900mhz Radios Going deaf

Lately within the last few months we have started seeing an increasing amount of 900mhz SM’s going deaf. Different antennas (yagis, Stingers, Mars panels) so i dont think its a antenna doing it.But we are seeing almost 2-3 a week now, the AP will see them fine, say at a -68, but the SM wont see anything better than a -80. Put in a new SM and -68 both sides. Has anybody else seen this and or know what might be causing this? its really hurting us.

Do you seal your connector between SM and Antenna? Could moisture be getting into the connector?

yes we do with vapor seal and electrical tape

Hmmm, are the software versions on AP and SM the same? It’s odd that you would have that many SMs with failed receivers.

Yea all of our stuff is running 9.0. and yes it is odd . and very annoying

Maybe you received a bad batch??

We have seen the same problem and replacing the SM has fixed it but have no idea what is causing it.

mbsi wrote:
Maybe you received a bad batch??


Its both P9 and P10 board types. so its unlikely

Can’t say I’ve seen it lately but I had a 25 pack where around half of them were mute. AP could be heard at around 20db better than the AP could hear the SM. I don’t know if it was bad SMs or the firmware upgrade process (it didn’t start happening until 9.x) but I’ve since stopped upgrading the firmware on the bench and letting Prizm handle upgrades. They’re going straight to 9.3.

have you adjusted the SM power settings like it says in that post from jerry?

That was our WHOLE problem with 2.4 failures.

You might try dropping to 1X if you are running in 2X. I recently had an SM very close to the tower (1/4 mile) - registering at around -55dbi, but would only get 40-60% on link tests both ways. I dropped to 1x and it went straight to 100%. By the way, I know this is a hot signal - I tried lowering the power level to drop it, but my link tests were worse in 2x.

V9.0 software and P9AP with P10SM.

No we have not tried load balancing. Our terrain is to flat and woody to be turning people down.

And i dont think they are going deaf because the signal is too hot, most of these links are -65 to -75

i have seen some do this too. we had a 25 pack and about 4-5 went deaf. if we factory restored them they seem to do ok for a while but most go deaf again. we just pull them now and send them in for warranty.

are you going on site and logging into the radio to do a spectrum and ap eval?

are you seeing alot of noise, can you see the AP

The power management is critical, if you have to poorer links, and one single being seen at the AP at a -45 it will blind the AP to alot of the -70 and lower, in the 2.4 spectrum, we couldnt get 2 mile links LOS without a reflector, once we did it, we were able to take the reflector off and turn its power down even. Makes a HUGE difference. Mr Richardson Knows what hes talking about

I could see what your saying about the power management BUT…these radios we are taking down and going to other towers/aps and testing them and the radios are still deaf.

On edit: no theres not alot of noise but we cannot see the ap with decent numbers unless we replace the sm with a new one. after that everything is fine and peachy no more problems

if theyre still in warranty poke motorola in the eye and get some new ones, tell them youre looking at alvarions new vl900 line, tell them to sweeten the pot and make things right.