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Could be radio interference. Have you tried disabling 2x mode? This will generally improve your efficiency.

tryed that, no help … how much of a metal roof can cross without bad RF also, how high above the roof do i need to be to get away from interfrence?

Every situation is unique depending on the material of the metal roof, and the pattern of corregation, etc. What you are probably seeing is reflected signal coming off the roof from the AP, arriving at the SM out of sync with the direct signal. That will effectively attenuate the received signal. If you’re using a connectorized radio try a different antenna (yagi for narrower beamwidth), or try a different location to avoid the bounce.

Rule of thumb we use is we always do a full survey from the installation location before mounting a radio. It saves putting extra holes in the client’s structure.

Good luck!

Thanks (i am logged in as a defferent user)

we have found an average of 4’ above the metal roof will take care of most of our problems

We just took over a Canopy network from another company yesterday. We had a service call that showed the exact same symptoms.
Uplink was 100%
Downlink was 20%

900 MHz AP with over 40 SMs registered. The AP only had it’s control slot value set to 0. I changed the number of control slots to 1. Rebooted and did a link capacity test from the SM. Uplink Efficiency 100%, Downlink Efficiency 100%.

I’d be interested to know how that solution plays out over the long haul. Is it possible for control slots to play that sort of havoc with a single SM? Or is it more likely that you caught the SM in different conditions; heat from direct sunlight gone, or maybe from the fresh reboot. I didn’t think that insufficient control slots would cause that kind of symptom. Report back to us if you get the chance.


So what does the control slot realy do?

Control slots are contention slots. The more SMs you have the more control slots you need so that all SMs have a fair and adequate opportunity to transmit and receive.

28 % downlink efficiency? Perhaps they have a continuous transmitting local interference source. Have you run the spectrum analyzer to see what’s out there?

it is local interference first ask ask your customer if he/she has a phone on the same freg of the SM 2nd is there a walmart or a nather ISP in your area? 3rd look in the SM logs and see if your getting wrong freq becons
if you are then tell the SM to only the freq that your AP is on