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Homepage Archive - April 2021 (page 1)

See Page 1 | 2 | 3 | 4 of the April 2021 homepage archives.

Wednesday the 7th

National Union Radio and Electronic Tubes

National Union Radio and Electronic Tubes, October 1944 Radio News - RF CafeBeing the old guy I am, seeing the tag line "No Sweater Girls, Please" in this 1944 National Union Radio and Tubes company advertisement in Radio News magazine reminded me of a comedian's bit about Sweater Girls. The reference could be interpreted as a slight to women of certain physical attributes, but in this case it was a play on a popular theme in Hollywood. The actual message pertained to how contaminant-free National Union kept its vacuum tube assembly areas. Radio News, being by default a men's magazine since in the day most electronics professional and hobbyists were male, and seeing what would today be considered sexist or misogynistic was not uncommon. Take a look at some of the comics that appeared to see what I mean. Most of the jokes were on men though; that kind of humor was also OK back then. Now jokes about men (dare I also specify White men?) are the only socially acceptable...

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.

RF Digitally Tunable Capacitors for Higher 5G Bands

RF Digitally Tunable Capacitors for Higher 5G Bands - RF Cafe"Nanusens, a MEMS-within-CMOS solutions provider, will be shipping evaluation samples of its new product line, RF Digital Tunable Capacitors (DTCs), in Q2 2021. These tunable capacitors solve the problem of current 5G antenna solutions that are becoming increasingly power hungry in the higher 5G bands. The key is the very high Q factor of above 100 at 1 GHz and at higher 5G bands to keep power losses very low. The Q factor of most rival products drop down significantly. Nanusens DTCs thus open up the power efficient use of higher 5G bands. The DTCs are created using the company’s award-winning techniques of creating nanostructure within CMOS using only standard techniques in a CMOS fab so there are no limits on production volumes...."

Whitepaper: Validity of Positive Phase Noise Values

Validity of Positive Phase Noise Values - RF CafeRohde & Schwarz recently published a new whitepaper entitled, "Validity of Positive Phase Noise Values." It was written to address concerns some users had over positive values being present in the single sideband phase noise numbers for offsets less than 0.01 Hz for oscillator frequencies above 1 GHz. Says R&S: "The basis of these questions stems from an obsolete spectrum analyzer based definition of single sideband phase noise L(f), where L(f) was defined as the spectral power density of the noise sidebands in a 1 Hz band at an offset frequency (f) away from the carrier divided by the total signal power. Th[e] old definition of L(f) results in confusion when measuring carrier noise with large angle phase fluctuations and has been corrected by the IEEE using more modern measurement methods..."

Carl & Jerry: Slow Motion for Quick Action

Carl & Jerry: Slow Motion for Quick Action, April 1963 Popular Electronics - RF CafeOur two intrepid techno-sleuths, Carl Anderson and Jerry Bishop, are in college by now, but that does not keep them from applying their well-honed mystery solving skills to hometown situations while on spring break. The boys invoke the scientific method of Mr. R.R. Dibble, a New Zealand scientist, to help prove to county commissioners that a certain part of their critical infrastructure was in need of repair. An nth-generation farmer's observation was not proof enough, so indisputable empirical data would be needed. Real-life inventors and company's unique instruments are often incorporated into the Carl & Jerry series by John T. Frye that ran for many years in Popular Electronics...

New for 2021! 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 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 Thank Lotus Communication Systems for Their Support!

Lotus Communication Systems Modular RF/Microwave Components - RF CafeLotus Communication Systems began in 2009, setting up CNC machine shop and RF/microwave assembling and testing lab in Middlesex Country, Massachusetts. Lotus is committed to highest quality and innovative products. Each RF/microwave module meets exceedingly high standards of quality, performance and excellent value, and are 100% MADE IN USA. Lotus' RF/microwave products cover frequency band up to 67 GHz. Lotus also offers an COTS shield enclosures for RF/microwave prototyping and production. All products are custom designed. We will find a solution and save your time and cost. Lotus has multiple 4 axis CNC machines and LPKF circuit plotters.

