September 1945 Radio-Craft
[Table of Contents]
Wax nostalgic about and learn from the history of early electronics.
See articles from Radio-Craft,
published 1929 - 1953. All copyrights are hereby acknowledged.
Two items particularly caught my eye in this group of news tidbits
from a 1945 edition of Radio-Craft magazine. The first
was the drawing of a scheme for mobile-to-mobile as well as fixed-station-to-mobile
radiophone service - cellular telephones! A frequency band of 152-162 MHz
had been allocated for "urban mobile service." Towers and base transceiver
stations (BTS) would be erected along the most commonly traveled
routes to ensure contiguous coverage. Two years later, in 1947,
Bell Systems initiated its
Mobile Telephone Service (MTS) based largely on the principle
presented here. The second thing that interested me was a plan by
Raytheon to institute a microwave relay system to facilitate intercontinental
phone traffic. Bidirectional service operated on 105 MHz and
107 MHz. Also in the news was rescinding of the prohibition
against production of non-war-related electronics for home use,
government-funded television research by the Ruskies, and FM radio
station frequency allocations.
Radio-Electronics Monthly Review
to the Technician
Two-Way radiophone between moving automobiles
and other motor vehicles and subscribers to the regular land telephone
will be in common use in the near future, according to plans announced
last month by the American Telephone and Telegraph Co. This will
mean that telephones on automobiles, trucks or other mobile units
such as boats and barges will be connected with the general telephone
system, so that a subscriber to the general two-way mobile service
can talk from an equipped vehicle to anyone of the millions of telephones
served directly by or connected with the Bell companies. Likewise,
the occupant of an equipped vehicle can be called from anyone of
the millions of telephones.
Calls to and from motor vehicles will be handled by special operators.
The conversation will travel part of the way by telephone wire and
part of the way by radio. If a caller at his desk wants to talk
to the occupant of a certain automobile, he first dials or asks
for the vehicular operator. He gives her the call number or designation
of the vehicle. She sends out a signal on the proper radio channel
by dialing the code number assigned to that particular vehicle.
An audible or visual signal indicates to the car occupant that he
is wanted. He picks up his dashboard telephone and the conversation
The operator of a mobile unit can originate calls merely by picking
up his telephone and pushing the "talk" button. This signals the
vehicular operator and she "comes in on the line." He gives her
the telephone number he wants and the call goes through.
Three classes of mobile service are contemplated:
1. A general two-way telephone service between any regular telephone
and any mobile unit, with a three-minute initial period and one-minute
2. A special two-way dispatch service between a particular telephone
at the dispatching office and specified mobile units. A direct line
from the dispatcher to the telephone central office would be furnished
as part of this service. A one-minute initial period and the usual
one-minute overtime period would probably apply here.
3. A one-way signaling service to mobile units, to notify the
operator of the unit that he should comply with some pre-arranged
instruction, such as calling his office from the nearest public
Radio signals in the frequency range between 152 and 162 megacycles
have been assigned for the urban mobile service. In general, transmission
of these frequencies is greatly improved by mounting transmitting
and receiving antennas on high buildings or on other commanding
automobile traveller would remain in touch with his home, even across
Transcontinental communications by microwave
are envisioned by Raytheon, which last month received construction
permits for five stations to form a relay circuit from New York
to Boston. These five are the first leg of the proposed route across
the country, which will be extended via Cleveland, Detroit and Chicago
to the Pacific coast.
The company received at the same time constructional permits
for two FM experimental stations, to be erected atop the Lincoln
Building, New York City. One of these on 105 megacycles, will transmit
in a southward direction, while the other, on 107 mc, will beam
its transmissions toward the west.
Swallow-Counting with the aid of electronics
can indicate the value of a trainee in actual aerial combat, according
to reports issued by Westinghouse last month. In high-altitude flying
a definite relationship has been found between the ease or difficulty
of compensation of the flier for changes in altitude and his ability
as an air fighter. This altitude accommodation is made by swallowing,
which equalizes the pressure on both sides of the ear drum or tympanum.
Regarding the accommodation as a function of the rate of change
of pressure is the chore of the electronic tympanometer.
