The Meccano Crystal Radio Receiving Set
by John Ince

One of the surprising products of Meccano Ltd in the early days of Meccano was the Meccano Radio receiver. Why did Frank Hornby embark on this product? Perhaps this is explained by his article in Meccano Magazine No 25 July-August 1922.

Meccano and Radio.

A WONDERFUL NEW DEVELOPMENT.

 

Most of our readers are doubtless aware of the tremendous interest now being taken in Wireless Telephony in all progressive countries. America has so far taken the lead in this movement, and in that country high-power installations are established in all important and thickly populated centres, from which are transmitted news bulletins, concerts, stock and weather reports; shipping news, children's bedtime stories, fashion reports, sermons, etc., by Wireless Telephony. These installations are known as Broadcasting Stations, and anyone with a suitable receiving apparatus is privileged to "listen-in," and receive their wondrous and varied messages without restriction or payment.

The subject of radio transmission and reception is in itself a vast and complex science, but the installation of a receiving apparatus of sufficient power to receive messages from broadcasting stations at reasonable distances, is something which any bright intelligent boy can accomplish for himself with little difficulty.

Mr. Frank Hornby, the inventor of Meccano, and the Editor of the "Meccano Magazine " has just returned from a visit to the United States, where they have made a very close study of this subject. With the aid of a receiving set, constructed entirely of Meccano parts, and the addition of telephone ear-pieces, crystal, and one or two inexpensive fittings, they have listened to concerts, speeches, reports, etc., broadcasted from points five to twenty miles distant, with the greatest enjoyment.

The closest attention is being given by us to the development of this wonderful science, and experiments are being made that we already know will result in any Meccano boy being able to instal his own receiving set made from Meccano parts. Fuller announcements will be made in our September issue, and in the meantime we shall be glad to receive queries from our readers on any point connected with Wireless Telephony and Telegraphy, and to reply to them in our next issue. 1f a reply is desired through the post, a stamped addressed envelope should accompany the query.

 

Our illustration shows the Meccano Crystal Receiving Set and we wish to draw our readers' special attention to. its great simplicity in design and manner of construction. Any intelligent boy can assemble it in one evening. It has been tested thoroughly in London, Paris and New York and in each of these cities clear telephonic and telegraphic messages have been received. In London we have listened to broadcasted concerts from Marconi House. In New York, where the opportunities for testing are much greater than in this country, it has proved to be as efficient as the more costly and elaborate instruments in use there. In Paris we have listened to concerts broadcasted from the Eiffel Tower and have heard them with great clarity.

No scientific instrument ever introduced has been subjected to more thorough tests than the Meccano Radio Receiving Set and if properly adjusted, according to the simple instructions, it will be found to be highly efficient. It is suitable for receiving telephonic or telegraphic messages on a wave length of 360 metres. Provided that the instrument is installed within a distance of about 25 miles from any of the broadcasting stations, it will be suitable for "listening in" to the concerts, etc., that will be broadcasted in accordance with the arrangements made by the Postmaster General with the Broadcasting Company of which Meccano Limited is a member. Tests and experiments are being made continuously by trained Radio experts in the Meccano factories. Already several valuable discoveries have led to improved results in Radio receiving with the aid of Meccano parts. These will be fully described in future numbers of the Meccano Magazine.

We are very desirous that ail Meccano boys shall be kept in close touch with the Radio movement and that they shall participate fully in the pleasures that this great invention will bring. If you live within 25 miles of a broadcasting station the Meccano Crystal Set is the simplest and most effective apparatus with which to commence to enjoy this wonderful new science. Your first step should be to send for the Meccano Radio Instruction Leaflet. This will be forwarded post free on receipt of 3d. in stamps. If you reside more than 25 miles from a broadcasting station you will require a more powerful receiving set, and in this connection our Radio Department is now at work on a Meccano Valve Set, and full particulars will be announced in' the "M.M.." as soon as it is ready.

If you are in any difficulty in regard either to your apparatus or to the erection of your aerial, do not hesitate to write to the Editor, Radio Department, Meccano Magazine, Old Swan, Liverpool, who will be glad to help you.

 

The illustration of this first Meccano Crystal Set is on the next page and as can be seen it makes extensive use of standard Meccano parts. In addition there were a number of special parts produced. At the time the construction of radio receivers was not something that anyone was permitted to do without first obtaining a constructors licence.

