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Homepage Archive - December 2023 (page 3)

See Page 1 | 2 | 3 | 4 | of the December 2023 homepage archives.

Thursday the 21st

Frozen Mercury Shapes Molds

Frozen Mercury Shapes Molds, July 1949 Popular Science - RF CafeAs with the health hazards of smoking, in 1949 when this "Frozen Mercury Shapes Molds" article appeared in Popular Science magazine, the severe harm possible from ingestion or absorption of various forms of mercury were not well-established. The history of determination of physiological effects of mercury, both elemental and organic, is abundantly available on the Web, so I won't attempt to replicate it here. Suffice it to say that except under strictly controlled processes, the use of mercury as an agent for forming casting molds would never be done nowadays. Wax and Styrofoam are commonly used materials for the "lost-" technique of molding whereby a solid of easily liquefied material is a "positive" form encased by a secondary material - often sand or plastic - and then removed after the "negative" form has set (become solid). A "refractory material," as mentioned here, is one that remains solid at high temperatures...

Polaritons Transforming Semiconductor Technology

Polaritons Transforming Semiconductor Technology - RF Cafe"On the highway of heat transfer, thermal energy is moved by way of quantum particles called phonons. But at the nanoscale of today's most cutting-edge semiconductors, those phonons don't remove enough heat. That's why Purdue University researchers are focused on opening a new nanoscale lane on the heat transfer highway by using hybrid quasiparticles called 'polaritons.' Thomas Beechem loves heat transfer. He talks about it loud and proud, like a preacher at a big tent revival. “We have several ways of describing energy,” said Beechem, associate professor of mechanical engineering. “When we talk about light, we describe it in terms of particles called 'photons.' Heat also carries energy in predictable ways, and we describe those waves of energy as 'phonons.' But sometimes depending on the material, photons and phonons will come together and make something new called a 'polariton.' It carries energy in its own way, distinct from both photons or phonons..."

Your Radio Training and the Defense Program

Your Radio Training and the Defense Program, December 1940 January 1941 National Radio News - RF CafeThe National Radio Institute (NRI) was one of the first country-wide organizations to offer formal electronics training both as classroom and as self-study courses. Magazines were filled with offers to train men in what was an exciting new career field. The drums of war were beating in the background in Europe and the South Pacific by December 1940 when this article appeared in National Radio News, and the U.S. military was gearing up for what was sure to be an eventuality. Three months earlier, the Tripartite Pact united Japan, Italy and Germany to formalize the Axis Powers, and Hitler's forces had invaded Western Europe. The push was on to train a large number of engineers and technicians to handle communications and control systems for Army and Navy forces. It is always interesting to read pieces penned at the time events were unfolding, rather than after having been filtered through the worldview of subsequent authors...

Polarities, Pin 1 & Anode/Cathode Markings

San Francisco Circuits: PCB Assembly Drawings - RF CafeSan Francisco Circuits, a leading provider of high-quality printed circuit board (PCB) solutions, has published a new resource on PCB assembly drawings covering polarities, Pin 1 marking and anode/cathode markings. Learn more about understanding the XY file, component locations, and polarized component orientations on their website. In the realm of printed circuit board (PCB) manufacturing and assembly, attention to detail is paramount. Every element, from component placement to orientation, plays a crucial role in ensuring a successful and efficient assembly process. One vital aspect of this process is the proper utilization of the assembly drawings...

Vintage Alliance Model U−100 Tenna−Rotor Installation

Vintage Alliance Model U-100 Tenna-Rotor Installation (Kirt's Cogitation #301) - RF CafeIf you grew up in the era of rooftop television antennas, then there is a good chance you are familiar with the electromechanical antenna pointing systems that were often installed as well. Alliance, Channel Master, Cornell Dubilier, Radio Shack, RCA, Winegard, and others made low cost, light-duty rotators for television antennas. Ham radio antenna rotators were/are more robust in order to handle higher weight and wind loads. Many television antennas also cover the FM radio band (88-108 MHz), allowing them to do double duty. Here are a few companies (Audiovox and RCA) who still sell antenna rotators that are modern transistorized units with digital readouts. Some allow you to store channel number / antenna direction combinations rather than having to remember the antenna direction for a particular channel. Customer reviews of the new units reveal dissatisfaction with the weakness of the rotator unit that mounts on the antenna mast, and the inability of it to prevent the antenna from being rotated...

