Letters from Readers, February 1949

Radio Pit Control

Sir,

As a member of the Radio Society of Great Britain and an ex R.A.F. wireless mechanic, I was interested to read the letter from Jack M. Reiss published in your July issue and your editorial comment thereon.

As you state Clark’s would appear to be the first really successful attempt at radio pit control and this was probably due to the application of V.H.F. technique.

You are probably aware that wireless waves travel at a speed of 300,000,000 metres per second, and if this figure is divided by the wavelength in metres we arrive at the number of “waves” per second or frequency.

In 1922 and 1923 when the first attempts were made to establish radio communication between racing cars and the pits it was generally believed that frequencies above 1.5 megacycles per second (wavelengths below 200 metres) were impracticable and it was, in fact, customary in those days to refer to the present medium wave band as “short waves.” I am not aware of the actual frequencies used by Edge and Alvis, but in each case it was probably considerably less than 1.5 mc/s., and for several technical reasons these comparatively low frequencies are unsuitable for radio pit control.

As more became known about the propagation of electro-magnetic waves it was found that frequencies above 1.5 mc/s. could be used, and this ultimately led to the widespread use of the short waves for broadcast and commununications purposes. These frequencies are, however, more suitable for long-distance work than for local working, although they can be used for this purpose.

Experimental work continued and by using special components and technique it was found that very high frequencies above 28 mc/s. could be used and these frequencies (V.H.F.) were excellent for short-distance work. This was particularly noticeable in the R.A.F. Prior to the introduction of V.H.F., communication between aircraft was by means of the ordinary short waves and results were far from ideal. When V.H.F. gear was installed it was found to be highly successful and for many reasons this form of transmission appears extremely suitable for radio pit control. One disadvantage of V.H.F. is its susceptibility to “man-made” static (e.g., ignition interference) as many owners of television sets are only too well aware. It can be, however, and probably is in the case of Clark’s installation, overcome by the use of frequency modulation.

It will thus be seen that although there have been several attempts to use radio as a means of communication in motor racing, the methods of utilising this medium differ considerably and might well be compared with the fundamental differences between the modern high-speed car engine and the slow-revving Edwardian. Please do not think that I am trying to set myself up as an authority on the above subject — even if I possessed the qualifications of Professor A. M. Low, I should hesitate to do so without further data as to the actual equipment used in each instance. The foregoing remarks are merely my own personal deductions.

Turning to other matters, I have been interested to read of the recent reemergence of Spike Rhiando. The last I had heard of Spike was in the mid-1930s when he was cinder-shifting at the Crystal Palace. And talking of cinder-shifting, you appear to have slipped up in the caption to the photograph of the departing American Dirt Track Circus. You state that they only held two meetings (or should I say performances), but I think you will find they held more. However, who cares! I am, Yours, etc.
R. S. Marriott
Chingford, E.4.

Sir,

The following notes, taken in Chiron’s pit [at Silverstone], might be of value.

A quarter of an hour before the start, Chiron’s manager Vallet was endeavouring to fix with wire the driver’s classical metal bottle with rubber tube for refreshment on the way. Chiron finally decided that the bottle would probably come astray among his feet and he left it in the pit. His rev, counter ceased to function. Somebody suggested that the reserve Talbot’s rev, counter could be removed and fitted to Chiron’s car, but Chiron said it was of a different type. His own had given trouble in practice, but he said he trusts his car for r.p.m. information. When he came in with excessive tyre pressure trouble, after having passed the pits several times shaking his fist and pointing to the tyres, he got half-way out of the car and shouted: “Merde, bande de salauds,” and called for a man who appeared to be the French Dunlop representative, to whom he made a number of unusual and energetic remarks, the Dunlop man defending himself as best he could. Etancelin regretted having refused his wife’s offer of his sun-glasses. When he retired, he consoled himself with a large Hennessey’s brandy from a bottle hugged by his wife and poured out by Vallet, who said it was good for colds. The Freikaiserwagen’s piston was an evil shape, like a pushed-in melon, and light-grey and pitted, but the bore appeared perfect. The machine was examined in the potato-field.

It was an excellent race, which I enjoyed almost as much as my first, the Grand Prix de Boulogne in 1922 (Circuit de Boulogne, I think).

I am, Yours, etc.
Bernard Coulter
Caterham, Surrey.

[It is just these intimate aspects of a long-distance event that make this form of racing so enthralling — Ed.]

Sir,
Some of your readers may be interested in details of my 1932 Lagonda which differs from standard in several respects.

Mainly it is a 3-litre, but: its rating is 20 instead of 21 h.p. The engine has a Ricardo head with side exhaust and o.h. inlet valves. The carburetters are on the off side and the exhaust system on the near side. It has a finned aluminium oil-cooler on the near side.

The chassis is a 4 1/2-litre and is fitted with vacuum brakes.

The dashboard is also 4 1/2-litre with a 120-m.p.h. speedo., and coil ignition switch. The ignition is by Scintilla magneto only, the switch being on the righthand side of the dash.

The car has a “fold-flat” windscreen which cannot be folded flat because of the standard Lagonda wiper motor mounted externally!

Davies Motors have afforded me the courtesy of seeing the original works card of this car which confirms the original 3/4 1/2-litre mixture, but I have found no one who can remember its origin and the why thereof.

The car is in excellent condition and I am very pleased with it, but am intrigued by its queer ingredients.

I’m hoping all this will strike a chord of memory somewhere.

I am, Yours, etc.
J. W> Aird
Brighton.

No 1921 T.T.