A COUNTERPOISE TO CUT OUT INTERFERENCE

Radio Record, Volume I, Issue 26, 13 January 1928, Page 13

A COUNTERPOISE TO CUT OUT INTERFERENCE

A counterpoise can in many cases give much better results from the point of view of selectivity than an earth connection. atid also the use of a counterpoise does much to eliminate noises due to earth currents which may be sect up by a neighbouring tramway or any other electrical power of lighting system. A good counterpoise may be made by stretching several wires at a distance of a few feet from the earth, underneath the aerial, the wires being parallel to the aerial and stretching, if possible, to a greater length than the aerial wire or wires. Needless to say, these counterpoise wires should be well insulated aud connection must be made ‘to the earth terminal of the set. This is a proper counterpoise, though it will be realised that such an arrangement ig impossible to some readers; but it should be pointed ont that in the case of interference from tramways, ¢tc., such as we have mentioned, which is often due to earth currents, much tan be done toward the elimination of the trouble by simply removing the earth connection from the set and _ attaching about 30ft. or so of rubber- covered wire to the earth terminal of the set, the wire being led away anywhere, stich as under the carpet or round the skirting board of a room, the far end being left ‘free’? and not con-

nected to anything. ‘his simple remedy will often cure an obstinate case yf interference, and at the same time will often greatly improve selectivity, though it will tend to.reduce volume m distance. _