[Table of Contents]People old and young enjoy waxing nostalgic about
and learning some of the history of early electronics. Popular Electronics was published from October 1954 through April 1985. All copyrights (if any) are hereby acknowledged.
telephone equipment installed in the trunk of the car takes up relatively
little space, is out of the way." That sentence seems really strange
in today's world of pocket-size mobile phones, but it was a big (literally)
deal in 1957. If you are getting old (but not old yet) like me, you'll
remember the prime time TV show called
where crafty private eye Joe Mannix had a "futuristic" Motorola car
phone in his convertible. Today, the only kind of radio you are likely
to find installed in a car trunk is a high-power Ham rig. Two-way messaging
was a big deal before the advent of cellphones. Service trucks were
dispatched by operators at the home base. As an electrician back in
the 1970s, most of the trucks I operated from had a two-way radio for
directing workers to job sites. I did a lot of troubleshooting and old
work (adding circuits and equipment to existing establishments, as opposed
to new construction work), so I typically went to numerous job locations
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Radio Keeps You in Touch
By Leo G. Sands and Mike Bienstock
and telephone systems use radio waves to keep pace with today's business
You're a doctor. You're out on a call this
evening, and it's a half-hour drive to your patient. When you get there
and call in, your nurse tells you one of your patients has had a serious
accident. He's in the hospital now, and they're operating.
a doctor. You're out on a call this evening, and it's a half-hour drive
to your patient. Suddenly the phone under the dash rings once. You pull
over, pick up the handset, press the button, and you are in instant
contact with your office. Your nurse tells you one of your patients
has had a serious accident. You speed to the hospital where you are
in time to supervise the operation.
Did that sound nice,
but a bit futuristic? You're partly right. It is nice, but communication
with a moving car is here today, a bustling youngster growing lustily
and with practically an unlimited future. The prospects are tremendous,
not only for the doctor who receives emergency calls, but for anyone
whose business requires him to keep in constant touch with home base
... salesmen, who may get tips on customers ... executives whose advice
may be needed to make a critical decision ... newspapermen, who may
be routed to cover a top story while it's happening ... radio and television
servicemen who may be sent on an emergency. The list is nearly endless.
There are a wide variety of services available. Let's examine
them in order of cost and complexity. One-Way Radio
. Not quite the same as the Dick Tracy wrist radios,
these receivers are pocket-size jobs which weigh a few ounces. They
can be rented or bought at a cost of about $50. The subscriber to this
private service takes the tiny radio out of his pocket, holds it to
his ear, presses a button and listens. The names or call numbers for
those with messages waiting are transmitted from a base station. Generally
the information is taped and rebroadcast until the subscriber calls
in, then the signal is erased.
The little lady is shown demonstrating one-way radio paging. Subscriber
presses button and hears the taped message.
To extend this service over a greater range, a mobile receiver with
a built-in speaker can be mounted under the dash. Since a superheterodyne
circuit is used, the range is stepped up. The car battery furnishes
the power to operate the set.
Telephone companies provide a
similar auto signaling service. The signal is a buzzer and light. Installation
for such service is half of the regular auto radio-to-telephone service
- $25 for most areas, plus $12.50 for rental and maintenance, plus a
minimum calling charge of $5 which would pay for 30 to 40 calls.
. This is handled by private communications
firms. The installation includes equipment similar to that used in regular
mobile radiotelephone, which will be described under that category.
The service differs in this way: instead of direct voice contact between
both parties, the message is shorts topped by a third person, the company
Suppose the doctor's nurse wants to call him. She
rings up the private operator and gives her the message she wants delivered.
Then the operator calls the doctor on the road. He gets the signal,
picks up his mike or handset, and answers her. She gives him the nurse's
message. Direct communication, of course, would be in violation of the
common carrier tariff filed by the telephone company.
charges in the New York area are as follows: a monthly fee of $36.30
allows 100 air-minute messages, after which you are charged 10 cents
per call. Incoming messages are billed at a straight 10 cents each.
The fee is broken down to $17.50 monthly for service, $10.50 for rental
and $5 for maintenance. There is a 10% Federal tax. Installation charge
is $25 per unit, and removal charge is $10 payable in advance.
Citizens Radio Service
Mobile telephone transmitter and receiver control panels at Pacific
Telephone & Telegraph Co.
Mobile telephone equipment installed in the trunk of the car takes
up relatively little space, is out of the way.
Message service control center is operated by two persons, one taking
telephone messages, the other on radio. (Anti-science people like
a certain country's president would lament the replacement of these
types of jobs with automated computerized equipment, similar to
ATMs stealing tellers' jobs
Car is equipped with a two-way Bendix mobile unit provided by message
service common carrier.
A typical mobile telephone is installed in the car below. Note handset
holder and control unit under dash.