RF & Electronics Symbols for Visio

RF Electronics Wireless Analog Block Diagrams Symbols Shapes for Visio - RF CafeWith more than 1000 custom-built symbols, this has got to be the most comprehensive set of Visio Symbols available for RF, analog, and digital system and schematic drawings! Every object has been built to fit proportionally on the provided A-, B- and C-size drawing page templates (or can use your own). Symbols are provided for equipment racks and test equipment, system block diagrams, conceptual drawings, and schematics. Unlike previous versions, these are NOT Stencils, but instead are all contained on tabbed pages within a single Visio document. That puts everything in front of you in its full glory. Just copy and paste what you need on your drawing. The file format is XML so everything plays nicely with Visio 2013 and later...

Please Visit Empower RF's Website in Appreciation of Their Support

Empower RF Systems - RF CafeEmpower RF Systems is the technological leader in RF & microwave power amplifier solutions for EW, Radar, Satcom, Threat Simulation, Communications, and Product Testing. Our air and liquid cooled amplifiers incorporate the latest semiconductor and power combining technologies and with a patented architecture we build the most sophisticated and flexible COTS system amplifiers in the world. Solutions range from tens of watts to hundreds of kilowatts and includes basic PA modules to scalable rack systems.

Wednesday the 20th

Radio-Radar Telescope Will Listen to Stars and Map Moon

Radio-Radar Telescope Will Listen to Stars and Map Moon, September 1961 Popular Mechanics - RF CafeThe 1,000-meter radiotelescope at Arecibo, Puerto Rico, the one used by Carl Sagan's team for broadcasting a "here we are" message toward the globular star cluster M13, in the constellation of Hercules, back in 1974, experienced a catastrophic mechanical failure in December of 2020. It saw "first light," a term used by astronomers for the first time a telescope is used for observation, in November 1963. This article on the proposed 1,000-meter Arecibo radiotelescope appeared in a 1961 issue of Popular Mechanics magazine. After many modifications over its lifetime, it operated over a 300 MHz to 10 GHz range, and although the dish is fixed in position, the moveable feedhorn facilitates a coverage of -1° to 39° relative to the zenith position. The transmitters were used for radar measurement of moons and planets. This document issues by the National Science Foundation in December 2010 announced the Arecibo Observatory retirement...

A Key to Radio as a Vocation

A Key to Radio as a Vocation, November 1936 Radio-Craft - RF CafeIn 1936, a high school graduate could expect to earn about $15 per week, or about 38¢ per hour (40−hour week), in the radio business. According to the U.S. Bureau of Labor Statistics' Inflation Calculator, that is the equivalent of around $329 per week in 2023, which is not much to live on these days. Today, many McDonalds burger flippers are being paid $15 per hour ($600/40−hour week). That equates to a little over $27 per week in 1936 - nearly twice as much as an electronics technician who likely has military and/or technical school training. This 1936 Radio−Craft magazine article discusses the benefits of formal education in regard to potential earnings in the nascent radio business in many roles ranging from maintenance technician to broadcaster to management. The principle generally holds today...

Magnetization by Laser Pulse

Magnetization by Laser Pulse - RF Cafe"In the world of materials science, discoveries that challenge established norms often lead to groundbreaking innovations. Such is the case with a fascinating development involving laser-induced magnetization, a technique that was initially uncovered in 2018 by researchers at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR). In a recent collaboration with the Laserinstitut Hochschule Mittweida (LHM), this method has been further explored, revealing its potential to revolutionize various industries. This article delves into the details of this discovery and its implications. The Unexpected Discovery In 2018, scientists at HZDR made a startling observation. They found that by subjecting a thin layer of an iron-aluminum alloy to ultrashort laser pulses, the material, which was previously non-magnetic, transformed into a magnet. This intriguing phenomenon occurred because the laser pulses triggered a rearrangement of the atoms within the crystal lattice, causing the iron atoms to move closer together. Subsequently, these atoms formed a magnet. Remarkably, the researchers could reverse this magnetization by employing a series of weaker laser pulses..."

