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About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024

Webmaster:

    Kirt Blattenberger,

    BSEE - KB3UON

RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The 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 -

• FCC Expands List of National Security Risk Equipment

• Día del Radioaficionado Celebrated May 10 in Puerto Rico

• IBM Targets 4,000-Qubit Processor by 2025

• mmWave Growth Slows But Outlook Still Favorable

• Radio Grew Advertiser's Business by 11%

• Armed Forces Day Cross-Band Exercise Set for May 14

• India Prepares to Build Its 1st Chip Fab

• Pentagon Harnessing 5G for Future Fight

• RF Semi Supply Shortage Should Ease in 2023

Transformers

Transformers, April 1952 Radio-Electronics - RF CafeThese days it is probably rare that a person would find the need to construct a custom transformer for a power supply since just about anything you need can be found on websites like eBay and Amazon. However, there are still many homebrew types out there who enjoy the challenge (and maybe nostalgia) of creating a transformer for a special need. For those folks, this article from a 1952 issue of Radio−Electronics magazine will be a welcome bit of information. Author T.W. Dresser presents the fundamental equations and design methodology needed for winding a transformer on a laminated steel core frame. There are plenty of abandoned transformers which can be stripped down and rebuilt as required. Even the newest electronic devices - radios, TVs, Blu−ray players, kitchen appliances, etc. - have a transformer of some sort...

How NOT to Use Transistors

How NOT to Use Transistors, September 1959 Popular Electronics - RF CafeTransistors were still relatively new when these cartoons were published in the September 1959 issue of Popular Electronics magazine. Most people had never seen a transistor, much less handled one. Soldering irons used for working on the point-to-point wiring used on vacuum tube gear could also be used for soldering the old copper guttering and downspouts - at least the ones that got hot enough and had enough thermal inertia to melt solder on sheet steel chassis'. Does the guy in this General Transistor infomercial look a bit like Dilbert - or maybe I should ask does Dilbert look a bit like this guy? BTW, are you thinking what I'm thinking about the picture on the bottom left?

Low-Frequency Magnetic Fields in e-Vehicles

Low-Frequency Magnetic Fields in e-Vehicles"Most electromagnetic interferences (EMIs) in the field are conducted emissions/immunities, radiated emissions/immunities, electric fast transients (EFT), and electrostatic discharge (ESD). There are, however, other types of EM-related disturbances, including low-frequency magnetic fields, the subject of this article. The power-frequency (50-60 Hz) magnetic field is a direct result of currents flowing in power networks. When low-frequency currents flow in the entire power network, depending on the size of the current-circulating loop, the impact on equipment/products in the environment can be significant. A typical case is an equipment with a cathode ray tube (CRT) screen. The display on a CRT screen would appear to wobble due to the presence of a nearby low-frequency field1. Professional audio equipment such as electric guitars, tape recorders, and loudspeakers are also sensitive to external magnetic fields..."

The Convair Analogue Computer

The Convair Analogue Computer, January 1954 Radio & Television News - RF CafeAs quoted in this 1954 Radio & Television News magazine article about analog[ue] computers as compared to digital computers, "Add two and two. Coming from an analogue computer, the answer would most likely be, 3.999 or 4.001." While that is a true statement, there is one important feature that an analog computer had over digital computers of the era: once initially set up with a transfer function, outputs were nearly instantaneous as the input was varied over a range of values, whereas a digital computer could take quite a bit of time to crank through involved mathematical equations. Performing tasks such as computing aircraft flight paths and other sequential operations was the analog computer's forte. If you needed to calculate exact values for atomic research or cryptographic code cracking, that was and still is the domain of digital computers...

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...

Thanks Again to Anatech Electronics for Long-Time Support!

Anatech Electronics logo - RF CafeAnatech Electronics (AEI) manufactures and supplies RF and microwave filters for military and commercial communication systems, providing standard LP, HP, BP, BS, notch, diplexer, and custom RF filters, and RF products. Standard RF filter and cable assembly products are published in our website database for ease of procurement. Custom RF filters designs are used when a standard cannot be found, or the requirements dictate a custom approach for your military and commercial communications needs. Sam Benzacar's monthly newsletters address contemporary wireless subjects. Please visit Anatech today to see how they can help your project succeed. 

