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Windfreak Technologies Frequency Synthesizers - RF Cafe

Homepage Archive - August 2020 (page 4)

See Page 1 | 2 | 3 | 4 | 5 | of the August 2020 homepage archives.

Monday 31

Mac's Service Shop: Tape Recorder Tips

Mac's Service Shop: Tape Recorder Tips, July 1958 Radio & TV News - RF CafeBarney, Mac McGregor's trusted technician sidekick, would be in a heap of trouble in today's workplace. His complimentary and sincere remarks to office secretary Matilda are considered as harassment and even misogynistic by current standards. The unintended consequences - or maybe they are intended - has been to cause tense and guarded environments where traditional interpersonal behaviors and attitudes are avoided rather than risk offending someone and paying a steep price for it. Mentioned in this "Tape Recorder Tips" from a 1958 issue of Radio & TV News magazine is the chemical compound carbon tetrachloride, aka carbon tet. At one time is was commonly used as a cleaning agent because of its ability to efficiently clean oily and fatty residues. Tape recorder heads, rubber drive wheels, and metal guide posts get gunked up fairly quickly...

Please Visit NorthEast RF's Website in Appreciation of Their Support

NorthEast RF - RF CafeNorthEast RF's comprehensive antenna testing services include linear | circular polarized antenna measurements and OTA cellular device pre-compliance. Up to 18" diameter and <10 kg weight. Antennas can be rapidly evaluated and optimized using our fast near field spherical system. Test results supplied in data file with pattern viewer software. A picture of the test configuration is included to help aligned axis. Our selection of human head and hand phantoms are ideal for verification of body worn devices. Turnaround time is usually 3-days.

Editorial Comment: Grounding & Line Fluxuations

Editorial Comment: Grounding & Line Fluxuations, March 9th The Wireless World Article - RF CafeAs radio equipment builders and operators, we still battle two fundamental issues that have been around since the beginning of time (well, from Marconi's time, anyway) - grounding and power supply fluxuations. Both topics are addressed briefly here in this editorial column from a 1932 The Wireless World magazine. Back in the day, grounding was referred to as "earthing," and was/is essential to optimal wireless and wired performance. Line voltage fluxuations are generally much less severe today than in the 1930s thanks to better transformers, automated monitoring and adjusting of line voltages, and better distribution designs. The worst type of power line fluxuation - a lightning-induced surge - has been greatly reduced thanks to superior engineering, primarily by the simple running of a grounded neutral "static" wire running at the top of all the lines below it on utility poles and transmission towers...

Patterns and Polarizations of Modestly-Sized Loop Antennas

Patterns and Polarizations of Modestly-Sized Loop Antennas - RF Cafe Darrel Emerson, AA7FV, G3SYS, has an article in the ARRL's QEX magazine entitled, "Patterns and Polarizations of Modestly-Sized Loop Antennas," which might be of interest to you. Inexpensive antenna field pattern software like EZNEC make experimentation very practical. "Patterns and polarizations of square loops up to about 0.4 wavelengths in perimeter are examined." "In 'Small Gap-resonated HF Loop Antenna Fed by a Secondary Loop1,' K. Siwiak, KE4PT, and R. Quick, W4RQ, provide improved formulas for loop current and impedance, leading to an accurate determination of far-fields and null depths for loops up to 0.3 λ (wavelengths) in circumference. See also, KE4PT and W4RQ, 'Small Gap-Resonated HF Loop Antennas.' In 'Effect of Small HF Loop Near Fields on Direction Finding,' KE4PT shows how the near-field response of a small loop can provide polarization at right angles to the normal far field..."

