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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 -

• 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

• Huawei to Launch 1st 6G Products Around 2030

• Non-Magnetic 2-D Materials Yield Designer Properties for Spintronics

• A Viable Path to Commercial Fusion Power

• 10 Important Trends in Semiconductor Electronics

• New Tool for Analyzing Large Superconducting Circuits

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!

Please Thank IPP for Their Long-Time Support!

Innovative Power ProductsInnovative Power Products (IPP) has over 30 years of experience designing & manufacturing RF & microwave passive components. Their high power, broadband couplers, combiners, resistors, baluns, terminations and attenuators are fabricated using the latest materials and design tools available, resulting in unrivaled product performance. Applications in military, medical, industrial and commercial markets are serviced around the world. Please take a couple minutes to visit their website and see how IPP can help you today.

Why the Tube Shortage

Why the Tube Shortage, June 1946, Radio-Craft - RF Cafe"Why the Tube Shortage" was not a question being asked by Radio−Craft magazine editor Hugo Gernsback, it was an explanation. It is similar to the present day situation with the "Global Chip Shortage" in all the headlines being blamed on the Wuhan Flu plandemic (sic) causing a worker shortage. It has affected everything from the production of smart watches to kitchen appliances to cars and trucks. In 1946, however, the cause of the vacuum tube shortage was a multi-faceted ordeal according to investigative work by Mr. Gernsback. Service shops were accusing tube manufacturers of favoring radio production companies while radio production companies accused the tube manufacturers of favoring service shops. The truth, ostensibly, was that the federal government still laid claims to a large portion of tube manufacturing for post-war defense needs, and at the same time labor strikes were crippling production lines...

Many Thanks to Berkeley Nucleonics for Continued Support!

Berkeley Nucleonics Corp - RF CafeBerkeley Nucleonics Corporation (BNC) is a leading manufacturer of precision electronic instrumentation for test, measurement, and nuclear research. Founded in 1963, BNC initially developed custom pulse generators. We became known for meeting the most stringent requirements for high precision and stability, and for producing instruments of unsurpassed reliability and performance. We continue to maintain a leadership position as a developer of custom pulse, signal, light, and function generators. Our designs incorporate the latest innovations in software and hardware engineering, surface mount production, and automated testing procedures.

Communicating via Long-Distance Lasers

Communicating via Long-Distance Lasers - RF Cafe"Visible light has been used to communicate for centuries. Lanterns on ships and Morse code flashes allowed information to be conveyed at a distance. But now there's a better way to use light to communicate over even further distances and with far more accuracy: lasers. Launching in 2021, NASA's Laser Communications Relay Demonstration (LCRD) is going to geostationary orbit, where it will communicate with the ground at gigabit speeds. It's the agency's latest step to get more data from space per downlink. Currently, most NASA missions use radio frequency communications to send data to and from spacecraft. Radio waves have been used in space communications since the beginning of space exploration and have a proven track record of success. However, as space missions generate and collect more data, the need for enhanced communications capabilities becomes paramount..."

ConductRF TEA80 TESTeCON Cables for DC - 18 GHz

ConductRF TEA80 TESTeCON Cables for DC to 18 GHz - RF CafeConductRF offers many lines of Lab & Production RF Test solutions for DC to 18 GHz. TEA80 series TESTeCON and TESTeLINK RF Cable lines feature standard connector choices include straight male, female, and bulkhead, and right angle male. Standard interfaces include type-N, TNC, SMA, 3.5 mm, and 2.92 mm. Phase stable testing ±4° to 18 GHz, amplitude stable to ±0.2 dB to 18 GHz, max power 170 W @ 18 GHz, flex life over 10,000 cycles, cable loss <0.330 dB/ft @ 18 GHz, VSWR <1.30:1 (typical < 1.20:1). These cables can be purchased directly from Digi-Key. ConductRF VNA series provides customers with reliable ruggedized solutions for lab and production vector network analyzer testing. With options for 18, 26.5, 40, 50 & 70 GHz...

Low-Frequency Narrow-Band FM

Low-Frequency Narrow-Band FM, July 1947 QST - RF CafeNarrow-band frequency modulation (NFM) was a relatively new technology in 1947, having been advanced significantly during World War II. Amateur radio operators were just getting their gear back on the air after having been prohibited from transmitting for the duration of the war (see "War Comes," January 1942 QST). Few were probably thinking about adopting and exploiting new modulation techniques, but for those who were and recognized FM as the path to the future of radio, QST published this fairly comprehensive treatment of both frequency modulation (FM) and phase modulation (PM). Mathematically, FM is the time derivative of PM. Both modulation schemes vary the carrier frequency in some proportion to the baseband signal. Author Byron Goodman provides some insight into the techniques...

Many Thanks to Bittele Electronics for Continued Support!

Bittele Electronics PCB Fabrication - RF CafeSince 2003, Bittele Electronics has consistently provided low-volume, electronic contract manufacturing (ECM) and turnkey PCB assembly services. It specializes in board level turnkey PCB assembly for design engineers needing low volume or prototype multi-layer printed circuit boards. Free Passive Components: Bittele Electronics is taking one further step in its commitment of offering the best service to clients of its PCB assembly business. Bittele is now offering common passive components to its clients FREE of Charge.

Modelithics Welcomes Dr. Ali Boudiaf as Director of Lab Operations

Modelithics Welcomes Dr. Ali Boudiaf as Director of Lab Operations - RF CafeModelithics, the leader in providing simulation models for RF, microwave, and mmWave devices is pleased to welcome Dr. Ali Boudiaf to the company as Director of Lab Operations. Dr. Boudiaf comes to Modelithics with 30 years of experience in the RF, microwave, and mmWave engineering arena. In his new role at Modelithics, his responsibilities include managing all aspects of lab operations as well as advancing Modelithics microwave and millimeter-wave test system capabilities. Prior to joining Modelithics, Dr. Boudiaf was the CEO and co-founder of Smart MedTech. He also previously worked at ERZIA Technologies as Director of Amplifier Systems. Dr. Boudiaf's prior experience also includes positions with Maury Microwave, Focus Microwaves, Agilent Technologies, and ATN Microwave...

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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