Tuesday the 6th

General Electric Sealed-Ignitron Rectifiers 

General Electric Sealed-Ignitron Rectifiers, October 1944 Radio News - RF Cafe"Ignitron" sounds like a contemporary pejorative term for someone who blindly follows orders. In the 1940s, though, it was a type of steel-jacketed vacuum tube manufactured by General Electric for use in conversion from alternating alternating to direct current (AC-DC) power supplies. According to this GE document, "Ignitrons are gas-discharge, pool-type cathode tubes in which the arc is started for each conducting cycle by means of a starting or ignition electrode. The tubes are of the half-wave type in which the current is carried through the tube during only the positive part of the cycle. During the remainder or non-conducting part the residual ionization reaches very low values in comparison with the ionization present in the multi-anode type of pool tube where it is proportional to the load current carried. As a result of the so-called dark, negative half-cycle, the shielding required in half-wave tubes is greatly reduced from that in the multi-anode tube. Reduction in shielding in turn lowers the arc voltages so that tubes of this type may be efficiently applied...

5G Network to Wirelessly Power IoT Devices

5G Network to Wirelessly Power IoT Devices - RF Cafe"Researchers at the Georgia Institute of Technology have uncovered an innovative way to tap into the over-capacity of 5G networks, turning them into 'a wireless power grid' for powering Internet of Things (IoT) devices that today need batteries to operate. The Georgia Tech inventors have developed a flexible Rotman lens-based rectifying antenna (rectenna) system capable, for the first time, of millimete-wave harvesting in the 28-GHz band. (The Rotman lens is key for beamforming networks and is frequently used in radar surveillance systems to see targets in multiple directions without physically moving the antenna system.) But to harvest enough power to supply low-power devices at long ranges, large aperture antennas are required..."

Intel's "Sponsors of Tomorrow" Videos

Intel's "Sponsors of Tomorrow" Videos - RF Cafe Cool VideoAbout a decade ago Intel produced a series of clever "Sponsors of Tomorrow" TV commercials that became YouTube sensations. Most poked fun at the nerdy nature of Intel-type employees. I believe the first one that really went viral was the "Our Rock Stars Aren't Like Your Rock Stars" video - ingenious, IMHO. It stars Ajay Bhatt, co-inventor of the Universal Serial Bus (USB). Another is a scenario only someone who has "been there" searching for a die can fully appreciate. Another of my favorites is "Our Jokes Aren't Like your Jokes." Rather than focusing specifically on new products, the "Sponsors of Tomorrow" ad campaign celebrates what makes Intel unique - culture, personality, heroes, and ways Intel has helped change the world for over 50 years. Kinda cool at the end of each one is a group of Intel employees "singing" the very familiar Bum' --- bum bum bum bum' sound. In pseudo Morse code that might be —  •••—, or... and this might be just an amazing coincidence...

Blog: Make Safer Products with Practical EMC Testing

Make Safer Products with Practical EMC Testing - RF CafeAxiom Test Equipment, an electronic test equipment rental and sales company, as published a new blog post that informs people about the importance of conducting EMC/EMI tests. This is important If you are looking to make measurements that test if an electronic design can operate effectively when near other electronic devices and not cause electromagnetic interference (EMI) to them. In addition, making smaller electronic products possible can be done by achieving electromagnetic compatibility (EMC) within the operating environment. Learn more about the variety of practical test equipment that has been developed to perform the many measurements needed for efficient EMC/EMI testing. EMC/EMI compliance and pre-compliance testing involves four different types of measurements: radiated immunity, radiated emissions, conducted immunity, and conducted emissions. EMC/EMI pre-compliance testing can be performed within a reasonable budget, with a wideband signal...

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.

Monday the 5th

A Radioman of the U.S.A.