FCC Wants to Charge $50 License Fee for Amateur Radio

FCC Wants to Charge $50 License Fee for Amateur Radio - RF CafeThere $1.7B Iran Cash - RF Cafethey go again. The same Federal Government that delivers billions of dollars in cash in the middle of the night to terrorist nations and hands out grants to every whacko special interest group now wants to charge Amateur Radio Operators a $50 licensing fee. What an excellent way to discourage participation in an educational and public service technical sport whose members volunteer incredible amounts of talent and equipment at no cost to taxpayers. "The $50 fee would apply to all Amateur Service applications, including those for vanity call signs. 'Although there is currently no fee for vanity call signs in the Amateur Radio Service, we find that such applications impose similar costs in aggregate on Commission resources as new applications and therefore propose a $50 fee,' the FCC said."  It's time to write to your Senators and Congressmen. BTW, the FAA has already implemented a similar licensing fee scheme to model airplane sportsmen.

Many Thanks to ConductRF for Continued Support!

ConductRF coaxial cables & connectors - RF CafeConductRF is continually innovating and developing new and improved solutions for RF Interconnect needs. See the latest TESTeCON RF Test Cables for labs. ConductRF makes production and test coax cable assemblies for amplitude and phased matched VNA applications as well as standard & precision RF connectors. Over 1,000 solutions for low PIM in-building to choose from in the iBwave component library. They also provide custom coax solutions for applications where some standard just won't do. A partnership with Newark assures fast, reliable access. Please visit ConductRF today to see how they can help your project! 

Sunday 30

Radio & Radar Crossword Puzzle for August 30th

Radio & Radar Crossword Puzzle for August 30th, 2020 - RF CafeAugust 30th's custom Radio & Radar themed crossword puzzle contains only only words from my custom-created lexicon related to engineering, science, mathematics, chemistry, physics, astronomy, etc (1,000s of them). You will never find among the words names of politicians, mountain ranges, exotic foods or plants, movie stars, or anything of the sort. You might, however, find someone or something in the otherwise excluded list directly related to this puzzle's technology theme, such as Hedy Lamarr or the Bikini Atoll, respectively. The technically inclined cruciverbalists amongst us will appreciate the effort.

Friday 28

Polarity Quiz

Polarity Quiz, March 1968 Popular Electronics - RF CafeHere's one last thing to do before you leave work for the weekend. This "Polarity Quiz" by Robert Balin appeared in a 1968 issue of Popular Electronics. If you know your left- and right-hand rules for magnetism and induction, then a 100% score is practically guaranteed... provided you also are a whiz at diode and meter connections. Since the author did not do so, I provided brief explanations for the answers at the bottom of the page. When applying the hand-rules, assume conventional current (flow from more positive to more negative), not electron current.

Project Kuiper More Than Amazon's Response to SpaceX

Project Kuiper More Than Amazon's Response to SpaceX - RF Cafe"Amazon cleared an important hurdle when the U.S. FCC announced on 30 July that the company was authorized to deploy and operate its Kuiper satellite constellation.. The authorization came with the caveat that Amazon would still have to demonstrate that Kuiper would not interfere with previously authorized satellite projects, such as SpaceX's Starlink. Even with the FCC's caveat, it's tempting to imagine that the idea of putting a mega-constellation of thousands of satellites in low-Earth orbit to provide uninterrupted broadband access anywhere on Earth will become a battle between Jeff Bezos' Kuiper and Elon Musk's Starlink. After all, even in space, how much room can there be for two mega-constellations..."

Heathkit SS-9000 Deluxe Synthesized HF Transceiver

Heathkit SS-9000 Deluxe Synthesized HF Transceiver - RF CafePrior to the availability of affordable synthesized transceivers under microprocessor control, Ham radio operators needed to tune a continuously variable local oscillator (internal or external) or have a selection of crystals for specific frequencies. Even by 1982 microprocessors were relatively expensive, so equipment incorporating them was also pricey. Heathkit's model SS−9000 transceiver claimed to be designed by amateurs for amateurs, and was "so feature-conscious, it has no options." That's right, anything and everything that could be imagined was included in the base model; there we no upgrades. It used a high accuracy and stability internal 10 MHz reference oscillator for the PLL synthesizer. Also incorporated was an RS−232 serial port for control via computer (up to 9600 baud!), such as the Heathkit/Zenith personal computer (the IBM PC had hit the market in the prior year, and the the Radio Shack TRS−80 and Apple II had been around since 1977). The SS−9000 was solid state throughout (likely where the "SS" prefix originated)...

