23857122-1403-531545-0022

SECRET RADAR OBSERVATION DATA SHEET I. QUESTIONS REGARDING DETECTING RADAR EQUIPMENT What type radar equipment is involved? AN/FPS~3 Has there been any recent maintenance difficulties? If so, describe. Negative What type modulator (i.e., spark gap, hard tube, etc.) is used in the radar equipment? Hard Tube Was the AFC (automatic frequency control) circuit of the receiver operating properly? AFC was performing efficiently on "Manual" position. Has interference from another. radar set been observed recently, and are personnel familiar with vhe effects caused by an interfering signal? No interference, and personnel are familiar. What type indicators, "A scope, "B scopet, etc.e, were used to follow the target? PPI Scope What was the radar scan rate? Five (5) RPM, 400 PRE What was the approximate frequency of the transmitter? 1290 MC II. GENERAL QUESTIONS What were the general weather conditions at the time unidentified target was observed? High thin overcast and low broken overcast. What weather data from nearby U.S. weather stations is available on temperature vs . altitude, humidity vs altitude, and wind velocity vs altitude? Nearest weather station is Kirtland AF Base, New Mexico. Was the target observed by any other nearby radar equipments? If so, give details. No Are the operator and the supervisor familiar with the effects of anomalous (duct- effect) propagation as they pertain to this type radar? Yes ADC Form 12 ; Page 1 of 3 20 October 1952 SECRET SECURITY INFORMATICiN MS 2/543 Declassification Authority: NND 57565