ABSTRACTS OF TECH MCA L ARTICLES 465 



complications ignored by the simple theory and to some of the practical 

 difficulties which are encountered in constructing guns according to these 

 principles. An experimental check on the theory is described, together 

 with some information as to the actual current distribution in abeam 

 produced by a gun based on this design procedure. 



Microwave Radiation from the Stm}° G. C. Southworth. During the 

 summer months of 1942 and 1943, a small but measurable amount of micro- 

 wave radiation was observed coming from the sun. This appeared as ran- 

 dom noise in the outputs of sensitive receivers designed to work at wave- 

 lengths between one and ten centimeters. Over a considerable portion of 

 the range, the energy was of the same order of magnitude as that predicted 

 by black-body radiation theory. 



Attempts were made to determine the effect of the earth's atmosphere on 

 this radiation. Measurements made near sunrise or sunset, when the 

 path through the earth's atmosphere was relatively long, differed only 

 slightly from those made at noon. This suggested that any absorption 

 that may have been present was small. In this connection it is of interest 

 that small temperature differences could be noted between points below the 

 horizon and the sky immediately above. This also suggested that the 

 earth's atmosphere was relatively transparent. 



In another kind of measurement the parabolic receiver was centered on 

 the sun and its output was observed as the sun's disc moved out of the aper- 

 ture of the receiver. The directional pattern so obtained indicated that 

 at the shorter wave-lengths the sun's apparent diameter was considerably 

 larger than that measured by ordinary optical means. This suggested that 

 there may have been some refraction or perhaps scattering by the earth's 

 atmosphere. 



Resistive Attenuators, Pads and Netivorks — An Analysis of their Applica- 

 tions in Mixer and Fader Systems {Part Eight of a Series)}^ Paul B. 

 Wright. In last month's discussion, the series-connected fader and the 

 parallel-connected fader systems were considered, together with an analysis 

 of their performance expressed both algebraically and in terms of the 

 hyperbolic functions of a real variable. In this instalhnent, the series- 

 parallel-connected fader system discussion is continued and equations 

 describing the complete behavior of this type network system are developed. 

 This is followed by further analytical work dealing with the parallel-series- 

 connected fader and mLxer system and several lesser known systems which 

 are quite useful to use. These are the midliple bridge and the lattice network 

 systems which may be utilized to advantage for some applications. All of 



^^ Jour. Franklin Institute, April 1945. 



1' Communications, September 1945. {Preceding parts of this Scries appeared in earlier 

 issues of Communications.) 



