ABSTRACTS OF TECHNICAL ARTICLES 139 



ance to the driving field, and the properties of the antenna are a composite 

 depending upon the proportions of the various harmonics present. The 

 behavior of the harmonics with frequency is discussed cjuahtatively; analyti- 

 cal expressions obtained are useful chiefly at the resonant frequencies of the 

 antenna, where the most important harmonic becomes sinusoidal in char- 

 acter. 



On Radiation from Antennas J S. A. Schelkunoff and C. B. Feldman. 

 This paper presents some theoretical remarks and experimental data relating 

 to applications of the transmission-line theory to antennas. It is empha- 

 sized that the voltage, the current, and the charge are affected by radiation 

 in different ways, a fact which should be considered in any adaptation of 

 line equations to antennas. 



It is shown experimentally and theoretically that in an antenna of length 

 equal to an integral number of half wave-lengths, which is energized at a 

 current antinode, the effect of radiation on the current and the charge 

 (but not on the voltage) can roughly be represented by adding to the resist- 

 ance of the wires another fairly simple term. 



The Use of Secondary Electron Emission to Obtain Trigger or Relay Action} 

 A. M. Skellett. The use of secondary electrons to obtain trigger action 

 similar to that of a thyratron is described. An experimental tube and the 

 necessary circuits by which this action is achieved are discussed. This 

 combination gives the features of a triode with a relay or on and off feature, 

 resulting in an amplifier, oscillator, modulator, or other vacuum tube device 

 which may be turned on or off abruptly at high or low frequencies. In 

 addition, it can be used to replace thyratrons in many of their circuits where 

 Very low impedance is not necessary and is capable of much greater speeds 

 of operation in such applications. 



A New Frequency-Modulation Broadcasting Transmitter} A. A. Skene 

 and N. C. Olmstead. A new frequency-modulation transmitter is de- 

 scribed which uses a novel amplifier circuit permitting an unusually simple 

 mechanical design and an economical vacuum-tube complement. 



The choice and design of circuit components, governed by both mechani- 

 cal and electrical considerations, are discussed in detail. 



A Secondary Frequency Standard Using Regenerative Frequency-Dividing 

 Circuits}'^ F. R. Stansel. A secondary frequency standard is described 



7 Proc. I. R. E., November 1942. 

 ^ Jour. Applied Physics, August 1942. 

 ^ Proc. I. i?. £., July 1942. 

 10 Proc. I. R. E., April 1942. 



