of its two preset frequencies or any two transceivers can be coupled through the special headset. The operator can trans­mit on either of the monitored frequen­cies by use of a special switch.

The command pack was designed, de­veloped, and produced in four months. It replaces approximately 300 pounds of equipment heretofore used to do the same job. Units have been delivered to the First Air Commando Group at Hurl-burt Field, Eglin Air Force Base, Fla., for field testing in this country before being shipped to Southeast Asia for fur­ther evaluation. They were built under a U.S. Air Force contract to Sylvania Elec­tronic Systems, a division of Sylvania Electric Products, Inc. It came into being in response to a high-priority request from the Special Air Warfare Center for new high reliability and light weight radio equipment for use in counter-guerilla operations and for training of native troops in Vietnam. In late Jan­uary the pack was exhibited publicly for the first time at the IEEE Interna­tional Convention at the New York Coliseum.

Telsfar II successfully launched A second Telstar experimental communi­cations satellite was launched in May from Cape Canaveral. An important ob­jective of the new Telstar will be to learn how to extend the useful life of communications satellites in space by avoiding or overcoming the effects of radiation, which twice disabled Telstar I's command circuit.

Telstar II was sent aloft for the American Telephone and Telegraph Co. by the National Aeronautics and Space Administration May 7, with the tele­phone company paying all costs for launching and tracking as it did for Telstar I.

An improved Delta rocket, more pow­erful than that used for Telstar I, was used to place Telstar i l in an orbit with a higher apogee (farthest distance from earth) where it will encounter less ra­diation. As with Telstar I, all technical information will be made available to NASA, and to the scientific community in general.

The satellite's elliptical orbit will take it from 575 miles at perigee (point nearest the earth) to 6,560 miles at apogee. Its predecessor, Telstar I, ranges in orbit from 592 miles to 3,531 miles, and takes 158 minutes to orbit the earth. Telstar II's orbit will take about 221 minutes.

The higher apogee of Telstar II will provide longer mutual visibility between the Bell System's ground station at An-dover, Maine, and ground stations in Europe. It will also give some mutual visibility between the Andover site and Japan, where ground stations are now under construction.

During its successful operation, Tel­star I carried out all the experiments originally planned. More than 300 tech­nical tests and over 400 demonstrations covered every aspect of transmission and proved the feasibility of communicating

via an active satellite. The demonstrations included multichannel telephony, telegra­phy, data, telephoto and other facsimile transmissions. Transatlantic television was demonstrated 50 times, including five color telecasts.

The difficulties with Telstar I were diagnosed by engineers and scientists as ionization of gases in transistors in the command decoders. To prevent this in Telstar II, "evacuated" transistors will be used in one of the decoders. These are transistors in which the cap en­closure that surrounds the transistor has been pumped free of air and other gases and sealed under a vacuum. Without any gas in the cap enclosure there should be no ionization.

Both Telstar satellites, which are nearly identical, were developed and built by Bell Telephone Laboratories, the Bell System's research and develop­ment organization.

The electron detector of Telstar II has been changed so that it can measure electrons in an energy range from 750.000 to 2 million electron volts, in­stead of from 250,000 to 1 million elec­tron volts as Telstar I did. This will make it possible to determine with greater precision the energy levels, num­ber, and location of these higher energy electrons. Such knowledge will be helpful in designing an operating communica­tions satellite system.

Telstar II's telemetry will report on some 118 items each minute when it is commanded "on" by a ground station. Telstar I made 112 such reports. The principle additions include measurements of the command circuit and a more pre­cise check on pressure inside the satellite.

Telstar II will be capable of sending its telemetry reports on the same microwave frequency (4,080 mc) that is used for precision tracking of both Telstar satel­lites—a desirable accomplishment in a commercial satellite communications sys­tem.

Space communicaffon course is planned for June A short course on space communication for practicing engineers will be pre­sented at the Long Island Graduate Cen­ter of the Polytechnic Institute of Brook­lyn June 17-21.