Merry Christmas from National Company

Merry Christmas and Happy New Year from National Company, January 1942 QST - RF CafeTake a look at the list of National Company's employee list wishing their customers a Merry Christmas and a Happy New Year. Every one of them is a licensed Ham radio operator. It appeared in the January 1942 issue of ARRL's QST magazine, but was for the 1941 Christmas. National Company was a major producer of amateur radio gear in the day. Little did they suspect when the magazine went to print that by the time readers received it, America would be newly engaged in World War II after the Japanese attack on Pearl Harbor on December 7, 1941. Many of the names would be different in1943 due to employees going off to fight the war in the European, Pacific, and North African Theaters of Operation...

Able Signal Amplified Digital Outdoor HDTV Antenna with Motorized 360° Rotation

Able Signal Amplified HD Digital Outdoor HDTV Antenna - RF CafeSince I do not have time to watch television on a regular basis, paying for a cable or satellite subscription cannot be justified. My plan was to install a traditional FM/VHF/UHF television antenna on the roof along with a rotator. Some pretty nice models are still available from Channel Master and a few others. TV broadcast stations in the Erie area are all within 10 miles or so, so signal strength would not be an issue. I listen to both AM and FM radio most of the day, so being able to get an FM signal boost from a steerable antenna would be a nice bonus since occasionally reorienting the FM dipole was needed to get a clear signal. The entire outfit would cost less than a year's subscription price for cable or satellite television...

RF & Electronics Symbols for Office™

RF & Electronics Schematic & Block Diagram Symbols for Office™ r2 - RF CafeIt was a lot of work, but I finally finished a version of the "RF & Electronics Schematic & Block Diagram Symbols"" that works well with Microsoft Office™ programs Word™, Excel™, and Power Point™. This is an equivalent of the extensive set of amplifier, mixer, filter, switch, connector, waveguide, digital, analog, antenna, and other commonly used symbols for system block diagrams and schematics created for Visio™. Each of the 1,000 or so symbols was exported individually from Visio in the EMF file format, then imported into Word on a Drawing Canvas. The EMF format allows an image to be scaled up or down without becoming pixelated, so all the shapes can be resized in a document and still look good. The imported symbols can also be UnGrouped into their original constituent parts for editing. Check them out!

Tuesday the 19th

Community TV-Antenna System

Community TV-Antenna System, January 1953 Popular Mechanics - RF CafeMost of the television programming I have watched in my 65+ years has been received over the air from a broadcast tower to a rooftop antenna (or occasionally a set of rabbit ears). Rarely have I had to resort to cable. An antenna, rotator, and lead-in cable in today's dollars represents an investment of around $100-$150. Most TV these days is delivered via an Internet connection. I don't even know whether old-fashioned set-top cable boxes are used exclusively for television. In 1953, when this "Community TV-Antenna System" article appeared in a 1953 issue of Popular Mechanics magazine, TV broadcast stations had been fairly well established across the country, but were not as dense as today. Some locations which did not have a station within 50 miles or so had difficulty getting acceptable reception - especially if surrounded by hills or mountains. As color broadcasts became more prevalent, demand for high quality signals increased, and people were willing to pay dearly for it. Residents of Laconia, New Hampshire, shelled out $169 ($1,954 in 2023 money) for installation and then a monthly subscription fee of $3.95 ($45 in 2023). According to the U.S. Census...

Varian Associates Radar Illustrations

Varian Associates Radar Illustrations by C.E.B. Bernard - RF CafeThanks to J.C. for providing three more of the Varian Associates radar comics - that's a total of twenty thus far. The original text on these is in German poem form, so the Google translations have lost some context. Fortunately J.C., a German who lives in Germany, provided a translation in modern lingo. A few years ago, another frequent RF Cafe visitor who goes by the moniker "Unknown Engineer" sent me a hyperlink to a PDF file on Amazon's CloudFront content delivery network (CDN - basically a file server) that contained no fewer than 17 amazing radar and vacuum tube related line drawings published by Varian Associates' TWT Division, Palo Alto Tube Division, Solid State Division, Eastern Tube Division, Western Tube Division, Solid State West Division. These highly detailed and busy drawings were done around 1975 by British illustrator/artist C.E.B. Bernard; a search for his works did not reveal much. The events shown are fictitious, as are the accompanying hand-printed stories. Some of the puns are pretty clever, but are somewhat dated for today's readers...

