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Homepage Archive - March 2023 (page 3)

See Page 1 | 2 | 3 | 4 | of the March 2023 homepage archives.

What Happened at Oslo? Color TV

What Happened at Oslo?, January 1967 Radio-Electronics - RF CafeIt is kind of hard to believe that even by 1966, when the International Telecommunications Union (ITU) met in Oslo, Norway, that the world had not yet agreed in a common transmission standard for color television. In January of 1967, Radio-Electronics magazine editor Thomas Hasket interviewed two major players in the industry, George Brown of Radio Corporation of America (RCA), and Frederick M. Remley, Jr. of Society of Motion Picture and Television Engineers (SMPTE), regarding the stalemate that was unarguably hampering the ramping up of color television set production. Consumers were pining for them, but companies hesitated to invest engineering and manufacturing resources when they couldn't be sure it would not be thwarted by a change in the modulation scheme. A battle was being waged between the U.S. NTSC standard and the European PAL system (and SÉCAM to a lesser sense). Both had strengths and weaknesses, but history has shown, NTSC ultimately won. Possibly due to the impasse, color TV sales in America did not surpass B&W sales until the early 1970s.

Tuesday the 21st

Inventors of Radio - Thomas A. Edison

Inventors of Radio - Thomas A. Edison, April 1960 Radio-Electronics - RF CafeUpsetters of apple carts, rockers of boats, makers of waves, creators of stirs. All idiomatically describe actions of those who commit the transgression of challenging accepted norms. There is always someone claiming to have discovered the "truth" about one subject or another. In the world of technology, most often the object of contestation is which person was the "first" to have discovered, written, or performed something. Here in this 1960 issue of Radio-Electronics magazine, Mr. Leslie asserts that Thomas Alva Edison actually made the world's first radio broadcast, not Guglielmo Marconi. For some reason the image of Edison's "Means for Transmitting Signals Electrically" patent omitted the ships at sea overtop of the antenna structures, which seem to me to be critical in portraying the "wireless" nature of the invention. His creative "spark" was motivated by observation of a powerful spark and noting, "seemed so strong that it struck us forcibly there might be something more than induction." Edward H. Loftin claims the credit goes to Lt.-Commander Edward H. Loftin, U.S. Navy...

Odes on Technology

Poems Odes on Technology, Kirt's Cogitations #351 - RF CafeOpenAI (ChatGPT) founder Greg Brockman, recently produced a video introducing some of the improvements and new features of GPT-4 (current public version is GPT-3.5). One thing he did was ask the AI machine for a single sentence summary using only words beginning with the letter "g." GPT-3.5 failed miserably, but GPT-4 succeeded. It even did a sentence using only words beginning with the letter "q." He also had GPT-4 create a poem about the tax preparation capability of ChatGPT (itself an impressive act). A few of the vintage issues of Popular Electronics and the ARRL's monthly QST magazine contained electronics-related poems submitted by readers (see "Unpopular Radio," and "Pre-Radio," et al). Some are pretty clever. It takes some cogitation, skill, and creative ability to come up with a rhyming poem on a technical subject like amateur radio. Since I am in insufficient possession of the aforementioned qualities, I decided to task ChatGPT to create a few topical poems for me. Is this amazing, or what? Be sure to see "Ode on Rhode & Schwarz" and...

How to Avoid Workbench Hazards

How to Avoid Workbench Hazards, September 1973 Popular Electronics - RF CafeCommon sense never goes out of style, especially as it pertains to safety in the presence of electricity. Most people who have worked in the electrical / electronics realm for a while are aware that lethal electrocution can occur with currents as low as 100 mA when it passes through the heart. Lower values cause progressively less profound maladies, but in practice any level of current great enough to be felt is not a good thing. I have written before about having received a few pretty scary shocks when working on high voltage equipment and many lesser jolts throughout my 50± years of exposure. Other than observing my father's being leery of using of anything with an electric cord attached to it, my first formal instruction about electrical safety was in my vocational classes in high school. Instructor Russ Lorenzen taught us to keep one hand in our pockets when working on live circuits, which of course was only to be done under the rare circumstance when it is not possible to first turn power off. In practice that often meant when doing so would be more inconvenient than the calculated risk of electrocution. Seriously, though...

