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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 typing 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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Remember when … solder joints were shiny after cleaning off the rosin flux?

Today in Science History

Tech Industry Headlines

Tech Industry Headlines - RF Cafe- Archive -

• ARISS Seeks Hosts for Ham Radio Contacts with ISS Crew

• Indian Government Throws Lifeline to Vodafone and Other Telcos

• How Radio Can Dominate the Connected Car

• UK's Future Force to Lean Heavily into Robotics

• Better Chiplet Packaging to Extends Moore's Law

• Space-Based Quantum Internet

• Challenges in Midband Spectrum

• Q3 Looking Good, Says IC Insights

• Quantum Materials Cut Closer Than Ever

• Huawei Publishes a Book on 6G

Aircraft Radio

Aircraft Radio, January 1950 Radio & Television News Article - RF CafeHaving never been a sports aficionado, I have not spent much money or time at baseball, football, or soccer fields, hockey rinks, bowling alleys, curling sheets, or basketball courts. When an air show comes to town, however, I'm there. I'll stand in line for 45 minutes to tour the inside of a DC-3, B-25, B-17, PBY-5, or just about anything that will admit me. What is particularly enjoyable is being able to inspect the radio equipment racks and bays. The sight and smell (I consider it an aroma) of the old UHF and VHF sets, recording equipment, power supplies, generators, synchros, and the associated wiring and connectors is something I never tire of experiencing. I always imagine the men who operated and maintained everything doing their assigned duties to keep those wonderful machines flying. Maybe you know of what I write. This article provides a nice overview of the state of the art for airborne electronics in the post WWII era.Dig the Zenith console radio...

World's Smallest Biomechanical Linkage

World's Smallest Biomechanical Linkage - RF Cafe"Researchers at Princeton University have built the world's smallest mechanically interlocked biological structure, a deceptively simple two-ring chain made from tiny strands of amino acids called peptides. In a paper published August 23 in Nature Chemistry, the team detailed a library of such structures made in their lab - two interlocked rings, a ring on a dumbbell, a daisy chain and an interlocked double lasso - each around one billionth of a meter in size. The study also demonstrates that some of these structures can toggle between at least two shapes, laying the groundwork for a biomolecular switch. 'We've been able to build a bunch of structures that no one's been able to build before,' said A. James Link, professor of chemical and biological engineering, the study's principal investigator...."

Copper Mountain's Online Help Manuals for S2VNA and PXIe

Copper Mountain Technologies' Online Help Manuals for S2VNA and PXIe - RF CafeCopper Mountain Technologies is pleased to announce that Online Help manuals are now available for S2VNA and PXIe software by selecting the Online Help buttons. These online manuals are easy to navigate and have been designed to deliver an enhanced user experience. Online Help manuals for additional software versions are in development. The existing operating manuals and documentation for all other versions of software are available for download. If you prefer to use a PDF manual for S2VNA or PXIe models, it is also available to download by clicking the "Download Documentation" button...

The Clapp Oscillator - and How!

The Clapp Oscillator - and How!, February 1953 QST - RF CafeJames Kilton Clapp in 1948 first published details on an oscillator that used positive feedback obtained from an LC (capacitive & inductive) voltage divider to initiate and sustain oscillations. Thus was born the now familiar Clapp oscillator. It had an advantage over both the Colpitts and Hartley oscillators because the feedback, not being dependent on a simple capacitive or inductive voltage division, respectively, made it more reliable as a variable frequency oscillator (VFO). This article does a nice job of explaining the operation of the Clapp oscillator. Just as the Colpitts and Hartley oscillators handily provide an easy mnemonic for being based on voltage dividers of capacitance with the Colpitts oscillator and inductance (Henries) with the Hartley oscillator, the Clapp oscillator...

Promote Your Company on RF Cafe

Sponsor RF Cafe for as Little as $40 per Month - RF CafeNew Scheme rotates all Banners in all locations on the page! RF Cafe typically receives 8,000-15,000 website visits each weekday. RF Cafe is a favorite of engineers, technicians, hobbyists, and students all over the world. With more than 16,000 pages in the Google search index, RF Cafe returns in favorable positions on many types of key searches, both for text and images. 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. I also re-broadcast homepage items on LinkedIn. If you need your company news to be seen, RF Cafe is the place to be.

Many Thanks to ISOTEC for Continued Support!

ISOTEC Corporation - RF CafeSince 1996, ISOTEC has designed, developed and manufactured an extensive line of RF/microwave connectors, between-series adapters, RF components and filters for wireless service providers including non-magnetic connectors for quantum computing and MRI equipments etc. ISOTEC's product line includes low-PIM RF connectors components such as power dividers and directional couplers. Off-the-shelf and customized products up to 40 GHz and our low-PIM products can meet -160 dBc with 2 tones and 20 W test. Quick prototyping, advanced in-house testing and high-performance. Designs that are cost effective practical and repeatable.