Receiver Step Attenuator

Receiver Step Attenuator - RF Cafe Scott Roleson, KC7CJ, had an article printed in the July-August issue of QEX magazine entitled, "Receiver Step Attenuator." It is the one free to the public article posted each month. QEX tends to have more construction features and be a bit more theoretical than QST. He begins, "This step attenuator is an easy way to improve a receiver's handling of strong signals and to add signal diagnostic capability. Having been bitten by the software defined receiver (SDR) bug and experimenting with simple SDR 'dongles' and an HF converter, it didn't take long for me to start thinking of ways to improve this simple receiver. It was readily apparent that an HF receiver like this was wide open to strong signal overload from commercial broadcast signals and even from the ham across town. One way to deal with strong signal overload is to add a broadband attenuator between the receiver and the antenna..."

Skyworks High Linearity PIN Limiter Module

Skyworks High Linearity PIN Limiter Module - RF CafeSkyworks is pleased to introduce a high linearity, low-threshold, dual PIN limiter diode module that addresses the growing need for receiver protection in cellular infrastructure (including 5G) and microwave radio communications. The SKY16603-632LF is a fully integrated module comprised of two PIN limiter diodes and two DC blocking caps designed for use as a passive receiver protector in wireless systems up to 6 GHz. Targeted for cellular infrastructure base station, repeater, and wireless backhaul OEMs, it can also be used in broad market wireless systems including VSAT, S-band radar, military communications transceivers... Be sure to also see their PIN Limiter Diode Design Guide.

Thanks to Copper Mountain Technologies for Continued Support

Copper Mountain TechnologiesCopper Mountain Technologies develops innovative and robust RF test and measurement solutions for engineers all over the world. Copper Mountain's extensive line of unique form factor Vector Network Analyzers include an RF measurement module and a software application which runs on any Windows PC, laptop or tablet, connecting to the measurement hardware via USB interface. The result is a lower cost, faster, more effective test process that fits into the modern workspace in lab, production, field and secure testing environments.

Thursday 27

"Wireless" for Americans

"Wireless" for Americans, December 1955 Radio & Television News - RF CafeAuthor Lawrence Sharpe pointed in 1955 in this Radio & Television News article the potential for confusion when reading columns and advertisements written by our brothers from Across the Pond when they appeared in American electronics magazines. Most of us are familiar with valve vs vacuum tube, bonnet vs. hood (car), football vs. soccer, fag vs. cigarette, holiday vs. vacation, nappy vs. diaper, petrol vs. gasoline, torch vs. flashlight, flat vs. apartment. There are many more, but those come to mind. Read through this short list of purely electronics terms and learn that "earthed" is the same as our "grounded." One thing that surprised me was how the Brits had already adopted pico (e.g. pF) for the numerical unit of 10−12 while we were still using micromicro (10−6 x 10−6 = 10−12, e.g., μμF). Note how I omitted a comma...

U.S. Army Sets Satellite Constellation Timeline

U.S. Army Sets Satellite Constellation Timeline - RF Cafe"The U.S. Army's tactical network program office expects to reap the full benefits of low-and medium-Earth orbit satellite constellations in the 2025-2027 time frame, the head of the office said August 18. Speaking on a webinar hosted by the Defense Advanced Research Projects Agency, Brig. Gen. Rob Collins, program executive officer at Program Executive Office Command, Control, Communications-Tactical, said the two constellations types offer 'game-changing technologies' that will likely be fully mature and ready for soldier use in Capability Set '25 or '27, the two-year cycle of new network tools the service is fielding. One of the connectivity benefits of the LEO and MEO constellations in the field, Collins said, is that they can allow for..."

