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Homepage Archive - September 2020 (page 4)

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

Wednesday 30

Applications of Small High-Voltage Selenium Rectifiers

Applications of Small High-Voltage Selenium Rectifiers, October 1956 Radio & Television News - RF CafeSelenium rectifiers were the first widely used as other-than-vacuum-tube circuit elements for various power supply designs. They were not very practical as detectors in receiver circuits unless signal levels were high. Properly manufactured selenium rectifiers were much more rugged and reliable than the tube equivalents, but generally were more expensive. Since the power supply is such a critical part of any electronic assembly, the tradeoff could be justified if only for the boost in a product's reputation for having fewer breakdown issues. While it is true that there are not many applications anymore for selenium rectifiers, vintage materials and methods sometime experience a reincarnation in some other form using modern formulations and manufacturing techniques. Having knowledge of previous work can help spawn ideas for research and development toward solving new problems...

Design Principles for Spin-Based Quantum Materials

Design Principles for Spin-Based Quantum Materials - RF Cafe"As our lives become increasingly intertwined with technology - whether supporting communication while working remotely or streaming our favorite show - so too does our reliance on the data these devices create. Data centers supporting these technology ecosystems produce a significant carbon footprint - and consume 200 terawatt hours of energy each year, greater than the annual energy consumption of Iran. To balance ecological concerns yet meet growing demand, advances in microelectronic processors must be efficient and environmentally friendly. Northwestern University materials scientists have developed new design principles that could help spur development of future quantum materials used to advance (IoT) devices and other resource-intensive technologies while limiting ecological damage..."

Skyworks SKY66430-11 Front End Module for 5G IoT

Skyworks SKY66430-11 Front End Module for 5G IoT - RF CafeThrough our flagship SKY66430-11, Skyworks is powering new devices in the rapidly emerging 5G Massive Internet of Things (IoT) market. SKY66430-11 is the world's smallest, fully pre-certified all-in-one system-in-package (SiP) incorporating cellular modem, transceiver, RF front-end, memory and power management functionality, enabling LTE-M and NB-IoT connected devices. This turnkey solution integrates Sequans' Monarch SoC platform to support a wide range of low power, low data rate consumer and industrial IoT applications including asset tracking, industrial monitoring, smart metering, wearables and more. Receive low-pass filters are integrated into the SiP along with the necessary matching to yield a 50 ohm single-ended impedance for the antenna. The filters provide a high level of rejection to out-of-band interferers, protecting the transceiver from high blocking signal levels...

Mantola Models 92505, 92506 Radio Service Data Sheet

Mantola Models 92505, 92506, July 1948 Radio News - RF CafeAccording to the Radio Museum website, B.F. Goodrich, of Akron, Ohio, manufactured the Mantola line of radio receivers. It was evidently a low quality, low price, short-lived run of models. The simplicity of the schematic shows the low parts count. A lack of multipole filter circuits likely means selectivity was fairly marginal. One good feature is that unlike many earlier radios and TVs, the AC line connection is DC-isolated through a 150 kΩ resistor (R13). Look at the schematics of older sets and it is not uncommon to see one line of the AC supply tied directly to the metal electronics chassis. An isolation transformer right at the input is the safest way to do it.

Get Your Custom-Designed RF Cafe Gear!

Custom-Designed RF-Themed Cups, T-Shirts, Mouse Pads, Clocks (Cafe Press) - RF CafeThis assortment of custom-designed themes by RF Cafe includes T-Shirts, Mouse Pads, Clocks, Tote Bags, Coffee Mugs and Steins, Purses, Sweatshirts, and Baseball Caps. Choose from amazingly clever "We Are the World's Matchmakers" Smith chart design or the "Engineer's Troubleshooting Flow Chart." My "Matchmaker's" design has been ripped off by other people and used on their products, so please be sure to purchase only official RF Cafe gear. My markup is only a paltry 50¢ per item - Cafe Press gets the rest of your purchase price. These would make excellent gifts for husbands, wives, kids, significant others, and for handing out at company events or as rewards for excellent service. It's a great way to help support RF Cafe. Thanks...

