AMATEUR RADIO

Evening Post, Volume CIV, Issue 25, 29 July 1922, Page 11

AMATEUR RADIO

THE LIMITED AERIAL BRITISH RESTRICTION GONE NEW) ZEALAND'S POSITION. | Amateur j wireless experimenters ;in New; Zealand are greatly , interested in ' an announcement which appeared in the British. periodical, The Wireless World, reporting a statement by Sir Henry Norman,'president of the Wireless Sub-Com-mittee of the Imperial Communications Committee, regarding the new regulations for amateur, wireless operations in' Britain., He stated that the committee had removed some 6f the' restrictions - under which amateurs had hitherto operated, and had sanctioned a new wavelength, 440 metres, for amateur transmission.. The wireless amateur was to be exempt from inspection of his receiving station, and would no longer be restricted as to-, the length of receiving aerials.;' '. .;. 'j. '■...', \

These! points have, of course, a special interest ; just, now in New Zealand, because of the' steps' that have been taken towards instituting the broadcasting, of radio communications in this country. The immediate result of such operations will vbe to increase greatly the. number of amateur enthusiasts, as well as to increase- the .interest' of their hobby for those'who already have apparatus. V i The amateurs in New. Zealand are under as number of ■> restrictions, and while no, intelligent person among them objects to regulations intended to safe-' guard: the proper conduct of commercial telegraphy, there is strong ' criticism of '■• rules which it Is held are, unnecessarily severe.;. The objection is intensified when' it appears that a restriction; unnecessar!ily limits the amateur's opportunities or puts him to added expense. '' '■■'.

, One of the most important'grievances of the amateur-to-day is the restriction of the size of the aerial he iis permitted to use. It is not legal for him po aave: an; aerial with a-greater active length, than 100 feet. Now, nothing is taov/i astonishing to' the person newly intro-; diiced to 'wireless than the way an amateur siatipn, with a V ridiculous-looking single strand of wire hung up between, two trees; can pick' up messages from the other side of the|world. The writer has heard,the German station, at Nauen, near Berlin, received- with' such" an aenal. by no'i means .well. situated.' But thst Boft of thing cannot ,be done ■• - w :th a 'cheap set. It requires a' 1 thermionic valve v for reception, and at'least one, and preferably two more, to gi7e one or two stages of amplification; and the major ity of young amateurs find llia^, at all. .events in the early-stages of their work,■ two ,or three valves' and, the l>.uteries]to runPthem are,too expensive! j On the other hand,- a .somewhat larger aerial enables .European stations! to be heard well, under favourable conditions, without >n : amplifying valve, that is, with only oneiyal«e. './'. .'''..."-.. .-'■■ ';. .';; /' '.-.' Still'mdre powerful as an argumentjor longer,' aerials, is the, fact that' such" "broadcasting." as is likely toi be done in Nevv.Zealand'will be, tarried on with transmitting stations fof rather small power. ''There seems to be,hardly any limit to the distance at which telephonic radiations''~can be detected with; valvereceivers.:. For example; it is stated that i ship V operator, . while :jn' the Hauraki,' Grul/, recently heard the telephony of a Sydney amateur who was at :'the ' time transmitting; with, a set using only 8 watts of, current—: less than half the current consumed by a 16-cahdle-power electric light: But for one ama-i teur ; who has, or .wiE have, a valfe set there will be quite a number whose detectors will be some-form of crystal set,. such as is still in common use for,com-j mercial work. .These are.far less senei-. tive than; valves,1 and though with iShort' aerials they .'can ■■, pick up commercial, messages sent,out with moderate; or high power, they' are not sensitive. enough for low-power telephony ;unlessthey are within a few: miles of the transmitter. The use of longer'aerials, however, would greatly'extend the area over which : lowpower v telephony could be heard by the use of 'the economical crystal detector..

■There is not,, so far as the amateur wireless man can see, any. reason whatever for limiting the length of a receiving aerial. The length of/the aerial doe* not place any limits-upon what the .operator can hear, providing ■■ his purse will allow him to install sufficiently sensi-: tive receiving plant. ) What the' limita-: tion of aerials does do, and apparently what'it'was intended to dp, is to prevent the amateur y stations interfering with commercial traffic. This can, occur (a) through ' the' amateur deliberately sending out messages,'.which he is forbidden by Jaw to do, unless he obtains 'ar sending license; (b) through the use of a valve set which is " oscillating" and generating waves on thesaerial sufficently1 strong to be heard by a commercial' station, and '■ to!' cause " jam--1 ruing." .-' The result of-enforcing the short aerial rule is, however, rather to increase, the number \of valve seta and -the possibility of such "jamming."; It is true that, if .long aerials are used, the " jamming " effect of an oscillating receiver upon some neighbouring station may be a little worse, but. the commercial stations have already the privilege of ordering'such a set to be silenced by means of a code call which the'amateur is'pledged to obey. ■' •'••'! V \ It is suggested'that the position might be met, if the authorities cannot see their way to placing no limit on the length of aerials, by placing no limit on the aerials used in conjunction with crys,tals, and by enlarging, say, to 200 ft, the permissible length of aerials for valve installations. This would enable crystal users to hear broadcasting Btations over a wide, area, and would greatly facilitate the reception of longrange, long-wave messages without the necessity t for very, costly multiple-valve sets.. •.' . ' 1 r -1..