Anatech Electronics August Product Update

Anatech Electronics August Product Update - RF CafeAnatech 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. The AE15550B10783 5G cavity bandpass filter has a passband range from 15350-15750 MHz, with an insertion loss of less than 1 dB in the passband. It can handle up to 150 W of power with a rejection of more than 50 dB at 11000 MHz and more than 40 dB at 20000 MHz. The AD6981-9800C131 combines the 6875-7087 MHz and 9600-10000 MHz bands. The bandpass filter exhibits a small package and a steep rejection above and below the passband. Insertion loss in the passband is less than 3 dB and more than 40 dB at the rejection frequencies. Custom RF power directional coupler designs can be designed and produced...

Absolute EMC Testing Services & Products

Absolute EMC Testing Services & Products - RF CafeJason Smith, engineer and owner of Absolute EMC, requested that his company be listed on the Technical Services page here on RF Cafe, which I was glad to do. Along with an extensive array of EMC industry products, there is an online calculator page that includes one for TEM/GTEM Cell fields and another for Antennas. "Absolute EMC is a North American company specializing in EMC testing knowledge and equipment. We offer consulting services for the use of all EMC & RF test equipment. This includes standards training, equipment training, and system building. With extensive background knowledge with all brands and available technologies. Also offering insight and market knowledge into equipment sales."

The Story of the Broadband Dipole

The Story of the Broadband Dipole - RF CafeThe ARRL's QEX monthly magazine usually makes one full article available online to all visitors, as opposed to the full edition only being available to subscribers. This is a good policy since it protects the investment of paying customers while providing a useful sample of content to the public. The December 2018 issue featured a piece by Dave Leeson, W6NL, entitled, "The Story of the Broadband Dipole." It begins: "A dipole can be broadbanded by a number of techniques including by matching with resonant sections of transmission feed lines. The 80-meter amateur band covers a very large fractional bandwidth. I was looking for a way to avoid retuning my 80-meter inverted V on a 140-foot guyed tower, since the ends are out of reach even if they are folded straight down. I found that lumped element matching networks or the often referenced Bazooka dipole and other forms of thicker conductors were neither practical nor effective for me at the lower HF bands.1 In a November 1997 posting on the Tower Talk..."

After Class: Explaining Tuned Circuits

After Class: Explaining Tuned Circuits, May 1961 Popular Electronics - RF CafeFundamentals of resonant tank circuits has not changed since they were first investigated more than a century ago. This "After Class" tutorial that ran in the May 1961 edition of Popular Electronics is typical of the series where the author speaks as though he was giving an impromptu lesson to a gathering of students after the scheduled classroom period was over or, in this instance as though he was having a casual discussion with a friend who was perplexed by a particular electronics phenomenon. Figures and equations are often drawn by hand to augment the informal setting rather than being typeset. Here, "Larry" is amazed by the great performance of his Ham radio with its ability to filter out adjacent channel interference. Mentor "Ken" takes the opportunity to explain the mathematics and physics of resonant circuits both to tuning antennas...

Many Thanks to Atenlab for Their Continued Support!

Atenlab microwave components - RF CafeAtenlab has been operating in Taiwan for more than a decade, and has sold and installed hundreds chambers around the world. Holistic, affordable Over-the-Air (OTA) measurement systems perform comprehensive measurement and test in a controlled environment. Compact Antenna Test Range (CATR) with one-touch operation supports multiple systems - 2G, 3G, 4G, 5G - and major instrument brands. [M]ulti-probe OTA measurement systems offer reduced time measurements over single-probe systems.

