Homepage Archive - April 2024 (page 3)

See Page 1 | 2 | 3 | 4 | of the April 2024 homepage archives.

Friday the 19th

Thursday the 18th

Wednesday the 17th

Mac's Service Shop: Customer Cues

Mac's Service Shop: Customer Cues, October 1958 Radio & TV News Article - RF CafeIn 1958 when this "Customer Cues" installment of John T. Frye's "Mac's Service Shop" series of technodramas in Radio & TV News magazine, color television was a relatively new phenomenon. The first commercially sold color TV set - the Admiral C1617A - went on sale at the very end of 1953. The NTSC approved the first standardized specification for a composite color television composite signal (color, gray scale, audio, brightness, synchronization) earlier that year. It allowed the same signal to work with both black and white (B&W) and color receivers. A lot of research went into making sure the viewing public was happy with their sets, using polls, hands-on instruction and publications on how to properly adjust tuning and picture controls, plus tips on installing outdoor antennas and running the twin lead transmission cable down to the set. Of course the proper way to fiddle with the built-in "rabbit ears" antenna was covered as well. I don't think any official pamphlets included mashing tinfoil onto the rabbit ears in complex patterns as many people did - truth is, it must have worked in some cases. In the story, Mac schools Barney on the situation.

3D Magnetic Recording for Ultra Storage HDDs

3D Magnetic Recording: Unprecedented Hard Drive Storage Density - RF Cafe"Research groups from NIMS, Seagate Technology, and Tohoku University have made a breakthrough in the field of hard disk drives (HDD) by demonstrating the feasibility of multi-level recording using a three-dimensional magnetic recording medium to store digital information. The research groups have shown that this technology can be used to increase the storage capacity of HDDs, which could lead to more efficient and cost-effective data storage solutions in the future. Enhancing Data Storage Capacity Data centers are increasingly storing vast amounts of data on hard disk drives (HDDs) that use perpendicular magnetic recording (PMR) to store information at areal densities of around 1.5 Tbit/in². However, to transition to higher areal densities, a high anisotropy magnetic recording medium consisting of FePt grains combined with heat-assisted laser writing is required. This method, known as heat-assisted magnetic recording (HAMR), is capable of sustaining areal recording densities of up to 10 Tbit/in². Furthermore, densities of larger than 10 Tbit/in² are possible based on a new principle demonstrated by storing multiple recording levels of 3 or 4 compared..."

Clairvoyant Dr. Fox

Clairvoyant Dr. Fox, May 1937 Radio-Craft - RF CafeMystery stories were broadcast on radio stations in the days before television - and for quite a while after TV was available for that matter. Families gathered around the living room radio set in excited anticipation of the next adventure of shows like "The Shadow," "Amos 'n' Andy," "Tales of the Texas Rangers," "Dragnet," and "The Green Hornet." During that era, it was common also for electronics magazines, which focused largely on radio communications, to experiment with printed dramas that had a radio-centric theme. Here is the first of a series tried by Radio-Craft magazine in the late 1930s. A couple decades later the "Carl & Jerry" adventures were run in Popular Electronics, but other than that I don't recall seeing a lot of these things. If you're a mystery fan, then here you go. A great collection of old time radio broadcasts can be heard on the Old Radio World and Old Radio Programs websites...

Help Needed with Capacitor Markings

RF Cafe visitor James G. sent me photos of some paper capacitors he plans to replace in a 1950s vintage radio set. It is a foreign job, most likely from France, based on the schematic. Some markings on the capacitors are not familiar; maybe you have seen them. The photos show things like "ESSAI 1.500 V.C.C." which I assume means 1,500 V (1.5 kV) working voltage, based on the European swapping of dots and commas for decimal points. "Essai" in French means "test," or "trial." "V.C.C." is probably a French marking for voltage similar to WVDC (DC working voltage). Another marking shows "100/1000 deF," which could be μμF, but unlikely given it is a paper capacitor. Maybe millifarad? Any insight will be appreciated.

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...

Please Welcome Temwell as an RF Cafe Sponsor!