A Radioman of the U.S.A., January 1940 Radio News - RF CafeThis is a story of G.I. Joe, the Army radioman. It is actually a form of recruitment pitch looking to lure experienced radio operators and technicians into the military. At a time when America was finally beginning to pull itself out of the worst of The Great Depression, the promises of steady work, worldwide travel, training, a chance to work with modern equipment, three meals a day, a place to sleep and clothes on your back - and a paycheck to boot - was very appealing. The Japanese attack on Pearl Harbor which finally drew us formally into World War II was still nearly a year away. War efforts would ultimately provide hundreds of thousands of jobs for both military and civilian workers. Author 1st Lt. Charles Chapel does a pretty good job of laying out the skills requirements and tasks that go along with the position of an U.S. Signal Corps Radioman, including both wired and wireless systems. The clincher, though, is a promise of a tidy retirement check from Uncle Sam after 30 years of service - more than $100 per month for life...

A For-Real, Officially Bogus Patent Application

A For-Real, Officially Bogus Patent Application - RF CafeAs you might imagine, the staff at the U.S. Patent and Trademark Office (USPTO) has seen some real doozies over the years in the form of applications. An RF Cafe visitor who is a registered patent agent sent a note about his office's reaction of hilarity to United States Patent Application # 20040161257 . The link goes directly to the official document on file with the USPTO, so it is real. Look at number nine (9) on page 16 in the opening "Claims" section: "9. The method of providing user interface displays in an image forming apparatus which is really a bogus claim included amongst real claims, and which should be removed before filing [emphasis added]; wherein the claim is included to determine if the inventor...

Crystal Photocell Circuits

Crystal Photocell Circuits, January 1957 Radio & Television News - RF CafeElectronics hobbyists are always anxious to hear the announcement of a new device that is forecast to revolutionize the tech world. In the late 1950s something as relatively tame as a crystal photocell satisfied that urge. This 1957 article in Radio & Television News magazine is a prime example. Today it takes something like a negative refractive index metamaterial to invoke the same sense of awe and wonder. Those were simpler times, but then again even today's beginners in the world of electronics circuit designing and building have to start somewhere, and these types of circuits are as good as any place...

Nanotransistors Keep Cool at High Voltages

Nanotransistors Keep Cool at High Voltages - RF Cafe"Power converters are the little-known systems that make electricity so magical. They are what allow us to plug in our computers, lamps and televisions and turn them on in a snap. Converters transform the alternating current (AC) that comes out of wall sockets into the exact level of direct current (DC) that our electronics need. But they also tend to lose, on average, up to 20% of their energy in the process. Power converters work by using power transistors - tiny semiconductor components designed to switch on and off and withstand high voltages. Designing novel power transistors to improve the converters' efficiency is the aim of the team of EPFL engineers. With their entirely new transistor design, based on the counterintuitive application of nanoscale structures for high voltage applications, much less heat is lost during the conversion process, making the transistors especially well-suited to high-power applications like electric vehicles and solar panels..."

RF Cascade Workbook 2018

RF Cascade Workbook 2018 Is Available Now! - RF CafeRF Cascade Workbook 2018 is the next phase in the evolution of RF Cafe's long-running series, RF Cascade Workbook. Chances are you have never used a spreadsheet quite like this (click here for screen capture). It is a full-featured RF system cascade parameter and frequency planner that includes filters and mixers for a mere $45. Built in MS Excel, using RF Cascade Workbook 2018 is a cinch and the format is entirely customizable. It is significantly easier and faster than using a multi-thousand dollar simulator when a high level system analysis is all that is needed. An intro video takes you through the main features...

Sunday the 4th

Technology Theme Crossword Puzzle for April 4th

Technology Theme Crossword Puzzle for April 4th, 2021 - RF CafeThis Technology Theme Crossword Puzzle for April 4th has many 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. Enjoy!

