The old age of “electrics” ends and the new age of “electronics” begins. To see how this came about, we need to go back to 1883 when Thomas Edison, while trying to improve the
incandescent light bulb (he didn't invent it despite the popular myth), built several versions with electrically isolated metal plates. He connected a galvanometer and observed
when the plate was connected to the positive side of the meter it showed current flow (in vacuo), and reversing the connection indicated no current flow; none of the scientists of the day could explain this "Edison Effect" (the electron wasn't discovered until 1897). He also observed increasing the filament voltage increased the plate voltage, and that his new device could drive a telegraph sounder (among other things); being the genius he was, Edison patented the world's first "electronic" voltage regulator and changed the future world!
The Edison Effect is actually thermionic emission, and today we know electrons boil off the heated filament and are attracted to the plate when it has positive voltage allowing the flow of electrons (current); electrons are repelled when the plate has a negative voltage cutting of the current flow.
incandescent light bulb (he didn't invent it despite the popular myth), built several versions with electrically isolated metal plates. He connected a galvanometer and observed
when the plate was connected to the positive side of the meter it showed current flow (in vacuo), and reversing the connection indicated no current flow; none of the scientists of the day could explain this "Edison Effect" (the electron wasn't discovered until 1897). He also observed increasing the filament voltage increased the plate voltage, and that his new device could drive a telegraph sounder (among other things); being the genius he was, Edison patented the world's first "electronic" voltage regulator and changed the future world!
The Edison Effect is actually thermionic emission, and today we know electrons boil off the heated filament and are attracted to the plate when it has positive voltage allowing the flow of electrons (current); electrons are repelled when the plate has a negative voltage cutting of the current flow.
In the early 20th century, Edison's former engineer John Fleming (UK) and Lee DeForest (US) would "borrow" the design to create the "oscillation valve" (radio detector) and the "Audion". The Audion, with its added negative voltage control grid between the plate (anode) and filament (cathode), could both detect and amplify radio signals, but the inconsistent manufacturing quality, cost, warm-up time, 3 voltage supplies (A, B, and C batteries), plus their tendency to explode, limited their use because wireless operators preferred the much safer and more reliable Marconi magnetic detector or "Maggie"; it was always ready to receive and needed no batteries, and didn't start shipboard fires! It was WWI that lead to the development of the modern "triode" vacuum tube, and the creation of many modern electronic circuits we still use, 100 years later!
During summer of 1937, all Canadian Great Lakes marine radio stations were equipped with MF AM voice transceivers. VBA Port Arthur and VBG Toronto were also equipped with phone patch equipment and now shore parties and ships could connect landline telephones to radios through the station's equipment. Shipping companies, captains, pilots and the public could now communicate directly without needing a trained Morse code wireless operator for domestic voyages. Morse code would still be used (albeit infrequently) on the Great Lakes by ocean going vessels (salties) until the mid-1990's with VBB Sault Ste. Marie being the last of the Great Lakes stations to provide this service.
In 1938, the newly created Department of Transport (DOT) took over control of all marine and air radio stations from the Department of Marine and Fisheries, and after 28 years at Port Arthur, now superintendent J. H. Bartlett transferred to Kingston, Ontario.
In the fall of 1939, a new government wireless station was built 6 miles farther inland on Dawson Road. The new VBA Port Arthur consisted of a 7.9m x 13.3m (26' x 44') radio
operations building, two houses for the radio operators and families with a two-car garage!
KPE Seattle harbour department radio station, ca. 1921. Photo courtesy John D. Jenkins from "Discovery Sparks Imagination", p. 108. Used with permission.
Marconi MC1 transmitter, ca. 1922. Photo courtesy John D. Jenkins. Used with permission.
Marconi 226A receiver, ca. 1916. Photo courtesy John D. Jenkins. Used with permission.
Armstrong regenerative receivers ("Gennys") are still built by radio hobbyists, using either transistors or tubes. Modern designs allow the use of a single low voltage (12 volt DC) power supply. From the one tube AM radio to the 3 tube AM/shortwave version, nothing says "old-time" radio more than the glowing tubes of "real" radio!
By the 1920's, AM (amplitude modulation) radiotelephony (voice) and radiotelegraphy CW (continuous wave) were in common use. VBA Port Arthur's old rotary spark-gap transmitters were replaced with CW electronic vacuum tube versions (1925) allowing the use of very frequency stable, narrow band signals, and stopped most interference with the new and expanding commercial AM radio broadcasting stations. Receivers, using the Armstrong superheterodyne circuit, were easy to use, highly sensitive and selective, and could amplify the weakest of radio signals.
However the marine and commercial broadcasting worlds were in constant conflict, fighting over the same range of frequencies 400 kHz to 1800 kHz, and the voting public wasn't very amused with Morse code and/or ship voice signals drowning out their favourite radio shows! As a result, governments moved the marine Morse code frequencies down below 526 kHz, and marine voice frequencies were moved up to the MF (medium frequency) band with 2182 kHz becoming the new voice international maritime calling and distress frequency. The commercial AM radio band would eventually occupy 526.5 kHz to 1705 kHz (depending on location). The Amateur Radio Service used the 160 metre band (1800-2000 kHz), established in 1913, and this is why the marine voice band had to start above 2000 kHz!
However the marine and commercial broadcasting worlds were in constant conflict, fighting over the same range of frequencies 400 kHz to 1800 kHz, and the voting public wasn't very amused with Morse code and/or ship voice signals drowning out their favourite radio shows! As a result, governments moved the marine Morse code frequencies down below 526 kHz, and marine voice frequencies were moved up to the MF (medium frequency) band with 2182 kHz becoming the new voice international maritime calling and distress frequency. The commercial AM radio band would eventually occupy 526.5 kHz to 1705 kHz (depending on location). The Amateur Radio Service used the 160 metre band (1800-2000 kHz), established in 1913, and this is why the marine voice band had to start above 2000 kHz!
The "Edison Effect" or thermionic emission
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