Wednesday 26

Three Anecdotes of the Audion's Early Days

Three Anecdotes of the Audion's Early Days, January 1947 Radio-Craft - RF CafeWhat better subject is there to post on the birthday of Dr. Lee de Forest than an article entitled, "Three Anecdotes of the Audion's Early Days," which appeared in the January 1947 issue of Radio-Craft magazine whose theme was the 40th anniversary of the Audio's invention? That was a rhetorical question, of course, sort-of, because any of the multiple Audion article from that issue would be a great subject. Find out from the man who coined the term how the vacuum tube's grid was named. Did you know that thanks to lawsuits and unscrupulous actions by competitors, that de Forest went through multiple cycles of plenty and near poverty? In a related note, as chronicled in "Lee de Forest and the Navy," faced powerful skeptics when attempting to facilitate adoption of wireless communications aboard U.S. Navy ships - not unlike the Wright Brothers' struggles with convincing the U.S. Army of their aeroplane's usefulness in armed conflict...

Guerrilla RF GRF5507 ¼W Power Amplifier w/Ultimate in Native Linearity

Guerrilla RF GRF5507 ¼W Power Amplifier Delivers the Ultimate in Native Linearity - RF CafeGuerrilla RF introduces the GRF5507, one of ten new ¼ W linear power amplifiers being released over the next two quarters as part of the company's expansion into the cellular market. These new InGaP HBT amplifiers were designed specifically for 5G/4G wireless infrastructure applications requiring exceptional native linearity over temperature extremes of -40°C to 85°C. Spanning a frequency range of 700-800 MHz, the GRF5507 variant is tuned to operate within the n12, n14, n28 and n29 5G new radio (NR) bands. The device can deliver over 24 dBm of linear power over the entire -40°C to 85°C temperature range...

Room-Temperature Magnon Switch

Room-Temperature Magnon Switch - RF CafeIf this device used chromium oxide, would that make it a "Cro-Magnon" switch? "Researchers have demonstrated a potentially new way to make switches inside a computer's processing chips, enabling them to use less energy and radiate less heat. The practical technique controls magnons, which are essentially waves that travel through magnetic materials and can carry information. To use magnons for information processing requires a switching mechanism that can control the transmission of a magnon signal through the device. While other work created techniques that carry and control magnons, the new approach brings two important firsts: Its elements can be built on silicon rather than exotic and expensive substrates..."

Thanks to PCB Directory for Continued Support!

PCB  Directory - RF CafePCB 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.

Lingo of the Schematic

Lingo of the Schematic, August 1955 Popular Electronics - RF CafeHere is a very basic introduction to schematic reading from the August 1955 edition of Popular Electronics.. To someone who has been exposed to schematics and mechanical drawings for five decades, reading them is second nature. However, to the newcomer to electronics, it can be a bit cryptic. It is the equivalent of handing someone who has never read sheet music from Beethoven's 5th and asking him to make sense of it. Of course there is a lot more to schematics than presented here, but you have to begin somewhere...

Declassified Footage Of Biggest Nuke Ever Tested

Nuclear Bomb Size Comparison - RF CafeRussia recently declassified and released to the public information and a video of testing of what was (and still is) the largest nuclear bomb ever detonated - Tsar Bomba (aka "Ivan"). The graph  shows the comparative sizes of Tsar Bomba "Ivan" video - RF Cafenuclear bombs detonated by the USA and Russia during testing. That little circled area in the lower left represents the Hiroshima and Trinity bombs. On the right is the massive Tsar Bomba hydrogen bomb. At 50 megatons, it was 3300x the power of the 15 kiloton Hiroshima (Little Boy) explosion on the left. Ivan's length of 26' and 7' diameter dwarfed Little Boy's 10' length and 28" diameter. Ivan created a mushroom 7x the height of Mount Everest. Tsar Bomba represents 1961 technology. Nowadays, explosions are done by supercomputer simulations. Imagine what 2020 science can produce - scary.

