Just as early cellphones (Motorola's Bag Phone, e.g.)
required large carrying cases to contain both the large electronics and the large battery
required to operate the phone, some of the first commercially available portable personal
radio sets came with shoulder straps. Those that didn't have straps had wheels and a handle.
The "walkie-talkie" (originally called "handi-talkies")
designs were first seen during World War II and then in
Korea. In fact, this
1955 article from Popular Electronics was printed shortly after the end of the conflict in
1953. Don't confuse the radio-based portable
with the ones that had a pair of wires (sometimes thousands of feet of it) that did not need
complicated circuitry for over-the-air transmitting and receiving.
See The Walkie-Talkie in
the March 1955 Popular Electronics,
A Self-Contained Handie-Talkie
in the June 1944 QST, and
The New Handy-Talkie
in the December 1942 Radio-Craft, and
Walkie-Talkies: Something for
Everyone in the April 1974 Popular Electronics.
By Leo G. Sands
Bendix's MRT-9 portable two-way radio unit for
the 152-174 mc. band.
The Bendix MRT-9 packset in its shoulder-strap protective case.
Motorola packset with a monitoring speaker on top of case.
The Motorola "Handie-Talkie" for 152-174 mc. band. Case is available to protect set from
Vibrator power supply section of Motorola "Handie-Talkie." Note the non-spillable storage
batteries in unit.
Two-way radio has captured the imagination of the public - here is the story on available
units and operating rules.
The portable two-way radio has been brought vividly to the attention of the public by "Dick
Tracy." His is the two-way radio which would sell like the proverbial hot cakes if it really
existed. Many are trying to develop a "Dick Tracy" radio and no doubt someone will succeed.
Today, crime fighters must content themselves with somewhat heavier and bulkier portable
two-way radio sets. Several excellent portable units are on the market and they do a commendable
job, even if they fall short of the performance of "Dick Tracy's" wrist radio.
Depending, upon their size and form factor, they have been called, among other things,
a walkie-talkie, "Handie-Talkie" (a trade name), pack set, "Port-A-Fone" (also a trade name),
and a breakie-backie.
If you buy a pair of walkie-talkies, there is no assurance you can use them. All radio
transmitters, even flea-powered, hand-carried portables, must be licensed by the Federal Communications
Commission (FCC). Different kinds of walkie-talkies are designed for licensed operation in
different categories of radio services as defined by the FCC. Equipment for use in the industrial,
land transportation, and public safety radio services must generally meet more rigid technical
standards than equipment to be used in the Citizens or amateur radio services.
Unless you operate a business which is eligible for licensing in the land transportation
or industrial radio services or unless you are an amateur radio operator, you as an individual
can only operate walkie-talkies in the Citizens radio band. The Citizens band is open to all
citizens whether for private personal use or in connection with a legal commercial enterprise.
For use only in the Citizens radio service on 465 megacycles are such low-priced, hand-carried
two-way radio units as the Stewart-Warner "Port-A-Fone." Here, the range is limited from a
few hundred feet to a mile or more, depending upon local conditions. This type of unit uses
a super-regenerative receiver which is converted into a self-excited AM transmitter.
The more widely used and more expensive portable two-way radio units are designed for operation
in either the 25 to 50 megacycle or 152 to 174 megacycle v.h.f. (very-high-frequency) bands
which are reserved exclusively for eligible commercial enterprises and government agencies.
To meet FCC requirements, these commercial pack sets employ crystal-controlled transmitters
operable on one or two specifically assigned fixed frequencies within the band for which the
equipment was designed. Fixed tuned superheterodyne receivers, which are also crystal controlled,
are used. Transmitter and receiver are packaged in the same enclosure along with either wet
or dry batteries.
When wet batteries are used, they rare of the non-spillable type and are used to supply filament
power and to drive a vibrator power supply for plate power for the tubes in the transmitter
and receiver. Generally, when dry batteries are used, plate power is derived directly from
"B" batteries instead of a vibrator power supply.
