Part A
On June 17, 1946 in Saint Louis, Missouri, AT&T and Southwestern Bell introduced the first American commercial mobile radio-telephone service to private customers. Mobiles used newly issued vehicle radio-telephone licenses granted to Southwestern Bell by the F.C.C. Mobiles operated on six channels in the 150 MHz band. Bad cross channel interference, something like cross talk on a normal telephone line, soon forced the Bell System to use only three channels. No more than 25 people at once could use the system. Operators placed calls for each customer. Despite high costs and constant busy signals, waiting lists developed in every city where radio-telephone service was offered. The chief problem was that the F.C.C. would not make enough channels available for a high capacity mobile telephone system. Still, technology and planning moves on, even if bureaucracies do not.
What might have made up an early mobile telephone; equipment is actually unrelated. "A" is the control head, the mechanism placed inside the cab which controls volume and channel selection. "B" is the microphone, no telephone handset or keypad used. "C" is the actual radio gear, the transceiver, which gets built into the trunk. Massive size, weight and bulk. Click here for closeups
In December 1947 Bell Lab scientists circulated a paper amongst themselves describing a prototype cellular system. It would overcome every limitation of the present mobile telephone service. They now knew everything needed for cellular radio, but it would take hundreds of new frequencies, a digital telephone switch, microprocessors, and digital signal processing circuitry to make this dream a reality. One major step toward completing that dream occurred the next year.
On July 1, 1948 AT&T unveiled the transistor, a joint invention of Bell Laboratories scientists William Shockley, John Bardeen, and Walter Brattain. It would revolutionize every aspect of the telephone industry and all of communications. Some say that it was the greatest invention of the 20th century. One engineer remarked, "Asking us to predict what transistors will do is like asking the man who first put wheels on an ox cart to foresee the automobile, the wristwatch, or the high speed generator." The transistor would dependably amplify and switch signals while producing little heat. Equipment size would be reduced and reliability increased. Hearing aids, radios, phonographs, computers, electronic telephone switching equipment, satellites, and moon rockets would all be improved or made possible because of the transistor.
My writing on the transistor / Michael Riordan's writing on the transistor
The first transistor looking as crude, perhaps, as the first telephone. Click here for a slightly larger photo.
Fostering world wide transistor development was a relaxed patent policy by AT&T. Fearing an anti-monopoly lawsuit by the U.S. States Justice department, the Bell System allowed anyone for $25,000 to use its transistor patents. Starting then in the late 1940s, and continuing for twenty years, radio engineers around the world replaced fragile, bulky, high current vacuum tubes with rugged, miniature, low powered transistor circuits. It was not until the mid 1960s that most electronics eliminated tubes and become all solid state. Still, radio advanced in other ways throughout this period.
In 1950 the PRC-6 Handie-Talkie debuted as a replacement to the badly aging World War II Handie-Talkie. The military's first F.M. hand-held radio, the PRC-6 weighed less than its older brother, used less power, and contained fewer tubes. Few saw actual service in the Korean War, with most battlefield communications using World War II equipment. Then, in 1951 an improved backpack or Walkie-Talkie also began production. The PRC-10 had a range of three to five kilometers. Again, owing to limited numbers being made, few were actually deployed to Korea.
The handheld PRC-6 on the left and the backpack PRC-10 (without the backpack that normally contains it) on the right. Photos are from this great radio resource: http://www.armyradio.co.uk (external link), the place to buy used military radio gear.
On January 31, 1954 a 64 year old man wrote a letter to his wife, dressed for work, and walked out of his 13th floor apartment window, plunging to his death. Colonel Edwin Armstrong, the father of modern radio, and the creator of the first F.M. system, had committed suicide. A brilliant but sensitive man, Armstrong allowed the U.S. military to use his patents royalty-free for the duration of World War II. Before that he played a crucial role in communications during the First World War. He pioneered vacuum tube technology, making it practical, and invented radio circuits that transformed the entire communications industry.
Armstrong rightly believed that F.M. was a revolutionary operating system and that it should replace A.M. equipment for broadcasting. Indeed, no technical reason exists for A.M. broadcasting to continue. A.M., with its static, high power requirements, and fading, continues only because of tradition, bureaucracy, and sloth. Tired and despondent after fighting one patent lawsuit after another against industry giants like RCA, his personal fortune spent on promoting and defending F.M., Armstrong finally gave up and killed himself. Every radio today has circuits Armstrong designed. 1954 also marked happier events.
Edwin Armstrong, radio genius.
In October, 1954 the Regency TR-1 became the world's first commercial transistor radio, using Texas Instrument's new silicon based transistors. Built by the little known American firm Industrial Development Engineer Associates, but actually designed by Texas Instruments, it was followed six months later by Japan's first transistor radio, the Sony TR-52, an experimental set never actually released for sale. In 1957 the Sony TR-63 came to America. These transistor radio receivers were important milestones but both radio-telephone and military radio used higher current to transmit than transistors of that era could handle. Transmitting was still a job best left for tubes and an all transistor Handie-Talkie would have to wait.
Regency's TR-1 (1954) on the left, and Sony's TR-63 (1957) on the right
Radio research and development increased in the late 1950s when America entered the Space Race with the former Soviet Union. One great achievement was the integrated circuit by Jack Kilby of Texas Instruments in 1958. Putting several dozen transistors on a single silicon chip quickly reduced radio size and weight. In that same year the Bell System petitioned the F.C.C. for more conventional radio-telephone channels. Citizens Band had become more popular but people really wanted to communicate by telephone. Every radio-telephone system AT&T maintained was at capacity and there were no more frequencies to service new customers. Worried they would give more power to the Bell System, which had in effect a monopoly on most wired telephones in America, The F.C.C. did not seriously consider their wireless appeal for ten long years.
In 1962 Motorola introduced a fully transistorized two-way radio. The Handie-Talkie HT200 weighed approximately 1 kilogram and was known affectionately by its users as "The Brick." Shortly thereafter, in 1965, the military got the PRR-9, the first all solid state portable for the armed forces. This VHF equipment received but did not transmit, it's companion, the FM PRT-4 transmitter did that. The PRR-9 clipped onto a soldier's helmet. I don't have a photograph of that model in action, but check out this well dressed warrior from 1963; the principle is the same.
By 1968 the U.S. military was using many new portables in the Vietnam War, including tiny models called survival radios that provided communication between downed fliers and rescue services. The greatest change from previous wars was a decision to make voice and data communications secure if needed, hence all radios became encryption ready from that year on.