retroelectro
– while every effort would be made to make the best cable,
audio quality had to be amplified with the intended signal.
transcontinental telephone line. This is a problem they had already been trying to solve for nearly a decade when he joined. In an interview, he tells the secret of his success at Western Electric. Frustrated after being passed over for a raise following his first three months at West Street Labs, Harold
Black briefly considered quitting, only to decide the next morning that “I am going to go to work and learn everything that I can about the business.” He realized that everything an engineer did had to be documented in a memorandum, and all of those were archived.
visit the archive with a special pass from the guards. He methodically read the firm’s archival memoranda, dating back to his birth year, 1898, absorbing technical reports and organizational histories that spanned all twelve floors of 463 West Street. While smoking in the archives was not permitted for obvious reasons, he would repeatedly get caught smoking his pipe while reading. After being written up for it four times by the guards, he was allowed to spend his time reading in one of the higher supervisors’ offices, where smoking was permitted. This gave him additional access to a wide range of new information. The problem of developing a perfect amplifier In 1921, the new goal was to make transcontinental telephony practical. The first transcontinental telephone call was made in January 1915, which included President Woodrow Wilson. The quality of this call was terrible by any measure. The attenuation over the thousands of miles of copper forced each side to yell into the microphone, in hopes that it would make it through to the other side. The voices were described as hollow and ‘metallic.’ The higher frequencies in the voice were lost. There was a significant delay and echo, making the conversation difficult and disjointed. The many repeaters between the participants amplified all of the noise and distortion
transmission line theory was still poorly understood. Quality was all over the place ■ Impedance mismatch – inconsistent quality caused signal reflections, propagation delays, and a noticeable echo. Stations attempted to remedy this by using long adjustable coils to help balance the lines. An operator had to monitor the resistance on the lines and adjust the coil and the amplifier’s gain accordingly ■ Environmental noise – in addition to thermal noise and the vacuum tube ‘hiss,’ weather conditions significantly affected phone signal quality. Lightning strikes would produce loud bursts of noise, which would be amplified through the repeater stations. Ice buildup on the lines would consistently disrupt the impedance, requiring continuous adjustment of loading coils
Harold S. Black Harold Stephen Black was born on April 14, 1898. His father worked at a ‘shirt shop’ and had an eighth- grade education. His mother was a Stenographer. As a teenager, he bought a series of books on the subject of electricity. The Hawkins Electrical Guide, published between 1914 and 1917 by Nehemiah Hawkins, was a comprehensive and accessible series of small volumes designed to teach readers about electricity and its practical applications. Spanning numerous concise books, the guide covered a wide range of electrical topics, from basic principles of electricity, wiring, lighting, and circuits to detailed explanations of electric motors, generators, batteries, telegraphy, telephony, and electrical measurement instruments. Each volume was full of diagrams and technical drawings, making complex concepts understandable to many people, including teenage hobbyists of the day, like Harold Black. Starting in 1914, with these books, he started gathering ‘electrical things’ from the local town dump in the attic of the house they were renting. He tells of when he was 16, he built a microphone out of some scrap wood and some carbon that he pulled out of an old battery. He ran wires across the street to the
To that end, each Sunday, he would
The Hawkins Electrical Guide series of books was very influential to engineers and hobbyists of the day.
neighbor’s house, and he said that he could hear everything in their house, even the ticking of a watch. Soon, the father came home and saw it, ripping it out of the window and destroying the microphone. His first telecommunications system didn’t last very long. Joining Western Electric After high school, he attended Worcester Polytechnic Institute (WPI), where he earned a degree in electrical engineering in 1921. Western Electric’s Systems Engineering Laboratory at 463 West Street, New York, soon hired him, starting at $32 a week. He was assigned to a team that was trying to solve issues surrounding long-distance calling and the
…and every imperfection in the
Retro Electro fun fact: as this is going on, at the same time Frank J Sprague was perfecting is electric traction motor, bringing electric mass transportation to reality. Learn more in the Retro Electro article, Frank J Sprague and the Richmond Union Passenger Railway. (Link: https://emedia.digikey. com/view/251481832/17/)
The offices at 463 West Street in New York City.
we get technical
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