Intermittent connection loss between SM and AP

We are experiencing intermittent connection problems with two P9 SMs on our network. Over 10 other SMs are functioning fine, with steady sessions.

I’ll focus on one of the problem SMs. First off, the connection is great when it is on:
RSSI: 1500
Jitter: 2
Power Level: -71
AP running 8.1.4
SM running 7.3.6

Originally the SM was running 8.1.4 so we tried downgrading to 7.3.6 but it didn’t change the symptoms. The SM logs have some interesting entries, but I’m not sure what to make of them. Currently the SM log is being filled with frequent messages (every 10 min or so) as follows:

xx:xx:xx UT: 01/02/01 : File C:/ISIPPC/pssppc.250/bsps/devices/whisp/syslog.c : Line 1062 Time set

According to this thread, this might be related to having hardware scheduling enabled on the SM. Note that the date is not being set correctly (unlike all other SMs).

A link test results in 0% loss in both directions.

Important note: The connection losses seem to only occur during the day time. This is leading us to believe that it is in some way related to human activity…

What do you think the most probably causes might be? What else can we try after having gone through the troubleshooting in the manual?

Thanks in advance,


Interference? We notice similar symptoms on our 5.2 and 900mhz systems.

Important note: The connection losses seem to only occur during the day time. This is leading us to believe that it is in some way related to human activity...

Seems like some sort of interference...maybe a wireless phone that is transmitting on the same freq?

We have been thinking about it, but don’t have any reason to believe that interference would be causing the problem.

What procedure would you use to determine whether or not interference is the problem?


Check the Spectrum on the SM.


Interference for sure. I have a similar situation.

AP on 5795 with 23 subscribers with CMM worked great till someone put up a pair of Canopys with reflectors near my tower. He put them on 5775 and 5815 with no GPS sync, thank you very much… Called him to work it out and he said he was taking the 5775 radio down. Changed my AP over to 5785 and all the signal levels to and from the SMs improved dramatically, except for one minor annoyance. He claims there is no traffic on 5775 but every half hour 6 of the 23 radios get knocked off line, even one that is showing -60 db normally. The radios are offline for about 2 minute and the reg count is incremented by 3-4 and then all is well for 28 mins. Calling him again on Monday to see if in fact he shut down the radio on 5775, but it must take a helluva signal to knock out an SM with -60 db showing on both ends. All the affected radios are in the 6 degree beamwidth of one of his radios with a Canopy reflector on it.

Bottom line is to try to monitor your AP session screen to see if you can pick up a pattern. The time set lines from your SM log should give you an idea of when they are being dropped. I haven’t verified this but I would imagine that the number of time sets in the SM log should be the same as the reg count in the AP sessions page (assuming you haven’t rebooted the AP). Then if you have a spare SM, use it in spectrum analyzer mode to see if you can track down the source and hope he’s open to working it out with you.

if there are not more quiet frecuencys both should try the cmm to be sincroniced. al the radios transmit at the same time…