Super Flower Blood Moon Lunar Eclipse Tonight

Super Flower Blood Moon Lunar Eclipse Tonight - RF CafeDon't miss this chance to observe one of the longest possible lunar eclipses tonight, Sunday, May 15th - a super flower blood moon. The earth's umbral shadow first touches the edge at 10:27 pm EDT, then totality begins at 11:29 pm. The 85-minute-long total eclipse is midway at 12:11 am, then leaves the umbral shadow at 12:53 am. A lesser darkening of the moon happens on both sides of the eclipse while in the earth's penumbral shadow, but it is not as stark. A second, nearly identical, lunar eclipse will occur in November of this year, so if the weather does not cooperate in allowing you to see this one, maybe you will get luckier in half a year. The skies here in Greensboro, NC, are forecast to be clear tonight. I hope yours are, too.

s-Parameters Theme Crossword Puzzle for May15th

s-Parameters Theme Crossword Puzzle for May 15th, 2022 - RF CafeThis custom s-Parameters themed Crossword Puzzle for May 15th, 2022, is brought to you by RF Cafe. Clues for words relevant to the theme are marked with asterisks (*). 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 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...

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...

Many Thanks to Axiom Test Equipment for Continued Support!

Axiom Test Equipment - RF CafeAxiom Test Equipment allows you to rent or buy test equipment, repair test equipment, or sell or trade test equipment. They are committed to providing superior customer service and high quality electronic test equipment. Axiom offers customers several practical, efficient, and cost effective solutions for their projects' TE needs and is committed to providing superior customer service and high quality electronic test equipment. For anyone seeking a way to offload surplus or obsolete equipment, they offer a trade-in program or they will buy the equipment from you. Some vintage items are available fully calibrated. Please check out Axiom Test Equipment today!

Grayburne TV-IF Signal Boosters

Grayburne TV-IF Signal Boosters, April 1952 Radio-Electronics - RF CafeAdd-on devices like this "TV-IF Signal Booster" began appearing in all sorts of magazines back in the early 1950s as television sets became more and more of a household fixture, and people were beginning to assume the now well-establish couch potato domestic class. According to this advertisement by Grayburne Corporation, "experience proves a 20% average boost in overall signal is all that's needed to give satisfactory reception." Since their signal booster plugs into the IF path, it is probably safe to assume the gain refers to voltage and not power. A 20% gain in voltage is 10 * log (1.2) = 0.79 dB, which is not much. Most likely the vast majority of TV installations would benefit much more from fine tuning of the antenna and transmission cable system, but to be fair, this devices targets indoor installations where the antenna is rabbit ears that came installed on the set. In that case, relocating the television to another place in the room and fiddling with the rabbit ears would also likely result in as much or more of an improvement as the booster...

Retentive GaN Non-Volatile Memory

Speedy, Durable Retentive GaN Non-Volatile Memory - RF Cafe"Hong Kong University of Science and Technology (HKUST) reports on a gallium nitride (GaN) non-volatile memory (NVM) with good speed, retention and endurance at the same time. In silicon-based NVMs there tends to be a trade-off in these characteristics, creating a manufacturing 'trilemma' due to the use of Fowler-Nordheim tunneling across a tunnel oxide (TO) to change the memory state. The researchers comment: 'This work shows that the mainstream GaN-on-Si platform can also accommodate high-performance non-volatile memory devices in addition to the power and radio frequency (RF) devices, to enable highly intelligent electronic systems.' The device integrated a p-channel field-effect transistor (p-FET) with p-i-n heterojunction diode. The p-FET consisted of aluminium oxide (Al2O3) gate insulator on p-GaN..."