The tiny microwave transmitter fits in a case no larger
than a big telephone earpiece.
Heretofore, physicians have had to enter a high-altitude chamber
with the prospective flier and count the swallows, and relate them
to the rate of change of pressure, i.e., altitude. To make the examination
more accurate and obviate the necessity of the physician remaining
in the high-altitude chamber during the test, instruments that appear
to be oversize earphones with "horns" have been developed at the
Westinghouse Research Laboratories. Clamped on the head of the flier,
an earpiece over each ear, the swallows are automatically registered
by the instruments and recorded on a chart outside the chamber.
Against each ear of the subject are placed fluid-filled chambers.
The fluid rests against the ear drum on one side, and on the other
against a diaphragm in the "earphone". The "earphone" is a microwave
radio transmitter - the "horn" its antenna. The diaphragm, coupled
by the liquid to the eardrum, with each swallow moves a pin within
the instrument. This movement of the pin causes a peak in the transmitted
wave. Thus, the record of a compensation appears as a peak in an
otherwise smooth graph.
The problem of transmitting the impulses to the recorder outside
the high-altitude chamber is essentially one of telemetering. Because
the chamber is a metal enclosure, the receiving antenna is strung
inside, emerging by means of a coaxial cable. Accurately plotted
graphs of swallows versus altitude (or pressure) are made without
the doctor being required to undergo the discomfort involved in
the high-altitude cycle.
Swallowing is a voluntary compensation for differences in altitude.
There are other entirely involuntary compensations of great importance
in determining the fitness of an individual for high-altitude. The
end result of these involuntary accommodations also equalization
of pressure on both sides of the tympanum and the rate of response
of these to outside pressure variations is also shown.
Proposals to extend the standard-frequency broadcast
downward 10 kilocycles, adding a new broadcast channel to the band,
were tentatively approved by the FCC last month. The Commission
stated that about 54 percent of existing radios will be capable
of receiving stations on the new frequency.
Some objection has been raised to the proposal on the ground
of possible interference with the 50-Kc. international distress
band. This can be avoided by spotting stations on the new frequency
in the interior, where there would be no possibility of blanketing
coastal areas with strong signals.
The proposal is supported by Howard S. Frazier, chairman of the
Radio Technical Planning Board Panel 4 on Standard Broadcasting,
who is also chief engineer of the National Association of Broadcasters.
Mr. Frazier points out that the new channel would be especially
valuable in broadcasting for rural coverage, as the daylight ground
wave of a radio station has a greater range at that end of the broadcast
band, and the zone of serious fading is further from the transmitter.
Procedure for applying for permission to produce
home radio sets and other electronic equipment was announced last
month by the Radio and Radar Division of the War Production Board.
As a result of this and other lifting of restrictions, on materials
for home radio manufacture, optimistic predictions of early commercial
production are circulating. Some of these insist that the first
sets may come off the production line in October. In any case, numbers
are likely to be limited till after V-J Day.
Direction 2 to Order L-265, gives instructions for filing Form
WPB-4000 for permission to build civilian radios and other electronic
equipment restricted by the order, under the provisions of Priorities
Regulation 25, the "spot': authorization order.
Applicants for "spot authorization" to produce electronic equipment
under PR-25 must include on the WPB-4000 application form a description
of each type and model of the product and the quantity (by quarters)
to be produced. In addition, for each type and, model to be produced,
the proposed net unit factory billing value of the equipment and
a statement of the quantity of each of the following types of components
that are to be used in the manufacture of the equipment must be
shown in a letter filed with the application:
Tubes; Transformers and Reactors (excluding intermediate frequency
and radio frequency coils); Capacitors, fixed and variable; Resistors,
fixed and variable; Loud speakers; Switches; Sockets.
Favorable opinions on the new FM allocations
were expressed last month by a number of leaders in the industry.
Though a number of them had pulled for one of the alternate plans,
all but a few feel that the final allocation has rendered a real
service by putting an end to uncertainty and making it possible
to proceed with confidence in the future.