Friday the 2nd

Mac's Radio Service Shop: Service Shop Advertising

Mac's Radio Service Shop: Service Shop Advertising, June 1954 Radio & Television News - RF CafeThe opening paragraph of this installment of Mac's Radio Service Shop includes a reference to someone named Dr. Kildare. As the article appeared in a 1954 issue of Radio & Television News magazine, you are excused for likely not being familiar with the good doctor. I remember Dr. Kildare (a fictional character) as a Prime Time TV show that aired in the 1960s, but his legacy goes back to the 1930s in movies and radio. Back to the story line, though. Mac is wearing a newfangled type of headphone that must have looked like a stethoscope, and that triggered Barney's comment. However, as is often the case, the subject quickly changes to advertising techniques where Mac explains his philosophy of honesty being the best policy. Along with such probity must be an effort to convince potential customers that preventative maintenance is a sign of responsible ownership. Just as you would take your car in for a relatively low cost annual checkup to hopefully avoid a major bill later, TVs, radios...

Gallium Oxide: The Supercharged Semiconductor

Gallium Oxide: The Supercharged Semiconductor - RF Cafe"In the May 2002 issue of this magazine, the late Lester F. Eastman and Umesh K. Mishra made the case for what was then a long-shot technology in the world of power semiconductors: gallium nitride (GaN). They presented an optimistic outlook for powerful, rugged radio-frequency amplifiers in the then-nascent broadband wireless networks and in radar, as well as in power-switching applications for the electric grid. They called GaN devices -the toughest transistor yet. Eastman and Mishra were right. GaN's wide bandgap - the energy needed to cause bound electrons to break free and contribute to conduction - and other qualities enabled us to exploit the material's ability to withstand high electric fields, and that led to devices with unprecedented performance..."

Inside the Third Reich's Radio

Inside the Third Reich's Radio - RF CafeIf you are curious about vintage radio equipment, particularly development during the World War II era, then Allison Marsh's article on the IEEE Spectrum website entitled "Inside the Third Reich's Radio" will certainly be interesting reading. It is not a deep dive, but does contain some good references to the propaganda efforts of the Nazis. She begins, "Joseph Goebbels understood the art of persuasion. As propaganda minister for the Nazis, he sought to exploit radio's tremendous potential to broadcast Hitler's messages. But first he needed a way for people to tune in. Radio helped bring the Nazis to power and keep them there. On 18 August 1933, Goebbels opened the 10th International Radio Show, in Berlin, with a speech declaring 'Radio as the Eighth Great Power' - a nod to Napoleon's notion that the press was the seventh great power..."

New for 2021! 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 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!

Keying the Crystal Oscillator

Keying the Crystal Oscillator, May 1941 QST - RF CafeThere is still a lot of vintage ham radio equipment in use both by the original owners and by newcomers who buy the equipment at Hamfests and on eBay. User's manuals are hard to come by, since they often were separated from the original gear a long time ago. Knowing how to operate, repair, and align everything properly is still necessary, especially as the airwaves get ever more crowded and the FCC gets more serious about prosecuting violators. Old editions of QST are the perfect resource for locating such information. This article covers some of the basics of oscillators - tritet types in particular - used for CW keying. The tritet oscillator gets is name from having been designed originally to efficiently generate third and fourth harmonics, per James Lamb's June 1933 QST article "A More Stable Crystal Oscillator of High Harmonic Output." ARRL members can download the article...

Exodus Intros 1-6 GHz, 400 W PA w/Quiet-Cool Technology

Exodus Advanced Communications Intros 1-6 GHz, 400 W PA w/Quiet-Cool Technology - RF CafeExodus Advanced Communications' AMP2030B-LC is a powerhouse in a compact 6U chassis! Covering 1.0-6.0 GHz, produces >400 W minimum, >500 W nominal power, typical P1dB >300 W. Excellent gain flatness with a minimum power gain of 56 dB. Included are amplifier monitoring parameters for Forward/Reflected power, VSWR, as well as voltage, current & temperature sensing for optimum reliability & ruggedness. Nominal weight is 50 kg, and dimensions of 19"W x 25"L x 10.5"H...

