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About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024


    Kirt Blattenberger,


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...

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.

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Today in Science History

Tech Industry Headlines

Tech Industry Headlines - RF Cafe - Archive -

• Wholesale Prices up 9.7% in 2021

• FAA List of Airports Having C-Band Buffer Zones

• Teen Hacker Claims to Control 25 Teslas Worldwide

• James Webb Telescope Sunshield Fully Deployed

• Indonesia Telco Launches with Big Coverage Goals

• OLED with Graphene Anode Could Replace ITO in Displays

Eight-Satellite TEVEL Mission to Launch January 13

• FCC Mulls Nutrition-Style Broadband Labeling

• Best U.S. Cities for Hiring Remote Tech Workers

• Quantum Dots + OLED = Your Next TV

Electrical Engineering Theme Crossword for January 16th

Electrical Engineering Theme Crossword Puzzle for January 16th, 2022 - RF CafeThis custom made crossword puzzle for January 16th, 2022, from RF Cafe has an electrical engineering theme. All RF Cafe crossword puzzles are custom made by me, Kirt Blattenberger, and have only words and clues related to RF, microwave, and mm-wave engineering, optics, mathematics, chemistry, physics, and other technical subjects. As always, this crossword puzzle contains no names of politicians, mountain ranges, exotic foods or plants, movie stars, or anything of the sort unless it/he/she is related to this puzzle's technology theme (e.g., Reginald Denny or the Tunguska event in Siberia). The technically inclined cruciverbalists amongst us will appreciate the effort. Enjoy!

Transistor Dictionary

Transistor Dictionary, May 1958 Radio-Electronics - RF CafeA few (many, actually) new terms have been added to the transistor lexicon since 1958, but this list from Radio-Electronics magazine contains more than 150 definitions that are still useful today. It is amazing that this list was created just a decade after the transistor was invented, and now half a century later the most commonly used terms have not changed much. A huge number of elemental compounds, configurations, and process terms have been added since then, though. All of these are included in my custom dictionary used for creating the weekly crossword puzzles - compiled over more than two decades...

Hobnobbing with Harbaugh: School Days

Hobnobbing with Harbaugh: School Days - School Days, December 1963 Popular Electronics - RF CafeDave Harbaugh did a number of different humorous features for Popular Electronics magazine back in the 1960s and '70s (see list at bottom of page). "Hobnobbing with Harbaugh" was one of the more popular comic series he did. Article topics ranged from husband-wife relationships where the husband is an über-enthusiastic technophile of some sort and the wife has to put up with his crazy schemes and inventions. These comics poke fun at technical schools and colleges, and their alumni. My favorite is the "suicidal" waveform.

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, and Baseball Caps. Choose from amazingly clever "We Are the World's Matchmakers" Smith chart design or the "Engineer's Troubleshooting Flow Chart." My "Matchmaker's" design has been ripped off by other people and used on their products, so please be sure to purchase only official RF Cafe gear. My markup is only a paltry 50¢ per item - Cafe Press gets the rest of your purchase price. These would make excellent gifts for husbands, wives, kids, significant others, and for handing out at company events or as rewards for excellent service. It's a great way to help support RF Cafe. Thanks...

Many Thanks to Exodus Advanced Communications for Their Support

Exodus Advanced Communications - RF CafeExodus Advanced Communications is a multinational RF communication equipment and engineering service company serving both commercial and government entities and their affiliates worldwide. Power amplifiers ranging from 10 kHz to 51 GHz with various output power levels and noise figure ranges, we fully support custom designs and manufacturing requirements for both small and large volume levels. decades of combined experience in the RF field for numerous applications including military jamming, communications, radar, EMI/EMC and various commercial projects with all designing and manufacturing of our HPA, MPA, and LNA products in-house.

Quantum Radar Might Boost Accuracy

Quantum Radar Might Boost Accuracy - RF Cafe"A combined team of researchers from the University of Arizona and MIT reports that quantum radar might be able to boost the accuracy of radar systems more than has been thought. In their paper published in the journal Physical Review Letters, the group describes a new approach to developing quantum radar and the obstacles that stand in the way of its development. Radar works by firing microwave radiation at an object and then measuring the signals that bounce back from it. And while quite effective for many applications, it still falls short for long-distance applications. Over the past few decades, as scientists came to learn more about quantum entanglement, some suggested it might be used to improve radar systems. And indeed, sending just one of two paired photons to a target..."