Photonic Chips Changing Wireless Communication

Photonic Chips Changing Wireless Communication - RF Cafe"New advanced photonic chips have been developed that optimize light transmission for optical wireless systems. These chips, essential for future 5G and 6G networks, represent a shift towards energy-efficient analog technologies and have wide-ranging applications in high-speed data processing and communication. A new breakthrough in optical wireless technology features photonic chips that efficiently shape light for improved data transmission, pivotal for the advancement of future wireless networks and high-speed data processing. Optical wireless may no longer have any obstacles. A study by Politecnico di Milano, conducted together with Scuola Superiore Sant'Anna in Pisa, the University of Glasgow, and Stanford University, and published in the prestigious journal Nature Photonics, has made it possible to create photonic chips that mathematically calculate the optimal shape of light to best pass through any environment, even one that is unknown or changing over time. The problem is well known: light is sensitive to any form of obstacle, even very small ones..."

Japan Short-Wave Phone to America Open

Japan Short-Wave Phone to America Open, March 1935 Short Wave Craft - RF Cafe"Tokyo is now a next-door neighbor - thanks to the magic of short-waves." That statement was made in a 1935 edition of Short Wave Craft magazine after the American Telephone and Telegraph (AT&T) company completed its wireless phone (voice) link between the U.S. and Japan; which is the first "T" in AT&T. Most people today would probably have a hard time guessing that the second "T" in AT&T stands for "telegraph." Its surprising that the name has not been changed to reflect the outdated-ness. Western Union sent its final telegraph in 2006. Another news headline a couple years ago reported on India sending its final official telegraph message. Note that this predated the attack on Pearl Harbor in December of 1941.

Promote Your Company on RF Cafe

Sponsor RF Cafe for as Little as $40 per Month - RF CafeBanner Ads are rotated in all locations on the page! RF Cafe typically receives 8,000-15,000 visits each weekday. RF Cafe is a favorite of engineers, technicians, hobbyists, and students all over the world. With more than 17,000 pages in the Google search index, RF Cafe returns in favorable positions on many types of key searches, both for text and images. Your Banner Ads are displayed on average 280,000 times per year! New content is added on a daily basis, which keeps the major search engines interested enough to spider it multiple times each day. Items added on the homepage often can be found in a Google search within a few hours of being posted. If you need your company news to be seen, RF Cafe is the place to be...

Monday the 18th

National Schools - Electronics, Television, Radio Home Training

National Schools - Electronics, Television, Radio Home Training, December 1950 Mechanix Illustrated - RF CafeThis is just one of many full-page advertisements in the December 1950 issue of Mechanix Illustrated magazine for electronics service schools. There was also Coyne Electrical & Television-Radio School, De Forests' Training (yes, THAT de Forest), deVry Institute, and a couple others. Electronics for home and industry was big business following World War II, both from the enormous amount of new knowledge gained in components, circuits, and manufacturing, and from the near total lack of consumer products being turned out by manufacturers while wartime rules mandated that all available resources be dedicated to the effort. In fact, immediately after the end of the war, aircraft, electronics, automobile, and many other industries went into a major downturn as government contracts were pulled overnight, leaving companies high and dry with no orders and factory floors which had been reconfigured to meet government demands. Of course those companies and employees enjoyed handsome profits and all the work they could handle for half a decade, so they couldn't complain too much...

A New Tool for the Serviceman

A New Tool for the Serviceman, March 1930 Radio News - RF CafeYou are taught early in your electronics career to be mindful of the tendency for measurement equipment to affect the circuit it is measuring, and therefore the indicated results. In the case of high frequency circuits, even minute amounts of capacitance and/or inductance can render results utterly unusable, but even in circuits operating down to D.C. the simple internal resistance of a meter can profoundly affect measurement accuracy. High impedance circuits are particularly vulnerable to such "loading" effects by test equipment. For example, consider a circuit being measured (device under test, aka DUT) that has an impedance of 10 kΩ and the internal resistance of the VOM is 100 kΩ (see diagram to left). If the open circuit "true" voltage level is 11 V, then voltage division effected by the 100 kΩ meter in series with the DUT's 10 kΩ internal resistance would produce a VOM reading of 10 V...