Tech-Related Comics from The Saturday Evening Post

Tech-Related Comics from The Saturday Evening Post - RF CafeA few years back, I bought the issues of The Saturday Evening Post which contained the very first published comics from Peanuts creator Charles Schulz. As with just about everything else, they were available on eBay for a few bucks apiece (although prices have really gone up since the beginning of the year). Most of the issues also had articles and advertisements - and even comics - that make appropriate fodder for both RF Cafe and my hobby website, Airplanes and Rockets. Here are a few of the tech-related comics I found. The first one might seem to be a bit distasteful to the survivors of the RMS Titanic disaster and/or their relatives, given that only 36 years had passed. The next one is about architectural engineer - ahem, and the Hazel comic applies for obvious reasons...

Thanks Again for Windfreak Technologies' Continued Support!

Windfreak TechnologiesWindfreak Technologies designs, manufactures, tests and sells high value USB powered and controlled radio frequency products such as RF signal generators, RF synthesizers, RF power detectors, mixers, up / downconverters. Since the conception of WFT, we have introduced products that have been purchased by a wide range of customers, from hobbyists to education facilities to government agencies. Worldwide customers include Europe, Australia, and Asia. Please contact Windfreak today to learn how they might help you with your current project.

Tuesday 29

The Man Who Made Gasoline from Water

The Man Who Made Gasoline from Water, 1976 OFA - RF CafeThis story from the 1976 issue of Old Farmer's Almanac (OFA) is fair game for RF Cafe because of its technical aspect, but there is yet another interesting reason that might require an amateur radio operator to notice. "The Man Who Made Gasoline from Water" is about a 70-year-old inventor named Louis Enricht who in 1916 tried to convince would-be investors that he had discovered a method for converting a fuel tank filled with drinking water into gasoline merely by dropping a magic pill into the filler tube. Henry Ford expressed interest in the miracle pill, but a more skeptical businessman and chemist investigated the matter. You'll have to read the story to learn the results (very interesting), but you might be interested to know the name of that wise entrepreneur: Hudson Maxim. Does that name sound familiar...

Electron Beam Sculpts Graphene in 3D

Electron Beam Sculpts Graphene in 3D - RF Cafe"Graphene can be sculptured by electron beams, according to researchers at Georgia Tech. Carbon atoms can be added or subtracted - and in the case of graphene oxide, surface oxygen can be used to remove carbon atoms with no additional chemicals. 'By timing and tuning the energy of the electron beam, we can activate interaction of the beam with oxygen in the graphene oxide to do etching, or interaction with hydrocarbons on the surface to create carbon deposition,' said mechanical engineer Professor Andrei Fedorov. 'With atomic-scale control, we can produce complicated..."

Antenova Adds High Performer to Its 5G Antennas

Antenova Adds High Performer to Its 5G Antennas - RF CafeAntenova Ltd, UK manufacturer of antennas and RF antenna modules for the Internet of Things (IoT) and Machine-to-Machine (M2M) applications, has added a high performing 5G SMD design to its array of 5G antennas. This brand-new antenna, Lepida SR4L054, is a wideband antenna in SMD form, designed to achieve high efficiency and performance right across the spectrum from 600 MHz to 3800 MHz. Lepida operates right across the cellular bands B71 (617-698 MHz), LTE 700, GSM850, GSM900, DCS1800, PCS1900, WCDMA2100, B40 (2300–2400 MHz), B7 (2500-2690 MHz), and B78 (3300-3800 MHz). The antenna is linear polarised and has been designed to ensure excellent coplanarity. Antenova has built Lepida for the more demanding applications in 5G, 4G and LTE where antenna performance and reliability...

The Clairvoyant Dr. Fox

Clairvoyant Dr. Fox, May 1937 Radio-Craft - RF CafeMystery stories were broadcast on radio stations in the days before television - and for quite a while after TV was available for that matter. Families gathered around the living room radio set in excited anticipation of the next adventure of shows like "The Shadow," "Amos 'n' Andy," "Tales of the Texas Rangers," "Dragnet," and "The Green Hornet." During that era, it was common also for electronics magazines, which focused largely on radio communications, to experiment with printed dramas that had a radio-centric theme. Here is the first of a series tried by Radio-Craft in the late 1930s. A couple decades later the Carl & Jerry adventures were run in Popular Electronics, but other than that I don't recall seeing a lot of these things. If you're a mystery fan, then here you are.