Please Visit Triad RF Systems to Thank Them for Their Support

Triad RF SystemsTriad RF Systems designs and manufactures RF power amplifiers and systems. Triad RF Systems comprises three partners (hence 'Triad') with over 40 years of accumulated knowledge of what is required to design, manufacture, market, sell and service RF/Microwave amplifiers and amplifier systems. PA, LNA, bi-directional, and frequency translating amplifiers are available, in formats including tower mount, benchtop, rack mount, and chassis mount. "We view Triad more as a technology partner than a vendor for our line-of-sight communications product line." Please check to see how they can help your project.

Tuesday 25

Tin Whiskers, Bell Telephone Laboratories

Tin Whiskers, Bell Telephone Laboratories, December 1955 Radio & Television News - RF CafeThe famous words of Jorge Agustín Nicolás Ruiz de Santayana y Borrás (aka George Santayana) immediately came to mind when I saw this Bell Telephone Laboratories advertisement in a 1955 issue of Radio & Television News magazine: "Those who cannot remember the past are condemned to repeat it." Anyone involved in the electronics field at the beginning of the lead-free (Pb-Free) craze in the early 2000's probably remembers the purportedly unexpected phenomenon of tin whiskers growing out of lead-free solder joints and wreaking havoc with the short circuits caused when whiskers between adjacent elements made contact. The problem appeared with closely spaced connector pins, fine pitch integrated circuit packages, high density surface mount circuit board layouts, etc. Military and aerospace engineers and scientists had fits initially trying to figure out what was going on...

Linear-Array Beam Characteristics and Array Factor

Linear-Array Beam Characteristics and Array Factor - RF CafePart 3 of a 6-part series of articles on phased arrays by Peter Delos, Jon Kraft, Bob Broughton is about Linear-Array Beam Characteristics and Array Factor, and is available on the Microwaves & RF website. "In Part 1, we covered beam direction and working with a uniformly spaced linear array of antennas. Part 2 focused on antenna gain, directivity, and aperture, as well as array factors. In Part 3, we'll dive into beamwidth, combining element and array factors, and antenna plots. Beamwidth Beamwidth provides a metric of angular resolution for antennas. Most commonly, beamwidth is defined by either the half-power beamwidth (HPBW) or the null-to-null spacing of the main lobe (FNBW). To find the HPBW, we move 3 dB down from the peak and measure the angular distance..."

Black Silicon Photodetector Breaks 100% Efficiency Limit

 Black Silicon Photodetector Breaks 100% Efficiency Limit - RF Cafe"Aalto University researchers have developed a black silicon photodetector that has reached above 130% efficiency. Thus, for the first time, a photovoltaic device has exceeded the 100% limit, which has earlier been considered as the theoretical maximum for external quantum efficiency. 'When we saw the results, we could hardly believe our eyes. Straight away we wanted to verify the results by independent measurements,' says Professor Hele Savin, head of the Electron Physics research group at Aalto University. The independent measurements were carried out by the German National Metrology Institute, Physikalisch-Technische Bundesanstalt (PTB), which is known to provide the most accurate and reliable measurement services in Europe. Head of the PTB Laboratory of Detector Radiometry, Dr. Lutz Werner comments, 'After seeing the results, I instantly realized that this is a significant breakthrough..."

Sylvania News Radio Service Edition

Sylvania News Radio Service Edition, September 1945, Radio-Craft - RF CafeOnce mobile and other high-vibration and impact operational environments became the norm for communications, it became necessary to design hardware so that electronic components would not work themselves loose and cause intermittent or total failure. With vacuum tubes, placing locking shields over them did the job, but that caused other issues such as increased cost, poor cooling, and increased chassis size and weight. Some circuits with high power and/or frequency benefited from shields, but most did not need them. Sylvania introduced a scheme called "Lock-In" (trademark name of "Loktal")where the center pin incorporated a circumferential groove that latched into a capturing mechanism...

