WIRELESS on an M.C.C. RELIABILITY TRIAL

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WIRELESS on an M.C.C. RELIABILITY TRIAL

A Thousand Miles Test of a ” Radiola” Wireless Set. By RICHARD TWELVETREES, A.M.I.Mech.E.

EVER since the early days of Broadcasting, the problem of using wireless sets as an additional pleasure to the joys of the road has always had the greatest fascination for motorists, but hitherto the design and construction of instruments intended for use in cars has left much to be desired.

In the ordinary way, the commercially produced receiving set is incapable of resisting the continued vibrations set up whilst travelling for long distances, even at moderate speeds, and for fast touring the conditions become very much worse. The problem of carrying the instrument on the car is one which has exercised the minds of the wireless motoring enthusiast, and after many attempts to incor

porate the apparatus as a permanent fixture to the car, the writer is forced to the conclusion that a really efficient and compact portable set, carried in an ” Autokrat ” grid, is the most satisfactory solution.

In order to arrive at any definite conclusions as to the all-round efficiency of any set designed for use with motor cars, the tests must be of a very severe character, for whilst it is a fairly simple matter to obtain an instrument which will give good results for short periods, those capable of standing up to hard work on the road continuously are few and far between. During the Annual Club Run from London to Edinburgh, organised by The Motor Cycling Club in

1924, I took the opportunity of testing a receiving set of my own design, and for this year’s event decided to compare results with those obtained when using the ” Radiola ” receiving set produced by the British Thomson-Houston Company. The compact character of this instrument, together with the new folding frame aerial and the loud speaker amplifier unit, greatly simplified the question of accommodation. The provision of an expanding grid on each running board of the car, prevented any wastage of passenger space, whilst waterproof covers gave adequate protection for the instrument during the entire trip, which, with a detour on the return journey, made up a total distance of one thousand miles.

The Start from Barnet.

On arriving at Wrotham Park at about 7 p.m. on the evening of the start, some 150 cars were lined up in readiness for the long trip to the Scottish capital, and great interest was aroused as soon as the ” Radiola ” was tuned in to receive the 2L0 programme. This little impromptu concert was rendered all the more interesting on account of the absence of the aerial, in fact the whole set was so inconspicuous that many casual listeners were under the impression that the ” Radiola ” was a portable gramophone; though it is difficult how they could mistake the mellow tones

of the loud speaker for the sounds usually given out by a scratching needle.

The nine o’clock time signal from Big Ben was especially useful on this occasion, and many of the competitors were seen to be checking their watches and clocks, in order to keep accurate time on the run, and thus safeguard their chances of winning a coveted Gold Medal.

Receiving on the Car in Motion. “

Soon after nine fifteen, the wireless-equipped” Bean ” was given the signal to start and created something of a sensation amongst the officials, by drawing up to the timekeepers’ box with the London concert in full swing. The strains of the orchestra were heard quite clearly above the hum of the cars as they sped away, and it was not until I3iggleswade was reached that the volume decreased to any great extent. By this time it was a question of risking the Gold Medal or keeping the wireless going, so choosing the run for the “Gold,” the set was stored away for the rest of the journey, and for the next 360 miles it was submitted to as severe a shaking as any scientific instrtunent could be expected to withstand.

The route took us over the roughest of the Yorkshire Moors, up unexpectedly steep hills, to surmount which the car had to be forced to its last ounce of power, round hairpin bends which jolted it from side to side of the narrow tracks, not to mention the terrific rain and hail storms which added to the trials of the competitors. Had it not been for the extraordinary rough weather, further tests would have been made on the outward journey, but as it was the experiments were discontinued until Edinburgh was left behind, and the more peaceful atmosphere of Windermere gave a renewed interest in the wireless set.

Taking a well-earned rest on Sunday evening, we once more tuned in, this time using the frame aerial, and were delighted to find that 2L0 came in very strongly and clearly on the loud speaker at a distance of 260 miles. Birmingham, Newcastle, Edinburgh and Bournemouth also came in perfectly at real loud speaker strength, the selectivity of the set, combined with the ease of finding the different stations, being one of its principal charms.

Our little concert was not without an interruption, however, and for a few minutes we were completely at a loss to understand the absolute failure to receive any signals, except a pronounced buzzing of a most weird description.

This interruption was eventually traced to the turbinedriven dynamo used for lighting the hotel, and the proprietor was so interested in the set as to persuade all his guests to use the gas, in order that the offending dynamo could be switched off.

Another diversion was caused by carrying the set into the garden, with the loud speaker still going.

To give some idea as to the general convenience of the” Radiola,” it may be mentioned that from the time it was all packed away in the car to the moment when one tuned in on a station a space of only three minutes elapsed. This included removing the waterproof covers from the set and amplifier, unfolding the frame aerial and tuning in according to the settings given on the tablet fixed inside the case.

Another remarkable feature of this instrument is its absolute stability, and once it is set there is no need to interfere with the adjustments, the reception being absolutely uninterrupted, save for occasional “fading,” which is beyond the control of the most expert operator.

As a final test at the conclusion of the thousand miles run, the set was tuned in on the morning transmission from Bournemouth, and from the quality of the reception it was obvious that the instrument was none the worse for the severe treatment to which it had been submitted.