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A RESISTANCE RADIO TELEPHONE. 
R. R. RAMSEY. 
In radio telephones we have a source of alternating current of high fre- 
queney which sends current out into the aerial. The disturbance in the 
ether which is caused by this current is called the carrier wave. The 
amplitude of this wave is changed or varied by some means which is con- 
trolled by the voice. This device is known as the modulator. 
Since the three electrode vacuum tube has come into use, tubes are used 
as generators of the carrier wave and also as modulators. This is usually 
accomplished by connecting the telephone transmitter to the tubes with 
tuned or untuned inductance coils. In the case of the tuned coils, each 
set of coils must be separately tuned for every change of wave length. The 
untuned inductance method avoids this difficulty with a certain loss of 
efficiency. In either case one coil is liable to affect the second coil so that 
disagreeable cross squeals are set up in the set. 
The cascade amplifying receiving sets have the same defects so that 
all amplification is produced by audio coils, untuned iron core coils, or by 
resistance amplification. Tuning being in the main circuits alone. 
With the idea of simplicity and cheapness, I have devised a wireless tele- 
Fig. 1.—A Resistance Radio Telephone. 
phone connection in which the modulation is accomplished by means of re- 
sistances alone. The circuit is diagramed in figure 1. The oscillating cir- 
cuit consists of the aerial, the inductance, L, and the variable oil con- 
denser, C, connected to the ground at G. All tuning is accomplished by 