Antenna with Waveform-Selective Metasurfaces

Antenna with Waveform-Selective Metasurfaces - RF Cafe"When you tap on your phone screen to check something on the internet, you make use of wireless communications technology. With the advent of 5G networks, this technology has made our lives easier than we could imagine. As we progress towards 6G communication, the use of IoT devices to monitor and perform tasks is becoming inevitable. As a result, there is a growing demand for the services provided by such devices. However, the frequency resources accessible to the IoT devices remain limited. Consequently, there has been a lot of research focused on using various modulation schemes to fit in more data without causing interference. Yet, however, they have ignored one important aspect of wireless communication: conventional antennas respond to signals at the same frequency in the same manner. However, if one were to modulate the antenna performance for a fixed frequency based on other aspects of the signal waveform, like its pulse width, it would add a whole new degree of freedom that can be exploited to transfer data efficiently... the researchers put forth a new system that uses 'metasurfaces' to create waveform-based selectivity in antennas..."

Visions of 1946

Visions of 1946, December 1936, Radio-Craft - RF CafeDecember is traditionally the issue for magazines to sum up accomplishments of the ending year and make predictions for the next year. Radio-Craft magazine was no exception, but in 1936 they went ten steps farther and prognosticated a decade into the future - all the way to 1946! It is actually a tongue-in-cheek reprint from Pathe News magazine. However, note the drawing of 'professor teaches 2 million pupils,' where he is instructing via television and the railroad company boss checking in on the conductors en route via wireless teleconferencing. It might have seemed like a pipe dream in 1936, but now it is commonplace. Not only do we now have live classroom broadcasts, but millions of YouTube videos of instruction for performing just about every task and teaching every subject imaginable...

Promote Your Company on RF Cafe

Sponsor RF Cafe for as Little as $40 per Month - RF CafeNew Scheme rotates all Banners in all locations on the page! RF Cafe typically receives 8,000-15,000 website visits each weekday. RF Cafe is a favorite of engineers, technicians, hobbyists, and students all over the world. With more than 17,000 pages in the Google search index, RF Cafe returns in favorable positions on many types of key searches, both for text and images. New content is added on a daily basis, which keeps the major search engines interested enough to spider it multiple times each day. Items added on the homepage often can be found in a Google search within a few hours of being posted. If you need your company news to be seen, RF Cafe is the place to be.

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. In stock, 1-day free shipping.

Monday the 20th

Magnetometer at Work in Outer Space

Magnetometer at Work in Outer Space, April 1960 Radio-Electronics - RF CafeWhen I saw the photo of the Vanguard III satellite in Figure 5 of this 1960 Radio-Electronics magazine article, my thought was how much it looks like the Russian Sputnik satellite with its spherical body and the antennas from four sides pointed upward. In fact, the antennas were spring loaded to stick out perpendicular to the body after deployment, as shown in Figure 1. The thick "horn" on the top is the magnetometer probe. As can be seen in the schematic of the magnetometer circuit, solid state device dominated the electronics, although almost certainly the transmitter used at least one vacuum tube as a power amplifier. It can be argued that the "Space Age" would not have been possible without solid state electronics because of size, weight, power consumption, and reliability improvements over tube technology. These satellites immediately followed the International Geophysical Year (IGY) activities conducted on atmospheric parameters...

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.