(Left) RCA's lightweight walkie-talkie for the
25-50 mc. band. It uses a Western Electric type 500 handset. (Right) Interior view of typical
unit using miniature and subminiature tubes.
Both subminiature and miniature type tubes are used in commercially available walkie-talkies.
The transistorized walkie-talkie has not yet made its debut and is not expected to do so,
at competitive prices at least, for quite some time.
The antenna used with nearly all of the commercially available walkie-talkies is either
a vertical flexible quarter-wave whip or a telescoping antenna similar to those used in automobiles.
An external antenna may be used in fixed or mobile applications by removing the antenna and
plugging in a coaxial cable leading to the antenna.
The range obtainable with walkie-talkies is sometimes amazing, especially when operating
in the 25 to 50 megacycle band. A range of 8 or 10 miles between a walkie-talkie and a higher
powered base station is often reported. However, much depends upon terrain conditions.
Operating in the 152 to 174 megacycle band, the range is generally considerably less. However,
communication between a walkie-talkie on this band and a higher powered base station up to
8 or 10 miles has been achieved but not as regularly as when operating in the 25 to 50 megacycle
Pack sets are used by many railroads to extend
communications to the man on foot. The unit shown here is manufactured by Hallicrafters.
The range between a pair of walkie-talkies is generally quite limited because of the power
output of the transmitters and because of the low effective antenna elevation. Of course,
the range can be several miles if one walkie-talkie is operated on a hill top and the other
one is within line-of-sight or at a point where signals are easily reflected.
In railroad yards, for example, many have been disappointed to find the range attainable
between a pair of pack sets is so short as to be unsatisfactory. This is particularly true
when one or both walkie-talkies are carried by personnel standing or walking between freight
cars. This would also apply in congested areas as in city streets lined by tall buildings
or many trees.
The cure in such cases is to employ a relay station if permitted by FCC regulations in
the service in which the equipment is to be operated. When using a relay station, two different
radio frequencies are required, one for transmitting and one for receiving.
Motorola and General Railway Signal Company have developed novel portable transmitters
for one-way radio communication. They are not much larger than a flashlight and are primarily
used in railroad yards where personnel on foot talk out over a portable transmitter and receive
calls and replies over a public address system. A typical walkie-talkie like the MRT-8 manufactured
by Bendix weighs only eight pounds and is available for hand carrying or for mounting on personnel
with suitable straps. Hallicrafters manufactures portable two-way radio units which can be
adapted for installation in motor vehicles. Power is derived from the vehicle's electrical
Three versions of the Hallicrafters "Littlefone."
(Left) The standard model with handset. (Center) Unit adapted for under-the-dash mounting
in a car. It is powered by car battery. (Right) "Littlefone" with a 4" speaker mounted on
Surplus walkie-talkies offered at bargain prices are seldom licensable without extensive
modification. Very few, if any, military surplus portable radio telephones can be readily
modified for use in the 25 to 50 mc., 152 to 174 mc., or the 450 to 470 mc. bands. Some, however,
can be modified for operation in one or more of the amateur bands. However, to be eligible
to operate walkie-talkies in the amateur bands, it is necessary to possess an amateur operator's
license which requires taking a code test and passing a written examination on radio theory
and FCC regulations.
In the land transportation, industrial, and public safety radio services, persons using
mobile and portable stations do not need operator's licenses although the operator of an associated
base station must possess a restricted radio telephone operator's permit. Although a station
license is required for Citizens band walkie-talkies, an operator's license is not needed.
It is possible to build your own walkie-talkies for use in the Citizens band or in one
of the commercial radio services. However, to build such equipment so that it will comply
with FCC regulations requires considerable skill, a vast amount of precision test equipment,
a good deal of time, and ample funds. It is generally cheaper to buy factory-made equipment.
Commercially available walkie-talkies cost from $200 to $500 each.
Posted February 17, 2014