Halley's Comet Inbound Again

Halley's Comet Inbound Again - RF CafeI was too young to remember where I was when President Kennedy was shot in 1963, but I do remember hearing of Rev. King's shooting (and massive riots) in 1968, President Reagan being shot in 1981, and the Islamist attack in America on September 11, 2001. I also remember seeing Halley's Comet during its last appearance in 1986. Melanie and I were in a condo in Arnold, Maryland, preparing to move to Burlington, Vermont. The perihelion (orbit's closest point to sun) then was February 9th. The next perihelion is July 28, 2061. On December 8th of this year, Halley's Comet reached aphelion (farthest point from sun) and is now on its way back. Melanie will be 100 years old, and I will probably be taking a dirt nap by then (born 1958). Mark Twain (Samuel Clemmons) was born in 1835 under Halley's Comet, and predicted he would live until the next appearance in 1910. He was right.

A Few Winning Words on Hi-Fi

A Few Winning Words on Hi-Fi, July 1963 Popular Electronics - RF CafeComics in modern magazines are a rather rare phenomenon for some reason, but they were fairly regular features up until a couple decades ago. Maybe publishers are too afraid of offending some squish. This set of comics from the July 1963 edition of Popular Electronics magazine deals with high fidelity (Hi-Fi) stereo equipment, which was considered somewhat exotic and high-end for many people's budgets in the day. Inexplicably (not), that is about the time that increases in hearing losses among younger people were first being noticed in audiograms. I listened to my share of loud music beginning in the late 1960s, and operated many model airplane engines and lawnmower type engines my whole life, and still, at 65 years old, can hear a pin drop in the next room. I am blind as a bat, however (~20/240, corrected to nearly 20/20)...

Please Thank Werbel Microwave for Continued Support!

Werbel MicrowaveWerbel Microwave is a manufacturer of RF directional and bidirectional couplers (6 dB to 30 dB) and RF power dividers / combiners (2− to 16−way) with select models operating up to 26.5 GHz and 100 W of CW power (3 kW peak). All are RoHS and REACH compliant and are designed and manufactured in our Whippany, NJ, location. Custom products and private label service available. Please take a couple minutes to visit their website and see how Werbel Microwave can help you today.

Sunday the 17th

Electronics Theme Crossword for December 17th

Electronics Theme Crossword Puzzle for December 17th, 2023 - RF CafeThis custom RF Cafe electronics-themed crossword puzzle for December 17th contains words and clues which pertain exclusively to the subjects of electronics, science, physics, mechanics, engineering, power distribution, astronomy, chemistry, etc. Given that today is the 17th day of the month, many words in this crossword start or end (or contain) the 17th letter, "Q." Related clues are marked with an asterisk (*). You might expect a few Ham radio-related words and abbreviations in this one. If you do see names of people or places, they are intimately related to the aforementioned areas of study. As always, you will find no references to numbnut movie stars or fashion designers. Need more crossword RF Cafe puzzles? A list at the bottom of the page links to hundreds of them dating back to the year 2000. Enjoy...

Friday the 16th

Laser Weapons - How Close Are We?

Laser Weapons - How Close Are We?, March 1972 Popular Science - RF CafeThose of us who grew up in the 1960s and 1970s were inundated with books, movies, television shows, magazines, comic books, toys and other forms of promotion for the promises of lasers - both fictional and real - remember seeing articles like this one in a 1972 issue of Popular Science. Heck, there's a good chance I read this when it originally came out. At the time, laser power levels were measured in the hundreds or maybe a few thousands of watts. It wasn't long before that a watt produced from the lasing in rubies was considered an accomplishment. By this time chemical lasers were (and are today) the workhorses of laser weapons. Much of the state of the art in lasers has always been a well-kept secret by military and government research and defense contracting agencies. Interestingly, author Albright claims much of what he reports was gleaned by assimilating bits of information from diverse sources. It's a good example of the "loose lips sink ships" saying from World War II, whereby the enemy can figure out what you are doing even without clandestine sources (aka spies) embedded in the works...

Modelithics Merry Christmas 2023

Modelithics Merry Christmas 2023 - RF CafeModelithics sends out this holiday message: "To all our valued subscribers & customers, loyal partners, and our truly dedicated Modelithics team: we cannot thank each and every one of you enough for your continued support and patronage. We hope this year ends on a cheerful note for all, and the it will make way for a great New Year. Wishing you a very Merry Christmas and a Happy Holiday Season."