Thursday the 1st

Now - A Radio Pen

Now - A Radio Pen, April 1946, Radio-Craft - RF CafeWell-known radio communications futurist, visionary, and inventor Mohammed Ulysses Fips, I.I.R.R.E.E., published an article in the April 1946 issue of Radio-Craft magazine. He described a portable, compact, fully functional two-way radio disguised to look like an ink pen - the "Radio Pen." It measured approximately 3/4" in diameter and about 6" in length. Like early cellphones, the antenna was not a conformal internal job, but need to be extended externally for use. When I first saw the Radio Pen, it reminded me of the ones used by playboy spy Napoleon Solo and nuclear physicist spy Illya Kuryakin in the old television series "The Man from U.N.C.L.E." Whilst on assignment tracking down a THRUSH bad guy or girl, the master spies would covertly remove the cover of their pen communicators, attach it to the bottom of the pen, and initiate contact back at U.N.C.L.E. headquarters using the "Open Channel D" code phrase...

DARPA Developing Tech to Mitigate Interference for Wideband RF Systems

DARPA Announces Researchers Developing Tech to Mitigate Interference for Wideband RF Systems - RF Cafe"The radio frequency (RF) spectrum is a scarce resource that is becoming increasingly congested and contested as demand for spectrum access continues to grow. Within this crowded environment, the Department of Defense's (DoD) RF systems are hampered by mission-compromising interference from both self- and externally-generated signals. Wideband software-defined radio (SDR) systems provide unprecedented access to the RF spectrum and are beginning to proliferate throughout the DoD and commercial applications as a result. Unfortunately, as bandwidth increases, dynamic range tends to decrease, which impacts the radio's sensitivity and performance. To mitigate this challenge and support the continued use of these wideband radios, DARPA developed the Wideband Adaptive RF Protection (WARP) program..."

WWII Cable Production - in Color!

Color Photos of World War II Cable Production - RF CafeIn the last few years, many color photos from the WWII era have been appearing, being a stark contrast to the B&W photos we have been used to seeing. The Smithsonian Institute's Air & Space magazine published this photo of what appears to be an electrical cable production station. Obviously it was a staged public relations shot, but its color content, snaking arrays of cables, and excellent lighting effect could easily win it a prize. At first glance I though it might be steel control cables for the PB2Y flying boats into which they were installed. A close look at the ends of the cables inside the work station assembly area reveals ring lugs on the ends of the cables, as might be found on control lines between cockpit elevator and aileron control yokes (or joy sticks), rudder pedals, wing flaps, trim tabs, etc. However, notice that the cables are being terminated inside a rather small junction box, which suggests...

Overcoming a Spectrum Deficit in a 5G World

Overcoming a Spectrum Deficit in a 5G World - RF CafeMike Eddy has an article posted on the Electronic Design website entitled, "Overcoming a Spectrum Deficit in a 5G World," where he predicts that mobile operators could experience a spectrum deficit of up to 963 MHz. Mr. Eddy begins: "Radio-frequency spectrum is the lifeblood of the wireless industry. However, a deficit in the amount of spectrum available for growing mobile data services appears imminent. In mid-January 2021, a big step was taken for 5G networks in the U.S. as mobile network operators (MNOs) spent over $80 billion to acquire the spectrum upon which their network services will be built. But according to a model of spectral demand created by Resonant, an updated version of a model developed by the FCC increasing demand for data services threatens to result in a situation where data demand will overwhelm the available spectrum starting..."

Spreading the Stations with CSSB

Spreading the Stations with CSSB, November 1957 Popular Electronics - RF CafeIt's hard to believe that even by the end of 1957, single-sideband broadcasting was still in its infancy. The claim that, "CSSB's most remarkable feature is that although it uses but one sideband, a broadcast will still sound the same to even the simplest home radio," is still a matter of dispute amongst radio aficionados. Just as many audiophiles swear that even the most sophisticated solid-state driver is not as good as a vintage vacuum tube circuit, there are those who say that single-sideband reception is clearly distinguishable from standard double-sideband. Doubt me? Here I quote from page 2-7 of the "ARRL General Class License Manual for Ham Radio, "SSB transmitters tend to optimize the signal characteristics for strength at the expanse of some fidelity. AM transmitters, on the other hand, tend to give a 'warmer' sound to the speaker's voice..."

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