WIRELESS NEWS

Press, Volume LXVIII, Issue 20488, 5 March 1932, Page 8

WIRELESS NEWS

(By "MAX. ") * Cable news early this week refers to the discovery of the ' 'neutron ' by a British scientist. It will be nece.ssai.y to await fuller details and {itrhaps some time will be spent in ascertaining the real value oi this discovery. Until a comparatively, few years ago, the atom was considered to'be indivisible, but we now know that each atom i? similar to a miniature solar system with a central body and with "planets. ' 'lhe planets are negative particles ot electricity termed electrons and revolve in definite orbits around tho control body, which is electrically positive. Hydrogen has one planetary electron per atom and other elements have more, but always the same number for the atom of any particular element. The centre body has been called a prolon, but some writings indicate that the generally accepted belief is that the central body or nucleus consists of a number of protons and electrons closely bound together, but requiring additional semi-loose or planetary electrons to maintain a neutral electrical condition. Removing or adding electrons to atoms sets up electrical phenomena. 'Friction, chemical action (as in a battery) and rotating copper coils in a magnetic field are methods for setting the planetary electrons into motion. The composition of the nucleus of an atom has been engaging the attention

of scientific investigators in an endeavour to break it up, and the report of the of the neutron seems to indicate at least some success. The neutron is apparently one electron and one proton closely united and electrically neutral, hence tho name. Note the difference from the nucleus of an atom which consists of a number of electrons and protons in close affinity but electrically positive and needing certain planetary electrons to keep an electrical balance.

The "Radio Record" for March 4th givos full details of a Music-Lovers' Competition, which is to be launched from all the four main stations. Handsome pjrizes will be given the winners, and the competition will extend over ten weeks. The idea is to put over each song or piece for one minute, and the listener is to identify the name of the .piece. "Radio Record" intends giving weeklv lists of pieces which will include those from which parts will be "broadcast, thus enabling everybody to have an equal chance in the competition. At seven-thirty on Tuesday, March Bth. the first of the series from 3YA will commence, when ten pieces will be given.

Comment has been made regarding the composition of the Advisory Council, the appointed members' names being released last Thursday. It is considered. in some quarters that per-haps-the musical aspect has been overlooked in making'the selection of these 'ueipbers,* but tho explanation is that this feature is already covered in eacli centre by tha committees originally formed by the late Broadcasting Company, such -committees including musician#, who . attend to the musical side of broadcasting. <

Three Fultograpli machines ;uo due to arrive in Christchurch shortly. They are primarily for the reception of pictures sent by wireless transmission. It is • hoped to be able to adapt one machine for transmission purposes, and to use the others lor reception. In appearance, each machine is somewhat like an Edison phonograph with a, rotating cylinder, and a threaded rod for carrying a stylus ulong the cylinder, which is covered with iodised papei 1 . The incoming electrical impulses pass through the stylus and cause a brownish deposit, whose shade varies with the varying strength ot the impulses. The impulses themselves owe their strength to the original black and white or intermediate tones on the photograph being transmitted. The varying currents at the transmitting end are amplified and made to modulate the carrier wave, an extra, strong impulse being sent at each revolution as well. This trip signal operates the receiving end which consists of a suitable receiver coupled to the Fultograph. A catch operates at each revolution of the Fultograph cylinder and holds it until" the trip signal allows it to start each revolution again. The clockwork which drives the cylinder is coupled through a magnetic clutch, a direct drive being out of the question. A delicate relay acts when the trip impulse arrives *at each revolution and the catch on the Fultograpli. It would be a difficult matter to synchronise each receiver with the transmitter cylinder, and so they are set to run just a mite faster than the transmitting one, giving time to he caught ready for the release impulse. A milliammeter is incorporated to adjust for correct input, otherwise with too much strength the relay would be functioning, with any strong impulse. A smudged picture would also result.

Checking off a newly built receiver of the three coil honeycomb type, once so popular, showed connexions correei. but no signals in the headphones. The latter proved to' be functioning soothe valves were tested by simply substituting others known to be good. The detector circuit was now the only one not working though a loud squeal occurred upon touching the plate coil terminals. Together with a dead grid circuit' (no plops of any kind) this pointed to a faulty socket connexion which vvas soon rectified, the grid pin not touching being the cause of the error. Later tests of the valves at a dealer's showed absolutely no emission from two and next to nothing iroin the third, all being four volters and probably used with a six volt accumulator which had' run down occasionally. When recharging and connecting up, the rheostat was evidently not hrst turned back appin. The usual practice, when a battery rah down, was to turn the rheostat to offer less resistance.. Over-discharging is bad for the battery, causing stilphating and a shortening of the life. Omitting to return the rheostat to its proper position will put the full six to seven volts of a freshly-charged accumulator on and run nearly double the current through the filaments of four volt valTes.

. Here is an idea which might be ot usf- to our New Zealand broadcast stations. North country work-people, during January and February, gave talks on how they conduct their day's work. Amongst these speakers before the microphone were a Northwick saltworker. a Macclesfield silk weaver, a Yorkshire miner, a Lakeland slieepfarmer, and a Liverpool doek-lmnd. Tho Northern Region stations transmitted Ihe items.

If newly-constituted Advisqr.v Council could tackle the problem of electrical and other interference and produce suggestions of a practicable nature which could be taken up, they would find many grateful supporters. The main difficulty is probably one of finance, but there are many instances

Notes From Far and Near*

where small installation could be rendered innocuous at little expense. * * A double button microphone lias recently been completed by one of our local experimenters, who has also been making gramophone records. He states that quite a number of little difficulties cropped up but were being successfully overcome. The microphone is. well made and has a very thin metal diaphragm' tightly stretched between two cups containing carbon v granules. It gives quite a good response over a reasonable range of musical frequencies, the ordinary telephone type which also has carbon granules but a thickish diaphragm, not being at all suitable for using with record producing. It is limited to a Comparatively short range of sound frequencies but serves its purpose in a telephone well enough.