Radar Techniques - Primer Principles

Radar Techniques - Primer Principles, April 1945 QST - RF Cafe"The prospective peacetime applications of radar are beyond prediction. Among the more obvious are those relating to navigational aids and collision prevention. In some of these uses it will be a case of radar replacing radio." That was 78 years ago when real-world radar was still in its infancy that futurists were prognosticating on potential uses for radar beyond its use for the war effort. Just a month after this April issue of QST magazine was published, the war in Europe ended (V-E Day, May 8, 1945), and four months after that the war in Japan ended (V-J Day, August 14, 1945). Editor DeSoto would be utterly amazed at just how widespread radar is today. It not only surveys the airways for commercial, military, and civilian craft, but also for marine and land traffic, orbiting spacecraft, and planetary science. Law enforcement uses it to add to the department...

Espresso Engineering Workbook™ for Excel - 12.15.2023

RF Cafe Espresso Engineering Workbook™ for Excel - RF CafeThe newest release of RF Cafe's spreadsheet (Excel) based engineering and science calculator is now available - Espresso Engineering Workbook™. Among other additions, it now has a Butterworth Bandpass Calculator, and a Highpass Filter Calculator that does not just gain, but also phase and group delay! Since 2002, the original Calculator Workbook has been available as a free download. Continuing the tradition, RF Cafe Espresso Engineering Workbook™ is also provided at no cost, compliments of my generous sponsors. The original calculators are included, but with a vastly expanded and improved user interface. Error-trapped user input cells help prevent entry of invalid values. An extensive use of Visual Basic for Applications (VBA) functions now do most of the heavy lifting with calculations, and facilitates a wide user-selectable choice of units for voltage, frequency, speed, temperature, power, wavelength, weight, etc. In fact, a full page of units conversion calculators is included. A particularly handy feature is the ability to specify the the number of significant digits to display. Drop-down menus are provided for convenience...

Homodyne Reception

Homodyne Reception, December 1942 Radio-Craft - RF CafeHomodyne reception, although we don't often refer to it today using that term, involves mixing the modulated signal with a local oscillator that is tuned to the same frequency so that the demodulated signal is at baseband. In other words, the result of a homodyne nonlinear mixing process is a sum frequency of 2x the signal input and the difference frequency is DC (at the low end of the modulation). That is a simplistic explanation, and this 1942 Radio−Craft magazine article goes into a little more detail about methods, advantages, and disadvantages. Why not just make things simple and make every receiver a homodyne circuit? The answer is that with homodyne operation every theoretically possible mixer spurious product will fall inband without any means of filtering them out. Sometimes it doesn't matter, but especially in today's crowded radio spectrum it just is not workable because the interference level would be too intolerable...

How to Target RFCafe.com for Your Google Ads

Google AdSense - it makes good sense - RF CafeOne aspect of advertising on the RF Cafe website I have not covered is using Google AdSense. The reason is that I never took the time to explore how - or even whether it is possible - to target a specific website for displaying your banner ads. A couple display opportunities have always been provided for Google Ads to display, but the vast majority of advertising on RF Cafe is done via private advertisers. That is, companies deal with me directly and I handle inserting their banner ads into the html page code that randomly selects and displays them. My advertising scheme is what the industry refers to as a "Tenancy Campaign," whereby a flat price per month is paid regardless of number of impressions or clicks. It is the simplest format and has seemed to work well for many companies. With nearly 4 million pageviews per year for RFCafe.com, the average impression rate per banner ad is about 280,000 per year (in eight locations on each page, with >17,000 pages). That's pretty good exposure for $300 per month. Some companies have expressed an interest in being able to manage their advertising accounts themselves a la the Google AdSense program...

Thursday the 15th

Switchyards for the Nation's Power

Switchyards for the Nation's Power, June 1944 Popular Mechanics - RF CafeA relatively small number of people are responsible for building the world's most massive projects. Conceiving of, gathering support for, designing, building, and making operational gigantic dams, seaports, airliners, ships, railroads, skyscrapers, hospitals, highway systems, food processing plants, oil refineries, canals, is the domain of a very few engineers, scientists, managers, tradesmen, bankers, and manufacturing concerns. This article in the June 1944 issue of Popular Mechanics magazine reports on the building of the Grand Coulee Dam in Washington state. Take a look at the scale of the components being assembled, and consider the manufacturing facilities and people that built those parts. How does anyone take on such a monuments task? Imagine the satisfaction and pride in knowing you participated in such a project. From the late 19th century through the middle of the 20th century, Western minds and hands built the modern world's foundation. At the same time, some cultures were (and still are) living in mud huts and communicating with each other with tongue clicks and hand gestures. Now, we're supposed to feel guilty for advancing civilization while allowing others to degrade us and force us to "admit" that it was actually they who did all the thinking and work...

