Inter Office Dilemna about power levels on all spectrums

There has been some debate lately on whether there is any improvement made by adjusting power levels on SM’s across the 2.4, 5.2, 5.4 and 5.7 Spectrums.

I was told once upon a time that no matter what the frequency you always want to adjust your transmit power on your SM’s to get to anything higher than -55dBm, anything lower is running too hot.

Recently I have been told that it has no effect except on the 900Mhz radios and have been asked to adjust sites and associated SM’s to -60 to -65 with -63 being the sweet spot.

We have over 500 AP sites that we would like to QC and cleanup as much as possible, and wondering if anyone has any thoughts on this before we waste a bunch of time doing it?


There are lots of discussions about this (usually called “power balancing”). My opinion is that it is worthwhile. I’ve seen improvements (lower re-reg counts, better signal levels) by balancing my SMs and doing my best to keep them all within 10-15db of each other. For example, on an AP maybe the highest signal I’ll have is -55 and I try to keep all of the SMs on that AP between -55 and -65 to -70.

One of the best analogies I’ve heard to describe it is picture you in the center of a dark room. around the perimeter of this room are people standing, aiming flashlights at you. If you have one guy two feet from you shining a flashlight in your face and another 15 feet from you shining a flashlight, the closer guy is probably going to overpower your sense of sight and you won’t be able to see (or see as well) the guy farther away. If the closer guy adjusts the brightness on his flashlight, it’s not so overpowering. Same goes for wireless.

It’s been argued that because Canopy utilizes time slots instead of a free for all like an 802.11 technology, that this power balancing does no good, but again, first hand experience proved otherwise for my deployment, which is mostly 900MHz but also has some 2.4GHz.

this might be useful on towers where you are re-using frequencies. if you are never re-using frequencies, then don’t bother. tdma solves any other problems for you.

read the post on balancing, the flashlight anology will answer your question across the board

twinkletoes wrote:
this might be useful on towers where you are re-using frequencies. if you are never re-using frequencies, then don't bother. tdma solves any other problems for you.

I disagree because my setup is just as you describe - I don't reuse frequencies (or at least don't if I can help it). When I faced this problem I was having issues with clients less than 5 miles from the tower unable to connect, but able to see and connect to an AP 15 miles away in the same direction (we have very flat terrain). TX power balancing solved the problem.


What Spectrums did you balance on your sites, where you were having issues with close in customers and the furthur out ones were fine? Also thanks to everyone who has chimed in.


it would be beneficial on all spectrums

We primarily deploy 900MHz in very flat terrain, so that is where we were seeing our issues. Depending on your terrain and natural vegetation, you may not have the same problems we had, but I had customers connecting to access points 15-20 miles away instead of the one that was 3 miles away. After power balancing everything behaved as expected. This was before we started using different color codes at our sites, but the fact remains that power balancing did improve the situation.

I have not seen the problem on my 2.4GHz sites, but they are not close enough to each other and the customers connected to them rarely have the option to connect to another tower. I still balance the levels on these APs though.

our initial canopy 2.4 deployment failed because of this, it wasnt til a year later when we got into the 900mhz and I read the rf balancing thread that I did that there and now the initial site is hot.

It was bad, I could figure out why we couldnt get a link at over like 2.5 miles that would stay stable, even less than a mile LOS required a reflector, just terrible.

Did the rf balancing act and all became good.

I dont know how you guys with big canopy networks can mainatain the balance when the seasons change.

its easy to keep them balanced, if you install all SMs as they should, 2.4 5.7 ect only LOS you should never need to go back and rebalance, our 900s only gain 5 or DB to the towers in the winter and doesn’t become much of a problem. our target is 60 DB for uplink (55 in winter) and everythings runs great… once upon a time we did not practice this and it was bad, when the seasons change