Temwell (filters) - RF CafeTemwell is a manufacturer of 5G wireless communications filters for aerospace, satellite communication, AIoT, 5G networking, IoV, drone, mining transmission, IoT, medical, military, laboratory, transportation, energy, broadcasting (CATV), and etc. An RF helical bandpass specialist since 1994, we have posted >5,000 completed spec sheets online for all kinds of RF filters including helical, cavity, LC, and SMD. Standard highpass, lowpass, bandpass, and bandstop, as well as duplexer/diplexer, multiplexer. Also RF combiners, splitters, power dividers, attenuators, circulators, couplers, PA, LNA, and obsolete coil & inductor solutions.

Tuesday the 16th

Rare Metals, Once Forgotten, Now in Production

Rare Metals, Once Forgotten, Now in Production, October 1949 Popular Science - RF CafeHere is a really good synopsis of "rare earth" elements that explains how they came to be known in that way. Hint: It is not that they are so rare, in fact per Wikipedia, Cerium is the 25th most abundant element on Earth. The issue is they are not in concentrated lodes, but spread out as components of other mineral compounds, so extensive processing is needed to isolate and purify them. One of the first post-war commercial level extraction processes was the result of experimentations during nuclear bomb research. As you might know, "holes" existed in the Periodic Table of the Elements when it was first constructed in 1869 by Dmitri Mendeleev, because not all predicted naturally occurring elements had been found. Helium, atomic number 2, was not found on Earth until 1895, after first having been observed in the sun's spectrum a few years earlier (hence its name, from Helios). Author Alden Armagnac provides a primer in the original 15 rare earths (now 17) in this 1949 Popular Science magazine article...

Tiny Chip Generates High-Quality Microwave Signals

Tiny Chip Generates High-Quality Microwave Signals - RF Cafe"Columbia Engineering researchers have built a photonic chip that can produce high-quality, ultra-low-noise microwave signals using only a single laser. The compact device - a chip so small, it could fit on a sharp pencil point - results in the lowest microwave noise ever observed in an integrated photonics platform. The achievement provides a promising pathway towards small-footprint ultra-low-noise microwave generation for applications such as high-speed communication, atomic clocks, and autonomous vehicles. Electronic devices for global navigation, wireless communications, radar, and precision timing need stable microwave sources to serve as clocks and information carriers. A key aspect to increasing the performance of these devices is reducing the noise, or random fluctuations in phase, that is present on the microwave. 'In the past decade, a technique known as optical frequency division has resulted in the lowest noise microwave signals that have been generated to date,' said Alexander Gaeta, David M. Rickey Professor of Applied Physics and Materials Science and professor of electrical engineering at Columbia Engineering..."

Electronics: Washington Newsletter

Washington Newsletter, October 18, 1965 Electronics Magazine - RF Cafe1965 was the beginning of America's involvement in Vietnam. A mere decade had passed since the end of the Korean War (or "conflict" if you prefer), and the Department of Defense had not done much to modernize the military since then. Unlike with World War II when U.S. factories were turning out military aircraft, ships, and ground vehicles ahead of formal involvement, Congress was not interested in making headlines with news of war machines. When the first U.S. troops were sent in March of that year, things kicked into high gear. Lyndon Johnson was said to have tried to direct the war from the White House, but it was his Secretary of Defense, Robert McNamara, whose actions caused the Vietnam efforts to be nicknamed "McNamara's War." The "Washington Newsletter" feature of this October 1965 issue of Electronics magazine reported on, among other military-related items, the U.S. Air Force's plans to phase out the venerated (now, not then) B−52 Stratofortress bomber by sometime in the 1970s...

Testing RF Amplifiers

Testing RF Amplifier by Rhode & Schwarz - RF CafeRhode & Schwarz publishes a lot of very useful application notes that are particularly for newcomers to the field of RF and microwaves. All are forms of infomercials for their products, but than all companies do it. This new one entitled, "Testing RF Amplifier Designs," "...offers an overview from electronic design automation to real RF devices while focusing on verification, characterization, repeatability, and throughput. It explains the important characteristics and how they can be verified. In addition, it sheds light on the specialties along the value chain from development, validation and characterization to production." Here is a link to Testing RF Amplifier Designs that doesn't require registration...

