The biggest AP I have has about 47 users on one sector running PPPoe with MPPE128 stateless. I run 2.4ghz b/g on this 90 degree pac wireless horizontal sector with an engenius radio card at 400mw.

I have customers down in the -30s ranging up to the -70s on signal wise.

I have been doing some research on this and a lot of people are saying that if you have a lot of people running on the weaker signal side that it will bring the speed down to 6mb/6mb.
My thinking of this would say if the sector is idle it will run this. If it is at a good load then it will run 54mb/54mb. Why are you some of guys saying that it will hurt your performance if you have customers connected running a weaker signal than others?

Just wanting to clear some things up. Your input would be appreciated greatly.

If the radio has to communicate with a weak client, -80 or worse, it drops speed down to keep a stable signal to them. The radio then changes speeds again to communicate with the higher speed client, then back to communicate with the lower, back, etc...

It costs time to change speeds. Also, the other clients often drop to 6mb as the AP is 6mb, dropping your overall bandwidth.

I've got one customer at -85 that is causing issues for everyone else. I've had that happen before, and once I got the other client up into the -70's, everyone else quit disconnecting, performance went up.

-30 is a bit strong, -70 is about perfect. I try to keep everyone's signal at the AP around -75 so a strong client won't overpower the signal of a weaker one.

-30 is a bit of overload for receiver, try adjusting these as the AP will try to jump from 6 to 54Mb, locking down the data rates will also help.

My understanding is that the datarate scaleback is based upon packet loss NOT signal strength.

You can have a rockin' datarate with a -85 signal if your ccq =100/100.
I find that even with a -60 signal and trees with 2-3 meters of your transmit antenna, can have detrimental effects upon you ccq.

That is correct.