MikroTik

Hi All

What is the best way to space frequencies (between wireless interfaces) in a 5GHz network running a combination of 5MHz, 10MHz, 20MHz and 40MHz (turbo) bands? Thus, to ensure the least interference.

PS: My back haul links are horizontally polarized while my AP's are vertically polarized. The APs run in the 5MHz band and the back haul runs a combination of 10,20,40MHz.

Would appreciate your advice.

Thanks

Of course 5Mhz gives you less chance of interference, as it uses narrow channel space, but it also gives you less traffic, then wide channels 10/20/40.

You can use snooper from Winbox to get the detailed view of the network and select less overloaded space, as you may plan how much traffic will be required for the specific connection.

Thanks for the reply.

Are there some rule of thumb in terms of how far the the freqencies must be spaced? Eg, when running 5GHz-5MHz is it adequate to space the wireless interfaces with 5MHz intervals, eg, 5100, 5105, 5110 etc? Thus, when running normal 5GHz, one must space the frequencies by 20MHz?

Another question, when one has 3 access points on a tower, running the same SSID, must all 3 APs run on a different frequency - I presume so?

Thanks

Try and leave 5mhz or more be tween channels (edges) if gear is collocated. I find most cards seem to have selectivity of about -40db or so.. meaning if you do a scan can see a neighbouring channel at more the -60db you are likely to have problems particularly if there is no spacing between the channel edges and you need to receive signals that are weak. In general I use Vpol for back hauls and H for distribution. There tends to be less interference on Hpol which is important for P2MP. Back hauls have narrow beam widths and higher power so are less likely to be bothered by any interference.

Try and leave 5mhz or more be tween channels (edges) if gear is collocated. I find most cards seem to have selectivity of about -40db or so.. meaning if you do a scan can see a neighbouring channel at more the -60db you are likely to have problems particularly if there is no spacing between the channel edges and you need to receive signals that are weak. In general I use Vpol for back hauls and H for distribution. There tends to be less interference on Hpol which is important for P2MP. Back hauls have narrow beam widths and higher power so are less likely to be bothered by any interference.

Good reply here.
In general I would ad that you should try to keep freq. as far from each other as possible.
I made a sort of diagram in a spreadsheet that tells me which radio's use which freq's. and which radio's ´talk´ to another (BH).
Sometimes a BH radio on one end has no close freq band radio's near while on the other end it does. If you have several AP's and BH distributed over an area careful planning is needed.