Inflation Saps 2022 Tech Salaries

Inflation Saps 2022 Tech Salaries - RF CafeElections have consequences, as the old political says goes. If you're feeling the hurt of massive inflation over the last two years, then you might also identify with another saying: Misery loves company. You are not alone. IEEE Spectrum magazine uses data from "The Dice Tech Salary Report 2023 Edition" to plot how while salaries have increased in dollar numbers, the purchasing power has effectively gone down. "The numbers from job search firms Dice and Hired have been released. These 2022 numbers have been eagerly anticipated, given the turmoil generated by a spate of tech layoffs in the latter part of the year, which Dice estimates at more than 140,000. The data they collect doesn’t allow for apples-to-apples comparisons, but I've read through both reports, pulled out data from past years to give the numbers some perspective when possible, and summarized it in eight charts. Dice's numbers come from a survey administered to its registered job seekers and site visitors between 16 August 2022 and 17 October 2022, for a total of 7,098 completed surveys. Hired's analysis included data from 68,500 job candidates and 494,000 interview requests..."

Tech Headlines Quiz

Quiz #71: Tech Headlines Quiz for Week of 3/13/2023 - RF CafeThis "Recent Tech Headlines Quiz" challenges your ability to recall items from the homepage "Electronics & Tech Headlines" column for the week of March 13, 2023. Except for the questions and answers which I modified (and added two more sets), every line of JavaScript code for this multiple-choice quiz was generated based on a query made to the ChatGPT engine from OpenAI. It also generated code for the PHP language, and will presumable do so for many other computer languages. Just for the heck of it, I had ChatGPT generate a version of the quiz code in the COBOL language. COBOL, if you are old enough to recall, the a primary mainframe computer language before the PC era, and was a big deal during the run-up to Y2K because legacy code could not handle the century change. Lots of gray-haired, retired COBOL programmers made big bucks helping coders port code to C++, Delphi...

Modelithics & IMS Expanding Collaboration

Modelithics & IMS Expanding Collaboration with New 6 Year Plan - RF CafeModelithics and International Manufacturing Services (IMS) have expanded their long term collaboration commitment for an additional six (6) years, which includes development of simulation models for several additional IMS device families, as well as renewing their Sponsoring Modelithics Vendor Partner (MVP) status. Additional high frequency Modelithics Microwave Global Models™ for multiple IMS resistor and attenuator families are planned under the extended agreement. J.J. Silvia III, IMS Vice President, General Manager, states: "IMS is excited to continue this partnership. Applying bench-test data to scalable models found in their library not only provides valuable performance validation, but also benefits our customer design speed and capabilities. High tech customers design with high tech tools that are supported by Modelithics' software...

Ford-Philco FT9 Auto-Radio

Ford-Philco Radio, Model FT9, 6-Tube Auto-Radio Receiver Radio Service Data Sheet, April 1936 Radio-Craft - RF CafeThis Radio Service Data Sheet covers the Ford-Philco model FT9, 6-tube auto-radio receiver. It appeared in a 1936 issue of Radio-Craft magazine. Most - if not all - electronics servicemen had subscriptions to these magazines because they were a ready source of not just these service sheets, but because of the extensive articles offering advice on servicing radios and televisions. In fact, many electronics manufacturers had a policy of supplying service data only to bona fide shops. Thumbnail photos at the left came from a Ford-Philco FT9 radio on eBay. A large list is included at the bottom of the page of similar documents from vintage receiver schematics, troubleshooting tips, and alignment procedures. They were originally published in magazines like this one, Radio and Television News, Radio News, etc. I scan and post them for the benefit of hobbyists who restore and service vintage electronics equipment...

Promote Your Company on RF Cafe

Sponsor RF Cafe for as Little as $40 per Month - RF CafeNew Scheme rotates all Banners in all locations on the page! RF Cafe typically receives 8,000-15,000 website visits each weekday. RF Cafe is a favorite of engineers, technicians, hobbyists, and students all over the world. With more than 17,000 pages in the Google search index, RF Cafe returns in favorable positions on many types of key searches, both for text and images. New content is added on a daily basis, which keeps the major search engines interested enough to spider it multiple times each day. Items added on the homepage often can be found in a Google search within a few hours of being posted. If you need your company news to be seen, RF Cafe is the place to be.

