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Homepage Archive - December 2020 (page 5)

See Page 1 | 2 | 3 | 4 | 5 of the December 2020 homepage archives.

Thursday 31

Electronics-Themed Comics

Electronics-Themed Comics, April 1941 Radio News - RF CafeThere's no denying that 2020 has been one of the worst years in a long time. The Wuhan Virus is responsible for more deaths in America than the September 11, 2001 terrorist attacks, and has crippled nearly the entire world medically, psychologically, and financially. Overzealous government officials have gotten away with imposing restrictions on personal freedoms beyond anyone's imaginations. With few exceptions, we all are required to wear facemasks that are practically useless in public, and are forced to isolate from our fellow human beings with the threat of fines and imprisonment for non-compliance. Self-appointed busybodies have appeared to tongue-lash anyone not fitting their idea of a fully state-compliant citizen. Although it will not erase the darker moments of 2020, hopefully this handful of electronics-themed comics from a 1941 issue of Radio News magazine will help take the edge off. Here's hoping 2021 will be a better year!

Toxic Air: Our Other Import from China

Toxic Air: Our Other Import from China - RF Cafe SmorgasbordYay for us. Our pollution production levels are way down compared to what they were in the middle of the last century. Seriously, things were getting really bad. Pittsburgh was considered such a hopeless mess that famed architect Frank Lloyd Wright, whose landmark Fallingwater home sat nearby, when asked what to do about Pittsburg's terrible pollution responded, "Abandon it." Lake Erie had been declared officially dead. Love Canal dominated headlines. Los Angeles air was (and still is, BTW) unbreathable. After huge public awareness campaigns, cleanup efforts, and stricter enforcement of pollution laws, the trend halted and has reversed. That is unquestionably good news. The bad news is that as pollution control got better, companies found continuing manufacturing operations in the U.S. was unprofitable based on what people were willing to pay for their products. Steel, the literal and figurative backbone of industry, could not be mined, smelted, and processed into finished goods at a price that would encourage innovation and growth...

Miniature Antenna Enables Robotic Teaming in Complex Environments

Miniature Antenna Enables Robotic Teaming in Complex Environments - RF Cafe"Researchers have developed a novel design approach that improves upon limitations of conventional antennas operating at low frequencies, demonstrating smaller antennas that maintain performance. Impedance matching is a key aspect of antenna design, ensuring that the radio transmits power through the antenna with minimal reflections while in transmit mode and that when the antenna is in receive mode, it captures power to efficiently couple to the radio over all frequencies within the operational bandwidth. Impedance matching techniques with passive components..."

Red Cross Emergency Communications Test

Red Cross Emergency Communications Test, May 1941 QST - RF CafeComic strips used to be a popular venue for instruction as well as for humor. Early editions of QST and many other magazines often had many small comics scattered throughout. The one featured here came from the May 1941 QST. Amateurs were and still are a vital part of disaster response efforts. In fact it is pretty much inarguable that a big part of why the FCC has not stripped away a larger portion of the allocated Ham bands is due to the thousands of operators who volunteer their time and equipment to assist government and private agencies with communications during times of duress. Some have argued that the "amateurs" often do a much better job at disseminating time-critical information that the "professionals."

PCBONLINE Blog: What's Going on in Testing the PCB Assembly?

PCBONLINE Blog: What's Going on in Testing the Printed Circuit Board Assembly? - RF CafePCBONLINE, a one-stop custom PCB/PCBA manufacturer for prototypes, has posted a blog that answers the question, "What's going on in testing the printed circuit board assembly?" Unlike most PCB assemblers, the advanced PCB manufacturer PCBONLINE can process functional tests before delivery so that our clients don't have to test on their own. PCBA testing at PCBONLINE includes the Automated Optical Inspection (AOI) test during the assembly process, functional test, and thermal aging test after the assembly. During the AOI and functional test, if the PCBA is good, the computer screen will display OK. Otherwise, it will display NG (no good), and all test process data can be recorded. The aging test consists of powering on the PCBA to let it work for some time depending on the product application. If the indicator light is on, the PCBA test is good...

Thanks Again for Windfreak Technologies' Continued Support!

Windfreak TechnologiesWindfreak Technologies designs, manufactures, tests and sells high value USB powered and controlled radio frequency products such as RF signal generators, RF synthesizers, RF power detectors, mixers, up / downconverters. Since the conception of WFT, we have introduced products that have been purchased by a wide range of customers, from hobbyists to education facilities to government agencies. Worldwide customers include Europe, Australia, and Asia. Please contact Windfreak today to learn how they might help you with your current project.

