Today I went to replace an older Enterasys AP with a RB532 with a CM9 in it. I bench tested the unit for a couple days prior to installation, and performance was as expected.
When I went to put it in place, it basically wouldn’t work…
The first thing I did was try to associate with my laptop. I was on the roof, about 30 feet away from the radio (it was hooked up to a 120deg sector). My laptop saw something in the high -40s, about what I’d expect. I couldn’t associate.
I went inside and logged in over ethernet. None of the other clients had associated (about a dozen clients, between .25 and 1.25 miles - mind you, these were all online on the Enterasys AP, same antenna, same piece of coax, same channel, and the Enterasys AP has a 15dBm card in it…)
Here’s where it gets strange: I do a snooper snoop - I see nothing. No activity on any channel, no networks, etc. This radio is in a position where I should be able to see like 30 networks (light commercial/strip mall area). Indeed, with my laptop I can see dozen or so networks. I think to myself wtf. Like I said, I bench tested this unit for a couple days prior to deployment. I switch out the radio card. Same results. I switch out the pigtail. Same results. WTF… On a whim, I switch it to the ant-b connector and do a snooper snoop. Lo and behold, I see a couple networks, like 3 or 4. I am 100% absolutely certain the pigtail was connected to ant-a. I go out and swap the pigtail to the ant-b connector. Now, I see nothing on ant-b, but ant-a (with no pigtail attached) sees a couple networks. W T F.
I pull the unit down and bring it inside. I put it back on ant-a and slap a little antenna on it. Now, everything looks normal. I see -30ish on my laptop, can associate, ping flood the thing no problem. I switch to ant-b (which has nothing on it) and I see like -70something, as I would expect. I switch the tests around, and everything looks totally normal (it’s not some freak cm9 with the antennas switched around…)
I haul it back outside and put it back on the frame and hook it up to the antenna. Everything is as before.
Couple more tidbits of info: before I gave up, I noticed that if I did a frequency-monitor, the first listing/measurement showed a shit-ton of activity, but successive listings showed 0s across the board. snooper snoop never shows anything. Also this roof has a ton of gear on it. I couple cell providers (and their backhauls) and clearwire, with its backhauls, and some other stuff. Nothing is in 2.4 (several backhauls in 5.8 though…) However, the clearwire broadcast gear is in 2.5, and is using high power levels (just how high, I dunno).
In the end, I had to give up on the RB+CM9 and put the Enterasys back in service…
My current theory is that the frontend of the CM9 radio is incapable of rejecting the loud ass 2.5 stuff and is basically being overloaded and shutting down (in some sense). The Lucent/Orinoco radio in the Enterasys is unable to hear the 2.5 stuff at all, and thus functions.
That’s my theory anyway. Any thoughts would be appreciated. The reason I’m even bothering with the long ass post is that the weather was total shit today (freezing rain, 1.5" radial ice on some of our stuff) and the fact that this didn’t work really screwed my day. Because this pissed me off so much I really want to get to the bottom of it (I also want to migrate this site to MT…).
-Ryan