AMATEUR WIRELESS

New Zealand Times, Volume XLVII, Issue 10957, 20 July 1921, Page 9

AMATEUR WIRELESS

DEPARTMENTAL . RESTRICTIONS. STATEMENT IN EXPLANATION. The restrictions .placed by the Post and Telegraph Department upon ; the operations of "wireless” amateurs have formed the subject of inquiry lately, and a statement by the Postmaster-Geno-/ral (the Hon. J. G-- Coates) indicates the position of the department. The state ment is as follows: — - "The action of this department in restricting the dimensions of amateur aerials is In keeping with that of other Administrations, and is more libera) than some of them, the object being to reduce as far as possible interference with reception at public radio stations. "The reasons underlying this action : are somewhat technical, but may be elucidated as * follows :—The sudden application of an oscillatory voltage to an oscillatory circuit gives rise to concurrent free or natural and vibrations, the frequency and the former being determined solely by the constants of the circuit. The amateur experimentalist is liable-.at any time to set such a sudden voltage in his antennae with disastrous results to adjacent commercial wireless station#* Such interference can only be reducecL to a minimum by restricting the dimensions of the amateur aerial, and, consequently, ■ its*-natural or free period of vibration, it is for this reason that the overall length of the aerial has been limited to 100 feet except in special cases of bona fide experimentalists who 'have some y other object than amusement and who know sufficient of the principles of radio engineering to prevent them from becoming a nuisance and a source of danger to public wireless communication. "The letter, from 'Ameateur Radio Bug/ now under consideration, indicates that the writer is very •amateurish and not conversant with the possibilities of radio reception by means of modern apparatus, otherwise he would know that with suitable apparatus find a knowledge of its use, he could, with a 100, foot aerial, receive messages from practically all the high-power wireless stations in the world/'