RF characteristics of the hoop column antenna for the land mobile satellite system mission

A communication system using a satellite with a 118 meter diameter quad aperture antenna to provide telephone service to mobile users remotely located from the large metropolitan areas where the telephone companies are presently implementing their cellular system is described. In this system, which is compatible with the cellular system, the mobile user communicates with the satellite at UHF frequencies. The satellite connects him at S-Band, to the existing telephone network via a base station. The results of the RF definition work for the quad aperture antenna are presented. The elements of the study requirements for the LMSS are summarized, followed by a beam topology plan which satisfies the mission requirements with a practical and realiable configuration. The geometry of the UHF antenna and its radiation characteristics are defined. The various feed alternatives, and the S-band aperture are described

On the polyhedral cones of convex and concave vectors

Convex or concave sequences of n positive terms, viewed as vectors in n-space, constitute convex cones with 2n − 2 and n extreme rays, respectively. Explicit description is given of vectors spanning these extreme rays, as well as of non-singular linear transformations between the positive orthant and the simplicial cones formed by the positive concave vectors. The simplicial cones of monotone convex and concave vectors can be described similarly

The Kraft sum as a monotone function on the refinement-ordered set of uniquely decipherable codes

The set of all uniquely decipherable (UD) codes is partially ordered by re nement, meaning that all strings in the cruder code can be represented as con- catenations of strings taken from the ner code. The Kraft sum is a monotone (increasing) function on this poset. In the re nement order, chains of UD codes having the same Kraft sum are necessarily of the simple descending type