Mockingbird Improved

As of about an hour ago, we believe we have found our issue with Mockingbird Tower Central, and taken steps to provide immediate improvement. Although speeds are not at the level they were three weeks ago (due to suspected antenna hardware damage and pending part arrival and replacement), they should be greatly improved over the degraded performance seen over the past week. Please drop us an email if you are not seeing adequate performance for your equipment.

Technical details follow for the curious.

We’ve been testing the equipment at Mockingbird continually over the past few days, mostly in the wee hours. We have repeatedly assured ourselves that the feeds into the tower from both sides were fast and flawless, and that the performance problem was only in the final hop to each subscriber. We replaced the radio unit and pigtails two weeks ago, and we replaced the main router hardware Friday evening with a brand-new gigabit-capable model; still the problem persisted. Both we and our consultant could see nothing wrong with the routing configuration, which at any rate had not changed for months.

The most obvious remaining culprit was the antenna, but short of an obvious EM discharge (such as a nearby lightning strike, which would have taken out our radios and routers as well), this would be highly unusual.

It occurred to us this afternoon that a fault in a dual-polarity antenna might be localized to one or the other of the polarities, but not both; and that MikroTik equipment offered controls allowing us to route all traffic exclusively through either polarity, entirely idling the other.

Finally, a test that appeared to produce valuable results: we found that chain 0 passed practically no traffic at all, while chain 1 passed a healthy bandwidth.

We’ve left chain 0 disabled until we can get our consultant (who is much stronger in radio theory than we are) to concur with this analysis, at which point we will order a replacement antenna. (It’s difficult to find a dealer who keeps these very high-end antenna units stocked, and the manufacturer doesn’t sell direct).

This change appears to us to be delivering immediate relief to our Mockingbird subscribers. While the lack of the defective chain robs us of the full speeds available prior to the damage, bypassing it at least allows the good chain to deliver its own full bandwidth properly without the introduction of performance-destroying errors.

Thank you for your valued patience, and thank you for using Grand Avenue Broadband.


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