The Oscillation Choke Coil.--The choke coil in the power circuit is made of about 260 turns of No. 30 B. & S. cotton covered magnet wire wound on a spool 2-1/4 inches in diameter and 3-1/4 inches long.
The Filament Rheostat.--This is made to take care of a 10 volt current and it costs $10.00.
The Filament Storage Battery.--This must develop 12 volts and one having an output of 40 ampere-hours costs about $25.00.
The Protective Condenser.--This condenser has a capacitance of 1 mfd. and costs $2.00.
The Motor-Generator.--Where you use one 50 watt oscillator tube you will need a motor-generator that develops a plate potential of 1000 volts and has an output of 200 watts. This machine will stand you about $100.00.
The different pieces of apparatus for this set are connected up exactly the same as shown in the wiring diagram in Fig. 78.
A 1000 Mile C. W. Telegraph Transmitter.--All of the parts of this transmitting set are the same as for the 500 mile transmitter just described except the motor generator and while this develops the same plate potential, i.e., 1,000 volts, it must have an output of 500 watts; it will cost you in the neighborhood of $175.00. For this long distance transmitter you use two 50 watt oscillator tubes in parallel and all of the parts are connected together exactly the same as for the 200 mile transmitter shown in the wiring diagram in Fig. 79.
[CHAPTER XVII]
CONTINUOUS WAVE TELEGRAPH TRANSMITTING SETS WITH ALTERNATING CURRENT
Within the last few years alternating current has largely taken the place of direct current for light, heat and power purposes in and around towns and cities and if you have alternating current service in your home you can install a long distance continuous wave telegraph transmitter with very little trouble and at a comparatively small expense.