AMATEUR WIRELESS

Dominion, Volume 14, Issue 253, 20 July 1921, Page 6

AMATEUR WIRELESS

WHY RESTRICTIONS ARE ENFORCED INTERFERENCE WITH OFFICIAL STATIONS An official statement regarding the restriction of tho operations of wireless amateurs was issued yesterday by tho Postmaster-General (lion. J. G. Coates). Private wireless installations are not permitted to bo established without the consent of tho Post Office, and aro subject to strict regulations, which have drawn some complaints from students and others who wish to conduct experiments. "The action of the Department in restricting the dimensions of amateur aerials,’’ runs the statement. “is in keeping *With that of other administrations, and is more liberal 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 arc somewhat technical, but may bo elucidated as follows:—The sudden application of an oscillatory voltage to an oscillatory circuit gives rise to concurrent free or natural and forced vibrations, the frequency and damping of the former being determined solely by tho 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 stations. Such interference can only be reduced to a minimum by restricting the dimensions of the amateur aerial, and, consequently, its natural or free period of vibration, and 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 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."