Editor’s note: I copied this article off of a Facebook post because of what I consider to be the importance of the history and the “primitive”, by today’s standards, technology. Just 56 years ago, I was sitting in Mr. Rutherford’s class in Placer High School in Auburn learning about electronics. First, we learned the basics like voltage, current, and resistance. All very cool. But what can we do with that? Enter the vacuum tube (‘electron valve’ to Brits). I’ll never forget that day we hooked up a tube to the necessary power supplies and then sent a tiny voltage change to the control grid and observed a much larger voltage change come off the plate, aka: “anode”, part of the tube. My first understanding of how AMPLIFICATION works!! I was hooked for life. I was so enthralled, I went on to learn about electronic communications in college. When I read the following article, it brought me back to those days in high school where I first learned about amplification. I know that some of you may not appreciate the technical aspects and the challenges that these pioneers faced, but the historical significance is profound. Enjoy:
Today is the 109th anniversary of the first transcontinental telephone call. The call was made possible by three men working in August of 1912 at the Federal Telegraph Company lab at 913 Emerson St in Palo Alto, CA when they unknowingly made a discovery which would become the foundation of modern electronics.
Federal Telegraph, formed in 1909 as the Poulsen Wireless Telephone & Telegraph Company, had the license to sell the Danish company’s arc transmitters in the United States. After taking the Federal name in 1910, they established a wireless telegraph company on the West Coast.
Federal also had the rights to the Poulsen Telegraphone wire recording system which stored telegraphic signals on a wire which could be played back at a slower speed for transcription. Lee de Forest, assisted by Herbert Van Etten and Charles Logwood, was assigned the task of developing an amplifier to assist in better utilizing the wire recorder in their telegraph business.
In 1906 Lee de Forest added a a grid wire between the filament and the plate of a two-element vacuum tube. By applying an electrical signal to the grid, it could control the current flowing between the cathode and the anode. When de Forest applied for a patent on his three-element Audion he included the description, “a device for amplifying feeble electric currents” but he did not take any further steps to utilize his invention. De Forest named the third element, “a grid” as its shape reminded him of a football field. De Forest brought his Audion tube with him when he joined Federal Telegraph in 1912. During their experimentation, the men discovered that by connecting two audions in sequence, a regenerative circuit was created, thus making weak signals stronger. De Forest called this a “cascade amplifier.” In achieving their objective, they also observed a phenomenon where the signal would self-oscillate to produce an audible howl, much like the unwanted squeal when a microphone is placed too close to a speaker
De Forest perceived the oscillation as something to be eliminated. It wasn't until months later when he realized that if a circuit could produce (oscillate) at an audible frequency then it could also produce the much higher frequencies of radio waves. This oscillating circuit would replace the more primitive methods of creating continuous high frequency waves, ultimately making radio and modern electronics possible.
In 1908 AT&T announced their intention to build on a transcontinental telephone line even though they lacked some critical components including a way to amplify to the signal. They set a goal of having it ready by the opening of the Panama-Pacific International Exhibition in San Francisco in 1915. The construction of the line was similar to how the Transcontinental Railroad was built 50 years earlier. Lines were built east from Sacramento and west from Denver. Just as the railroad met in Promontory Point, UT, the AT&T lines met in Wendover on the Utah/Nevada state line. Upon completion it consisted of 130,000 telephone poles and stretched 3400 miles.
Unbeknownst to AT&T at the time they began building lines from Sacramento, the three men 100 miles away in Palo Alto were solving their amplifier problem.
When Federal hired de Forest, they never signed a contract to own his patent rights. Not recognizing all the value of his Audion tube would have as both and oscillator and amplifier, he sold the patent rights to AT&T for a nominal amount. Having no rights to the patent itself, or the results of what it could do after the research was done in their lab, Federal had no claims to the profits it would produce. They did own the shop rights so they could use it in their equipment but could not sell that equipment to others.
AT&T engineers utilized de Forest’s technology to build suitable amplifiers for their long distance operation.
On January 25, 1915, AT&T demonstrated this technology by making the first transcontinental telephone call from New York to San Francisco. Alexander Graham Bell used his original telephone apparatus from 1877 to replicate his first call to Thomas Watson who was in the telephone company building at 333 Grant Ave in San Francisco. Graham repeated his famous first words of, “Mr Watson, come here. I want you.” Watson replied, “Sorry Mr Bell, it will take me a week now.” A second call was made by President Wilson and then a call between New York City Mayor John Mitchel and San Francisco Mayor James Rolph (to whom every newspaper account, including the New York Times, referred to as James Roth.)
AT&T announced that coast-to-coast telephone calls would cost $20.70 ($540 in 2024) for the first three minutes. Calls could take up to 10 minutes to get through due to the number of connections that had to be made across the country.
Others, most notably Edwin Armstrong, had done similar work to de Forest. A patent lawsuit between Armstrong (who sold his patents to Westinghouse) and de Forest (AT&T and RCA) lasted 20 years until 1934 when the Supreme Court ruled in favor of de Forest. The Court set the date of invention as August 6, 1912 based on entries that Herbert Van Etten made in his lab notes.
Other inventors and companies quickly exploited the capabilities of the Audion tube creating a great leap forward in modern electronics, especially after World War 1. Radio, television, early computers, RADAR and other electronics were all made possible by the three-element vacuum tube. De Forest became known as the Father of Modern Electronics.
In a bit of an historical coincidence, at the time that de Forest was working in the Federal lab on Emerson Street in Palo Alto, William and Mary Shockley, along with their 3-year old son, William Jr., moved into a house a few blocks away at 959 Waverly. It was years later, in 1947, when the younger Shockley led the Bell Labs team that invented the transistor, the solid-state replacement to de Forest’s triode vacuum tube.
An interesting parallel - flight: 1903 (+ or -), the Wright Brothers first powered flight. 1969: Moon landing. 63 years. (There were a couple of major steps along the way.)
1906: De Forest's Audion. 1947: the transistor. 41 years. 1959: the integrated circuit. Only 12 years this time.