Wednesday 30

Are Radio Symbols Wrong?

Are Radio Symbols Wrong?, March 1944 Radio-Craft - RF CafeDo you remember back in the 1980s when adoption of the IEEE−type logic schematic symbols* got a big push? It proposed a logical approach (pun intended) to building any type of combinational logic or sequential logic devices based on strict rules of construction. Curved lines are nowhere in sight. Interestingly, the same type of schematic symbol "simplification" was proposed in the 1940s. The motivation for removing curved lines was to prevent draftsmen from needing to use a compass or special drawing template rather than using only a straight edge. Vacuum tube outlines, light bulbs, inductors, etc., required more time to pencil in. In 1944, this article entitled "Are Radio Symbols Wrong?" appeared in Radio-Craft magazine...

Thanks to PCB Directory for Continued Support!

PCB  Directory - RF CafePCB Directory is the largest directory of Printed Circuit Board (PCB) Manufacturers, Assembly houses, and Design Services on the Internet. We have listed the leading printed circuit board manufacturers around the world and made them searchable by their capabilities - Number of laminates used, Board thicknesses supported, Number of layers supported, Types of substrates (FR-4, Rogers, flexible, rigid), Geographical location (U.S., China), kinds of services (manufacturing, fabrication, assembly, prototype), and more. Fast turn-around on quotations for PCB fabrication and assembly.

When Light and Atoms Share a Common Vibe

When Light and Atoms Share a Common Vibe - RF Cafe"An especially counter-intuitive feature of quantum mechanics is that a single event can exist in a state of superposition - happening both here and there, or both today and tomorrow. Such superpositions are hard to create, as they are destroyed if any kind of information about the place and time of the event leaks into the surrounding - and even if nobody actually records this information. But when superpositions do occur, they lead to observations that are very different from that of classical physics, raising questions that spill over into our very understanding of space and time. Scientists from EPFL, MIT, and CEA Saclay, publishing in Science Advances, demonstrate a state of vibration that exists simultaneously at two different times..."

Titanic Radio, Compliments of Marconi Wireless Telegraph Company

Titanic Radio, Compliments of Marconi Wireless Telegraph Company - RF Cafe SmorgasbordIn 2012, we were inundated with stories on the 100-year anniversary of the "unsinkable" RMS Titanic, on April 15, 1912. Even after a century of research and exploration, no definitive cause has been determined relating to how the ship's crew managed to hit a gigantic iceberg on a star-lit, glass-smooth sea. The prevailing theory seems to be that an optical illusion due to an atmospheric inversion caused the crew to misjudge the position of the iceberg. An article in the March 2012 Smithsonian magazine lays out the scenario, complete with diagrams. The same edition has a story titled, "They Missed the Boat," discussing some of the famous people who were originally scheduled to make the voyage, but decided not to before it departed. Amongst the notables was none other than 1909 Nobel Prize in Physics honoree Guglielmo Marconi. Instead, he left for America on the Lusitania three days earlier. Interestingly, he also made the Atlantic passage on the Lusitania three years later on the trip immediately before a German U-Boat sunk it...

RF Cascade Workbook 2018

RF Cascade Workbook 2018 Is Available Now! - RF CafeRF Cascade Workbook 2018 is the next phase in the evolution of RF Cafe's long-running series, RF Cascade Workbook. Chances are you have never used a spreadsheet quite like this (click here for screen capture). It is a full-featured RF system cascade parameter and frequency planner that includes filters and mixers for a mere $45. Built in MS Excel, using RF Cascade Workbook 2018 is a cinch and the format is entirely customizable. It is significantly easier and faster than using a multi-thousand dollar simulator when a high level system analysis is all that is needed. An intro video takes you through the main features...

Please Thank San Francisco Circuits for Supporting RF Cafe

San Francisco CircuitsSF Circuits' specialty is in the complex, advanced technology of PCB fabrication and assembly, producing high quality multi-layered PCBs from elaborate layouts. With them, you receive unparalleled technical expertise at competitive prices as well as the most progressive solutions available. Their customers request PCB production that is outside the capabilities of normal circuit board providers. Please take a moment to visit San Francisco Circuits today. "Printed Circuit Fabrication & Assembly with No Limit on Technology or Quantity."

