Help with 5.2 Backhaul levels

Not quite sure what is going on but I have 4 back haul links whose power levels have dropped about 20 to 30 dB. I did a spectrum analysis of one link and it looked pretty clean. Noise floor was about -82dB. The signal levels for my links WERE -41, -45, -48, -65. Now they are -61, -72, -76, and -79. I have several other backhaul links that are just fine and their signal levels never changed from what they had when installed. Again, all these links, as well as some of teh links that are unchanged, are on 5.2, BH20 backhauls. Please, any advise or suggestions would be appreicated. My first thought is interference but the one spectrum analysis seemed to shoot that down. Has anyone else seen soemthign like this?

have you made an upgrade? The 4 links are on the same tower?
how are link tests?

All BHs have version 9.3 on them which is not the version that was on when installed. Sadly I have to admit, I don’t know if the signal level problem appeared whien the upgrades were performed but I don’t believe they did as the last software upgrades were done when 9.3 came out and we saw no problems until last week when a link dropped out.

Link tests passed 100% both ways.

backhauls are on different towers covering the southern part on our county. Only two backhauls are located on a tower, slaves on the same tower and masters on a same tower, creating a chain from teh center of the county to the southern end.

Upgrades can vary the signal levels quite a bit. Moto has been trying to get the dB level to more accurate than in previous versions.

I will take the software on the backhauls to the newest version and see if that helps. The problem I’m facing is that on one of the links, it began to drop out as the signal level changed to a -80 with a noise floor of -82.

Thanks for your responses. I’ll post back with my results after the software upgrade.

The software version will change the displayed dBm level but not change actual signal level. It may be that the links were closer to the noise floor than you originally thought thus your margins were less than you thought.

If the link is dropping, then you do in fact have a signal level problem.