Post Your Engineer & Technician Job Openings on RF Cafe for Free

Engineering Job Board - RF CafeRF Cafe's raison d'être is and always has been to provide useful, quality content for engineers, technicians, engineering managers, students, and hobbyists. Part of that mission is offering to post applicable job openings. HR department employees and/or managers of hiring companies are welcome to submit opportunities for posting at no charge. 3rd party recruiters and temp agencies are not included so as to assure a high quality of listings. Please read through the easy procedure to benefit from RF Cafe's high quality visitors...

Keys to Successful Naval Defense Using MIMO/MANET Radio System Deployments

Keys to Successful Naval Defense Using MIMO/MANET Radio System Deployments - RF CafeTriad RF Systems, a leading designer and manufacturer of integrated radio systems and high performance RF/Microwave amplifiers, just published a very nice Tech Brief entitled "Keys to Successful Naval Defense Using MIMO/MANET Radio System Deployments." Beginning with a review of applicable radio history (HF, VHF, UHF, SATCOM), the document extolls the virtues of MIMO (Multiple-Input / Multiple-Output) and its antenna diversity scheme (a la your Wi-Fi router). Building on the technology is MANET (Mobile Ad-Hoc Networking), which exhibits self-forming and self-healing networks that survive in hostile signal environments. While the title specifies naval applications because of Triad RF's extensive involvement in the realm, this technology extends into other military services as well as domestic law enforcement...

Thanks to Reactel for Their Long-Time Support!

Reactel Filters - RF Cafe

Reactel has become one of the industry leaders in the design and manufacture of RF and microwave filters, diplexers, and sub-assemblies. They offer the generally known tubular, LC, cavity, and waveguide designs, as well as state of the art high performance suspended substrate models. Through a continuous process of research and development, they have established a full line of filters of filters of all types - lowpass, highpass, bandpass, bandstop, diplexer, and more. Established in 1979. Please contact Reactel today to see how they might help your project.

Monday 28

RFI Grows Up

RFI Grows Up, September 1976 QST - RF CafeAccording to this 1976 issue of QST magazine, in 1974 the FCC received 42,000 complaints of radio frequency interference (RFI). 38,000 of them (90%) involved interference to home-entertainment devices such as stereos and TV sets. 34,000 (89%) of were found to be due to design deficiencies in the home-electronic devices themselves. Since that time, and especially since Wi-Fi and cellphones, the potential for RFI has increased significantly. Fortunately, thanks to much more stringent compliance testing, the likelihood of interference from a commercially produced device has been reduced, but the sheer volume of stuff spewing some level of RF energy has raised the overall noise floor in heavily populated regions around the world. Concurrently - and also fortunately - technology advances in filtering, oscillator frequency stability, shielding, and modulation schemes...

Many Thanks to San Francisco Circuits for Continued Support!

San Francisco CircuitsSF Circuits' specialty is in the complex, advanced technology of PCB fabrication and assembly, producing high quality multi-layered PCBs from elaborate layouts. With them, you receive unparalleled technical expertise at competitive prices as well as the most progressive solutions available. Their customers request PCB production that is outside the capabilities of normal circuit board providers. Please take a moment to visit San Francisco Circuits today. "Printed Circuit Fabrication & Assembly with No Limit on Technology or Quantity."

PCBONLINE Blog: Comprehensive Guide to SMT Stencils

PCBONLINE Blog: Comprehensive Guide to SMT Stencils - RF CafePCBONLINE, a global high-end PCB manufacturer servicing electronics manufacturing (EMS) customers in defense, aerospace, medical, and other high-end industries, has posted a technical blog entitled, "Comprehensive Guide to SMT Stencils." It answers questions about what are SMT (Surface Mount Technology) and SMT stencils and what are they used for, where do you get SMT stencils for PCB assembly, what are the different types of SMT stencils, and how do you use SMT stencils? SMT (Surface Mount Technology) stencils are very important for PCB designing and manufacturing. If you can't decide which type of SMT stencil to go for and you need a detailed guide for this topic, then you're in the right place. This article will focus on every aspect of PCB stencils and by the time you reach the end...