Greek Alphabet Quiz

Greek Alphabet Quiz, December 1963 Popular Electronics - RF CafeThis "Greek Alphabet Quiz" created by Robert Balin appeared in the December 1963 issue of Popular Electronics magazine. Years from now most people will probably have forgotten about how prominently Greek letters appeared in the news in this current era (2022) regarding the COVID-19 plandemic and the destruction caused by politicians and others with power and financial agendas. Delta and Omicron variants (but notably not Xi since it might offend the leader of the country of the virus' origin) are the most publicized. For centuries prior, from a scientific and engineering perspective we looked either positively or benignly toward Greek letters when assigning them as unique identifiers for quantitative units or physical configurations. When Robert Balin created this "Greek Alphabet Quiz" for Popular Electronics magazine in 1963, he had no idea how the aforementioned people would manage to bastardize the revered letters. No vaccination, mask, or social distancing is required while working this quiz...

"ASC Intros the ASC2437C100-1800 MHz, 4 Watt Amplifier

ASC Intros the ASC2437C 100-1800 MHz, 4 Watt Amplifier - RF CafeAmplifier Solutions Corporation (ASC), founded in 2004 by a team of experienced engineers from Phoenix Microwave (M/A-COM), is a designer and manufacturer of RF & Microwave hybrid amplifiers for the military and commercial markets. Amplifier Solutions is proud to introduce our ASC2437C RF Amplifier. It features a bandwidth of 100 to 1,800 MHz with typical flatness of ±1.0 across the band, 42 dB of gain, and a 4 watt power output. Maximum input power is 0 dBm. SMA connectors are standard with DC feedthrough pins for the supply. 0 to 50°C operational temperature range. 1.00" x 2.50" x 4.00". Please contact ASC today with your RF amplifier requirements. Our engineers will be happy to assist you with application requirements...

Mackay Radio's Press Station

Mackay Radio's Press Station, August 1945, Radio-Craft - RF CafeMackay Radio & Telegraph Company, established in 1925 in Nevada by Clarence Mackay as a sort of spin-off of his father's Commercial Cable Company, is not usually a name that comes to mind when recalling early communications pioneers. Mackay was one of the earliest radio and telegraph companies, but also is still in business today under the name of Mackay Communications, based in Raleigh, NC. That makes Mackay one of the oldest electronics companies in the United States and in the world. Congratulations to them for surviving the cut-throat realm of corporate mergers, buy-outs, and hostile takeovers. As with nearly all technology concerns during World War II, Mackay did its part to help the Allies beat back the advances of Communism, Marxism, and Socialism by designing and manufacturing state-of-the-art radio communications systems that would work reliably under fire - literally...

Post Your Engineer & Technician Job Openings on RF Cafe for Free

Engineering Job Board - RF Cafe RF Cafe's raison d'être is and always has been to provide useful, quality content for engineers, technicians, engineering managers, students, and hobbyists. Part of that mission is offering to post applicable job openings. HR department employees and/or managers of hiring companies are welcome to submit opportunities for posting at no charge. 3rd party recruiters and temp agencies are not included so as to assure a high quality of listings. Please read through the easy procedure to benefit from RF Cafe's high quality visitors...

Many Thanks to Withwave for Long−Time Support!

Withwave RF & Microwave Components - RF CafeWithwave manufactures an extensive line of metrology quality coaxial test cable assemblies, connectors (wave-, end-, vertical-launch, board edge, panel mount), calibration kits (SOLT), a fully automated 4-port vector network analyzer (VNA) calibrator, between- and in-series connector adaptors, attenuators, terminations, DC blocks, torque wrenches, test probes & probe positioner. Special test fixtures for calibration and multicoax cable assemblies. Frequency ranges from DC through 110 GHz. Please contact Withwave today to see how they can help your project succeed.

Landing Blind - the Instrument Landing System

Landing Blind - Instrument Landing System, July 1938 Radio News - RF Cafe Only three and a half decades had passed since the Wright Brothers made the first flight of an aeroplane taking off under its own power when this "Landing Blind" article appeared in a 1938 issue of Radio News magazine. By then, an entire World War had been fought with air power having been determined to be a primary strategic force, and a commercial airline industry was thriving as travelers everywhere entrusted pilots and air traffic controllers with their very lives. The main impediment to further progress from an navigational and scheduling perspective was inclement weather. Pilots had long ago learned to fly by instruments, and taking off into nearly zero visibility was not a problem, but landing confidently and safely under the same conditions was still impossible. Aviation researchers were hard at work...

