Close Physical Proximity AP's on 2.4GHz

RouterOS Wireless Networking
1

Hi,

We share a hi site with a competitor. They have 5 AP’s and we have 4, all within a 50m radius. I noticed that the “seen” signal strengths of client units connected to the one AP would float between -60 and -100, which I put down to cross modulation (interference) from adjacent channels having a de-sensing effect on our AP’s, and I can only assume our competitor would be experiencing the same. Our one AP services a link of 25km to another node we have setup for a rural community, and this link would disconnect and connect every minute or so, within a second or two, annoying and disruptive.

In my search for a solution, I came across this image, which has proved to be very useful in resolving the problem.

Our competitor has his 5 AP’s set on 3 channels, 1,6 and 9. Channel 6 and 9 each have 2 AP’s on them.

I eventuality found stability by moving one of my AP’s to 5.8Ghz (it’s a backhaul), and placing the others at Channels 3,6,11 and 13. What is interesting is the 25km link mentioned earlier is now on Channel 6, with the two competitor AP’s, and that link has now been connected for 2 days 1hr without a drop. This defies logic, but works.

All our AP’s are either 411 or 433 RB’s, with four running R52 AR5413 wireless cards, and the 25km running a R52HN card, all at default power settings.Antenna are 15dBi 90 degree sector panels.

Thought I’d share this in the hope that a discussion can follow as to how others have dealt with these issues.

Regards

Brian

2

We use super cheap tplink 501 cpe’s so do not have channel 14.

and i can have only 2 frequencies on my tower. nething else kills. i am having 3 ap’s 433ah running channel 3 and channel 13. and rest ap’s operating at 5 ghz . but i am not satisfied with my 3rd AP running on channel 3. as soon as the bandwidth demand on that ap goes high it disturbs my other 2 AP’s running on channel 3 and 13.

just trying to do all sorts of things to keep ccq high and pthroughput high

3

I would suggest running the third AP on Channel 8 and 13. Channels 3,8 and 13 do not interfere with each other, and the problem you may be having is that if all 3 AP’s run on channel 3, when load gets very high on that Channel, the “noise” on the Channel (traffic that an AP “hears”, that is not directed to it) could slow ALL the AP’s on that channel down. An AP will not transmit whilst it hears other traffic on it’s frequency.