RCA installation of a two-way mobile radio system at a large trucking
. There are three types in this
category: Class A, B and C stations. We are concerned with only the
first two, since Class C is strictly for remote control transmission.
Class B stations may only be operated on 465 mc., with a maximum
input power of 10 watts. Class A may be operated on any frequency in
the 460 to 470 mc. band, with power limited to 10 watts between 462
and 468 mc. and 50 watts on the other frequencies.
distinction between the two is that equipment cost for Class A transmission
pretty well limits its use to commercial firms interested in getting
distance, which is usually eight to ten miles, depending on terrain
and conditions. Class B, therefore, is generally used by private citizens
who get a range of one-and-a-half to six miles, depending on conditions.
Vocaline makes transceivers for this band which sell for $139.50 a pair.
They require no installation.
For a Class A installation, initial
cost may run to about $700 for the car equipment and $1200 for the base
station, which can be at home or in the office. It may cost more if
a tall antenna support is needed at the base and if a heavy-duty generator
is necessary in the car. The equipment will give a range of eight to
ten miles in most areas even without elaborate antenna systems at the
base. The higher the base antenna, of course, the greater the range.
Reflection characteristics of u.h.f. make it possible to enjoy good
communication in shielded areas such as streets lined with tal1 buildings.
The car antenna is a small vertical whip about 6" long, mounted
on the car roof. The radio equipment is usually mounted in the trunk
and is housed in a single metal case which includes the transmitter,
receiver and power supply. A loudspeaker, hand microphone and a small
control unit are mounted on or near the dash.
The base station
transmitter, receiver and power supply are generally enclosed in a desk-mounted
cabinet. It is only necessary to plug it into the closest outlet and
connect to an antenna system.
With such a Citizens Radio setup,
operation is very similar to police or taxi operations. Since it operates
on u.h.f, there is little or no noise. No special skill is needed to
work it. It is already pre-tuned to your frequency. In the car there
are only three controls: an "on-off" switch, a volume control, and a
squelch control which eliminates background noise.
hear your office call, you pick up the microphone, press the button
on it and talk. When you are through, you release the button to hear
the incoming message. The base station operation is similar except that
a desk-type microphone is generally used. Telephone handsets may be
used in place of microphones.
Specific frequencies are not assigned
in Citizens Radio. You can order your equipment for any frequency in
the band. If you find that someone else's system interferes with yours,
you may have your frequency changed.
No operator's license is
required. To get your station license, fill out and mail FCC Form 555
to the nearest FCC field office or to the FCC in Washington. Your equipment
must meet FCC approval. Mobile Telephone Service
Just as the name implies, this means a telephone in your car. Similar
to ship-to-shore radio-telephone, the system is operated by the local
telephone company and makes a phone booth of your car. Under the dash
there is a control unit with signals to light when power is on, a bell
and a hand phone which fits into a hanger on the unit. When you are
called, the bell rings, a "call" light goes on and you pick up the handset,
press the button in it and talk - just as simply as if you picked up
your home phone. The latest addition is a "dial-direct" system by Du
Mont, which allows direct dialing in the local phone network.
In the trunk of the car, there is a v.h.f. transmitter, receiver,
power supply and dialing decoder. A short antenna is mounted on the
car roof, and sometimes an oversize generator is furnished to take the
added load from the battery.
By picking up the handset and pressing
the push-to-talk button, the driver can signal the phone exchange. When
the operator answers, he gives the number of the phone he wants to reach,
identifies his own unit by number, and the call is placed. Calls to
mobile units can be placed from any telephone or from similar mobile
To sum up, this system is essentially the same
as an ordinary phone installation, with radio being used in place of
phone wires. Generally the phone company has one transmitter in the
headquarters building, with several receiving stations at strategic
locations. Transmitting and receiving stations are connected by telephone
lines to the central office.
The range of the system is generally
confined to the 15 to 25 mile radius of the transmitter. The service
is on a "party line" basis, with several subscribers using the same
channel. Charges for such service - in a large area of the country (including
such cities as New York, Cleveland, Chicago, Philadelphia, Los Angeles
and Dallas) are $50 for initial equipment installation and $32 monthly.
The monthly cost includes maintenance as well as a minimum charge which
pays for 15 to 20 calls. Additional calls cost 30 cents or more, depending
on distance and length of conversation. Other Services
There are, of course, other services. These, however, will only be mentioned,
since they ordinarily are not available to the private individual. Private
Two-Way Radio, Licensed, includes police, taxis, railroads, bus lines,
utilities and pipeline companies who have for years used their own mobile
sets. Amateur Radio Mobile Service is ordinary amateur radio moved into
the air. An operator's license is needed, which limits the latter service
to relatively few people. Note that while Citizens Radio is open to
any citizen for private or commercial use, Amateur Radio Mobile Service
is strictly limited to personal use with no profit motive.
Dispatcher is shown in communication with
one of the local pickup and delivery trucks.