# aps without CMM

Can I have 3 APs covering 180 spread with Frequency Separation of 20 Mhz
without CMM …?

I’m far from an RF expert, but I don’t think that will work without a CMM. Consider the following:

AP 1 - 5750 MHz

AP 2 - 5770 MHz

AP 3 - 5790 MHz

So we have 20 MHz of seperation between the AP’s. I believe that when these signals are modulated, the carrier frequency is modulated 10 MHz in each direction. If this is case, then suppose AP-1 is transmitting while AP-2 is receiving. If AP-1 modulates its base frequency of 5750 MHz up 10 MHz, we are up to 5760 MHz. If AP-2 is receiving and is listening 10 MHz below its carrier of 5770 MHz, then it is listening at 5760 MHz, and we might have some desense problems.

I could be way off on this one, perhaps someone with more knowledge can confirm or deny my information. It all depends on the physical placement of your access-points, also. If they have enough physical seperation then it may work.

My recommendation -> use the CMM.

We r on 2.4 GHZ . I set as follows.

2417.5 from 2427.5 AP .

We r seeing lot of registration 7 re-registations on 2457.5 .

But seems ok . I mean we can postpone the CMM procurement for some time.

Changed to 1X at SM end for 2457.5 AP & made other 2 APs work on same frequency.

So far since the other 2 APs have single SM , not issues detected.The registrations / re-registrations r now nill…

Did you run the frame calculator since you have colocated advantage/non-advantage AP’s? Also, why are you not putting in max distance on the frequencies?

On Advantage AP which is on Freq. 2457.5 the Furthest SM is at 9 Miles . So I have put the distance as 10 miles in that AP. The SM at 9 miles is on 7.0.7 & is seeing lot of registrationsespecially after 6:30 PM to Morning 8:00 .It passes to some extent over river.

The Other 2 APs which r on 2417.5 (One Advantage AP & One Normal AP)
we have 1 Sm Each at 3 Miles.This SMs r rock solid stable.

We r trying to add One more SM whcih is in direction which is just between the above 2 APs at a distance of 13 miles.it registers with Normal AP but signal strength is very less.We need height at AP end & will be around 8/15 days to sort out this new AP as well as the Other SM which is 9 miles & seeing lot of registrations,sessions & registraations.

We would be updating to 7.2 .

we tried running our system without a cmm, it doesn’t work well. it will cause a timming issue. If there are any other aps in the area you will also be fighting them.

That is true.