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July Fact-of-the-Day Index
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| Date | Fact of the Day Topic |
|---|---|
| July 1 | Hertzian Waves In 1887, Heinrich (Rudolph) Hertz verified James C. Maxwell's 1864 theory that electrical disturbances should propagate through ... |
| July 2 | Photoelectric Effect Discovery Heinrich Herz was a Professor of Physics at Karlsruhe and Bonn. In 1887 one his students, Wilhelm Hallwachs ... |
| July 3 | 1880 Optical Telephone Transmission Patent Alexander Graham Bell and Sumner Tainter were granted a U.S. patent in 1880 for a wireless ... |
| July 4 | The Edison Effect Thomas Edison created a vacuum-tube diode in 1883, but didn't understand how it worked or appreciate what could be done with it ... |
| July 5 | Diode and Triode Vacuum Tube Development University College (London) Professor John Ambrose Fleming was employed by the Marconi Company ... |
| July 6 | First Voice Radio Transmission Professor Reginald Aubrey Fessenden was the first person to successfully transmit human voice by radio. The transmission ... |
| July 7 | Heterodyne Signal Detection Invention Communication receivers use a Beat Frequency Oscillator (BFO) to make unmodulated continuous wave ... |
| July 8 | Superheterodyne Invention The earliest radio receivers consisted merely of RF amplitude-detectors of various kinds connected to antennas. The detectors ... |
| July 9 | The First Radio Commercial New York radio station WEAF (which later became WNBC) was the first to transmit a radio commercial ... |
| July 10 | Yagi Antenna Invention If asked, many who have studied electronics would tell you Yagi antennas were invented by someone named Yagi ... |
| July 11 | Speech Clipping Consonants contain the majority of the intelligence information in speech (the portion that makes it possible to understand ... |
| July 12 | Superheterodyne Spurious Responses The intermediate-frequency filter selectivity of a superheterodyne receiver is not a complete indication ... |
| July 13 | Speech Articulation and Intelligibility The audio bandpass of communication systems can be limited where the objective is merely to ... |
| July 14 | HF Mobile Antenna Efficiency The power radiated by any antenna is equal to the current flowing through its radiation resistance squared, times ... |
| July 15 | Radiation Resistance vs. Antenna Resistance The terms 'radiation resistance' and 'antenna resistance' are sometimes used interchangeably by ... |
| July 16 | The Term 'Audio' The term 'audio' is widely used by both the general public and engineers, but what exactly does it apply to? Is the sound of your voice ... |
| July 17 | Information Theory Information Theory is a branch of statistical communication theory where physical observation information or the information content of ... |
| July 18 | Epoxy Resins Epoxy resins are a family of thermosetting resins widely used in potting, casting and encapsulating electrical and electronic components ... |
| July 19 | Crosscorrelation Detectors A crosscorrelation detector compares a received signal waveform point-by-point with an internally-generated reference ... |
| July 20 | Vacuum Tubes above 100 MHz Several factors degrade the performance of vacuum tubes with increasing frequency. Interelectrode capacitance ... |
| July 21 | Parabolic Antenna Feed Illumination An optimal parabolic transmitting antenna converts cylindrical waves radiating from an electromagnetic source ... |
| July 22 | Barkhausen Oscillation There is an unusual and little-known way to make triode vacuum tubes oscillate at frequencies far above where they normally ... |
| July 23 | Steerable Antenna Vertical Directivity HF dipoles, Yagi's, log-periodic arrays, and other types of antennas are often made horizontally rotatable to ... |
| July 24 | Aurora Sputter Fading A particular type of very-rapid and easily-recognizable VHF signal fading was first heard in the 1930's where ... |
| July 25 | Meanings of the Term 'Flux' There are many specific applications for the term 'flux' in electronics. One refers to a material that facilitates ... |
| July 26 | The Doppler Effect Christian Doppler predicted in 1842 that the frequencies of received waves are dependent upon any motion of a ... |
| July 27 | Ferromagnetism Certain materials have a property called ferromagnetism that gives them relative magnetic permeabilities exceeding unity ... |
| July 28 | Buffer Amplifiers The term 'buffer amplifier' generally refers to an amplifier whose main function is to provide ... |
| July 29 | Does Your Antenna Radiate Particles? There are two correct, but intuitively much different, ways to perceive electromagnetic radiation ... |
| July 30 | Vertical HF Antennas Vertical antennas are used far less than horizontal antennas throughout most of the HF spectrum, because ... |
| July 31 | Analog TV Transmissions are Partly SSB A variety analog broadcast television transmission standards and sub-standards exist throughout ... |
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