The Counterpoise

Radio Record, Volume II, Issue 40, 19 April 1929, Page 29

The Counterpoise

An Engineer’s Experience

HE advantages of a counterpoise instead of an earth are well known, especially in cases where there is much interference from artificial causes, such as electrical machinery. A wellknown radio engineer has recently described his experiences in this direction, in which he found that a suitable counterpoise gave him practically a perfect solution of his problem. His account runs as follows :- "A counterpoise was decided upon as, being the best of a bad bargain. There was simply nothing else we could do. A piece of No. 14 rubber enamelled wire was run out of the window, and strung horizontally around two sides of the building. "It was attached to several window ledges on the same floor. We hooked up

the set to the aerial, which was located on the roof, and to our new counterpoise as an earth, instead of using a common earth connection of the building; the counterpoise was not connected in any way with the earth, in fact, the set was not earthed at all in the ordinary sense.

Good Results. "THE result was little short of a miracle. All traces of the artifical static and motor noises absolutely disappeared. Furthermore, the strength of reception was increased about 50 per cent., and there was a marked increase in selectivity. "The motor noise was coming through the set in the original arrangement through the common earth connection, and not by direct radiation and pick-up from the aerial. By disconnecting the set from the earth, this source. of interference was entirely eliminated. As soon as the counterpoise was employed, the signals increased, and the tuning became sharper because the aerial and counterpoise were much lower in resistance than the aerial and the long earth connection previously used." . .