OCR Text |
Show Service of Loop Aerial in Securing Selectivity The greatest objection to the use of a loop aerial in securing maximum selectivity is the loss of volume. When difficulty is experienced from the interference in-terference of two or more stations near the same wave length, or when the static becomes so heavy as to drown out even the locals, the trouble nay be reduced at least 75 per cent by closing the ground switch, thus grounding the aerial, and connectin. the set to a 3 or 4-foot loop of 10 or l" ; turns, shunted by a variable conden" ser, the loop to be placed as near as possible to the wire connecting the aerial to the ground. L'sing an ordinary three-circuit tuner and a WD-11 tube, a correspondent correspon-dent writes, I regularly receive 1 0O0 miles through static that would make reception impossible otherwise, and also cut out code Interference practically prac-tically entirely. The method is equally efficient with a two-circuit set, the only requisite being that the loop be not more than 2 or 3 feet from the ground wire. A plaster wall separat-lug separat-lug them seems to make no difference, however. Radio Digest. |