Kennedy Superheterodyne Short-Wave Converter Radio Service Data Sheet

Kennedy Superheterodyne Short-Wave Converter Radio Service Data Sheet, April 1932 Radio-Craft - RF CafeThis Radio Service Data Sheet for the Kennedy Superheterodyne Short-Wave Converter (Model 54 "Globe Trotter") is an example of the dozens of similar schematic and alignment instruction sheets that have been posted on RF Cafe over the years. It appeared in a 1932 issue of Radio−Craft. Obtaining technical information on most things, even readily available items, prior to the Internet era was often very difficult - if not impossible. Service centers had what was need provided by manufacturers and distributors, but if you wanted to find a part number or service data on a refrigerator, radio, lawn mower, garage door opener, etc., and did not have the original paperwork, you were usually out of luck. Nowadays a Web search will quite often get you what you need thanks to people (like me) who go to the trouble of making the information available. The stuff doesn't just magically appear or get posted by benevolent governmental entities...

Senior Principal Engineer: TWT and HPA Design Needed by Raytheon

Senior Principal Engineer: TWT and HPA Design Needed by Raytheon Missiles & Defense - RF CafeAt Raytheon Missiles & Defense, you have the opportunity to try new things and make a bigger difference across a broader end-to-end solution, a richer technology and product set, an expanded range of disciplines, a growing global footprint and a more diverse team of colleagues and customers. Raytheon now has an opportunity for an experienced Senior Electrical Engineer: TWT & HPA Design who is seeking to utilize their strong academic background and experience in High Power/High Voltage Transmitters. This position requires an experienced senior technical and business leader with a proven track record of invention, capture, and successful execution in High Power Microwave (HPM) and Pulsed Power technologies. Responsibilities include design and hands-on testing of high voltage/high power RF components plus providing technical support to production activities across multiple programs. Team leadership skills including cost and schedule management plus proposal writing and presentation experience are desired...

National Company Advertisement: Modulation

National Company: Modulation, October 1947 QST - RF Cafe"It is anybody's guess as to what modulation system the amateur of 1975 will be using." That forward-looking line appeared in this 1947 QST magazine infomercial by the National Company. The writers probably had no real idea how different electronics would be 25 years in the future, especially since John Bardeen et al would not invent the transistor until two more months (December 1947) after the publication of this issue. In their traditional style, this full-page advertisement was heavy on text and light on images. The company invested in customer education with the hope being a well-informed and appreciative hobbyist would reward them with patronage...

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...

Many Thanks to Centric RF for Their Continued Support!

Centric RF microwave components - RF CafeCentric RF is a company offering from stock various RF and Microwave coaxial components, including attenuators, adapters, cable assemblies, terminations, power dividers, and more. We believe in offering high performance parts from stock at a reasonable cost. Frequency ranges of 0-110 GHz at power levels from 0.5-500 watts are available off the shelf. Order today, ship today! Centric RF is currently looking for vendors to partner with them. Please visit Centric RF today.

Bell Telephone Labs - Electron Beams

Bell Telephone Laboratories - Electron Beams, April 1952 Radio-Electronics - RF CafeThere is a physical limit to how small of a distance may separate two distinct objects (line, dots, etc.), generally agreed to be about half a wavelength of the color being observed, and be seen with perfect human eye. Applying that rule of thumb to blue light with a wavelength of approximately 4000 Å (400 nm) yields a distance of 200 nm. Accordingly, there is no amount of magnification possible which will allow a healthy human eye to resolve objects closer together than that. Even with perfect optics, magnifications of greater than about 1500x are not able to render greater detail. To resolve smaller distance requires shorter wavelengths, but we cannot see them directly and need a device to transform the detected image into a visible image. That is what an electron microscope does to enable molecule sized particle to be "seen." The SARS-CoV-2 particle has been measured by electron microscopy and found to range between 50 to 140 nm, so it cannot be viewed directly with an optical microscope. Cigarette smoke is about 400 nm in diameter...

Printable Logic Circuits from Self-Assembled Protein Complexes

Printable Logic Circuits from Self-Assembled Protein Complexes - RF Cafe"This paper describes the fabrication of digital logic circuits comprising resistors and diodes made from protein complexes and wired together using printed liquid metal electrodes. These resistors and diodes exhibit temperature-independent charge-transport over a distance of approximately 10 nm and require no encapsulation or special handling. The function of the protein complexes is determined entirely by self-assembly. When induced to self-assembly into anisotropic monolayers, the collective action of the aligned dipole moments increases the electrical conductivity of the ensemble in one direction and decreases it in the other. When induced to self-assemble into isotropic monolayers, the dipole moments are randomized and the electrical conductivity is approximately equal in both directions. We demonstrate the robustness and utility of these all-protein logic circuits by constructing pulse modulators based on AND and OR logic gates that function nearly identically to simulated circuits. These results show that digital circuits..."

