When the problem happens, the rssi is "frozen" so I suspect there's actually no 
connectivity any more. Definitely no data. I haven't been able to get someone 
to look at the other end while it's happening, to see what they see.  During 
normal operation the s/n is around 30 to 35 db on the varous legs, and 
bandwidth, latency, etc is as we would expect. As you probably know the CM9s 
only put out around 50 mw but that's usually adequate for short-haul apps like 
this.

At present I can't access the system at all,  because the client has apparently 
allowed palm trees to grow into the path of the 5-mile (XR5) ptp backhaul we 
put in to feed it :-( and with today's rain it's killed the link. Once those 
are cut I should have access again and can run more tests.

Thanks,

Tom S.

  ----- Original Message ----- 
  From: Marlon K. Schafer (509-982-2181) 
  To: Tom Sharples ; WISPA General List 
  Sent: Thursday, November 01, 2012 11:00 AM
  Subject: Re: [WISPA] CM9 Rx blocking problem?


  Are you loosing connectivity to the client radios or only loosing data from 
them?

  What do your link stats show?  Signal quality etc.

  What are your eirp levels at normally and during the events?

    ----- Original Message ----- 
    From: Tom Sharples 
    To: Wireless@wispa.org 
    Sent: Wednesday, October 31, 2012 1:46 PM
    Subject: [WISPA] CM9 Rx blocking problem?


    Hello all,

    We're seeing an odd problem at a customer location in Honolulu. About a 
year ago, we set up a pretty conventional point-to-multipoint 5.8 Ghz setup for 
video surveillance - a dual-radio gateway node attached to a pair of sector 
antennas, and 4 client radios (2 on each sector) attached to IP cams. The 
client radios are between 1/4 to 1/2 mile away from the gateway node. This is a 
multi-building industrial project in a fairly heavily polluted (RF wise) area. 
There's a Home Depot and Lowes nearby with equipment on all 5.8 Ghz channels. 
However our radios scan well above the noise floor.

    Our equipment uses pcengines alix boards running our own linux-based OS and 
CM9's using standard madwifi-style drivers. Same thing we've been using for 
years.

    This installation worked well at first. However, we are now seeing a 
situation in which both gateway radios suddenly stop receiving data from the 
downstream clients. This lasts from 5 to 20 minutes or so and then magically 
fixes itself. When I ssh in during the problem, there'e no indication of 
low-level driver problems or crashes, everything looks normal except for the 
sudden lack of data and connectivity with the client devices. 

    This installation is near Pearl Harbor and there are constant overflights 
from military aircraft. I'm wondering if this is a sensitivity issue to e.g. 
radar or some other high-powered signals from these planes. I've seen things 
like this before but never lasting up to 20 minutes. Would we see an 
improvement by switching to XR5's? We don't normally use those on short hauls 
like but they have better OOB filters than the CM9's. Thoughts?

    Thanks,

    Tom S.



----------------------------------------------------------------------------


    _______________________________________________
    Wireless mailing list
    Wireless@wispa.org
    http://lists.wispa.org/mailman/listinfo/wireless
_______________________________________________
Wireless mailing list
Wireless@wispa.org
http://lists.wispa.org/mailman/listinfo/wireless

Reply via email to