A rotary gap is placed in the transmitting circuit in the same position as any other gap. Its use will result in a wonderful increase in the transmitting range of almost any station, for not only will the amount of energy passing through the aerial be raised, but the clear musical tone given off is more plainly distinguishable at a greater distance in the receiving station than a spark of the ordinary sort.
"KICK BACK."
The oscillations taking place in the closed circuit and aerial system of a wireless transmitter continue to surge after the current in the condenser has dropped below a certain value, and react upon the primary winding of the coil or transformer by induction and produce high voltage, high frequency currents termed "kick back," in wireless telegraph parlance.
"Kick back," wherever it exists to an appreciable extent, is liable to damage insulation and cause possible "burn-outs." The "kick-back" preventers illustrated in the accompanying diagrams will be found an efficient method of avoiding this danger.
Fig. 160. Methods of Preventing "Kick Back."
The first method shows an ordinary pressed telephone condenser of about two microfarads capacity connected directly across the A. C. mains near the transformer terminals, in series with two 6-ampere fuses. The condenser is shunted by a small spark gap made of needle points with a very small space, about .005 of an inch, between them.
The second method is an elaboration of the first and shows two sets of condensers in series with fuses and bridged by spark gaps with a "ground" through a third condenser connected between. This second method is the best and is often used to prevent delicate instruments, such as a voltmeter, from the effects of "kick back."
A proper "kick-back" preventer is part of the Fire Insurance Underwriters requirements for a wireless telegraph station.