All Elements Heavier Than Helium Are Metals?

All Elements Heavier Than Helium Are Metals? - RF CafeAstronomers consider all elements heavier than helium to be metals. That definition obviously does not jive with the standard chemical definition of a metal as an element that readily conducts electricity, but a concept called "metallicity" argues that from a star (and therefore the universe) formation perspective, extremely high temperatures and pressures in first generation stars (like our sun) preclude the identification of distinct elements other than hydrogen and helium. Heavier elements, such as lithium (#3 on the periodic chart and a major component in LiIon batteries, is classified as a metal in chemistry) are overwhelmingly created after a massive enough hydrogen star collapses and begins fusing H and He into heavier elements. The relative abundance of hydrogen in the universe is deemed to be about 92%, and helium is 7.1%, so together they comprise about 99% of all elements. Universally, oxygen is at 0.1%, carbon is 0.06%, nitrogen is 0.015%, silicon is 0.006%, and iron is 0.004%. By comparison, the Earth's elemental composition is 48.8% oxygen, 14.3% iron, 13.8% silicon, 0.2% hydrogen...

RF Electronics/CCA Design Sr. Principal Engineer Needed by Raytheon

RF Electronics / CCA Design - Sr. Principal Electrical Engineer Needed by Raytheon Missiles & Defense - RF CafeAt Raytheon Missiles & Defense, you have the opportunity to try new things and make a bigger difference across a broader end-to-end solution, a richer technology and product set, an expanded range of disciplines, a growing global footprint and a more diverse team of colleagues and customers. Raytheon Missiles and Defense is seeking an engineering professional to work with a variety of programs as a contributor to detailed design, simulation, product development, and initial product testing. The RF Products Department is currently searching for Electrical Engineers who have experience designing RF and Microwave hardware & CCA design, including transmitters, receivers, and exciters. This role includes design and test activities that span preliminary design to integration. Products we develop support radar and datalink applications on a variety of tactical missile programs. Critical to this role will be designing for challenging mechanical constraints and extreme environments...

Pilotless Plane Run by Radio

Pilotless Plane Run by Radio, May 1946 Radio News - RF CafeNews reports are full of features about the wave of radio controlled (R/C) "drones" terrorizing citizens with their often inexperienced pilots navigating their camera-laden craft to peer into bedroom windows, obtain "birds-eye" views of sporting events, and to be a general pain in the posterior to people trying to enjoy their right to privacy and safety (except, of course, unless it is the Government choosing to violate them). Incredible advances in radio, navigation, and sensor systems has facilitated a wide variety of very affordable multirotor (the correct term, not "drone") aircraft that can literally fly themselves. For under $500 you can buy a GPS-guided multirotor that can be programmed to fly to one or more waypoints and return to the launch location, with range and flight duration limited only by battery capacity. Gimbaled, remotely steerable cameras can snap photos or record video and either store it onboard for later retrieval or wirelessly transmit the images back to the operator. Platform stabilization is provided by ultra-miniature, ultra-lightweight orientation and rate gyros...

RF Cafe Quiz #33: Battlespace Technologies

RF Cafe Quiz #33: Battlespace Technologies: Network-Enabled Information Dominance - RF CafeThis quiz is based on the information presented in Battlespace Technologies: Network-Enabled Information Dominance, by Richard S. Deakin. Published by Artech House. Note: Some of these books are available as prizes in the monthly RF Cafe Giveaway. This book has some of the best photos of modern war-fighting technology that I have seen. "The era of mechanized warfare is rapidly giving way to the battle for information superiority enabled by electronic technologies that provide data for detailed analysis of enemy forces and capabilities. this book discusses how to use sensor technologies, including radar and electronic warfare systems, to disseminate information to key decision makers in timely and relevant manner..."

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

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