In November 1922 MM the following statement was issued:-

Technical objections having been raised by the Postmaster General to the Meccano Crystal Receiving Set in its original form, certain modifications have been made in the design in order to secure official approval. This approval has now been given and we have pleasure in illustrating herewith the new Meccano Crystal Receiving Set. The new set has been tested thoroughly, receiving telephony and Morse with great clearness.

Perhaps for this reason a fully assembled set was introduced so that by December 1923 the Meccano Magazine carried an advertisement for No 1 Crystal Receiver and No 2 Crystal Receiver. The advertisement is reproduced below.

The entry of Meccano into the radio receiver market did not go unnoticed by the BBC as this message from the company's General manager in the December 1923 MM shows:

A Message from British Broadcasting Co.

THE readers of the Meccano Magazine live in a happy age. There are few greater pleasures than that of constructing things for ourselves. Young and old alike seem to find a good deal of enjoyment in the construction of homemade wireless sets, and in the use of them afterwards.

It has sometimes struck me that the boys of the present day know so much, that they may lose the sense of wonder. This would be a great loss, and one which, I hope, they may never experience. I know one of our greatest scientists who never uses a telephone without feeling what a marvellous thing it is. Although I spend all my days thinking about Broadcasting, it still seems to me a marvellous thing that a person may speak from our studios in London, or from any of our stations throughout the country, and be heard by over a million people, from Land's End to John O'Groats. Every day and every evening, there is speech and music in your home. All that is necessary to hear it is an aerial and a receiving apparatus, which many of you will no doubt be making for yourselves, or buying complete.

The British Broadcasting Company has all along been anxious to cater for +those who wish to make their own wireless sets, and at last a licence has been provided for this purpose. I do not like to intrude upon the of a Christmas number by talking about pains and penalties, but I expect you know that nobody may use a wireless receiving set without a licence. Without a licence they are disobeying the law, and such a course is not wise. Apart from this, they are avoiding payment towards the heavy costs of maintaining the broadcasting service.

Another point, I wish to make clear to you is that the

 

Constructors Licence is issued to those who will use only British parts. When you go to your dealer to ask for parts, it would be better to say to him Are you sure that these are British parts?

There are a great many people out of employment just now, but we are already finding work for many of them in the wireless industry. If everybody who constructs a set will loyally observe the condition of the licence (that only British parts are used) there will be a great deal more employment for British labour. I am sure that you realise this and will do your best to help. The pleasure of constructing your own set will be all the greater if you knew you have helped to keep in employment someone belonging to your country.

There are a number of items already included in our programmes that are of special interest to readers of the "M.M.". If there are items not at present provided, which a number of you would like, perhaps you could let your editor know. If he will pass the suggestions on to us we will see what we can do about it. Your interest in wireless should not end when your set is complete, for we wish you to realise that when you have a really good British set, you are in touch with one of the greatest services that the world has ever known.

J. C. W. REITH,

General Manager B.B.C..

Note. I shall be very pleased to hear from readers of the "MM" with suggestions or new items to be broadcast. Write neatly on a postcard and address to "Broadcasting," Meccano Magazine Liverpool

EDITOR.

As not many of these Meccano Crystal Sets survive it is difficult to determine how many might have been sold. A clue is provided by the advertisement on page 180 of the December 1923 MM where Peto-Scott Co Ltd offer owners of Meccano Crystal Sets three ways of improving it. These upgrades consist essentially of a signal amplifier to extend the range of the set, an output amplifier to increase the volume and the two combined. To have justified production of these upgrades there must have been a lot of Meccano Crystal Sets around. The same MM contains several other advertisements for radio receivers.

By October 1925 Meccano Ltd were advertising just the No 1 Meccano receiver. In the February issue it did not appear but there were several other more sophisticated radio sets offered by other companies. The MM of December 1927 contains an advertisement for the Meccano No 1 Crystal set now featuring two sliders, "one on each side of the inductance, giving greater selectivity and clearness of reception." The 1928 MMs contain no advertisements for Meccano Crystal sets. There are, however, advertisements for more sophisticated radios by other companies. In April 1928 the MM announced a Grand New Meccano Model-building competition. The prizes included 13 Meccano Radio Crystal Receiving Sets and 30 single telephone receivers. In May 1928 the competition prizes included Meccano Double Headphones. Were they clearing out the last of the stock?

In 1928 the MM featured the conclusion of a series of articles on Electricity Applied to Meccano. The December one was XIV - Crystal Receiving Set. Evidently any remaining problems with the British Post Office about building radio sets from Meccano parts must have been resolved. Here are the edited instructions for this set.

