900MHz Sessions out of control

Hi all,

I currently have a 900MHz network that has been running great until the last week or so.

I have a single 900MHz AP running at 906, with 2 SMs.
In an average 8 hour period, both SMs will have as many as 120 sessions, with many reg and re-regs.
Signal @ both SMs is -71dBm, Jitter 2-3.
SM 1 distance is 12.47miles
SM 2 distance is 16.45miles

Sessions Status shows both SMs being seen @ AP with -68dBm, Jitter 2-3.
Link capaicty tests show 97-99% downlink, 100% uplink to both SMs when they are registered.
Distance Setting in AP is 17miles
All radios running 9.4.2
Spectrum analyzer @ AP shows noise level to be about -85dBmish. Everything running at 1X.
As this is a standalone AP, I have configured to Generate Sync.

Any ideas?


Interference by the AP maybe. Sit by the AP with a real spectrum analyzer for about an hour and see if you see anything. Did you try changing frequencies?


As it turns out the spectrum analyzer screenshot from Dec 23rd is now obsolete. I switched AP to SM and did new spectrum analysis.
Found noise floor to be -65 from 902 all the way up to about 922. (was running at 906)

I changed frequency to 924, seems to have helped one of the SMs, but the other is still dropping out.

I have ordered a CTM Express and will try to implement GPS sync as a last resort. If this does not help, then will have to move out of band.

You may also want to increase your range a bit. Add another couple miles in there. You might also turn the AP in SM mode, scan the channels and look at the AP Eval to see if it is another Canopy AP causing the interference.

Those are impressive link lengths…

I’ve tried to view the AP eval data, but they are hidden.

These links when first installed back in 2005, using the original tower location, were 22miles and 28miles. Interference levels got too high, built a new tower and moved the AP closer to shorten the links and improve signals…lasted for about 6 weeks, and now interfering ISP has moved in.

I also had the range set to 20 miles before dropping it to 17…no real changes positive or negative.