Cosmos Radiophone Crystal Set by Metropolitan-Vickers Electrical Co.Ltd.

Just an empty box alas, but a perfect interior instruction label and a decent Post Master General type approval badge.

   

 The instruction card is quite interesting. First one must ask why the aerial emerges from the front of the house rather than the more discrete rear? Presumably possession of a wireless aerial in those distant days was considered a status symbol?

Although the aerial would be visible the receiver would not, and it's worth pointing out that this humble crystal set was considerably cheaper than those sets currently available at the time employing valves, which could cost as much as a years wages of an ordinary worker. Not that anyone would ever spend a years wages on a receiver but you get the drift.

Having shelled out more than two weeks grocery money on one of these crystal sets, and coughed up for a license (well you did put up this 100 foot advert for your receiver in your front garden didn't you!), the intial mastering of the operation of a crystal set was quite a technical achievement. Basically one fiddled simultaneously with a cats whisker and a tuning knob until a sort of ethereal hubub of voices was heard. Getting the crystal to work was a bit hit and miss... note the comment about giving up and trying the spare one! There were so many hurdles.. was the aerial connected properly? Did the crystal work? Was the cats whisker OK, and in contact with a suitable point on the uncertain crystal? Were the headphones working and connected correctly?

Of course, once initial success was behind one, in retrospect, it all seemed easy.

Tuning in this model was carried out with a "handle" that connected to tappings on a coil, which in conjunction with the aerial, resonated roughly at the frequency of the desired station, and once adjusted resulted in one station becoming slightly louder than lots of others. Daytime listening was a lot different than night time listening. During the day one would really only be able to hear one or two stations but, at night, when the sun went down, the airwaves came alive with dozens of strange foreign voices, often turning into English at pre-arranged times, as the continental stations were very aware of their avid British listeners and published programmes to suit.

Because of the very low average level of technical skills in wireless reception in the early 1920s, tuning a station was generally not an easy matter. First one had to have constructed a suitable aerial, a device covered by government legislation dictating that it was not to exceed 100 feet from distant tip to receiver terminal. Secondly, for decent reception a good earth connection had also to be made and, if one listened to the proper authorities and advertisers, it was pretty well essential to include a safety switch to minimise electrocution from lightning. There were also articles on making provision for getting the wire into one's house, using suitable porcelain insulators and the like. Next came the intricasies of connecting up the aerial and earth wires and headphones. In fact there were lots of pitfalls on the way to settling down and listening in. Once an enthusiast was successful and had demonstrated his prowess to his own family, no doubt he became a consultant to his neighbours.

The use of a loudspeaker in those early days was rare, and most listeners used headphones. It's worth pointing out that these headphones were very different to modern types. Crystal set headphones were high resistance instruments that would offer a relatively low loading on the simple crystal set circuitry (equals loud reception). Note that the instruction label above mentions the fact that two pairs of headphones can be used but implicit in the directions for their connection is the fact that these are wired in series not in parallel. Modern headphones are useless for crystal set use because they have a very low impedance. This would result in only a tiny fraction of the available radio signal getting to the listeners ear (equals very quiet reception), and anyone experimenting with an old crstal set would be very disappointed with the results unless high impedance headphones were used.

 

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