Using Satellites in the Classroom: A Guide for Science Educators.
The function, design, and ground statics ceguirements of the AMSAT-OSCAR ncn-ccmmercial space satellite system are described, and various experiments designed for direct student participation in space communications are provided in this text primarily written for the science educator. Six chapters include:) (1) an introduction to general satellite crtit problems and sclutione, (2) a number of tracking methods_ for ccmputing the positicns of 1 satellites, (3) onboard systems common to most satellites, (4) ai complete descripticn of each of the satellites currently in orbit or planned for the near future, (5) specifics fcr ground stations, and (6) four complete student satellite experiments, 15 detailed prcject outlines, and 19 suggestions for topics and activities. AppendiCes include listings of equipment manufactirers and publishers, as well as a glossary of terms. .(Author/RAO) #31g4g###########*31g#714########*###*######****************7144**714*71444714### * Reproductions supplied by EDRS are the ,best that car be made * * from the original document. * *********************************************************************** U.S. DEPARTMENT OF HEALTH. EDUCATION & WELFARE NATIONAL INSTITUTE OF EDUCATION THIS DOCUMENT HAS BEEN REPRO'. DUCED EXACTLY AS RECEIVED FROM THE PERSON OR ORGANIZATION. ORIGIN''ATING IT POINTS OF VIEW OF. JPINIOkS STATED-4:X) NOT NECESSARi'.Y REPRESENT OFFICIAL NATIONAL I,1 iTITUTE OF EDUCATION POSITION OR PGL:CY USING SATELLITES IN THE CLASSROOM: A GUIDE FOR SCIENCE EDUCATORS Martin R. Davidoff, Ph.D. "PERMISSION TO REPRODUCE THIS MATERIAL HAS BEEN GRANTED BY
Antennas for Circular Polarization
A formula is derived to give the variation in received voltage when an elliptically polarized antenna is rotated in a plane ransverse to the direction of propagation of the incident elliptically tolarized wave. It is shown that a circularly polarized antenna will pot receive any of its transmitted energy which is reflected from a nighly conducting smooth surface. Conditions that must be satisfied ho obtain an omnidirectional circularly polarized pattern are derived. Experimental results are given.
Loop Antennas with Uniform Current
The properties of a circular loop carrying uniform current are calculated for loops of any size relative to the wavelength. The radiation resistance and the greatest directivity pass through a series of maxima and minima as the frequency is increased. At frequencies below that for which one wavelength is contained in the circumference, the directivity graph is nearly independent of frequency. As the frequency is increased, additional lobes appear, the principal lobe tending to point more nearly in the direction normal to the loop. The paper includes a note on other loops, and a mathematical appendix dealing with certain integrals involving Bessel functions.