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Day in Engineering History Archive - April 18

April 18

World Amateur Radio Day (WARD) - RF CafeDay in Engineering History April 18 Archive - RF Cafe1756: Jacques Cassini, discoverer of the Cassini Division between the A and B rings of Saturn, died. 1775: Paul Revere began his famous ride from Charlestown to Lexington, MA, warning American colonists that the British were coming. 1838: Lecoq de Boisbaudran, discoverer of gallium, was born. 1906: San Francisco was hit by a disastrous earthquake. 1907: Denmark became the first country to use fingerprinting to identify criminals. 1923: Yankee Stadium opened. Paul Revere's Midnight Ride - Please click here to visit RF Cafe.1925: World Amateur Radio Day (WARD) established to commemorate the founding of the International Amateur Radio Union (IARU). The first U.S. commercial transcontinental radio transmission of a radio facsimile was sent from San Francisco to New York City. 1942: An air squadron from the USS Hornet led by Lt. Col. James H. Doolittle raided Tokyo and other Japanese cities. 1945: Sir John Ambrose Fleming, inventor of the diode tube (Fleming valve), died. 1955: Nobel laureate Albert Einstein, died. 1989: Thousands of Chinese students demanding democracy tried to storm Communist Party headquarters in Beijing.

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Note: These historical tidbits have been collected from various sources, mostly on the Internet. As detailed in this article, there is a lot of wrong information that is repeated hundreds of times because most websites do not validate with authoritative sources. On RF Cafe, events with hyperlinks have been verified. Many years ago, I began commemorating the birthdays of notable people and events with special RF Cafe logos. Where available, I like to use images from postage stamps from the country where the person or event occurred. Images used in the logos are often from open source websites like Wikipedia, and are specifically credited with a hyperlink back to the source where possible. Fair Use laws permit small samples of copyrighted content.

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RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...

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