RCA Institutes Ad - A Prophecy

RCA Institutes Ad - A Prophecy, October 1961 Electronics World - RF CafeIn the original radio broadcast of Jean Shepherd's "A Christmas Story," which was set in the Great Depression era, he spoke of magazine advertisements promising rewarding careers in electronics for men of adventure. Over the last few years I have posted many such advertisements from vintage electronics magazines, but they were also commonly seen in women's magazines, Life, The Saturday Evening Post, and many others. This ad pitching the Radio Corporation of America's (RCA) home study courses for electronics technology ran in a 1961 edition of Electronics World. Chairman of the Board, David Sarnoff, sends the message to readers. Sarnoff was commissioned as a Brigadier General in the Army Air Corps during World War II. He orchestrated radio broadcasts for the D−Day invasion (June 6, 1944), and also the Radio Free Europe system for post-war years... 

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 15th

Army/Air Force Rotary Beam Parasitic Array Antenna

U.S. Army and U.S. Air Force Rotary Beam Parasitic Array Antenna, March 1948 Popular Science - RF CafeThe U.S. Air Force became a separate branch of the armed forces on September 18th, 1947, almost exactly two years after Japan unconditionally surrendered to Allied Forces (Germany had unconditionally surrendered back in May). This recruitment advertisement appeared in the March 1948 issue of Popular Science magazine, a year after the Selective Training and Service Act of 1940 expired on March 31st, 1947. It was a joint appeal by the Army and the Air Force for men seeking careers in communications - particularly targeting, it seems, amateur radio operators, by touting a steerable beam antenna. I could not find numbers on how many conscripted and volunteer troops left the service immediately after the war. Many articles reported a big force drawdown in personnel, which combined with massive layoffs in war equipment industries, led to employment problems. It did not last for long, as the Military Selective Service Act of 1948 reinstated draft registration again. After all, the Military Industrial Complex, as 5-star General/President Eisenhower would eventually call it, needed work.

Transistor Takes Advantage of Quantum Interference

Transistor Takes Advantage of Quantum Interference - RF Cafe"As transistors are made ever tinier to fit more computing power into a smaller footprint, they bump up against a big problem: quantum mechanics. Electrons get jumpy in small devices and leak out, which wastes energy while degrading performance. Now a team of researchers is showing that it doesn't have to be that way. With careful engineering, it's possible to turn electrons' quantum behavior into an advantage. A team of English, Canadian, and Italian researchers have developed a single-molecule transistor that harnesses quantum effects. At low temperatures, the single-molecule device shows a strong change in current with only a small change in gate voltage, nearing a physical limit known as the sub-threshold swing. Getting near or beyond this limit will allow transistors to be switched with lower voltages, making them more efficient and generating less waste heat. The research team, including physicists at Queen Mary University of London, achieved this by taking advantage of how quantum interference alters the flow of current in single molecules..."

Calculation of Potentiometer Linearity and Power Dissipation

Calculation of Potentiometer Linearity and Power Dissipation, August 1967 Electronics World - RF CafeHere in this 1967 issue of Electronics World magazine is yet another example of where the basics in electronics never changes. There are always new people entering into the realm, so even if the subject has been covered countless times already, there is always a need to print it again. Remember that at one time you were a newbie and appreciated seeing beginners' concepts explained. The old-timers of the day probably complained about being tired of seeing the simple stuff re-hashed over and over. Most standard potentiometers (pots) are linear in operation, that is, the resistance between the moveable wiper contact and the overall resistance between the two ends is directly proportional to the percentage of travel along the length of the resistive element (printed or wirewound). One of more popular specialty pots is the logarithmically tapered type that is used in audio circuits in order to effect an audible linear sound volume change relative to the percentage of travel of the wiper arm. Analog stereo systems are major users of tapered potentiometers. The more things change, the more they remain the same...