Specific topics of communication theory to be presented include: Problems arising in the design of space com­munication systems: Channel charac­terization; Propagation and antennas; Characterization of noise; Low noise receivers using masers and parametric amplifiers; Tracking behavior of phase-locked loops; Theory of analog and digi­tal modulation and detection; Coding and decoding of signals, and Communi­cation systems and problems found in the Telestar, Relay, and Ranger experi­ments.

Four members of the Polytechnic Electrical Engineering faculty. Profs. D. T. Hess, D. L. Schilling, A. G. Schil­linger, and M. Schwartz will present talks during the course, and there will be several speakers from the Bell Tele­phone Laboratories, Radio Corporation

of America, and Sylvania's Applied Re­search Laboratories.

The fee is $200, and attendance will be limited to 40 persons. A set of notes on the course will be issued. Further in­formation may be obtained from Prof. Schwartz, or Prof. Schilling, Electrical Engineering Department, Polytechnic In­stitute of Brooklyn, 333 Jay St., Brook­lyn 1, N. Y.

Ultrasonics fakes the ocean's tentperature Exploring the ocean's depths offers to the scientist as much challenge as ex­ploring the environments of space. Oceanographers, aiming at an under­standing of general conditions, are par­ticularly interested in accurate tempera­ture measurements, and for very practi­cal reasons. For example, small changes in water temperature are known to affect the performance of sonar systems, the eyes and ears of submarines.

A new kind of "thermometer" for the ocean's depths involves ultrasonics— sound waves too high in frequency to be audible to the human ear. Laboratory versions of the ultrasonic thermometer can pinpoint underwater temperatures to 5/100 degree F. The new system con­tains a transducer that changes electrical pulsations into mechanical vibrations of ultrasonic frequency. It can also reverse the process, converting the mechanical vibrations into electric pulses.

The transducer contains a small alumi­num disk, about an inch in diameter, which has a natural frequency of vibra­tion of about 40,000 vibrations per sec­ond. It is set in motion by a transistor­ized electronic circuit. Once in vibration, the disk precisely fixes the frequency at which the circuit oscillates, or produces electrical pulsations. Generated deep in the ocean, these pulses are sent along wires to the water's surface, where they are counted. The natural vibration rate

Sound waves far above the range of human hearing are used to take the ocean's temperature. Temperatures to 5/100 degree F can be recorded with

ultrasonic vibrations

422 ELECTRICAL ENGINEERING · JUNE 1963

of the disk changes with temperature. Therefore, temperatures are measured simply by observing the corresponding shift in frequency of the electrical oscil­lations.

Two wires, feeding d-c power to the instrument, extend down into the ocean depths. The pulses that measure the water temperature are carried upward over the same power leads. These leads can be relatively long without introduc­ing errors into the readings. Accurate measurements up to depths of 10 miles appear feasible for future models.

A good conductor of heat, the alumi­num transducer disk responds rapidly to changes in temperature and makes good thermal contact to the surrounding water. The transducer is mechanically rugged and has a high response to changes in temperature. Scientists at Westinghouse, J. H. Thompson and F. G. Geil, were the codevelopers of the instrument.

Advantages of the new device appear to be its ability to operate at extreme depths, its simplicity, and its character­istics of being a good thermal coupling between the ocean water and the metal transducer. Also, the temperature infor­mation is in digital form, and can be fed directly into a digital computer.

New color tube uses single gun A new color cathode-ray tube for tele­vision sets, that can be produced for sub­stantially less than present color televi­sion tubes, has been patented bv D. M. Goodman of New York University.

The tube employs a single electron gun instead of using three guns, which is now standard practice in the industry. The new tube also dispenses with the mechan­ical "shadow mask," a selection device that cuts down the brightness of the pro­jected picture.