Building the Meccano Model

The Meccano crystal set is of very simple construction, as will be seen from Fig. 1, but this fact does not detract from its efficiency

The plates forming the " panel" may be made from stout cardboard or fibre strip. The best way to make the holes is to place the material between two 51/2" x 21/2" Flat Plates; a Meccano Rod may then be punched through the fibre, the holes in the Meccano Plates acting as a guide for the Rod. After the holes have been punched, the edges of the fibre plate may be trimmed.

The coil formers may be made out of the same material as the panel, or if preferred, they may be bought already shaped in various sizes. If cardboard is used it should be soaked in melted paraffin wax. Sufficient fibre for the panel and formers should be obtainable for about sixpence.

On each of the coil formers 25 turns of 26 S.C.C. Copper Wire are wound. In order to secure its end, the wire is first passed through two small holes that are made near the centre of the former. The winding is then commenced, the wire being laid on alternate sides of each of the segments of the former until the 25 turns have been completed, and the coil is finished off by passing the end of the wire through two other small holes near the circumference.

The coil 1 is attached by a nut and bolt to -a 57-teeth Gear Wheel that is secured to a 3" Rod journalled in a 21/2" x 11/2" Double Angle Strip 3. The latter is bolted to the fibre plates forming the base of the model. The 57-teeth Gear meshes with a Worm on a 31/2" Threaded Rod that is journalled in a 21/2" x 1/2" Double Angle Strip, and this Strip is secured to the base at right angles to the Double Angle Strip 3. By rotating the insulating knob that is locked by a nut on the end of the Threaded Rod, the coil 1 may be moved slowly round, thus altering the position in relation to the fixed coil 2. This alteration of the coils tunes the set to the desired wave length.

The fixed coil is attached to a 1"x 1" Angle Bracket secured to the base. The 57-teeth Gear with the coil 1 attached should be now adjusted on its Rod so that the two coils are as close to each other as possible without actually touching. The 1" x 1" Angle Bracket is provided with a terminal to which the aerial lead-in is attached and the commencement of the winding of the fixed coil 2 should be secured to the bolt that holds the coil to the Angle Bracket.

The crystal is mounted in two Double Brackets that are bolted to 1" x 1" Angle Brackets, 4. Suitable crystals with cat whisker may easily be obtained, but we recommend readers to use only the best. Several well-known and reliable makes of crystal are on the market.

A Cranked Bent Strip 5, pivotally mounted by a lock-nutted bolt (see Standard Mechanism 263) on the panel, carries at its upper end a Threaded Boss that is attached to tile Cranked Bent Strip by bolts. The bolts are inserted in the tapped transverse holes of the Threaded Boss and are locked in position by nuts so that they do not grip the 2" Threaded Rod passing through the longitudinal bore of the Boss. This Rod carries the cat whisker at one end and an insulating knob at the other. (A suitable knob may be purchased from any wireless stores or, if appearance is of secondary importance, a 1" fast Pulley fitted with a small Rubber Ring (part 155) may be used in its place).

The theoretical diagram of the set (Fig. 4) should make the following description the wiring perfectly clear. The "aerial terminal" attached to the Angle Bracket carrying the fixed coil, is connected by a short length of wire to the retaining bolt of the Cranked Bent Strip, 5, and a wire from the 1" X 1" Angle Bracket 4 carrying the crystal leads to of the phone terminals 6, the other ne terminal being connected to one the bolts fixing the 21/2" x 11/2" Double Angle Strip 3 to the base and also to the "earth" terminal (the latter can just be seen in Fig. 3; it is secured to the base to the right of the 57-teeth Gear Wheel) The wires of the remaining ends of the variometer coils should be connected together. It only remains now to connect the aerial and earth wires and phones to their respective terminals and the set is ready for use.

There are two known Meccano Crystal Sets in New Zealand. One of these, belonging to Graeme O'Neill, was featured in this magazine in October 1996 and subsequently in the Constructor Quarterly in March 1997. The other was unearthed at MOTAT by William Irwin. Both sets are discussed in the October 2003 issue of this magazine.

So what happened to Frank Hornby's great interest in radio? I think the new radio technology was advancing so quickly that Meccano Ltd were rapidly overtaken by other companies. The Crystal Sets offered as competition prizes were probably a good way of disposing of the remaining stock while the build your own crystal set described above provided an honourable exit from radio.

One can almost imagine hearing Hornby shouting to his staff, "Come on chaps, lets get back to Nuts and Bolts!"

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