Hi to everyone who reads this, and thanks in advance to any help I recieve.

I am the Manager of a small not for-profit company in Ontario. We have been setting up a large scale 802.11b network across our city for the last year and a half. Our goal is to provide cheap highspeed internet access to other not for-profit and caritable organizations. Currently we have a modest 20 clients spread out over several km's. We server these clients from 2 primary access points.

Our main access point is currently setup with 3 radios in it, one minipci, and 2 pcmcia, as well as a fourth e-zy bridge linked in through the secondary ethernet connection. The e-zy bridge, mini-pci radio, and one of the pcmcia cards all feed into small 9dbi panel antenna's that feed dedicated sites, including a backhaul to our second primary access point. The last pcmcia radio feeds into an omni directional antenna which until recently served a secondary access point and half a dozen clients. This setup is located on the roof of a 7 story building, 20 feet above the roof on the elevator house. the building is situated on one of the highest points in the city.

Around the start of January these clients and our secondary access point started to experience signal loss, and lag spikes periodically. This increased until January 19th, when we decided that it wasn't the bad weather and went to inspect the antenna. On inspection the duel omni direction antenna we installed a year before had suffered a failure of the sealing around he plastic dome portion. The plastic dome has then filled with water and frozen. On January 20th we replaced the antenna with a simple whip omni antenna of comparable gain. The following day, at 7am, a bad storm with lots of driving rain, high winds, and ultimately snow, caused that section of our network to fail again. Less than 24 hours from replacing the antenna.

Since then, January 21st, we have replaced the following.

The Mikrotik router board, running Router OS 2.8.2.3
The 2 PCMCIA radio cards.
The cable connecting the antenna
The antenna with a 10dbi 120 sector, then a 9dbi panel, finally another 9dbi omni.

We have not replaced

The pig tail connecting the radio to the antenna cable. We have however swapped the pig tails around in the box, with no change to either connections.

At best, with a client within 200ft, we can make a pretty unstable connection, -90dbi. We used to be connecting clients as far out as 3km with this setup, with a good -40dbi connection. The rest of the radios in the box are still connecting at the same levels to their dedicated sites. All of our clients are connecting with dedicated bridges through 9dbi panel antenna's. Nothing fancy. None of our clients are seeing our radio anymore. Its as if it was turned off. The fact that a connection from 200ft away is spoty at best leads me to believe we are experiencing a dramatic power loss in transmission strength, but I do not know why, or from where. Another theory we are throwing around is the possibility of an Interference problem, although I find that hard to believe given that the setup failed during a bad storm.

We have no idea whats wrong with our setup at this point. We replaced all the major hardware with no success. This setup worked for a year without issue. We have made no significant changes to it before this problem occured.

On the plus side, having to go up and down from the roof of the elevator house is helping my manage my fear of heights. I normally don't do this sort of thing you see, but our regular installer is not available currently. That said, I am well versed with 802.11, and quite familiar with the hardware we use.

So anyone have any ideas? If you need more info, ask.

Did you re-point any CPE's after you replaced the antenna?

Hi Evan_reBOOT

Firstly here you will get no help from MikroTik unless you are running the latest version of their RouterOS 2.9.11 (Sorry but someone had to say it ) 2.9.11 will give you some benefits over 2.8.2 which is pretty old I’d really think about an upgrade to 2.8.28 at least, in this situation 2.9 has a snooper (for atheros based cards) that will show any other 802.11 networks and what % of the radio spectrum they occupy.

That said I'm fairly certain from your description of the problem that you do not have RouterOS trouble but trouble on your radios, feeder cables or antennas.

I see from you post that you have been swapping kit about but have you disabled all but one of the radios.... once you get one running properly then bring the others up one at a time. I'm sure you have been doing this systematically but I know that I've been in this situation myself and I get into a "headless chicken" methodology and miss the bleeding obvious!

Let us know how you get on and I’m sure you will get more help the more we know….

Good luck

Harvey