An Impulse Excitation Transmitter

Ideal "impulse excitation," as opposed to the usual quenching gap phenomena, is described. The best conditions for impulse excitation are explained. The development of a rotary sectored gap of small separation operating in a hydrocarbon atmosphere is considered. A 2,500 volt, 60 cycle transformer charges a large capacity which discharges thru the gap and a small inductance. Effective impulse excitation requires about 2,400 R.P.M. of the gap or more. Using alcohol vapor, an adjustable pressure, (safety) valve must be fitted to the gap to prevent excessive pressures which raise the gap voltage inordinately. A complete 2 kilowatt transmitter of this type is described. The antenna circuit need not be in tune with the closed circuit; hence wave changing is accomplished by merely shifting the antenna lead along the antenna loading inductance. The radiation remains constant over a wide range of wave lengths without closed circuit tuning. Smooth-disc gap experiments are also described.