NIST's Key Role in 5G Development

NIST's Key Role in 5G Development - RF CafeEditor emeritus of Microwaves & RF magazine Barry Manz has an interesting article on the Microwave Product Digest (MPD) website entitled, "NIST's Key Role in 5G Development." NIST is the new name (as of 1988) for the National Bureau of Standards, which was first instituted in 1901. He begins, "The National Institute of Science and Technology (NIST) may be the most underappreciated player in the development and advancement of systems that rely on electromagnetic energy. Its role today is arguably as important as at any time in its 119-year history, as the wireless industry moves into uncharted territory. For example, researchers at NIST recently used state-of-the-art atomic clocks, light detectors, and a measurement tool called a frequency comb to increase the stability of microwave signals by 100 times. This should enable much more accurate dissemination of time, improved navigation, more reliable communications, and higher-resolution imaging for radar and astronomy. The approach transfers the stability of a laboratory ytterbium lattice atomic clock operating..."

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. 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...

Thanks Once Again to everythingRF for Long-Time Support!

everything RF Searchable Database - RF CafePlease take a few moments to visit the everythingRF website to see how they can assist you with your project. everythingRF is a product discovery platform for RF and microwave products and services. They currently have 267,269 products from more than 1397 companies across 314 categories in their database and enable engineers to search for them using their customized parametric search tool. Amplifiers, test equipment, power couplers and dividers, coaxial connectors, waveguide, antennas, filters, mixers, power supplies, and everything else. Please visit everythingRF today to see how they can help you.

Monday 24

An Early Radiophone

An Early Radiophone, January 1947 Radio-Craft - RF CafeThe January 1947 issue of Radio-Craft magazine was dedicated to editor Hugo Gernsback to articles celebrating the 40th anniversary of his personal friend Lee de Forest's invention of the Audion amplifying vacuum tube. Click on the Table of Contents link to access many of the other articles - all of which are very insightful into the many amazing activities of Mr. de Forest. Many of the articles were written by friends and business associates of him. The "radiophone" addresses here is actually one of the earliest mobile phone, being interconnected by radio signals rather than a twisted pair of wires. Take note of the "flame audion" mention, which believe it or not describes de Forest's earliest experiments which used a pair of salted platinum plates embedded in an actual flame. Yes, that actually constituted an amplifying element...

Electronic Components Take up 10x Less Space on Computer Chips

Electronic Components Take up 10x Less Space on Computer Chips - RF Cafe"Electronic filters are essential to the inner workings of our phones and other wireless devices. They eliminate or enhance specific input signals to achieve the desired output signals. They are essential, but take up space on the chips that researchers are on a constant quest to make smaller. A new study demonstrates the successful integration of the individual elements that make up electronic filters onto a single component, significantly reducing the amount of space taken up by the device. Researchers at the University of Illinois, Urbana-Champaign have ditched the conventional 2-D on-chip lumped or distributed filter network design - composed of separate inductors and capacitors - for a single, space-saving 3-D rolled membrane that contains both independently designed elements. The results of the study, led by electrical and computer engineering professor Xiuling Li..."

2020 Top 50 Electronics Distributors

2020 Top 50 Electronics Distributors - RF CafeSource Today has published the 2020 Top 50 Electronics Distributors list. This linked PDF file gives a rundown on a few of the companies, with a complete tally on the last page. Ranking is evidently according to total revenue. Arrow Electronics takes top prize with nearly $29B in sales, and Avnet comes in second at $18B - that's a huge gap. Digi-Key takes 5th place with $2.8B, and Mouser takes #7 at $1.9B. Richardson Electronics gets 21st place with $167M, and March Electronics hits 41st at $30M. Bringing up the rear is Marine Air Supply at a paltry $18M. So goes the 2020 rankings.

Thanks to LadyBug Technologies for Their Continued Support!

LadyBug Technologies RF Power Sensors - RF CafeLadyBug Technologies was founded in 2004 by two microwave engineers with a passion for quality microwave test instrumentation. Our employees offer many years experience in the design and manufacture of the worlds best vector network analyzers, spectrum analyzers, power meters and associated components. The management team has additional experience in optical power testing, military radar and a variety of programming environments including LabVIEW, VEE and other languages often used in programmatic systems. Extensive experience in a broad spectrum of demanding measurement applications. You can be assured that our Power Sensors are designed, built, tested and calibrated without compromise.

