Patent GB-1050626-A (GB)
IPC: H03K3/78
Abstract: 1,050,626. Radio transmission systems. UNIVERSITY OF NEW ENGLAND. March 20, 1964 [March 20, 1963], No. 11997/64. Addition to 884,337. Headings H3B and H4A. A radio frequency generator and transmitter comprises a symmetrical circular array of concondensers C, Figs. 1a 1b, which are connected by conductors a, b to a single spark gap S centrally disposed between terminal rings A, B, the condensers being charged from a D.C. source through resistors connected to the rings. The frequency of the transmitted wave is determined by the capacitance and internal inductance of the condensers and by the inductance as determined by the circle diameter, while the radiation resistance is determined by the circle diameter only. Minor frequency adjustment is possible by varying the mutual inductance coupling between the conductors a, b, the adjustment being effected by limited rotation of the rings whereby the conductors a, b cross, Fig. 2a or diverge' Fig. 2b. Each conductor pair a, b, may be a twin low-loss line or a coaxial line TL, Fig. 3b, which may be one half of the wavelength long or the longer equivalent, the resistance of the single spark gap being then reflected across the terminals α, # of adjacent capacitors and hence corresponding to the arrangement in Specification 884,337. In a modification the single spark gap is spaced from the function of the lines by an auxiliary line of half wave length long or the longer equivalent, Fig. 4 (not shown). An auxiliary line TP of length #/50 is used in Fig. 5 for tuning the arrangement, this line comprising flat metal strips on opposite sides of an insulating sheet to which the spark gap is coupled by sliding contacts. To balance the short added length of auxiliary line, each line TL is reduced in length by X/100. The Fig. 4 arrangement is modified in Fig. 6a (not shown) by an inductor and capacitor connected in series across the spark gap and tuned to the operational frequency. A modification is shown in Fig. 6b in which part of the tuned circuit comprises a decoupling condenser C2 across the spark gap. The arrangements described may be used as transmitters only in which case separate oscillators are provided. In Fig. 7a the connected ends of the lines TL form a coupling circuit with a similar circular array D which is enclosed in a metal screen and serves as an oscillator only. The equivalent of a circular array is used in Fig. 8a in which a single spark gap S<SP>1</SP> is provided between a conducting shell S and a multiple ceramic-dielectric capacitor d. The casing may contain insulating oil or pressurized air or inert gases. In a modification, Fig. 8b, the conducting shell is in two parts S1, S2 and two spark gaps S1, S2 are provided. The arrangement includes two condensers d 1 , d 2 , one cylindrical and the other in the form of a ring. The condensers are effectively in parallel during charging and in series when discharged through the spark gaps. Coupling between the oscillator and transmitter may be through a cavity resonator CR, Fig. 9, through a diode rectifier bridge, or through ferrite saturable reactors, Fig. 10 (not shown). The spark gap may be replaced by one or more thyratrons, gas filled relays, transistors, or high vacuum thermionic or field emission tubes.