From: Michael Dillon [mailto:wavetossed@googlemail.com]
(for example, after a good thunderstorm, the wireless link will be down for at least 12 hours, but will fix itself eventually.
Sounds like there are trees in the line of sight, and maybe they are getting leafier over the years. The only solution to that is to change the path if it is possible.
The line of sight is all clear, no trees. Only one building along the way has a rooftop of similar height, but the antennas are extended far above the roofline. We have used a rifle scope to confirm line of sight is all clear at all angles.
From: Tim Huffman [mailto:Tim@bobbroadband.com] We're a WISP, so I have lots of experience with this kind of thing. The problem with using 2.4GHz equipment is that there's a whole lot of noise out there (run Network Stumbler sometime on a laptop with a wireless card, and you'll be shocked by just how many wi-fi APs are floating around).
Oh I know. Luckily it's located in an industrial area just on the outskirts of the city. There isn't a lot of other WiFi (in my opinion); 3-5 total SSIDs spread across 2 of the 3 physical channels (1,6,11) depending on which rooftop you measure from.
You didn't mention your bandwidth requirements, but I'm assuming that you're trying to get more (and spend less), so I'll only recommend unlicensed gear. For that distance, you might want to consider using a 5.2GHz radio. The FCC limits their transmit power, so they only work well in short-range applications (>2 miles or so), and 5.2GHz doesn't propagate the way that 2.4GHz does, so there tends to be much less noise in that band.
Bandwidth requirements aren't too picky. If it can handle minimum 9 Mbps full-duplex everyone will be happy. Of course, the faster the better. I don't know if it makes a difference or not but this is all taking place in Canada. I don't know of any regulations drastically different from the U.S's regarding frequency use here. The biggest problem I've ever had though has just been payment/shipping depending on the supplier (some don't ship to Canada or are very specific about payment methods!). Just to answer a few more questions I've been getting, the access points are located inside, connected to a small UPS. The antenna wire is a very thick coax up to the roof, BNC connectors to the access point and I'm fairly certain BNC connectors on the antenna end as well. I'll double check grounding on the poles but I'm somewhat afraid to turn it into a lightning rod. I'm fairly certain that the ground in the antenna wire is clean but again, something to double check. Rain/moisture doesn't seem to cause problems. In fact the connection is more reliable through the winter. The last 2 months here have been cold/warm, dry/wet and there's been no pattern to the stability issues. The only correlation between weather and stability that they have noticed there is lightning related.
From: Jason Gurtz [mailto:jasongurtz@npumail.com] Are you sure there's not a moisture problem in the antennae cabling?
I hope I just answered most of your questions Jason. Good tips to check for too. I'll answer more of your specific questions ASAP. Thanks everyone for the responses so far on and off list. I've been getting lots of product suggestions as well as ideas for troubleshooting the current implementation for the short term. I'm working on another project for today so I've just been skimming through the responses. Later tonight I'll go through all the options in more detail and report back/answer more questions. Keep 'em coming and thanks again, Peter