Interference at the new frequencies is expected to be insignificant
as compared with the present band, the FCC stated. "Sporadic E"
transmissions have been reported by amateurs in the thousands between
56 and 60 megacycles, but none have been accomplished between 112
and 116 mc, just above the present band, according to George Grammer
of the A. R.R.L., whose members have operated in both those bands.
Interference from the higher F2 layers, frequent enough to be troublesome
at times below 84 mc, is negligible on the spectrum.
Among those expressing satisfaction with the new band were William
Halligan of the Hallicrafters, John Ballantyne of Philco, and officials
of Stromberg-Carlson, General Electric and the American and Mutual
Broadcasting Systems. Adverse reports were filed by Arthur Freed
of Freed Radio Corporation, and by Commander MacDonald of Zenith
Radio. Major Armstrong, who had been the most vigorous opponent
of the spectrum finally allotted by the FCC, expressed himself definitely
by applying immediately for permission to change his station WFMN
to 92,100 Kc.
Items of the Radio Month
Libel by radio is made punishable by penalties ranging up to
a $500 fine and a year in jail by a law passed last month by the
Illinois Legislature. Libel is defined by the law as "Malicious
defamation broadcast by radio tending to blacken the memory of one
who is dead, or to impeach the honesty, integrity, virtue or reputation,
or to publish the natural defects of one who is alive, and thereby
expose him to public hatred, contempt, ridicule or financial injury."
A mine detector was used by Sgt. Morris Press of the Eighty-Third
Infantry Division to find a missing watch. Losing his watch on the
banks of the Rhine one evening, he searched for it without success
till dark. Next morning he borrowed a mine detector and quickly
turned up the missing timepiece.
Radios in Great Britain total 9,710,850 - or an average of one
for every five persons, according to a survey published last month
by the British Post Office, which controls all communications. The
figure represents an increase of about 250,000 during the past year.
Electrostatic spraying of paint, in which the object to be sprayed
is charged to a high potential in one direction and the paint is
oppositely charged, is expected to save from 40 to 60 percent of
the paint now wasted in spraying. Not only will ,all the particles
approach and cling to the object sprayed, but their mutual repulsion
will tend to promote a more even spray and prevent "thick" and "thin"
areas on the part painted.
Radar was among the instruments used in observing the eclipse
of the sun last month. Radar instruments were part of the equipment
of several scientific parties making observations of the eclipse.
Zoning considerations may interfere with Washington television.
Last month the Zoning Adjustment Board of the District of Columbia
denied the application of the Bamberger Broadcasting Co. to erect
a television tower in a residential district. The decision - which
was by a two-to-one vote - was made principally on grounds of commercialization
and property depreciation. The decision has attracted a great deal
of attention because of its possible recurrence in other cities,
though Washington is in a special position because its terrain renders
erection of a satisfactory television aerial in any other than a
residential area a difficult problem.
One Billion dollars for the development of television
in the Soviet Union has been appropriated by the Russian government,
according to reports from Washington last month.
The Soviet investment of $1,000,000,000 in television virtually
eclipses the U. S. investment in video to date, which is estimated
variously as "upwards of $30,000,000" or "somewhere below $50,000,000."
1,000-Line television patent rights for the
United States were reported to have been purchased last month from
their French owners by Columbia Broadcasting System. Beside the
rights for the French high-definition system, the network is said
to have purchased a number of other new foreign patents, covering
color television. Television engineers from France are expected
to hold a demonstration under CBS sponsorship shortly, in which
the 1,000-line development will be revealed to sections of the American
Ownership of FM stations will be limited to
not more than six for any individual or group proprietor, according
to a tentative set of regulations issued last month by the FCC.
No person or group shall own, operate or control more than one station
in substantially the same service area.
Minimum operation of six hours daily will be required of the
FM broadcasters. At least one hour during the daytime period (8
am. to 6 pm.) and one hour during the evening period (6 pm. to 11
pm.) must be devoted to "programs not duplicated simultaneously
in the same area by any standard broadcast station or any FM station.
During these two one-hour periods a service utilizing the full fidelity
capability of the FM station shall be rendered."
Posted July 8, 2014