For the past week or so, WIckenburg subscribers west of Country Club have been experiencing extreme slowdowns and service outages. We have been working on the problem for several days, making configuration improvements and uncovering and reporting various manufacturer firmware bugs, but our efforts had no effect on the speed problems we were seeing on the network.
Today, we were able to schedule the prompt attentions of MikroTik consultant Butch Evans, who carefully combed through our configuration looking for the cause of the slowdown. His conclusion: we are seeing noise (interference) problems of a sort that don’t show up in the usual meters.
Currently, we serve Wickenburg on the 2.4GHz band, the same band used by inexpensive home WiFi routers. Many of our far-west users, particularly those off Vulture Mine Road, essentially have the bulk of the Town of Wickenburg between their homes and our Mockingbird tower. This means that every home WiFi unit that sits anywhere along their signal path, that is running on or near our channel, can knock holes in their signal to and from the tower. This results in “retried packets.” Enough retried packets, and your data throughput craters.
For some time, our intention has been to serve the Town proper from a more central piece of high ground, using equipment in the less-crowded 5GHz band. Although we haven’t given up, so far we’ve been able to make next to no progress with the folks controlling suitable properties. We’ve considered replacing our current west-facing sector antenna at Mockingbird with a 5GHz unit, but because of that band’s stricter requirement for line-of-sight availability and its lower tolerance for obstructions (including foliage), this would probably result in a number of current subscribers losing availability totally.
Instead, what Butch suggested we do is reconfigure our tower from a standard 20MHz channel width to a 10MHz channel width. This not only reduces imposed interference by half, but gives both the tower and the subscriber units an effective two-times boost in transmit power. We did that this afternoon, and our westernmost subscribers are now back in operation.
We realize that this is a temporary palliative, and as the number of WiFi routers continues to grow in town, interference will increase until this problem crops up again. If any of you have local pull with an owner of high ground in the central or west end of town, we’d appreciate an introduction.