Technical Notes:
Page 1

Why a vacuum tube museum?

My Dear museum visitor: You now stand before a (sit before a virtual) museum devoted to radio tubes.

What is the sense of such an exhibition?

1. We would like to show you the development of vacuum tubes during the forty years from 1920 to 1960

2. We would like these tubes of our youth to be received by future generations. Too many tubes were senselessly thrown away during the introduction of the transistor. Many young people do not at all know what radio tubes are and for what they were used.

3. We would like to encourage the viewers to check in cellars or under stones to see if tubes do not lie about somewhere in order to keep or bring to a curator of a museum such as this. You should find old radios or such things: Each museum is glad to have such rare pieces around. There are serious collections of such devices and tubes, some will even pay high prices for such items (Technical antiques!). For what were tubes used? We would like to address this question first. A historical line up follows:

David Edward Hughes (London 1831 - 1900) Designs a simple spark transmitter. It lets the current from a battery be interrupted by a spring with contacts in rapid consequence and receives thereby a set of electrical sparks. He finds that he with an earphone and a piece of coke (zinc and silver filings), that are affected by an electro magnetic wave, which can detect the electro magnetic noise of the spark up to 60 meters away. He demonstrates this experiment in 1879 to the Royal Society at a distance of 400 meters. Science colleagues dismiss his attempts as swindles and Hughes is in such a way disappointed that he does not publish his attempts for many years. The apparatuses constructed by Hughes may be seen at the Science museum in London. Hughes was the first to prove that one can transfer signals with electro magnetic waves wirelessly.

James C Maxwell 1831 - 1879 Theoreticly predicts the existence of an electro-magnetic field, without being able to prove it experimentally.

Heinrich Hertz 1857 - 1894 Proves it's (electro magnetic field) existence. To generate these fields he uses a Rhumkorff spark coil with two flagpole antennas. In the center of this dipole sparks jump over between two balls.