Kill Those Harmonics

Kill Those Harmonics, October 1960 Popular Electronics - RF CafeHere is a short tutorial on how to construct a ¼−wave stub "trap," or filter to attenuate even-order harmonics from transmission lines. It applies whether the transmission line is feeding an antenna or is a section of copper foil running on a microwave substrate. Author Kent Mitchell (W3WTO) discusses both an open stub and a shorted stub. In case you are not familiar with how quarter−wave transmission lines stub work, a short at the far end appears as an open circuit where the stub connects to the main transmission line, and an open stub line appears as a short circuit. That is because there is a 180° phase shift at the end of the shorted stub and a 0° phase shift at the end of the open stub. Therefore, there is a total of 360° (i.e., 90°+180°+90°=360°, equivalent to 0°) with the shorted ¼−wave stub so it has no effect where it attaches to the main transmission line. The open stub experiences no phase shift...

Very-High-Frequency Connectors in Defense Systems

Very-High-Frequency Connectors in Defense Systems - RF CafePeter McNeil has an article on the High Frequency Electronics website entitled, "Considerations for Very-High-Frequency Connectors in Defense Systems." He begins, "Of the hundreds of different environments in which microwave coaxial cables and connectors are used, defense systems are probably the most demanding. They're handled by people who don't realize they're not just 'wires,' but technically sophisticated, precision components. After all, they're warfighters, not microwave engineers. So, they're run over by heavy vehicles, used as a handy way to pull equipment carts, and exposed to chemicals, fuels, saltwater, and many other hazards. Aging and various environmental factors are major contributors to the failure of cables and connectors, but it is arguable that most of the damage is done by the people who use them. That's why, according to one assessment, about 75% of microwave cable assemblies are replaced frequently..."

Many Thanks to KR Electronics for Helping Deliver RF Cafe!

KR ElectronicsKR Electronics designs and manufactures high quality filters for both the commercial and military markets. KR Electronics' line of filters includes lowpass, highpass, bandpass, bandstop and individually synthesized filters for special applications - both commercial and military. State of the art computer synthesis, analysis and test methods are used to meet the most challenging specifications. All common connector types and package form factors are available. Please visit their website today to see how they might be of assistance. Products are designed and manufactured in the USA.

Sunday 23

Science & Engineering Crossword Puzzle for August 23rd

Science & Engineering Crossword Puzzle for August 23rd, 2020 - RF CafeAugust 23rd's custom Science & Engineering themed crossword puzzle contains only only words (1,000s of them) from my custom-created lexicon related to engineering, science, mathematics, chemistry, physics, astronomy, etc. You will never find among the words names of politicians, mountain ranges, exotic foods or plants, movie stars, or anything of the sort. You might, however, find someone or something in the otherwise excluded list directly related to this puzzle's technology theme, such as Hedy Lamarr or the Bikini Atoll, respectively. The technically inclined cruciverbalists amongst us will appreciate the effort.


These archive pages are provided in order to make it easier for you to find items that you remember seeing on the RF Cafe homepage. Of course probably the easiest way to find anything on the website is to use the "Search RF Cafe" box at the top of every page. About RF Cafe.

Homepage Archive Pages

2023:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec

2022:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec

2021:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec

2020:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec

2019:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec

2018:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec

2017:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec

2016:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec

2015:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec

2014:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec

2013:  Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec

2012:  1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 (no archives before 2012)

everythingRF RF & Microwave Parts Database (h1) - RF Cafe
Windfreak Technologies Frequency Synthesizers - RF Cafe
RF Cascade Workbook 2018 by RF Cafe
Anritsu Test Equipment - RF Cafe
Innovative Power Products Passive RF Products - RF Cafe

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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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