Mohave County miner and our mineral wealth., 1922-06-09

gree of coupling between these two circuits fis just right, nearly all of
 the energy so transferred will be rad
 lated by the antenna in one wave. It is impossible to attain the radiation of the entire energy in one wave, but | by careful adjustment aDvery great
 percentage of the energy can be so
 radiated. This method of adjustment,
 or Tuning" as it is called, eliminates
 the radiation of i the objectionable
 broad or impure wave, and concen- trates the radiated energy into nearly
 one sharp or pure wave, which is the
 result we desire. It should also be noted that due. to the fact that there is no air gap in the. antenna circuit, the oscillations are not damped out so quickly, and hence the total energy output of this circuit is' greater. By the use of special spark gaps in the oscillation generator circuit, such as
 quenchedA gaps or rotary gaps, the oscillation of that circuit may be: so
 governed that there will be no back discharge of energy after the antenna circuit has been given energy by one spark discharge rifIl;fsglN,t..,,igniF.s lsiIWith this type of transmitter, tele- graphic communication may be main tained over very great distance. All
 damped wave transmitters. are con-
 structed in this manner. For the use
 of high power, modifications must necessarily be made, but the principle
 of operation is the same. The partic- ;ular outfit. which has been described1 is that, used by comparatively low power stations, such as ship stations
 and amateur stations. It should be remembered that the chief limitation
 to the use of damped wave transmits sion is that it can only be used for telegraphic communication. Tele- .phonic communication requires the use of undamped waves, .Jy Iss:EaF
 Continuous waves, or undamped waves, are able to travel farther than damped waves due to the fact that they have constant amplitude and therefore have greater energy .., than an equal number of damped waves. In order to generate continuous waves, we must devise some method by which
 an amount of energy may be added to each oscillation equal to the amount of energy lost in the preceding os- cillation. It is seen that if this can be done, each oscillation will have the same amplitude as the preceding oscil- lation, and accordingly each radiated wave will have the same amplitude as the preceding wave, giving us 1un- damped wave radiation. It has been found that undamped waves can be generated either with an electric arc, similar to the arc in street lamps or with special type of electric. light
 bulb. Due to the lack of space, only
 this latter method will be. discussed here. ,,,,--.,,,...-ry, y,,., I This special type of electric light bulb is called by number of names, such as audion, ionic. tube, thermionic tube, pliotron, vacuum valve, electron tube,, vacuum tube, and others. It will be called vacuum tube in this. dis cussion. The vacuum tube is made of glass container from which the air has been pumped. In this con tainer are three elements, the fila ment, the grid, and the plate. The fil- ament is very much like the filament of the ordinary electric light bulb, but is generally lighted by a six volt storage battery. The grid is a net work of fine wire surrounding the fil- ament and close to it. The plate is a solid piece of metal placed on the outer side of the grid. The action of the vacuum tube is as follows:
 When any metal is heated, electrons are thrown off from the metal. If the metal is in air, the friction between the rapidly moving electrons and the