How to deal with interference?

Hello everyone,
I’m having a big interference problem on two of my APs.

There are A LOT of competitors and every channel except two is used and I can see them both client and AP side with signal > -75

My competitors are near me with their AP.

I’m using two free frequencies for two sectors, on a RB433 with two wireless card.
Protocol is nv2 and band 5GHz-N, 20MHz channel.

Some clients are getting high CCQ (>90%) and good speed (15-18mbps), others terrible CCQ (<40%) and low speed (< 2Mbps).

I scanned on the CPE side and I’m the only one who is using these frequencies.

I tried with nstreme instead of nv2, better speed but disconnections. 802.11 low speed.

Can you please tell me how do you solve this kind of problems?
I’m sure everyone had to deal with RF interference :slight_smile:

Thank you!

Fortunately, the FCC just authorized the expanded use of the UNII 1 band so you can change frequencies to that band if your clients will support it. Changing freqs is the only real solution. If the air space is saturated all you are going to do is beat your head against the wall.

Thank you for your reply!
Unfortunately also UNII 1 band channels are used, and i already tried to beat my head against the wall, but it didn’t solve the problem :laughing:

i already tried to beat my head against the wall, but it didn’t solve the problem

I’ve been there too :smiley:

Unfortunately, without clean air space everything becomes a trade off. You can decrease the channel size. That will help considerably, but the trade off is throughput. Have you ever used a wifi router in a crowed apartment complex? There may be dozens of routers, maybe even a hundreds of them, but for the most part, your stuff will work with your router. That’s because of the distance and and the power. If every bit of spectrum is dirty, you are going to have to increase the signal to noise ratio for everyone of your clients and your APs. You can accomplish this by:
Reducing the channel size
Using more directivity with your antennas
Installing customers closer to your APs
Using increased power

Many people will disagree with this next statement, but spend some time thinking about it. Broadcasting from tall towers and from the top of tall buildings is the worst way to build a network. An experienced network engineer will only used the high space for BHs. Use the landscape to your advantage. When you can drop down below the tree line everybody else’s signal is attenuated. That’s how you deliver good service for a long period of time. Make your hopes small, always use as much directivity as possible, and use the landscape to your advantage.

Changing the antenna polarity in crowded locations has helped me in the past.

Totally agree, once you have calculated height to clear freznel zone then look around and use a disadvantage to your advantage by placing say on the side of a building facing your clients rather than on top which would pick up unwanted signals also.

Change polarity is another good method to use

You can use closer sector antennas (40-60degrees) - Integrated with rb912. For example we use antennas with AL box
http://www.raytra.com/en/5g-anteny-parabola.php

433 - discard

What is wrong with 433?

I’m using two free frequencies for two sectors, on a > RB433 with two wireless card> .

This is problem in noisy enviroment!
Better is using → One antenna with one routerboard

+1

Thank you all guys, great feedback about your experiences!



What about using MIMO antennas?

If your interference is on say vertical polarity then there is no point using Vertical?

MIMO use both vertical and horizontal, is it a problem?

Some don’t use V+h but slant polarity but first establish which polarity gives you the least amount of interference and plan from there.

The dual polarity only come into to play with integrated antennas. For exanmple, you could use two horizontal antennas instead of a dual polarity antenna and it will work just fine.

http://www.rfelements.com/assets/sheets/MiMoSectorAntennasDatasheetEN2.pdf

If I use this and on client enable both or only horizontal polarities, does it work like using only horizontal?
I would like to use it as I have lots of clients already set on vertical polarity only!

You mentioned

I’m having a big interference problem on two of my APs.

are they the sectors attached to 433,

Yes, they are attached to 433, i meant “two of my sectors on an AP” :slight_smile:

Then the the first step in reducing interference caused by two radio cards attached to a 433 is to as others will advise is use 1 routerboard + 1 radiocard to a sector antenna

The problem is this place is very uncomfortable and I would like to reduce the number of RB to the minimum.
Do you know any trick to shield them better?
Is using 1RB => 1 Radio the only real solution?

Why is MikroTik selling routerboards with 2, 3, 4, 5 radio cards if using these slots is an issue?