A Christmastide Muddle

A Christmastide Muddle, January 1930 Radio-Craft - RF CafeMerriam-Webster defines Christmastide as "the festival season from Christmas Eve till after New Year's Day or especially in England till Epiphany." In 1930 when this article appeared in Radio-Craft magazine, most likely everyone knew what Christmastide was, but not so much today; hence, I provide the meaning. Wikipedia goes into more detail. While reading and scanning vintage magazine articles throughout the year, I set aside ones specific to holidays like Christmas, Thanksgiving, Halloween, etc., and post them during their respective seasons. This story is about the trouble caused by a well-meaning but unqualified family member attempting to fix a radio that wasn't broken by gifting dear old Dad a Balkite trickle charger (which the radiomuseum.org website happens to have in their collection of data) for his battery-powered radio set. It also mentions using a potato to test the DC polarity of a power supply or battery. Last but not least is the "Hemco" 3-way socket plug adapter (this is a single adapter), a type of which is still in use today - much to the dismay of some safety advocates...

Far Field Antenna Range Measurement Uncertainties

Far Field Antenna Range Measurement Uncertainties - RF cafe"Since the advent of compact antenna test ranges and, somewhat more recently, near-field antenna test ranges, the number of newly built indoor test facilities has far surpassed the number of outdoor test facilities that have been constructed. Outdoor far-field testing requires suitable real estate, is subject to interference from external transmissions, and requires favorable weather conditions. However, the measurement of very large or very low-frequency antennas sometimes precludes a suitable indoor configuration. While the antenna measurement methodology for outdoor far-field direct illumination ranges is well established, and there are several references to estimates of specific uncertainty terms, there are no comprehensive recommended practices for the estimation of measurement uncertainty. This is in contrast to the existing recommended practices for near-field and compact antenna range measurements. In this article, we identify key uncertainty terms for an outdoor elevated far-field antenna range and present a procedural methodology for predicting and evaluating the measure of uncertainty. The method for analyzing each term is described in detail in accordance with, commonly referred to as the Guide to the Expression of Uncertainty in Measurement (GUM)..."

ARRL Christmas Gifts & Free Calendar

ARRL Christmas Gifts & Free Calendar - RF CafeThe American Radio Relay League (ARRL) is having a sale on its books and other items - but you'd better hurry to get them delivered in time for Christmas. Choose from the Radio Handbook or Antenna Handbook, license study guides (with question pools), kits, apparel, coffee mugs, patches, pins, and stickers, logbooks, regulation manuals, and many instructional books on a wide variety of radio topics. Deadlines are closing in. For a limited time, a free 2024 W1AW Calendar is included with any order, providing a monthly look inside the ARRL's flagship station.

Electronics-Themed Comics December 1947

Electronics-Themed Comics December 1947 & February 1954 Radio News - RF CafeThe December 1947 issue of Radio News and the February 1954 issue of Radio & Television News published these electronics-themed comics. Humor evolves over time, which is apparent when you look over these and many of the other comics from these vintage electronics magazines. The AVC comic is the best, IMHO. For those of you not around in the olden days of vacuum tubes, tapping on a tube would often make it work properly again, either because of a dirty contact in the socket or crud that had accumulated on the screen grid. I give this batch a score of about 7 out of 10, but you might think otherwise. There is a growing list of other comics at the bottom of the page. Enjoy...

RF & Electronics Stencils for Visio

RF & Electronics stencils for Visio r4 - RF CafeWith more than 1000 custom-built stencils, this has got to be the most comprehensive set of Visio Stencils available for RF, analog, and digital system and schematic drawings! Every stencil symbol has been built to fit proportionally on the included A-, B-, and C-size drawing page templates (or use your own page if preferred). Components are provided for system block diagrams, conceptual drawings, schematics, test equipment, racks (EIA 19", ETSI 21"), and more. Test equipment and racks are built at a 1:1 scale so that measurements can be made directly using Visio built-in dimensioning objects. Page templates are provided with a preset scale (changeable) for a good presentation that can incorporate all provided symbols...

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Temwell Filters
Rigol DHO1000 Oscilloscope - RF Cafe

ConductRF Phased Matched RF Cables - RF Cafe

Anatech Electronics RF Microwave Filters - RF Cafe