RADIATING RECEIVERS

Poverty Bay Herald, Volume LII, Issue 17152, 30 September 1926, Page 3

RADIATING RECEIVERS

SOME EVILS OF ''BLOOPING." The static bug-hear of radio reception litis been practically overcome by improved higher power transmitting sets. Code interference has been eliminated by the conversion of spark apparatus to tube equipment, and service men are constantly- eliminating sources of electrical interference) (says the Christchiire.il Sun). On the other hand, radio fans are making- reception worse by operating receivers that radiate and "bloop" sending out a whistle on the same wave tho sot is tuned to, which is usually on a. distant station. These whistles heterodyne with each oilier and the carrier wave of the station to produce an unintelligible maze of sounds. Competent authorities agree that ''.blooping" is the worst radio evil to-day, and that unless, individually, every one takes it upon himself to obey the. law of common decency and respect .for others-, blooping will continue until reception of anything- but local stations will be an impossibility. It is frankly up lo every radio fan to ''clean house" first to do his share to remedy llio sit nation. "Many people have the mistaken idea that only regenerative sets art! bloopers. This is not exactly true, for oven ihougli regenerative sets tire bad offenders, practically any type of set that is callable of squealing is a blooper. A so-called nun-regenerative s.et may be, and .frequently is, (he worst, offender. Any set radiates or bloops when the tubes oscillate and thus cause the antenna likewise to oscillate and give off energy. Many .fans think that .one or two little squeals or bloops will do no harm. Many (tine in with their sets oscillating in order to locate the earlier wave more readily, then turn down the controls until the set stops oscillating. One or two bloops during the evening does little 'harm, but, the accumulation and total of till of these grows to alarming proportions when the thousands of sets are being operated,in a small area. Another idea prevalent among fans is that the -use of a stage of radio frequency amplification between the antenna and the receiver will prevent radiation or blooping. If this were true then all tuned radiofrequency sets'would be non-radiating, but this is far from the case. If the additional stage or radio-frequency amplification is absolutely balanced, at all frequencies so that the added tube not only cannot oscillate, but also will not allow energy to pass through it except in the direction from antenna to detector, such, as in the method which uses the isofarad bridge circuit, then the detector tube may oscillate without blooping. The addition of a balanced stage of radio frequency will at tile same time increase the selectivity and range of present receivers as well as preserving peace of (he atmosphere. DEPARTMENT'S ACTION. The intercference caused by prohibited circuits and improperly operated receivers has reached such a pitch"in New Zealand that the Post; and Telegraph Department .has considered it necessary to take (he muljer in. hand. In dune last a circular was issued lo all radio licensees drawing attention, to certain wireless regulations which prohibited the rise, or radiating receivers, and requesting owners of wireless receivers, to satisfy .themselves that they did not either intentionally or unintentionally cause interference to other radio licensees in their dl» tried. The Department found that on the whole the circular had a beneficial effect, and that in many directions a genuine attempt had .been made to comply with the regulations. Gisborne enthusiasts liave now received a second circular, which states that unfortunately a considerable amount of: interference still remains, a great deal of which is undoubtedly due to the fact that owners of low-power receiving sets are reaching out after stations which are beyond the natural compass of their instruments. Jn so doing reaction is employed to an' abnormal degree, the well-known indications of oscillation and radiation are disregarded, and the receiver functions as a low-power transmitter, causing considerable interference to all other licensees in the same area. It is hoped that licensees generally will do all in their power to prevent interference from suck causes, and thus render it unnecessary for the Department to take,action against offenders tinder its regulatory provisions. PROSECUTIONS NOT INTENDED. In order that, it may be deiormined whether the receiving sets in use are of such a, character as to cause interference under normal working' conditions, all owners of receiving HOtej are requested to notify the district radio inspector as early as possible of the type of circuit, in use. It is distinctly understood that the object of the Department at this stage is not to take action against the owners of offending circuits, but so that advice may be 'given . that will enable, tho owner of u prohibited circuit to amend it and make it conformable to tho requirements of tho regulations under which the license is issued.