Electronic Devices in TO- Packages

Silanna UV Devices (April 2024 Photonics) - RF CafeWhen's the last time you saw a magazine advertisement showing electronic devices in TO- type metal packages? "TO," by the way, stands for "transistor outline." It's been a long time for me. I did a double-take upon spotting this full-page ad by Silanna UV appeared in the April issue of Photonics. The products encased in the those vintage metal cans are ultraviolet light emitting diodes (UV LED), which are used primarily in sterilization processes for killing bacteria and viruses. Per the company website, 'Our best-in-class UV LED technologies can address everything from reducing healthcare-acquired infections and food contamination to minimizing the transmission of diseases and removing micro pollutants from drinking water. And in creating these products, Silanna focuses on minimizing its own use of natural resources and energy through innovative approaches to 'designing for manufacture' and investing in the latest, optimized production processes.'" That's it; I thought you might enjoy a trip back in time, a la the old Watkins Johnson, M/A-COM, and Avantek RF amps and mixers.

Stage Set for U.S.-Soviet Space Tests

Stage Set for U.S.-Soviet Space Tests, January 17, 1964 Electronics Magazine - RF CafeA love-hate relationship between major nations competing for leadership and dominance in the military and aerospace technology realms has existed in earnest at least since the space race began. Often, the pilots, astronauts, scientists and engineers are much more willing to set aside political differences in order to more effectively and efficiently advance the state of the art and/or basic knowledge. Maybe archeologists, biologists, endocrinologists, climatologists, zoologists, pathologists, and you-name-it-ologists feel the same way, but those types, dealing with squishy living things, are probably more altruistic than your typical physical sciences guy (or gal). It is the government management sides of the equation agonizing over the need to solicit or accept foreign assistance. There is (or was at the time) no better example than the U.S.A. (United States of America) and the U.S.S.R. (Union of Soviet Socialist Republics), particularly for space-based communications. Satellites were a very new entry into the radio world and both sides needed each other's help in testing and assessing the few "birds" being launched. In particular, high gain earth-based receiver systems were required...

Get Your Custom-Designed RF Cafe Gear!

Custom-Designed RF-Themed Cups, T-Shirts, Mouse Pads, Clocks (Cafe Press) - RF CafeThis assortment of custom-designed themes by RF Cafe includes T-Shirts, Mouse Pads, Clocks, Tote Bags, Coffee Mugs and Steins, Purses, Sweatshirts, Baseball Caps, and more, all sporting my amazingly clever "RF Engineers - We Are the World's Matchmakers" Smith chart design. These would make excellent gifts for husbands, wives, kids, significant others, and for handing out at company events or as rewards for excellent service. My graphic has been ripped off by other people and used on their products, so please be sure to purchase only official RF Cafe gear. I only make a couple bucks on each sale - the rest goes to Cafe Press. It's a great way to help support RF Cafe. Thanks...

Understanding Error Vector Magnitude (EVM)

Understanding Error Vector Magnitude (EVM) - RF CafeRhode & Schwarz publishes a lot of very useful application notes that are particularly for newcomers to the field of RF and microwaves. All are forms of infomercials for their products, but than all companies do it. This new one entitled, "Understanding EVM," provides "...an introduction to error vector magnitude (EVM), which is the primary metric of modulation accuracy. This paper is divided into three sections. The first section discusses the fundamentals of the digital modulation schemes used in modern radio frequency communications systems, in particular, APSK and QAM. The second section discusses the fundamentals of error vector magnitude. This section not only defines EVM, but also discusses the most common sources of EVM, how EVM is measured, and the effects of EVM. The final section explains the basics of constellation diagrams and how constellation diagrams can often be used to diagnose or troubleshoot the common root causes of EVM. EVM is measured at each symbol time, and larger values of EVM indicate greater distance between the measured and ideal points. Greater distance in turn means a higher probability that the receiver will mistake one symbol for another: higher EVM values mean a greater probability of bit errors. Minimizing EVM is therefore one of the most important goals in the design..."