Tuesday 29

Color Television Systems

Color Television Systems, January 1951 Radio-Electronics - RF CafeIt's probably a safe bet that most people, even at the dawn of color television, knew of the competition which occurred for the adoption of three different methods of implementation. Two of them - line-sequential by Color Television, Inc. (CTI), and dot-sequential by Radio Corporation of America (RCA) - were fully electronic while the third system by the Columbia Broadcast System (CBS) used a kludge of a spinning color wheel placed in front of a black and white display. The CBS field-sequential design used a synchronization component of the composite transmitted signal to position the correct color screen (red, yellow, or blue) in front of the screen as the electron gun scanned the CRT - analogous to how World War I airplane machine guns were synchronized with the engine to fire between propeller blades. Of course an out-of-synch scenario in the color wheel was not as serious as with the machine gun. The worst that could happen with the TV is a false color picture whereas with the machine gun your biplane instantly became a glider. Although I poke some fun at the CBS solution...

Hollow-Core Optical Fiber Clearer Than Glass

Hollow-Core Optical Fiber Clearer Than Glass"Conventional fiber optics guide light through solid glass cores that are extremely transparent. The clearest fibers have loss as low as 0.142 decibel per kilometer. Which means that more than one percent of input light remains after a hundred kilometers. Yet solid glass fibers cannot carry very high powers, particularly in short pulses, limiting their use for applications including delivering intense light for laser machining. Now a team at the University of Southampton's Optoelectronics Research Center has made hollow-core fibers that are clearer than solid-core fibers at some important wavelengths. They report their results in Nature Communications..."

Withwave Compact N-type Calibration Kit (DC to 8 GHz)

Withwave Compact N-type Calibration Kit (DC to 8 GHz) - RF CafeWithwave's New Compact N-Type Calibration Kit offers excellent performance characteristics that is specially designed for fine-tuning in production environments and quality testing facilities using N-type connectors from DC to 8 GHz. This Calibration Kit includes all needed calibration standard (Open, Short, Load) in one unit. It is the best solution available for ease of use in VNA calibration, especially in the field. Return loss (Load): <-42 dB for DC to 6 GHz, <-38 dB for 6 to 8 GHz...

Westinghouse Model WR 207 Superheterodyne Radio Service Data Sheet

Westinghouse Model WR 207 5-Tube Dual-Band Superheterodyne Radio Service Data Sheet, December 1936, Radio-Craft - RF CafeFor many years I have been scanning and posting Radio Service Data Sheets for sets like this Westinghouse Model WR 207 & WR 208 5-tube dual-band superheterodyne tabletop radio model. Hundreds of them appeared in magazines like Radio-Craft and Radio News from the 1910's up until around the 1960's. This one appeared in a 1936 issue. There were a couple companies (Sams Photofact, most notably) that sold packages of service data for all new domestic use electronics products, but smaller service shops could not easily afford the subscription cost, and the do-it-yourselfer was out of luck because the manufacturers did not sell such data to non-licensed dealers. Today it is even harder to come by the information. Often, images of these radios can be found on websites like RadioMuseum.org and RadioAttic.com. Another great source is eBay, but usually those are not as photogenic because they are in need of restoration...

World's Largest Commercial Airborne Antenna for 5G

World's Largest Commercial Airborne Antenna for 5G Applications - RF Cafe"Cambridge Consultants, part of Capgemini, revealed its role in a visionary program to realize the dream of superfast 5G for everyone and everything across the globe. Working in collaboration with Stratospheric Platforms Limited (SPL), Cambridge Consultants achieved a remarkable technical feat with a wireless antenna unlike anything seen before, delivering affordable connectivity from a fleet of zero emissions aircraft, airborne at an altitude of 20,000 meters for more than a week. Operating at a fraction of the cost of building and maintaining terrestrial infrastructure, and with minimal environmental impact due to its zero-emission hydrogen power system, such a fleet could rewrite..."

Thanks Again for Alliance Test Equipment's Support!

Allied Test Equipment Products - RF CafeAlliance Test Equipment sells used / refurbished test equipment and offers short- and long-term rentals. They also offer repair, maintenance and calibration. Prices discounted up to 80% off list price. Agilent/HP, Tektronix, Anritsu, Fluke, R&S and other major brands. A global organization with ability to source hard to find equipment through our network of suppliers. Alliance Test will purchase your excess test equipment in large or small lots. Blog posts offer advice on application and use of a wide range of test equipment. Please visit Allied Test Equipment today to see how they can help your project.


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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 World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

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