)

If you both use the same settings you shouldn’t have any problems. 20miles is lots of distance.

Is one of your northern-facing sectors using the same frequency that he is? If you can coordinate to re-use the same freq to the south, that should minimize interference for both of you. I’m not sure what the thinking is behind all AP on the same frequncy. That would kill your setup, not really an option, and would only make things worse.

If he’s operating with an omni, your best bet is to reuse one of the non-overlapping frequncies on your south AP and his omni. Also make sure that you use the same max distance, downlink ratio, and control slots, as those settings all affect how the band is used and the timing of the transmit/receive cycles. That should be an interference-free setup at that distance. Can you confirm for sure he’s using GPS sync and not generating it?

One last piece of advice: Balance your clients.

See this post for the definitive explanation of why and how to balance your clients.

You don’t have to have the same Max Distance, Control Slots and Downlink as the other guy to be in sync with him.

You can use the frame calculator to get the same Uplink Start time (included in every version 7.3.6 and below and 8.2 and above).

Good luck!