Extracted from Chatham, Rochester, and Gillingham OBSERVER 24^th March 1933

To All Quarters of the Globe

 

HOW MEDWAY HAMS MADE THE BIG BROADCAST

 

First Winner of the Observer Trophy and Full Results

 

Interest among members of the Medway Amateur Transmitters Society—and indeed amongst Medway townsfolk generally in their radio transmission and reception contest for The Observer challenge cup reached a very high point, and we are now able to publish the complete results. The first winner of the handsome trophy offered by THE OBSERVER is:-

Mr. J. A. Mackinnon of Radio Supply Company, Ltd., Medway Street Chatham, who operating from station G6VV Chatham, secured a total of 51 points.

The runner-up is Mr. A. 0. Milne. South Cottage, Larkfield, near West Mailing, secretary of the Society, who operates from G2MI, and secured 30 points.

Next in order of merit came Mr. S.A. Howell, 117a, Trafalgar Street, Gillingham G5FN, 20 points.

Mr. E. Pethers, 17, Tainton Street, Rainham. G6QC, 19 points.

Mr. R. Maidment, Red House, Hoo. G5MM, 18 points.

Mr. H. Harding, 3 Pond cottages Tunstall. G6RQ, 13 points.

Mr. R. Smith Keston, Woodlands Road ,Gillinghain.G6TQ, 12 points.

Mr. S. A. Cook, 2, Queen's Avenue, Snodland. G5XB, 4 points.

Mr. N. Kirby, 5, Station Road, Teynham. G6FV, 4 points.

The reception contest was won by Mr Ellis, of Strood, with 143 points, and Mr. Howlett, also of Strood, was runner up with 67.

Mr. Cook uses very low power, and was unfortunate in having a powerful French station on his wavelength throughout the day of the contest. Mr. W. E. Nutton (G6NU) experienced a breakdown in his power supply early in the day which put him out of the contest. This was very bad luck for Messrs Cook and Nutton, to whom the wish for better fortune in next years contest is extended.

 

ROUND THE WORLD.

 

During the day of the contest competitors made contact with twenty-four countries in four different continents -Europe-, North America, Africa and Australasia—as follows:  England and Scotland, 32 stations; France 5; Northern Ireland 1; Irish Free State 1; Belgium 1; Holland 3; Germany 10; Sweden 2; Norway 1; Russia 2; Denmark 2; Romania 1; Hungary 3;Czecho-Slovakia 1; Portugal 3; Austria 1;Finland 1; Poland 9; Morocco 2; Algeria The Azores 1; U.S.A. 3; Australia 1;

 

“Who interfered” I asked innocently, where upon Mr. Mackinnon looked ill and asked me to examine the set. There was one thing in it which to me was most intriguing. It was u long knitting-needle affair with a circle of wire atone end and a small torch bulb in the circle. No matter where one held that circle the bulb always glowed brightly. I held it close to a cylinder of thick curly wire - a short wave coil, I understand-and it glowed. I held it by the aerial and it, glowed. For no reason at all that bulb came to life—and in another land I would be made witch doctor on the spot for that. The main characteristic of Mr. Mackinnon's apparatus seems to be its propensity to light bulbs. An electric light bulb glowed When ever it was brought near wires aim coils, and it glowed when it was touched upon the aerial wire. Can you get a shock from the aerial I asked? “Just a little burning feeling”, Mr. Mackinnon replied. A few minutes later he went out of the room to find an ohm or something, and I touched the aerial. He was right. When he told me the transmitter was crystal oscillated I felt at home. I remember seeing, way back through the years, crystals sold in wireless shops. I asked to see the cat's whisker, and once again Mr. Mackinnon looked ill. He showed me the crystal, which locked like a little piece of glass and there was nothing near it even slightly resembling a cat's whisker.

 

ANOTHER STATION “WORKED.”