The tube has a target screen consisting of repeating groups of vertical color strios and thin indexing strips, all de­posited on the face of the tube. When bombarded by the scanning beam re­leased from the single electron gun, the mdex strips give off short bursts of ultra­violet and X-ray index signals, which locate the position of the electron beam on the target screen. Attached to the electron gun are light pipes that pick up the index signals and send them through the neck of the tube to verv rapid gating circuits. These circuits sample the various video color signpjs, and then control the modulation of the electron beam to en­sure registry of the color signals on the target screen.

The new tube does not employ the wire grids or, as mentioned, the apertured masks used bv the color cathode-ray tubes now in use. Instead, index strips and color strips on the fa:e plate of tfie tube form a unitary, nonvibrat'ng, sand­wich assembly. The index strips operate at the same voltage as the color strips, requiring no additional high-voltage pow­er at the target screen. Also, because the index signals are transmitted as electro­magnetic radiation to the light pine mem­bers, additional high-voltage circuitry is not needed. This arrangement, which

I N D E X I G E N E R A T O R I

S C I N T I L L A T O R

S C I N T I L L A T O R

simplifies the target screen and index signal pick-up structures, makes the tube less expensive to produce. In addition, the new tube is better adapted to meet the broad range of environmental condi­tions likely to be imposed by industrial and military users.

The tube will be produced in the 21-inch 72-degree round envelope now avail­able, and also in the 23-inch 90-degree rectangular envelope.

The tube, in addition to its obvious use in television receivers, is expected to have wide application to information dis­play and electronic data presentation sys­tems for civilian use and for military in­stallations.

Further information can be obtained from D. M. Goodman, 3843 Debra Court, Seaford, N.Y.

U.S. contribution to IQSY is outlined Government scientists have released a de­tailed blueprint for their contribution to the International Years of the Quiet Sun (IQSY), a sequel to the International Geophysical Year (IGY) in the study of earth-sun relations. More than 50 nations are planning to collaborate in the new effort to understand how the explosive, million-degree solar atmosphere governs the environment of earth and the inter­planetary medium.

The two-year program, called IQSY for phonetic reasons, is scheduled to be­gin Jan. 1, 1964, as the 11-year cycle of sunspot and solar flare activity ap­proaches a low point.

A principal objective of IQSY will be to contrast the data to be gathered at solar minimum with that from the IGY in 1957-58, when solar activity was at the highest level since the beginning of systematic observations 200 years ago.

Plans for U.S. participation were pre­pared by the U.S. Committee for IQSY under the Geophysics Research Board of the National Academy of Sciences-Na­tional Research Council. The Committee

Goodman I—color cathode-ray tube

represents the United States scientific community on the international body es­tablished by the Comité International Geophysique (CIG) of the International Council of Scientific Unions to coordi­nate the IQSY effort.

IQSY is to be a full-scale follow-up to the IGY, in its emphasis on the simul­taneous world-wide recording of solar-dependent geophysical events and free exchange of data among nations.

While many IGY observations are to be repeated, to provide the first consistent set of geophysical bench marks for the high and low points of the solar cycle, the program also includes special experi­ments made possible by recent advances in techniques.

IQSY will concentrate on atmosphere and space phenomena directly affected by both the large periodic bursts of charged particles and associated magnetic fields escaping from the sun, and the confinu-ous background activity known as the "solar wind.*' IGY studies not bearing on the solar cycle have been omitted.

The goal of IQSY will be to obtain a portrait of the inn'i r s^lar svste^n at a time of relative quiet and, if possible, to isolate the atmospheric e f f e c t and distor­tions of the earth's magne field that re­sult from a single solar event.

Consequently, the thre^ -^iterii estab­lished for IQSY project - r - : ( 1 ) St idies feasible only or best undertalc^n a* the time of minimum solar a^t'vi v: Studies of isolated solar events not com­plicated by the superposition in : if any different effects; and (3) Compari­sons of data characterizing solar mini­mum activity with the solar maximum of the IGY.

fast breeder reactors to be studied Argonne National Laboratory, long a pioneer in the development of advanced reactors for the production of electric power, will begin design of a proposed Fast Reactor Test Facility (FARET) to

J U N E 1963 ELECTRICAL ENGINEERING 423