Electronic Oscillator Theme Crossword Puzzle for September 19th

Electronic Oscillator Theme Crossword Puzzle for September 19th, 2021 - RF CafeThis Electronic Oscillator Theme crossword puzzle for September 19th, 2021, contains only words and clues related to engineering, mathematics, chemistry, physics, and other technical words. 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., Hedy Lamarr or the Bikini Atoll). The technically inclined cruciverbalists amongst us will appreciate the effort. Enjoy!

Nomograph Construction

Nomograph Construction, June 1946, Radio-Craft - RF CafeEven in this current age of ubiquitous computers and cellphones (also computers), there is still ample reason to consider using nomographs for presenting data and providing a hand calculation or conversion resource. In days prior, nomographs were an indispensible tool for both design and troubleshooting circuits. A huge number of nomographs can be found here on RF Cafe as they appeared in vintage magazine articles. This 1946 issue of Radio-Craft presents the first of a two-part tutorial on creating nomographs for any purpose, and uses current, voltage, and resistance as an example. Their utility is not limited to electrical and electronic topics, as many have been created for plumbing, hydraulics, mechanics, chemistry, finance, aerodynamics, pneumatics, lighting, acoustics, and I've even seen one...

What the THF? Debate over Where THz Starts

What the THF? Debate over Where THz Starts - RF CafeIs it just me or does this seem like a moot / obvious arguement? "For anyone looking for an end-of-the-summer mind bender, this might be one to consider. Where does the terahertz (THz) spectrum range start? The subject came up during a symposium last year, and it was covered here. Some researchers figure it starts at 100 GHz. Others say it's 300 GHz. Suffice it to say, the debate is alive and well - depending on who you talk to. Why should we care? For one, it helps to know what’s what when it comes to spectrum, the idea being there's a finite amount in the lower bands. Some day, somebody will come knocking for even more spectrum, and these very high frequency ranges will come in handy when there's nowhere else to go. For another, it's part of the grand plan for 6G, and even though it's early days in a lot of ways for 5G..."

Safety Precautions It Pays to Be Safe

Safety Precautions It Pays to Be Safe - Navy Training Courses - RF CafeNavy electrical equipment is designed and installed with every possible provision for the safety of the men who use it and service it. But this does not completely prevent injury to you and your shipmates or damage to equipment. Safety also depends on the Electrician's training. To insure safety while standing watch or working on a circuit, he must always work safely and observe safety precautions. Men have been burned, electrocuted, or maimed for life because they became careless in their work or failed to observe safety precautions. You were selected to be an Electrician's Mate because of your intelligence, so use your brain to prevent accidents. Injury and damage can be avoided by staying alert, exercising intelligence...

Teledyne Intros Expanded Range of 50+ GHz Coax Switches

Teledyne Defense Electronics Announces Expanded Range of 50+ GHz Coax Switches for 5G and Other Demanding Application - RF CafeTeledyne Relays today announced availability of a significantly expanded line of 50+ GHz coax switches, adding transfer switching, terminated, and normally-open models to its product line-up. These join the CCR-50U SPDT DC-53 GHz failsafe/ latching relay and CCR-39 SPnT DC-52 GHz latching coax relays that already enjoy wide acceptance. In addition to excellent RF performance, the family offers the widest operational temperature range (-55 to +85 °C), lowest weight and amongst the longest life (up to 5 million actuator cycles) of any 50 GHz switches available today...

Carl & Jerry: Sonar Sleuthing

Carl & Jerry: Sonar Sleuthing, August 1963 Popular Electronics - RF CafeIn this August 1963 adventure from Popular Electronics magazine, teenage techno-investigators Carl Anderson and Jerry Bishop use their home-brew sonar device to help the local sheriff nab a couple bank robbers. The "Hydro Probe" mentioned in the article was a real product manufactured by the Raymond Development Company of Watertown, Massachusetts (no longer in business). By this time the duo were students pursuing electrical engineering degrees at Parvoo University (a play on Perdue University, located in the boys' home state of Indiana). Enjoy.

Promote Your Company on RF Cafe

Sponsor RF Cafe for as Little as $40 per Month - RF CafeNew Scheme rotates all Banners in all locations on the page! RF Cafe typically receives 8,000-15,000 website visits each weekday. RF Cafe is a favorite of engineers, technicians, hobbyists, and students all over the world. With more than 16,000 pages in the Google search index, RF Cafe returns in favorable positions on many types of key searches, both for text and images. 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. I also re-broadcast homepage items on LinkedIn. If you need your company news to be seen, RF Cafe is the place to be.