Mac's Radio Service Shop: Mac and Free Estimates

Mac's Radio Service Shop: Mac and Free Estimates, January 1950 Radio & Television News - RF CafeI always learn something new with each episode of "Mac's Radio Service Shop," but not necessarily related to electronics. Such is the case in this 1950 issue of Radio & Television News magazine where after Mac gives Barney a quick lesson in how to determine a transformer's winding turns ratio when needing to create an impedance match circuit. He then, while discussing whether 'free' repair estimates are truly free or of any real value at all, he uses the phrase 'a horse on you.' Maybe it is because I don't frequent bars that I had never heard that, but after a little research I now know it refers to a bar dice game called 'Horse.' 'A horse on you' is when you lose the final round of a 2-out-of-3 challenge. 'A horse apiece' is when you and your opponent...

ConductRF LSA Series of Flexible RF Cable Assemblies to 18 GHz

ConductRF LSA Series of Flexible RF Cable Assemblies - RF CafeConductRF LSA series of Low Loss, Performance flexible RF Cable Assemblies, provide microwave system designers with a versatile solution for most applications. Offered is a solution for 0.086" diameter cable that facilitates greater flexibility and handling or, 0.141" diameter that exploits the same great performance but with almost half the loss. Connector options include SMA, Type-N, TNC & SMP that provide excellent VSWR between DC and 18GHz, also solutions for MCX & SMB are available in a wide array of configurations. These assemblies are built using our own double shielded, FEP jacketed cable, that was developed specifically for performance solutions. With shielding effectiveness exceeding 90 dB through 18 GHz...

Beam Propagation mm-Wave Directed Energy Weapons

Beam Propagation mm-Wave Directed Energy Weapons - RF Cafe"Comparing the relatively simple Fraunhofer or 'far field' approximation commonly used in radar and high-powered microwave systems with the more complex near field propagation model based on the field equivalence principle demonstrates which approach achieves reasonable modeling fidelity with minimal compute power. Modeling and Simulation can be used to explore the design trade space of directed energy weapons. M&S can be particularly helpful when that trade space is influenced by a large number of parameters and when acquiring field data to explore those parameters requires a large amount of resources. One example involves the Active Denial Technology system, a non-lethal, counter-personnel..."

Please Thank RF Superstore for Their Continued Support

RF Superstore coaxial cable, connectors, adapters - RF CafeRF Superstore launched in 2017, marking the return of Murray Pasternack, founder of Pasternack Enterprises, to the RF and microwave Industry. Pasternack fundamentally changed the way RF components were sold. Partner Jason Wright manages day-to-day operations, while working closely with Mr. Pasternack to develop RF Superstore into a world class RF and microwave component supplier. RF coaxial connectors & adapters, coaxial cable & cable assemblies, surge protectors, attenuators. Items added daily. Free shipping on orders over $25. We're leading the way again!

Sunday 27

Engineering Themed Crossword Puzzle for September 27th

Engineering Themed Crossword Puzzle for September 27th, 2020 - RF CafeSeptember 27th's custom Engineering 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 25

Microwaves - Receiving and Transmitting Antennas

Microwaves - Receiving and Transmitting Antennas, December 1949 Radio-Electronics - RF CafeThis is the eighth and final installment on a "Microwaves" series of articles in Radio-Electronics magazine by author C.W. Palmer. Each part is a stand-alone tutorial that does not rely on previous parts to be useful. Unlike most of the preceding articles that dealt in one way or another with waveguide, this final one concerns "receiving and transmitting antennas for microwave communication." It touches lightly on various types of antennas, field patterns, impedance matching, and applications. If you've been around for a while, you've likely seen it all before, but there are some nice photos of antennas designed and deployed by Bell Telephone Laboratories for their nationwide microwave telephone relay network. Bell Labs has done a lot of ground-breaking research in all aspects of communications technology...

Power Electronics with Microscopic Plumbing Saves Lots of Money

Power Electronics with Microscopic Plumbing Saves Lots of Money - RF Cafe"Designing semiconductor circuits hand-in-hand with microfluidic cooling systems could mean huge boosts in efficiency. The heat generated by today's densely-packed electronics is a costly resource drain. To keep systems at the right temperature for optimal computational performance, data center cooling in the U.S. consumes the as much energy and water as all the residents of the city of Philadelphia. Now, by integrating liquid cooling channels directly into semiconductor chips, researchers hope to reduce that drain at least in power electronics devices, making them smaller, cheaper and less energy-intensive. Traditionally, the electronics and the heat management system are designed and made separately, says Elison Matioli, an electrical engineering professor at École Polytechnique Fédérale de Lausanne in Switzerland. That introduces a fundamental obstacle..."