 

For my benefit Mr. Mackinnon agreed to "work'' another station. He delved behind the cretonne and created a sinister humming sound. Switches were moved and lights appeared in several places. Then he played with the knitting needle, fiddled with dials and plugs, and started tapping out dots and dashes. For perhaps a quarter of an hour he tapped and then he switched over to transmission and before long was transcribing a reply from another amateur in Germany. Colossal!

 

IT REALLY IS.

 

For the benefit of readers who are still interested I will give a description of the apparatus. From Mr. Mckinnon's dictation I took down the details with infinite care, but if there should be a mistake I humbly offer apologies. Mr. Mackinnon said the transmitter is a straight forward crystal oscillated and power amplified arrangement on a frequency of 7160 K.C. The aerial is a 66ft. half-wave voltage fed Zepp. The power is 9.8 watts fed by Westinghouse metal rectifier, two type H.T.2’s in series. There is one H.T.1 separate supply to the C.O. Primary keying is used so as to reduce any possibility of QRM (interference) to outside listeners. Mr. Mackinnon said he was lucky because the crystal which was controlling the transmitter was on a frequency relatively free from interference. He worked with an indoor aerial so as to reduce interference to a minimum. Mr. Mackinnon extends a cordial invitation to my readers to inspect the apparatus. Send a post-card to: Colaba, Randall-Road, Chatham, for an appointment. But don't touch the aerial!   Written by W.L.D.

 

MR MILNE ON THE AIR.

 

The station of Mr. Milne, the runner up, is operated almost entirely from the 50 cycle A.C. mains with three aerials—a short low one for receiving and two larger aerials for transmitting, which are at right angles in order that the whole globe can be covered at maximum radiation.  High tension by means of a transformer is obtained from the mains and voltages between 250 and 1,400 are available. Two transmitters are at present in use, one operating on 1892.5 kilocycles (153 metres) and the other on 7078 kilocycles (42 metre band). Both are crystal controlled, the first-named employing two valves and the latter three valves. The maximum power on 153 metres is 10 watts and on 42 metres 50 watts. A two valve all-mains amplifier is used to obtain either loudspeaker reception or as an amplifier for the microphone during telephony transmission. The four valve receiver is totally screened and has a screen-grid detector, two L.F. valves and a volume control. The invitation extended to visitors by Mr. Mackinnon is echoed by Mr. Milne, who would also be pleased to hear from anyone genuinely interested in experimental radio.

 

THE OTHER STATIONS.

 

Appended are brief descriptions of the remaining stations which took part in the contest: G5FN, operated by Mr. S. A. Howell at Gillingham, is an excellent example of what may be done when space is limited. The whole station is situated in a small garden shed, and to it belongs the distinction of having covered the "greatest distance during the contest—ZL, New Zealand. Mr. Howell was also the only competitor to "work" Romania and altogether three continents and ten countries were worked" with a power of twenty watts. This station is operated from electric mainsthroughout.G6QI', operated by Mr. Pethers, was the only station to " work " U.S.A. more than once.G5MM, operated by Mr. Maidment, of Hoo, put up a great performance in scoring 18 points entirely on the short distance band 160 metres, which, in addition, were all on telephony. As 160 metres is not used during British broadcasting, Mr. Maidment's performance was accomplished in 24 hours. H.T. is from accumulators.G6TQ, of Gillingham, also favored the 160-metre band, but used both Morse and telephony.G6RQ "worked" one German on the 42-metre band and then turned to 160 metres to the rest of the tests.

G5XB’s hard luck has already been mentioned. His three contacts were England, Sweden and Hungary. This station had, during the earlier part of the week, contacted with U.S.A. on the infinitesimal power of 4 watts. This is a most remarkable effort, as G5XB's power supply is entirely taken from dry batteries. The tests are over and, as was anticipated, many weak points in station layout have asserted themselves, but these will be speedily corrected. Members feel that they have put up a very good show and have demonstrated what the amateur radio enthusiast can do with his few watts of power.