Unusual Storm Effect

Radio Record, Volume V, Issue 11, 25 September 1931, Page 6

Unusual Storm Effect

Valves of Set Burst [tz is not often an electric storm is sufficiently intense to burst all the valves in a set, but this was the experience of a Reefton listener recently. Although the aerial was protected with a standard lightning guard the severity of the discharge was not abated. Strangely enough, only the valves were affected. Following is a letter from the listener in question describing the queer effects of this storm :- This town was some ten days ago subjected to a severe electrical storm. It may be of some little interest to readers to describe its effects on radio sets. The writer’s set Wn particular seems to have come in fo the heaviest part of it. The aerial is of 7/22 copper 512ft. tong, supported by two iron-pipe masts, vne of which is on a hill, is 36ft. high and 175ft. above the mean town level; the other mast alongside the house is 50ft. high, stands on a glass bottle, und the stays wires are insulated. From the aerial to the lightning arrester is a No, 8 copper wire, and the same size is used to connect to the yround 3ft. away. Under the ground it is soldered to a henuvy iron bar driven deep into the subsoil. The aerial continues to the grid of the first valve and to earth through a 2 mf. condenser, this latter being used .on account of the d.c, eliminator. On the evening in question the set was being worked from 6 to 6.30, and the music was at times cut out altogether. During this interval fryingpan static of a pronounced type would | come in and go out suddenly. The music, when it came, was very clear.

The set was not working when lightning discharge took place, which happened in heavy rain. The writer was sitting near the set when the valves .burst with a sound like a heavy revolver shot. Glass flew to all quarters of the room, and an unpleasant odour arose from the set. Next evening I. tested the set and found that the 2 mf. condenser in the earth lead had not broken down, the arrester was also in working order, as were the transformers, eliminator, accumulator, filters, condensers, ond erystal detector, The elements of the first valve were smashed, and they were in a heap at the bottom: the second valve was smashed to pieces, and the elements melted into a lump; the third valve was also smashed and parts of it burned up. I replaced the valves, switched on the set, an’, wif worked as if nothing had happened. Other listeners report no damage. As regards the house, no windows were eracked, nor any of the fuses of the electric light blown out. One lamp ‘only had the filament broken. My aerial was not damaged. Houses around me_ had all their windows cracked and in some cases thrown on the floor and smashed. Wire swings and netting fences were melted, electric light poles were broken off and the mains fused; while in the power-house, even though the contactbreakers came out, the armature was in flames and some of the copper bars’ on it had pieces burnt out of them

and the insulation destroyed.-

A. E.

Elliston