Thanks to TotalTemp Technologies for Continued Support!

TotalTemp Technologies - RF CafeTotalTemp Technologies has more than 40 years of combined experience providing thermal platforms. Thermal Platforms are available to provide temperatures between −100°C and +200°C for cryogenic cooling, recirculating circulating coolers, temperature chambers and temperature controllers, thermal range safety controllers, space simulation chambers, hybrid benchtop chambers, custom systems and platforms. Manual and automated configurations for laboratory and production environments. Please contact TotalTemp Technologies today to learn how they can help your project.

Mathematics - Radio Tool

Mathematics - Radio Tool, June 1946, Radio-Craft - RF CafeRemember the early 1990s Teen Talk Barbie where one of her phrases, "Math class is tough!," caused a big kerfuffle because it ostensibly stereotyped girls as being afraid of math? Maybe if Talking GI Joe (this 1967 version is the one I had as a kid) also uttered a math phobia statement all would have been fine. The truth is that a large portion of both girls and boys (and men and women) of all ages break out in a cold sweat whenever the subject of math arises in print or in a conversation. The ARRL goes to great lengths to help ease the math anxiety of radio operators who are studying for a license exam. In this multi-part 1946 Radio−Craft magazine article, the authors attempt to assuage some of the reluctance of readers to apply mathematics to their electronics hobby endeavors...

Speed of GaN and Thermal Conductivity of Diamond

Speed of GaN and Thermal Conductivity of Diamond - RF Cafe"Seeking a route to high-performance power semiconductors, scientists in Japan have bonded gallium nitride to a diamond substrate – the latter an insulator whose thermal conductivity is many times that of copper or silver. 'The researchers succeed in the direct bonding of diamond and GaN at room temperature, and demonstrate that the bond can withstand heat treatments of 1,000°C, making it ideal for the high temperature fabrication process of GaN-based devices,' according to Osaka City University, home of the project. Unsurprisingly, attempts have already been made create a GaN-on-diamond, using some form of transition or adhesion layer..."

Log Polar Plane Stencil c1958

Log Polar Plane Stencil c1958 - RF Cafe SmorgasbordCanadian website visitor Richard F. sent me this photo of his "Log Polar Plane" acetate stencil, circa 1958. As a collector of vintage of science / technical paraphernalia, he ran across this as part of one of his acquisitions. "Computing Aids" is printed on it. I had never heard of the log polar plane, but according to the Wikipedia entry, "In mathematics, log-polar coordinates (or logarithmic polar coordinates) is a coordinate system in two dimensions, where a point is identified by two numbers, one for the logarithm of the distance to a certain point, and one for an angle. Log-polar coordinates are closely connected to polar coordinates, which are usually used to describe domains in the plane with some sort of rotational symmetry. In areas like harmonic and complex analysis, the log-polar coordinates are more canonical than polar coordinates." The David Young, on the University of Edinburgh website, explains, "Log-polar sampling is a spatially-variant image representation..."

December 1960 Popular Electronics Crossword Puzzle

Crossword Puzzle, December 1960 Popular Electronics - RF CafeIt was a little difficult to make out the shape within the crossword puzzle grid from this December 1960 issue of Popular Electronics magazine, so I got out my blue Crayon and filled in the hashed squares. It appears to be a transistor schematic symbol. Unlike the weekly RF Cafe crossword puzzles, not all of the clues and words are specifically related to science and engineering, but a large percentage of them are. Admittedly, I have the advantage of a software program to help place the words within the grid. Margaret LeFevre did not. Doing it by hand is a lot more work. I can't imagine how the people who created the New York Times' Sunday-size puzzles were able to do it without computer assistance!

Scanning Electron Microscope for Radio Engineers

New Scanning Electron Microscope Revealed to Radio Engineers, September 1942, Radio-Craft - RF CafeTelevision and radio facsimile machine electronics technology was credited for aiding in the development of a new type of scanning electron microscope (SEM) that could image the surface of opaque object to a resolution of 100 angstroms (Å). The television contribution part of the technology was precisely controlling a raster path for the electron beam. The facsimile part was the knowledge of how to assemble a printed image from streaming data. It is interesting to note that in order for an object to be imaged via SEM, its surface must be electrically conductive. Accordingly, non-metallic objects like bugs, plants, plastic, wood, etc., must receive a coating of metal by a process such as sputtering. Doing so can leave a few atoms thick later without losing too much resolution due to softening of features...

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