Hmm... I don't think the board is hung because it runs the code fine during the
events, with no dmesg errors from the dirvers. Another AP won't work here (at
least not easily) because this system has loads of custom code and scripts for
our video surveillance apps. We are working to port those over to the UBNT
environment, but that isn't done yet.
Have you seen any difference in rx sensitivity to interference between CM9's
and XR5's?
Thanks,
Tom S.
----- Original Message -----
From: Marlon K. Schafer (509-982-2181)
To: Tom Sharples ; WISPA General List
Sent: Friday, November 02, 2012 8:33 AM
Subject: Re: [WISPA] CM9 Rx blocking problem?
LOL Love those palm trees! I used to live there, don't envy you a bit. grin
I normally turn my radios way down anyway. With the sensitivity of today's
radios there's no need for hot links.
30 to 35dB of s/n is, in my not so humble opinion way too much. That's well
within the range of multipath signals. Lower power may actually help this link
perform better.
The fact that the rssi is frozen is strange. If there is no link there
should be no rssi either. I wonder about the health of the board. This sounds
a lot more like a lockup than it does a signal issue.
I don't know anything about the configuration that you have built so I don't
know what it should be telling you.
Is it possible for you to just replace the ap with something more standard
and newer?
I can do a really good AP for under a $500 these days. With good boards, an
amazing hinged enclosure, lots of room etc. We've gotten things dialed in so
that there is NO need for 25 tools, tape or anything up on the tower. A screw
driver and crescent wrench is about all that's needed to swap parts, including
antennas.
Sometimes it costs more to try to fix a problem like this than it does to
just replace the gear.
marlon
----- Original Message -----
From: Tom Sharples
To: Marlon K. Schafer (509-982-2181) ; WISPA General List
Sent: Thursday, November 01, 2012 5:53 PM
Subject: Re: [WISPA] CM9 Rx blocking problem?
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: [email protected]
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.
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