RADIO INTERFERENCE

Poverty Bay Herald, Volume LX, Issue 18204, 27 September 1933, Page 6

RADIO INTERFERENCE

TESTS AT POWER-HOUSE INCONCLUSIVE RESULTS LISTENERS TO CO-OPERATE References made in last night s issue to the possibility of corrective action at the Poverty Bay Electric-Power Board s power-house, with the object of eliminating electrical interference with radio reception, were followed to-day by intimation that tests have been initiated already. On Thursday last, the telegraph engineer, Air. E. Walpole, in conjunction with Power Board officials, attempted to define whether the constant noise which has recently been added to the troubles of listeners in this district was due to the operation of the rotary converter at the Power House, to which suspicions have been directed. The tests made were inconclusive, however, and at an early date they will bo repeated under- more favorable auspices, and with the co-operation of a considerable group of listeners. The difficulty experienced on Thursday was due mainly to the fact that d.c. motors were working in the commercial area’, and that when the tests were made, it was impossible'to effect a complete closing-down of d.c. production. In the ordinary course, direct current for the old style of commercial motors, .is • produced by the operation of the rotary j converter, which converts alternating current to direct current according to requirements. Da Thursday an opportunity occurred to make preliminary tests during a period at which the rotary converter was not, in operation, hut the tests failed to yield conclusive results for tho reason that direct current was being produced at the time from the old stand-by plant, and was passing into consumption. Tests made duringi /‘this period showed that there was no appreciable diminution in the noise which had been thought to emanate from the rotary converter, hut it could nut be said definitely that d.c. production, either froni the converter or from tiie old d.c. engines, was blameless for the noise in the ether. Had it been possible to stop completely the production of direct current, the test would have furnished more definite results. On the return of the Power Board engineer, Mr. G. T. Cuthbert, from Wellington in the course of a few days, Mr. Walpole proposes to arrange for a series of tests at an hour when no d.c. production is proceeding, probably at a late hour at night. The object will be to isolate the particular noise which has recently caused so much trouble to listeners, and to define whether this noise is due to one of the power-house machines or to any other of the appliances or circuits developed by the board. Mr. Walpore hopes that it will be possible to bring on one of the machines after another, for testing individually and collectively, and that the selected group of listeners will be able, from their reception points in various parts of tin- town, to furnish results of real value bearing on the question of elimination of noises from the ether.

In discussing interference with radhv reception at the Electrical Engineers’ Conference, Mr. C. S. Plank, chief telegraph engineer of the Post and Telegraph Department, gave instances. He nfflentioned a case of an oil-burning heating plant installed in the Hutt Valley. The machine was manufactured _in America, with a radio protective device, but when the plant was erected in New Zealand this device was removed on the ground of economy. It was obviously recognised in America that such a device was necessary, but- as a consequence of its removal in, the Hutt, radio reception within half a mile of the installation was impossible when the plant was in operation.