Snow caused signal outages

January 2010

After both of January's snow outages, the signal didn't recover immediately, and after the outage yesterday lunchtime, the signal was still down compared to its normal level after over 16 hours. Why would that be?

It's also interesting to note the different plots given by different combinations of hardware and drivers. Both the Dexatek box/driver and the older SkyStar 2.3 PCI card show a much more believable signal notch in both drop-outs, although the Dexatek box reports a finite signal strength even when there is no signal! Others have also seen this. by contrast, the SkyStar 2.6 cards seem unable to report an SNR of less than about 2.0dB.

The answer - a build-up of snow directly in front of the LNB which is very slow to melt away in the current -0.4°C temperatures. The black part is the remains of a snow-shield mounting. Unfortunately, the snow-shield itself has snapped off, and the remains can be seen at the ends of the cross-arm. It's possible that were the snow-shield mount not present, there wouldn't have been enough snow to block the LNB as much as there is. Yes, I would now be better off removing the unused mounting arm. Oh, well! Update: we got some sun later today, and the snow melted from immediately in front to the powered-up LNB, resulting in the signal level returning to normal.

November 2010

and here's the cause of the outage on Monday, 30 November 2010!