1996 - 2016
BSEE - KB3UON
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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This collection of video and a few audio files represents files that have been featured on the RF Cafe homepage. Every week or so a new file is added that should be of interest to RF Cafe visitors.
Please send me an e-mail if you have a good subject. Note: "Videos for Engineers" formerly went by the name "Cool Videos."
Note: There have been other videos posted, but I often forget to link to them on this page. Please use the website Search box at the at the top of the page to look for something you don't see here since many of the videos I have featured are not on these archive pages. Thanks.
Mjölnir's Secret: Microwave Oven Magnets - Who Knew?
The secret of Mjölnir, Thor's hammer, has finally been revealed. As it turns out, being found 'worthy' of lifting Mjölner requires having the right thumbprint. Well, at least inventor / maker Allen Pan's version of the hammer does. The July/August issue of Popular Science ran an article on Pan's cleverly converted toy Mjölnir wherein he buried four lead-acid batteries to power a scrounged microwave oven transformer for duty as an electromagnet. An Arduino Uno-driven sensor detects Pan's unique thumbprint and disables ...
Morse Code vs. Texting Contest on the Jay Leno's "The Tonight Show"
On the May 13, 2005 episode of The Tonight Show, Jay Leno held a speed contest between two Ham Radio operators using Morse code and two Millennials using their smartphones for texting (SMS). At least one member of the audience thought texting would win. Mr. Chip Margelli (K7JA) did the sending. He declares, "Let me assure you that we never saw that message before I flipped the blue card over. Each message, in rehearsal, was different. The character count was the same as the one during dress rehearsal ..."
FPV Drone Tour of the Russian Duga-1 OTH Radar Antenna
Radio controlled drones have gotten a bad name, mostly due to moronic operators that have no regard for other people's privacy or safety. I would like to be able to say those types are in the minority, but unfortunately they probably do make up the majority of drone owners. That is because unlike with R/C airplanes and helicopters that require at least a modicum of skill and common sense to fly successfully, even the cheapest drones incorporate stability systems that are so good even a caveman could fly one. At the opposite end of the drooling loser contingent of the drone pilot spectrum is the rapidly growing number of highly skilled pilots that advance not just ...
Explosive Charges Bring down 48 VOA Towers in North Carolina
This item appeared on the ARRL news website. It links to a video showing an engineered demolition of a shortwave antenna farm in North Carolina commissioned by the Voice of America (VOA) in 1963, during the Cold War. The video provides an aerial view of the entire line of towers collapsing as the precisely timed charges go off. The most impressive aspect is that explosives are detonated only on every other tower in such a way that the falling tower takes out the one next to it almost in a dominoes manner (see yellow circle). 25 pounds of explosives were used rather than possibly 50 if every tower's guy lines had been ...
Old vs. New Car Design - Video
Very recently while watching a 1960s era TV show I asked myself a question I've asked many times before: If one of those heavy, bulky vintage cars constructed of thick pressed sheet steel body components, full steel tube frames, and cast iron 8-cylinder engine blocks was to have a head-on collision with a modern car built with light-weight materials of composite construction and minimal structural bulk, which would be the victor? My gut reaction was to think that the result would be like a sledge hammer and a Coke can colliding; I'd rather be the sledge hammer. I know cars are engineered to sacrifice the car to preserve the passenger compartment by ...
"Marble Machine" by Wintergatan
Maybe you are one of the more than 11 million people who have already viewed this incredible "Marble Machine" video, by Swedish musician Martin Molin. Molin designed and built his wooden music machine using aircraft plywood, ball bearings, Lego blocks, pressure transducers, plastic tubing, lengths of wire, springs, and a host of other off-the-shelf components, none of which appear to have required custom metal machining. The huge wooden gears were designed on his computer, ut out on a band saw, and assembled with glue and screws. 2,000 metal marbles are the lifeblood of the instrument which, by function, must be classified as percussion. Even the integrated base guitar is ...
iPhone 6 Plus vs. Samsung