FM Wins in British Tests

FM Wins in British Tests, February 1952 Radio-Electronics - RF Cafe (business name: Kirt Blattenberger) Four months prior to the publishing of this article, Radio-Electronics magazine ran a piece by the same author, Ralph Hallows, asking the question Which - AM or FM? England Ponders. Here, Mr. Hallows lays out the process by which the British Broadcasting Corporation (BBC) and governmental entities decided on frequency modulation (FM) as the way forward in commercial broadcasting. You will not be surprised to learn that the primary drivers were wider bandwidth for greater fidelity and much high immunity to both manmade (QRM) and natural (QRN) electrical interference. Tests employing the help of non-technical radio listeners showed that the claim of off-tuning and frequency drift by small amounts did not appreciably degrade the quality of reception and listening satisfaction...

Chinese Researchers Claim Fusion Milestone

Chinese Researchers Claim Fusion Milestone - RF Cafe "Operators of China's HT-7U reactor, known as EAST (Experimental Advanced Superconducting Tokamak), have claimed a new fusion record, representing an incremental step in the long road to commercial energy production. According to the official Xinhua news agency, the EAST reactor was able to maintain stable plasma at high temperatures for 1,056 seconds (17.6 minutes). That represents a significant improvement above the previous record of 101 seconds set last year. EAST operates on deuterium, a stable hydrogen isotope abundant in nature. The experiment at Hefei, the capital of Anhui Province in eastern China, was directed by Gong Xianzu, a researcher at the Chinese Academy of Sciences' Institute of Plasma Physics. Details are here. EAST is among the nuclear fusion reactors located at the Chinese research institute. The doughnut-shaped tokamak produces a high-temperature plasma controlled by powerful electromagnets..."

Electronic Wife

Electronic Wife, January 1955 Popular Electronics - RF Cafe When electronics was relatively new and accessible to the common man, it was not unusual to find comical articles, poems, and even odes to the trade and those who plied it. To be an Electronics Technician was to wear a title of distinction, even awe. Radios and TVs were still using tubes and had chassis with point-to-point wiring, and everyone knew that the mysterious components within needed TLC to keep working optimally. Much as RF and microwave electronics is still considered a "black art" by many people, having any serious technical knowledge in circuit design, construction, and/or repair could earn a fellow a decent living, even without a college degree. Technical schools were popping up all over the country in the 1950s when this article was written. You will get a kick out of this story...

R&S Mobile Spectrum Monitoring System Expanded in Thailand

Rohde & Schwarz Mobile Spectrum Monitoring System Expanded in Thailand - RF Cafe Thailand's Office of National Broadcasting and Telecommunications Commission is expanding its R&S ARGUS spectrum monitoring system from Rohde & Schwarz with 26 additional interference hunting vehicles. The technical parameters for the vehicles/mobile stations and measurement equipment comply with ITU recommendations and guidelines, enabling both manual measurements and radio frequency direction finding. Since 2014, Rohde & Schwarz has supplied the NBTC with seven spectrum monitoring vehicles that use the R&S ARGUS monitoring system, allowing them to keep pace with advances in communications technology and the ever growing number of radio services. The authority can use the system to verify compliance...

Which - AM or FM? England Ponders

Which - AM or FM? England Ponders, October 1951 Radio-Electronics - RF Cafe It might be hard to believe that at one time there was cabinet-level debate in government offices regarding whether FM radio should be permitted to encroach on AM radio's well-established presence in the commercial broadcast radio domain. When this 1951 Radio-Electronics magazine article appeared, stereo was not even part of the contest since neither AM nor FM had implemented it. The primary points of contention were cost to purchase and maintain a receiver (AM wins) and consistency and quality of the sound over a broad range of frequencies and amplitudes (FM wins). Some argued frequency drift would cause FM to need constant re-tuning even with crystal control. Four months later, the February 1952 issue of Radio-Electronics reported on the winner in an article entitled "xM Wins in British Tests" (don't want to kill the suspense) for you...