Many Thanks for Alliance Test Equipment's Support!

Allied Test Equipment Products - RF CafeAlliance Test Equipment sells used / refurbished test equipment and offers short- and long-term rentals. They also offer repair, maintenance and calibration. Prices discounted up to 80% off list price. Agilent/HP, Tektronix, Anritsu, Fluke, R&S and other major brands. A global organization with ability to source hard to find equipment through our network of suppliers. Alliance Test will purchase your excess test equipment in large or small lots. Blog posts offer advice on application and use of a wide range of test equipment. Please visit Allied Test Equipment today to see how they can help your project.

Quickly Assess Coax Cable Shielding Quality

Quickly Assess Coax Cable Shielding Quality - RF CafeKenneth Wyatt has a good article on the EDN website entitled, "Quickly Assess Relative Coax-Cable-Shielding Quality." It begins: "Testing most products for radiated emissions usually requires all I/O and power cables to be attached to the equipment under test (EUT) and spread out in accordance with the specific product standard. In many cases, we test engineers simply grab the nearest cables and hope for the best during the compliance test. Unfortunately, poor-quality cables can lead to emissions failures due to poor shielding or poor shield termination (via 'pigtails') to the connectors. In an earlier article, I related the issue of HDMI cable radiation due to shield pigtails. I also graphically demonstrate why cable shield pigtails lead to radiated emissions in the video. In addition to the shield pigtail issue, coax cables..."

WWV Offers Additional Services

WWV Offers Additional Services, April 1958 Radio-Electronics - RF CafeWWV is the oldest continuously-operating radio station in the U.S. since first going on the air from Washington, D.C. in May 1920. It moved around an area near D.C. for a few years before being relocated to its current location in Boulder, Colorado, in 1966. WWVB, another time standard transmitter, had already been established in Boulder a few years earlier. Sister station WWVH is located in Hawaii. The National Bureau of Standards (NBS) was renamed National Institute of Standards and Technology (NIST) in 1988, nearly a century after its inception in 1890. Having grown up not too far from Beltsville, Maryland, I remember driving by their main campus when the NBS sign was still on the lawn. The decision to change the name never did make sense, but then most of what government bureaucrats do perplex me...

Russian COVID-19 Vaccine Tests

Russian COVID-19 Vaccine Tests - RF CafeIn response to an article about the ongoing Wuhan Flu serum development programs, here is one of the cleverest online forum posts I've ever seen: "This might surprise many of you, but I volunteered for the vaccine trials for Covid-19. The vaccine is the one that was created in Russia. I received my first shot yesterday and I'm excited because it seems completely safe, with иo side effects whatsoeveя, and I feel sκ χoρoshό я чувствую себя немного странно и я думаю, что вытащил ослиные уши." Plug the Ruskie part into a translator.

Many Thanks to Aegis Power Systems for Their Continued Support!

Aegis Power Systems - RF CafeAegis Power Systems is a leading supplier of AC-DC and DC-DC power supplies for custom and special applications. Aegis has been designing and building highly reliable custom power supplies since 1995. They offer a complete line of switch mode power supplies and power converters for a variety of markets including defense, industrial, aircraft, VME, and telecom. Supports military, aircraft, EV, telecom, and embedded computing applications. Design and manufacture of custom power supply solutions to meet each customer's exacting specifications. Please visit Aegis Power Systems today.

Thursday 24

Cakes Baked in 90 Seconds - Early Microwave Oven

Cakes Baked in 90 Seconds - Early Microwave Oven, November 1951 Radio & Television News - RF CafeLittle known to most people (including moi until recently), DeForest Training School was started by DeVry University's founder Herman A. DeVry. DeVry and DeForest were DeGood DeFriends, leading DeVry to name his electronics school after DeForest. It was re-named DeVry Technical Institute in 1953. Research at DeForest Training School produced one of the first RF / microwave food baking "ovens." The prototype reported in this 1951 Radio & Television News magazine article was not at all like modern microwave ovens. There was no enclosure into which baking bowls, pans, and dishes can be inserted. Rather, electrodes were arranged at the perimeters of the special pan that in this demonstration contained cake batter. It was adapted from a process originally developed for RF induction heating of industrial materials...

