In a World of Weird Wireless

Radio Record, Volume III, Issue 45, 23 May 1930, Page 3

In a World of Weird Wireless

Radio off the Beaten Track

HE ever-widening fields in which the principle of radio in its ‘primary sense is applied are amazing. Its adaptation. in the scientific and industrial worlds alone is enormous. . The following enlightening article (by D’Orsay Bell, M.A., published by "Wireless a ‘reveals just a few of the astonishing aYMl varied uses to which this marvel of selene is applied. . 7

O, it is not, a misprint for "Wired," as. you thought it was. Weird Wireless, as opposed to the ordinary forms of radio (wireless telegraphy, wired wireless, television and so on) about which the readers of radio journals know most that is

worth knowing, is that large branch of radio about which they know nothing. Do I realise what I am saying? . Ido. Am I not giving utterance to an unwarrantable and gratuitous piece of impertinence? I am not. I have never, for instance, come: across any animated correspondence on the subject of Paint and Varnish Radio. And yet paint and varnish radio-is a-very important-an increasingly im-_portant-subject. ‘The research laboratories of . and: V. manufacturing concerns are studying by radio technique, the effects. which heat and cold, oxidation and so.on, produce on the latest products. Particularly useful here is what might be called an "ultra" edition of the Ultramicrometer. If two. circuits, each kept oscillating by. a valve, are almost but not quite in tune and are carefully coupled together, the very least change in tune in the one will produce a great change in current in the other. In the Thoma variation of the ultra-micro-meter, a slight. increase in the thickness of a paint film alters the capacity of a condenser, brings out infinitesimal change of tune in one circuit, and gives such a magnified result: in the other circuit that the change in the thickness of the film’ can be recorded and studied very easily. Radio Robots. T is said that this new "tool" is enabling the _ research people to investigate: the: why and wherefore of important actions going on in their paints, the very existence of which was unknown til now. But this is only one way in which wWeless technique is being used in the paint industry. There is a most attractive superhuman gadget which analyses the colours of paints (and writes down the results) quite automatically and five times as accurately as can be done by the human eye. This machine flashes a beam of light (red, for instance) backwards and forwards between the sample under test and a standard colour. If the red beam is reflected more by the standard . than by the sample, the result-thanks :to the help of a photo-electric cell such as is used in pheto-telegraphy and television-is a. pulsating current. This, after passing through valveamplifiers, sets a little motor buzzing round and altering things so that the-red. beam now divides its attention between the sample and a second standard colour: if this does not correspond exactly to the sample, the motor keeps on buzzing round and tries a third standard, and:so it goes on till a standard is encountered which gives an exactly equal ‘reflection. -""°" °° ;

When this happens, there is no pulsating current to drive the motor, which comes-to rest with a feeling of duty well done. The machine makes a note of that, particular standard, switches ona test beam of another colour, and the whole process goes on all over again. The complete colour analysis takes only a few minutes, which’ is far quicker than can be done by human beings. Out in the Great Open Spaces. L=t us leave the stuffy laboratory and get ~ into the vast open spaces of America, Canada and Australia. Here, screen heroes in khaki shirts and shorts are busily using shortwave valve generators to explore for oil and minerals, . Various methods are used, but one favourite plan is to compare the velocity of sound waves through the ground with that of short radio waves. The latter keep their velocity, constant, while the sound waves vary theirs according to the nature of the soil; the presence of ‘oil, in particular, has a marked effect. The method usually employed involves the use of direction-finding loop aerials-plus the usual valve amplifiers. In fact, practically the whole resources of modern wireless are being concentrated on the unwarrantable spying-out of these harmless and. carefully-concealed minerals, oils, and s9

on. It is pleasant to be able to relate that occasionally the victims get a bit of their own back; it is reported from Wiesbaden that listeners-in have been worried by a strange kind of interference, rather like atmospherics, but more regular, and this has now been found to come from the radio-active mineral springs under the town. Perhaps that will teach people to let well-and spring-alone. Fresh Developments. VERY day seems to bring fresh developments which clamour for notice, Piezoelectric quartz, that high-brow laboratory phenomenon which was so promptly seized on tu keep radio transmitters to their proper wavelength, is now being used to register variations of pressure in water mains; so is the effect of capacity change on a heterodyne note, one plate of a condenser being forced in toward its second plate by an increasing pressure. roo The photo-electric cell-direct descendant of Dlster and Geitel’s "academic". experiment where light falling on to a spark-gap stopped the spark-is now used for about as many purposes as an Austin Seven. Apart from its jobs in picture telegraphy and television, it counts the ‘traffic’ passing through the big tunnel joining

New York to New Jersey; it judges the winning horse in a race; it sorts and counts mass-produc- « ed goods; it is used in chemical works to decide when enough alkali-for instance-has been added to complete a reaction (some of you may remember the titration tests at school, when the’. critical last drop suddenly wiped, away every’ trace of colour from a whole big flask-full of coloured liquid; the photo-electrie cell watches for this, and when it happens, turns off the: tap). ; . It, as well as its brother the selenium cell, is used as a burglar alrm; another burglar alarm, by the way, is one in which the action-or the mere presence-of the burglar upsets the tun-. ing of the grid circuit of an oscillating valve, and causes an anode current change whith : works a relay. The condenser-microphone, © which some engineers swear by for broadcasting, is now being used by doctors to give them a re-’ cord of their patient’ heart-beats. Thanks to the valve emplifier, the tiny resistance-changes " in the human body, due to emotion of various: kinds, can now be recorded-and this procedure,.. it is said, is going-to be very valuable in studying the effects of drugs and in investigating © nervous fatigue. Noises in gear boxes, ball-bearing and other machinery, and noises indicating insulation trouble and the consequent danger of break~ down in big trausformers, are being tracked ~ down by microphone and valve amplifier; the ordinary, normal running noises being filtered . out by electrical filters such as are used in wireless, so that the trouble-noises can be distinguished. LAWS in steel axles are now being looked for by rotating the axle rapidly and explor-. ing with an instrument rather like the magnet, arrangement of a telephone receiver-the dis- | turbances induced in the telephone windings by:; the presence of a flaw rapidly passing by are de-. tected after amplification in the usual valve. amplifier. A similar process is applied to steel" wire ropes-but here the rope remains still, and’, ‘the magnetic flux rotates, Think of the acci-. dents which may arise from flaws in axles and wire ropes, and you see how beneficial to man are these new applications of radio technique. At least one company exists in America for testing railway lines for flaws and other defects in the rails; it provides a specially equipped railway truck which runs over the track .at about five miles an hour. Two brushes, a Jjittle: distance apart, continually conduct direct cur-. (Continued on page 28.)

Weird Wireless :

(Concluded from page 3.) rent to and from the bit of rail be-| tween them. Half-way between these main brushes is a trio of searching brushes connected in a kind of pushpull way to a transformer. The secondary of this transformer goes to a fourvalve ampifier which works various relays, and when any kind of flaw upsets the symmetry of the current) flowing in the rail, these relays do their work-they sound a warning buzzer, record the exact position on a travelling tape, and even go so far} as to spray a blob of paint on to the offending. bit of rail. I. Having done all this, they send oft a wireless message to H.Q., packing the foreman responsible of laying that! bit of rail... and that is the only) bit of exaggeration this article con-} tains. i ae |