RF & Electronics Symbols for Visio

RF Electronics Wireless Analog Block Diagrams Symbols Shapes for Visio - RF Cafe With 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...

Thanks to PCB Directory for Continued Support!

PCB  Directory - RF Cafe PCB 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.

Postwar Citizens' Radio

Postwar Citizens' Radio, May 1945 Radio-Craft - RF Cafe For the last two centuries our wars have been fought to secure freedom from oppressive regimes, either for our own citizens or for citizens of allied countries requesting our assistance. In the entire history of the United States, no land has ever been claimed during or after the conclusion of the conflicts. Although the human cost has been tragic - especially for those who have lost family members or suffered injuries - one undeniable benefit has been the advancement of technology. "Necessity," it has been said, "is the mother of invention." World War II resulted in significant advances in wireless communications, and the civilian radio industry was quick to exploit the new devices and methods. Futurists wasted no time prognosticating about how the postwar technology world would shape up, and of course radio figured significantly into the vision. This 1945 article from Radio-Craft magazine is an early example...

Novel Whisker Mitigating Composite Conformal Coat

Novel Whisker Mitigating Composite Conformal Coat - RF Cafe "European Union RoHS compliant commercial lead-free electronics used in DoD electronics have an increased failure risk due to tin whisker short circuits unless properly mitigated by design. An electronic assembly is created by integrating thousands of parts from multiple suppliers utilizing a host of circuit card manufacturing processes. With the lead elimination from electronics resulting from the European Union Reduction of Hazardous Substances (RoHS) legislation, many of the heritage aerospace and defense commercial off the shelf (COTS) solder materials with tin–lead have become obsolete. Most notably there has been an increasing cost and schedule pressure..."

Electronics-Themed Comics - Radio-Electronics

Electronics-Themed Comics October & November 1958 Radio-Electronics - RF Cafe Comics are a great source of levity to take you away from the day's normal flow of events. My favorite comic strips contain themes that relate to familiar scenarios or that catch me by surprise with their message. Technically themed strips like this collection from Radio-Electronics magazine are particularly welcome, but I do not appreciate gratuitous meanness and never care to see death, dismemberment, or gore. Call me a prude, but I'm shocked sometime by what appears in the daily newspaper comic strips (yes, I still read the comics - and work the puzzles - every day). There are plenty more comics where these came from, so stay tuned if you like them, too. Come to think of it, maybe the "Fast" in "Fast TV Service" on page 102 in the November 1958 comic is a double entendre...

Anatech Electronics January 2022 Product Update

Anatech Electronics January 2022 Product Update: 3 New Filter Models - RF Cafe Anatech Electronics offers the industry's largest portfolio of high-performance standard and customized RF and microwave filters and filter-related products for military, commercial, aerospace and defense, and industrial applications up to 40 GHz. Three new filter models have been introduced - a DC-1200 MHz / 1400-3000 MHz suspended substrate diplexer, a 2140 MHz WiFi bandpass filter, and a 2360-2420 MHz / 2435-2495 MHz Cavity Duplexer. Custom RF power directional coupler designs can be designed and produced when a standard cannot be found, or the requirements are such that a custom approach is necessary...

Radio Craft Magazine Sought by Nazi Spies

Radio Craft Sought by Nazi Spies, September 1945, Radio-Craft - RF Cafe Just as with the poor, the spies will always be among us. This story reports on a bookstore in New York that during World War II funneled money and technical information back to the Nazi Party in Germany. Electronics, aerospace, and other technical publications (including Radio-Craft magazine) were chief among the sought-after sources. The shop was a front operation which lost a huge sum of money per the official accounting books, but had copious amounts of funds pouring in from German "investors." Today's enemy money fronting operations are largely radical religious and communist entities collecting funds from America-hating groups and individuals who live and thrive here. Did you know it was during WWII that Persia began being commonly referred to as "Iran," which has the same etymology as the Aryan (the similarity in sound is no coincidence) movement that accompanied Nazism? Both groups aspire(d) to eradicate the Jewish people from the face of the Earth. The more things change, the more things stay the same...

RF & Electronics Symbols for Office™

RF & Electronics Schematic & Block Diagram Symbols for Office™ r2 - RF Cafe It 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!

Please see the RF Cafe Homepage Archives for previous items of interest...

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