Many Thanks to Axiom Test Equipment for Continued Support!

Axiom Test Equipment - RF CafeAxiom Test Equipment allows you to rent or buy test equipment, repair test equipment, or sell or trade test equipment. They are committed to providing superior customer service and high quality electronic test equipment. Axiom offers customers several practical, efficient, and cost effective solutions for their projects' TE needs and is committed to providing superior customer service and high quality electronic test equipment. For anyone seeking a way to offload surplus or obsolete equipment, they offer a trade-in program or they will buy the equipment from you. Some vintage items are available fully calibrated. Please check out Axiom Test Equipment today - and don't miss the blog articles!

Sunday the 19th

Electronics Theme Crossword for March 19th

Electronics Theme Crossword Puzzle for March 19th, 2023 - RF CafeThis custom RF Cafe electronics-themed crossword puzzle for March 19th contains words and clues which pertain strictly to the subjects of electronics, mechanics, power distribution, engineering, science, physics, astronomy, chemistry, etc. If you do see names of people or places, they are directly related to the aforementioned areas of study. As always, you will find no references to numbnut movie stars or fashion designers. Need more crossword RF Cafe puzzles? A list at the bottom of the page links to hundreds of them dating back to the year 2000. Enjoy.

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...

Many Thanks to Centric RF for Their Continued Support!

Centric RF microwave components - RF CafeCentric RF is a company offering from stock various RF and Microwave coaxial components, including attenuators, adapters, cable assemblies, terminations, power dividers, and more. We believe in offering high performance parts from stock at a reasonable cost. Frequency ranges of 0-110 GHz at power levels from 0.5-500 watts are available off the shelf. Order today, ship today! Centric RF is currently looking for vendors to partner with them. Please visit Centric RF today.

Friday the 17th

Test Transistors Fast

Test Transistors Fast, February 1969 Radio-Electronics - RF CafeBy the time this "Test Transistors Fast" article appeared in a 1969 issue of Radio-Electronics magazine, the use of vacuum tubes in new designs had been relegated to the domain of hobby and specialized circuits. Very high power and frequency applications were still waiting for semiconductors capable of servicing such equipment, but the electronics industry, particularly the domestic consumer world, used transistors and what was available in the form of integrated circuits. While designers had already been using transistors for a decade or more, many of the aforementioned hobbyists and electronics repair servicemen were still getting accustomed to the newfangled technology and welcomed the publishing of these kinds of topics. In 1969, the only thing I knew about transistors was that they must have somehow been associated with the "transistor radio" I carried in my jacket pocket. It was too small to contain any of those glowing tubes we still had in our household TV set and tabletop radios (and in the dashboard of our family's 1960 Rambler auto for that matter), so surely there was a difference...

RF and EMC Formulas and Charts

RF and EMC Formulas and Charts (AR) - RF CafeThis "RF and EMC Formulas and Charts" poster by AR RF/Microwave Instrumentation, a manufacturer of amplifiers, antennas, anechoic chambers, and related equipment, is a great resource to have in your lab or at your desk for a handy and quick reference for the EMC professional. This poster covers the basics such as frequency-to-wavelengths and Ohms law relationships, Linear to Log conversions, as well as EMC-targeted content such as radiated field strength and antenna factor calculations. It also includes conversions for a 50 Ω environment, common EMC equations, VSWR conversion charts, antenna equations, unit conversions, and more. It is a great addition to any EMC lab. Other poster themes may also be downloaded...

