Beacon Receiver Research Articles

A Method for Calculating Error Probabilities in a Radar Communication System

Missfle range instrumentation radars are capable of transmitting pulse code groups in which some of the pulses in each group can be used to convey information from the ground to a space vehicle containing a suitable beacon receiver and decoder. Thus, a one-way communication system is provided with only a small increase in ground and vehicle equipment over that required for the tracking function. Since the system is one way, communication reliability becomes of paramount importance. This paper presents a method of computing bit error rates, word error rates, and frame error rates as a function of the SNR at the beacon receiver. The SNR vs range can then be computed by standard methods to obtain the ground-to-vehicle ranges over which reliable communications can be conducted.

Radiation-Tolerant Electronic Equipment

A study was made of electronic equipment capable of operating in radiation fields for long periods of time. To date the file contains radiation effects data on 1100 electronic components and materials. A color code based on how much nuclear radiation a device can be exposed to and still give satisfactory performance is used to mark the cards of the components. As a result of this compilation, several pieces of complex electronic equipment were subjected to a component interchange-replacement of radiation-sensitive with radiation-resistant components. An ARN-32 aircraft marker beacon receiver was modified and it operated for more than 370 hours during a 55 day period. After the ARN-32 was subjected to an epicadmium flux of 3 x 10/sup 17/ nvt the crystal had drifted but the unit was still operating within pertinent military specifications. (B.O.G.)

A Transistor Marker Beacon Receiver

Junction transistors and diodes are used to replace tubes and relays in a newly designed one-light marker beacon receiver. Ten transistors and three diodes are combined in a dual conversion superheterodyne receiver circuit which draws less than one watt of power and which has a sensitivity of 500 μv. Pass-band selectivity is 80 kc minimum at the 6-db down points and less than 300 kc at the 60-db down points. Dual conversion is used to transform the radio frequencies to a low IF for stable receiver gain. A three-light adapter has been developed utilizing seven junction transistors, two diodes, and miniature LC filters. The unit is the same size and weight as the one-light receiver. The weight of the entire three-light system is less than two pounds. The total current drain, from a 27.5-volt direct current supply, is less than 80 ma. A printed circuit board in a wrap-around case mounts most of the components in a design that withstands shock and vibration without the use of a shock mount.

Space ship telemetry

All too soon the industry will be faced with the problem of transmitting telemeter data over previously unconsidered enormous distances. The flight of an exploratory vehicle which will circle the moon before returning to earth is a definite possibility within the next ten years. The adaptation and refinement of presently available techniques for telemetry is shown to provide a number of feasible possibilities. This paper reviews the basic considerations of RF link design and presents nomographs illustrating their application to great distances, high powers, narrow bandwidths and high receiver sensitivities. New developments including the MASER amplifier, “Paraballoon” antennas and highly stabilized transmitters are discussed. System concepts such as interrogation, directional antenna steering by beacon receivers, data slow-down and storage, and encoding methods are explored.