Many Thanks to Electro-Photonics for Their Continued Support

Electro-PhotonicsElectro-Photonics is a global supplier of RF & Microwave components. Their products include SMT hybrid and directional couplers, wire bondable passive components, mounting tabs, filters, transmission lines, and very useful test boards for evaluating components (spiral inductors, single-layer capacitors). The Electro-Photonics team can support your small R&D design requirements with RF & Microwave test fixtures and save you valuable design and characterization time. Please take a moment to visit Electro-Photonics' website and see how your project might benefit. 

Radiation-Tolerant FPGAs Solve Spacecraft Design Challenges

Radiation-Tolerant FPGAs Solve Spacecraft Design Challenges - RF Cafe"Satellite and spacecraft system designers have a few different options when selecting field programmable gate arrays (FPGA) semiconductors. One FPGA option is commercial off-the-shelf (COTS) components that reduce component unit cost and lead time, but they are generally not reliable enough, must be up-screened (which increases cost and engineering resources), and require soft and hard Triple Modular Redundancy (TMR) to mitigate radiation effects in space. In missions where failure is not an option, designers typically choose higher-cost FPGAs that are radiation-hardened by design (RHBD). These are already screened and qualified to Qualified Manufacturers List (QML) Class Q and V standards..."

Hobnobbing with Harbaugh: Biocells Revisited

Hobnobbing with Harbaugh: Biocells Revisited, September 1964 Popular Electronics - RF Cafe"Hobnobbing with Harbaugh" was a regular comic feature in Popular Electronics magazine in the 1960s. Creator Dave Harbaugh chose topics ranging from husband-wife relationships where the husband is a technophile of some sort and the wife either purposely or unknowingly challenges his efforts to participate in his hobby, to contemporary (at the time) subjects such as this month's treatment of biocells. Like solid state electronics back in the day, bioengineering was a mysterious field few understood. It received a great deal of attention by comedians and sci-fi film makers who got a kick out of scaring people over the possibility of an alien contamination (a la "The Andromeda Strain") or some secret government laboratory brewing up a deadly contagion...

Anatech Microwave September 2020 Product Update

Anatech Microwave September 2020 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. One each new cavity-type duplexer and triplexer have been introduced. The AD1542-1643D296 is an Inmarsat duplexer with 1524-1560 MHz and 1626.5-1660.5 MHz passbands, and the AD1800-2072-2250TR293 is a triplexer with 2025-2120 MHz, 2200-2230 MHz, and 1750-1850 MHz. Passband insertion loos is >15 dB on all, and insertion loss is <1 dB. Custom RF power directional coupler designs can be designed and produced when a standard...

Free Webinar: Build Your Own Radar at Home

Professor David Ricketts, NCSU - RF CafeOn September 29th beginning at Noon EDT, Cadence | AWR will be presenting a free webinar entitled NCSU Rabbit Radar - Design, Simulate & Build Your Own Radar at Home. "In this webinar, Dr. Ricketts describes how to design, simulate, and build a 2.4GHz frequency modulated continuous wave (FMCW) radar at home or in a lab. The webinar begins with a short theory session followed by an explanation of the key components of an FMCW radar, which include a mixer, power amplifier, coupler, low noise amplifier, and filters. The components will use transmission line structures that attendees will design...

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.

Wednesday 23

Crystal Diodes in Modern Electronics

Crystal Diodes in Modern Electronics, November 1951 Radio & Television News - RF CafeUse of the word "modern" in titles of books and magazine articles has always bothered me because of how quickly the referenced topic becomes obsolete. It is only "modern" for a relatively short period of time. In 1951 when this article appeared in Radio & Television News magazine, germanium was the dominant semiconductor in use for diodes and transistors. They could be used in small signal circuits of up to about 500 MHz. That meant they could easily replace vacuum tubes in AM and FM radios, and at least the IF and baseband sections of TVs. You might think that would have represented a big component cost savings, but semiconductors were much more expensive than vacuum tubes at the time. Still, the power savings, size reduction, and higher reliability made the circuit changes worthwhile...