 

 

 

 

 

 

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...

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, and more. Page templates are provided with a preset scale (changeable) for a good presentation that can incorporate all provided symbols...

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+ 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...

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...

Get Your Custom-Designed RF Cafe Gear!

Custom-Designed RF-Themed Cups, T-Shirts, Mouse Pads, Clocks (Cafe Press) - RF CafeThis assortment of custom-designed themes by RF Cafe includes T-Shirts, Mouse Pads, Clocks, Tote Bags, Coffee Mugs and Steins, Purses, Sweatshirts, Baseball Caps, and more, all sporting my amazingly clever "RF Engineers - We Are the World's Matchmakers" Smith chart design. These would make excellent gifts for husbands, wives, kids, significant others, and for handing out at company events or as rewards for excellent service. My graphic has been ripped off by other people and used on their products, so please be sure to purchase only official RF Cafe gear. I only make a couple bucks on each sale - the rest goes to Cafe Press. It's a great way to help support RF Cafe. Thanks...

Espresso Engineering Workbook™ for Excel

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...

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 280k per year (in eight locations on each page, with >17k pages)...

Update Articles

Amateur Observations During the Total Eclipse of the Sun

Carl & Jerry: How to Haunt a House

Mac's Service Shop: Leakage Current Testing and Using Square Waves

Mac's Service Shop: Electronics and the Energy Crisis

June 1969 P-E, Kohler p40

August 1969, Hobnobbing Harbaugh p68

June 1969 P-E, Kohler p40

August 1969, Hobnobbing Harbaugh p68

Overcoming Heisenberg Uncertainty

Overcoming Heisenberg Uncertainty in Quantum Measurements - RF Cafe"Chasing ever-higher qubit counts in near-term quantum computers constantly demands new feats of engineering. Among the troublesome hurdles of this scaling-up race is refining how qubits are measured. Devices called parametric amplifiers are traditionally used to do these measurements. But as the name suggests, the device amplifies weak signals picked up from the qubits to conduct the readout, which causes unwanted noise and can lead to decoherence of the qubits if not protected by additional large components. More importantly, the bulky size of the amplification chain becomes technically challenging to work around as qubit counts increase in size-limited refrigerators. Bolometer-Based Qubit Measurement Cue the Aalto University research group Quantum Computing and Devices (QCD). They have a hefty track record of showing how thermal bolometers can be used as ultrasensitive detectors, and they just demonstrated..."

Tiny Ultrabright Laser Melts Steel

Tiny Ultrabright Laser Melts Steel - RF Cafe"In 2016, the Japanese government announced a plan for the emergence of a new kind of society. Human civilization, the proposal explained, had begun with hunter-gatherers, passed through the agrarian and industrial stages, and was fast approaching the end of the information age. As then Prime Minister Shinzo Abe put it, 'We are now witnessing the opening of the fifth chapter.' This chapter, called Society 5.0, would see made-on-demand goods and robot caretakers, taxis, and tractors. Many of the innovations that will enable it, like artificial intelligence, might be obvious. But there is one key technology that is easy to overlook: lasers. The lasers of Society 5.0 will need to meet several criteria. They must be small enough to fit inside everyday devices. They must be low-cost so that the average metalworker or car buyer can afford them - which means they must also be simple to manufacture and use energy efficiently. And because this dawning era will be about mass customization (rather than mass production), they must be highly controllable and adaptive. Semiconductor lasers would seem the perfect candidates, except for one fatal flaw: They are much too dim. Laser brightness - defined as optical power per unit area per unit of solid angle - is a measure of how intensely light can be focused as it exits the laser and how narrowly it diverges as it moves away. The threshold for materials work - cutting, welding, drilling - is on the order of 1 gigawatt per square centimeter per steradian (GW/cm2/sr)..."

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

These archive pages are provided in order to make it easier for you to find items that you remember seeing on the RF Cafe homepage. Of course probably the easiest way to find anything on the website is to use the "Search RF Cafe" box at the top of every page. About RF Cafe.

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