Ice Storm

This is not the article I wanted to finish the year with. On December 30 we had an ice storm that deposited from ¼" to ½" ice on all my towers and antennas. Unfortunately there has been damage. With all the tree limbs and chunks of ice falling it's still too hazardous to do a full inspection, not to mention the treacherous surface ice.

Freezing rain requires a fine balance of atmospheric conditions. There was little of it 100 km north in Ottawa and 200 km to the west. It's very possible that I am the only ham with a large station that has been affected.

The worst was to my new 80 meter vertical yagi. The stinger at the top of the tower folded from the weight of the ice on the parasitic wire element support ropes. Yet the weaker PVC pipe at the very top, to which the catenary ropes are attached, survived.

Shortly before the failure I tried to shake the ice loose because the stinger had a pronounced bend. Ice tumbled off the smooth surface of the insulated wire elements but was hooked deep into the rope fibres. An hour later the upper 1.5" × 0.095" wall tube collapsed at the joint with the larger pipe below.

This is disappointing since I thought it would withstand ice as well as it has 100+ kph winds. In this region ice is a greater menace than wind. The weight of ice on those long ropes is substantial. The towers themselves are fine since the ice is a modest addition to the tower weight and 1000 lb guy tension. Self supporting towers are more at risk should the wind blow hard while ice is present.

Luckily the yagis held up to the abuse. The elements bent quite a lot under the weight of the ice but bounced back afterward. The tips on the Hy-Gain yagis worried me since they're thin and low tensile strength aluminum alloy. They will break off with severe ice loads.

The XM240 elements curled downward quite a lot then bounced back as the ice broke off. Notice the condition of the trees in the photograph below. The boom of the 6 meter yagi above it was also sagging. The foreground guys are twice their normal thickness.

With most of the ice now fallen or melted all antennas other than the 80 meter array test fine. The SWR of the 80 meter vertical is low enough at 1.7 to at least be usable in its omni-directional mode. Wire antennas have stretched from the high load and will have to be tightened. Going by the SWR the stretch is in the ropes and not the soft drawn copper wires.

If repairs to the 80 meter yagi have to wait until spring I can fall back to the high inverted vee. Hopefully there will be enough mild weather to permit repairs to be done. A thorough upgrade will have to be scheduled later in the years. Antenna repairs will inevitably slow the pace of work on new antennas.

It's a somewhat sombre Happy New Year at VE3VN. See you on the bands in 2020.