DARPA's Ultra-Linear High-Speed GaN Advances to Next Phase

DARPA's Ultra-Linear High-Speed GaN Advances to Next Phase - RF Cafe"A team of researchers at HRL laboratories, led by Principal Investigator Dr. Jeong-Sun Moon, is developing the next generation of Gallium Nitride (GaN) transistors that will have a dramatic effect on electronic components that amplify electromagnetic signals for communications, radar, and 5G wireless networks. The ultra-linear monolithic microwave integrated circuit (MMIC) amplifiers that utilize these high-speed GaN transistors can see greatly improved linearity, noise reduction, and reduced power consumption. Moon's team has successfully met and exceeded the performance metrics defined by the Dynamic Range-enhanced Electronics and Materials (DREaM) program, a DARPA effort to improve dynamic range in millimeter-wave..."

IPP Needs an RF/Microwave Design Engineer

Innovative Power Products Needs an RF/Microwave Design Engineer - RF CafeInnovative Power Products (IPP), a company with over 35 years of experience designing and manufacturing RF and microwave passive components, wants to immediately fill an opening for an RF/Microwave Design Engineer. The position requires demonstrated success in the design and test of wide band, high power RF and microwave passive components. Candidate to be familiar with linear and full-wave EM simulators. Responsibilities include design, simulation, engineering document release, and prototype test of new products. He/she will communicate with customers, travel as required to visit customers or vendors, collaborate with Design and Drafting to satisfy customer requirements. Train and support technicians on S-parameters, test procedures, troubleshooting, and documentation of product...

Planes Can Land in Fog! Thanks to Short Waves

Planes Can Land in Fog! Thanks to Short Waves, December 1931/January 1932 Short Wave Craft - RF CafeThe Instrument Landing Systems (ILS) has been around since the early 1930s, as made apparent by this article in Short Wave Craft magazine. Frequencies, circuits, and infrastructure equipment have evolved over the years, but fundamentally, landing an aircraft (airplane, helicopter, dirigible) under 'blind' flying conditions has not changed. Two precision beams - one in elevation and one in azimuth - broadcast by ground-based installations are detected by airborne receivers and relative positions are displayed for the pilot's use in navigation. ILS does not help the pilot fly the aircraft; it only leads him to the runway threshold. In the past couple decades, space-based Global Positioning System (GPS) equipment has increasingly been used to replace ground-based microwave systems...

Teledyne e2v HiRel Intros 25 GHz Frequency Doubler

Teledyne e2v HiRel Expands RF Line with New 25 GHz Frequency Doubler - RF CafeTeledyne e2v HiRel, part of the Teledyne Defense Electronics Group, today announced the latest addition to its rapidly expanding line of RF solutions, a new RF MMIC Frequency Doubler. Launching Teledyne e2v HiRel's new Frequency Multiplier product line, this Active Doubler, TDFM001000, is designed for high reliability signal chain applications in Space. It is particularly well-suited specifically for satellite transponders, transmit/receive modules, microwave-based communications, millimeter-wave point-to-point radio, and related processes. The TDFM001000 is a 7.5-25.0 / 15.0-50.0 GHz single ended input (no external balun required) GaAs MMIC doubler...

KiloDrone: Intense Sound of 1,000 Analog Oscillators

KiloDrone Intense Sound of 1,000 Analog Oscillators - RF CafeThe October issue of IEEE's Spectrum magazine ran an article entitled, "Let a Thousand Analog Oscillators Sing." It reports on Sam Battle's "KiloDrone" DIY project consisting of 1,000 analog reverse-avalanche oscillators, each built with a transistor, capacitor, and resistor. A singe opamp isolates and amplifies the output of each unit. In his video Mr. Battle explains the project, runs through the tune-up procedure, and exhibits the final result. According to the story, only 1.2 A is used from a 12 V DC supply for the entire setup. There are 10 independently tuned oscillators on each rack-mountable panel. A printed PCB panel (not including components) can be purchased for $52. Bob Pease would have loved this guy whose motivation is summarized thusly: "I like the tangibility of analog. I hate working on computers. I just can't stand looking at screens. I like standing up and moving around and making things in a physical world."

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.

Tuesday 22

Electron Shadows Map Force Fields

Electron Shadows Map Force Fields, December 1949 Radio-Electronics - RF CafeWhen I saw the images in this "Electron Shadows Map Force Fields" article from a 1949 issue of Radio-Electronics magazine, the first thing I though of was how as kids back in the 1960s we would hold magnets against the front of the television cathode ray tube (CRT) to see how they distorted the picture. If I still had a CRT TV or computer monitor around, I'd take some photos of it for the sake of those who have never seen what happens. The difference between that and the images formed here is that the professionals inserted the object of interest directly in the electron beam, between the cathode and the fluorescent glass grid. As with the images in the article, magnets of various shapes created unique responses. If you drag the magnet across the face of the CRT...

DC to Daylight Microwave Absorbers Shield the Warfighter

DC to Daylight Microwave Absorbers Shield the Warfighter - RF Cafe"The evolution of military electronics is marked by an endless series of measures and countermeasures. The enemy meets an enhancement in U.S. fighter jet technology with an improvement in its missile-guidance capabilities, forcing additional innovations from the U.S. The never-ending effort to enhance the effectiveness of military technology and protect the warfighter on the battlefield propels forward innovation in the industry. Today, there's a battle underway that is dramatically expanding the frequency ranges used by the military for communications - soldier-to-soldier, soldier-to-satellite, aircraft-to-ground, missile-to-target, and more. Whereas military electronics used to operate in a narrow band of frequencies, today, military design engineers must protect equipment from damaging signal interference and enemy..."

Academy of EMC Standards Documents

Academy of EMC Standards Documents - RF CafeRF Cafe visitor Kire P. let me know about a really nice website with lots of information about EMC (electromagnetic compatibility) and governing industry standards. The Academy of EMC is a non-profit based in Switzerland. It  has a large variety of downloadable documents covering EMC guidelines (PCBs, cables, enclosures, etc.) for how to assure your products will pass testing global, EU, U.S. and other EMC standards, including compliance marks from countries and groups. An educational area contains suggestions for books and other resources. There are also half a dozen articles on the Blog page. Keep in mind when reviewing any standard that you must go to the source for the most up-to-date version. Failure to do so can be quite expensive.

RF/Microwave Switching Adds Flexibility to Diverse Applications

RF/Microwave Switching Adds Flexibility to Diverse Applications - RF CafeThe Evaluation Engineering website has a good article entitled, "RF/Microwave Switching Adds Flexibility to Diverse Applications" that runs through some state of the art hardware available for R&D and production test setups. It pitches products from multiple vendors, so it is not just an infomercial. "Engineers in industries ranging from telecommunications to military / aerospace need high-performance RF/microwave switching as part of their test setups. Consequently, vendors are offering products ranging from individual switches to complete switching systems to meet customer demand. This report describes the latest available RF / microwave switching products and the applications they serve..."

Radio Amateur Course - How the Vacuum Tube Works

Radio Amateur Course - How the Vacuum Tube Work, October 1935 Short Wave Craft - RF CafeA while back I was using the familiar analogy that relates water pressure, hose diameter, and flow rate to electrical voltage, resistance, and current, respectively, in an explanation to my daughter regarding why the water characteristics in her house changed after the well supply pipe and indoor plumbing changed. The cause, I proposed, was due to an increased distance between well and house, and the use of the plastic PEX tubing with a smaller inside diameter than the old copper pipe, respectively. The submersible pump and holding tank still supply the same 50 psi as before, but since that pressure now has to force the water through a path inside the house with more resistance to water flow, the delivery rate to fixtures is now lower. When I hold the contacts closed on the pump control relay, the most I can get is about 55 psi. Raising the pressure will require replacing...

1st Day of Autumn in Northern Hemisphere

Autumnal Equinox Northern Hemisphere 2020 - RF CafeFall has finally arrived! The autumnal equinox occurs today, September 22, 2020, at 9:30 A.M. EDT (13:30 UTC). The equinox occurs at the same moment worldwide, regardless of local time zone. The word "equinox" comes from Latin "aequus," meaning "equal," and the Latin "nox," meaning "night." It marks the moment the sun crosses the celestial equator, which is coincident with Earth's equatorial plane, as it descends from north to south (south to north transition marks the vernal equinox).  I've never seen this offered anywhere, but why not "equal day" rather than "equal night?"  "Pernox" means day, which would give us equipernox rather than equinox. The winter solstice (solstice = sol + stitium ≈ sun stands still) occurs December 21, 5:02 A.M. EST.

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.


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RF Cascade Workbook 2018 - RF Cafe
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    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...

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