Radio Control: How to Get an F.C.C. License

Radio Control How to Get F.C.C. License, from September 1962 American Modeler Magazine - Airplanes and RocketsIf you have only ever known a time in the R/C era when 2.4 GHz, spread spectrum radios were in use and not only were there no interference issues, but there were no licenses required, either, for legal operation, then it might be hard to imagine when this was not so. Most people in the R/C realm at least remember the 72 MHz frequency band where each system operated on a specific center frequency, where no two systems could be operated in the same vicinity. Before that there was the 27 MHz band, which is where I began, more specifically on 27.195 MHz. Only five frequencies were reserved by the FCC exclusively for radio control use. That meant never more than five planes in the air, or even being worked on with the radio on, at a time. The band was part of the original Citizens Band (CB) radio allocation. Commercial CB radios were notoriously lousy at controlling bandwidth and often overlapped the R/C bands with enough power to cause deadly (to a model) interference. My FCC operator's permits (Class C and Class D), obtained sometime around 1972, is long gone...

Revolutionary Electrochemical Transistor

Wearable Electronics Breakthrough: A Revolutionary Electrochemical Transistor - RF Cafe"A multidisciplinary Northwestern University research team has created a groundbreaking transistor that is expected to be optimal for bioelectronics that are high-performance, lightweight, and flexible. The new electrochemical transistor is compatible with both blood and water and has the ability to amplify significant signals, making it highly beneficial for biomedical sensing. This transistor could make it possible to develop wearable devices that can perform on-site signal processing right at the biology-device interface. Some potential applications include monitoring heart rate and levels of sodium and potassium in the blood, as well as tracking eye movements to study sleep disorders. 'All modern electronics use transistors, which rapidly turn current on and off,' said Tobin J. Marks, a co-corresponding author of the study. 'Here we use chemistry to enhance the switching. Our electrochemical transistor takes performance to a totally new level. You have all the properties of a conventional transistor but far higher transconductance..."

Six-Inch Radio Waves

Six-Inch Radio Waves, January 1930 Radio-Craft - RF Cafe2.1 GHz (5.6-inch, or 14 cm wavelength) radio waves were an almost totally unexplored realm in 1930, with it and higher frequencies being the domain of theoretical research laboratories. Signal generators capable of producing much more than a few hundred megahertz were rare even in commercial applications. As reported here, centimeter-length electromagnetic waves were "according to the theories of Barkhausen and Kurz, [the] result of purely electronic vibrations, whose frequency was determined only by the operative data of the tube and was not dependent on any internal or external oscillation circuit." A half-wave receiving antenna picked up the transmitted signal with a simple diode detector to enable, after a couple stages of amplification, an audible signal. These are some of the earliest experiments at radio frequencies (RF) with parabolic metallic reflectors and polarization with a diffraction grid that could be rotated to set the polarization direction...

RF & Electronics Symbols for Visio

RF Electronics Wireless Analog Block Diagrams Symbols Shapes for Visio - RF CafeWith more than 1000 custom-built symbols, this has got to be the most comprehensive set of Visio Symbols available for RF, analog, and digital system and schematic drawings! Every object has been built to fit proportionally on the provided A-, B- and C-size drawing page templates (or can use your own). Symbols are provided for equipment racks and test equipment, system block diagrams, conceptual drawings, and schematics. Unlike previous versions, these are NOT Stencils, but instead are all contained on tabbed pages within a single Visio document. That puts everything in front of you in its full glory. Just copy and paste what you need on your drawing. The file format is XML so everything plays nicely with Visio 2013 and later...

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! 

Thursday the 16th

Radio-Electronics News Briefs

News Briefs, August 1960 Radio-Electronics - RF CafeLong distance communications via satellite were a few years off when Pacific Scatter Communications System (PSCS) was established as a network of microwave radio relays that spanned the Pacific Ocean during the Cold War era. It was established by the U.S. in the late 1950s as a means of maintaining secure communications with its military and diplomatic installations in Asia, particularly in Japan and South Korea. PSCS consisted of a series of shortwave and microwave relay stations located on islands throughout the Pacific, including Hawaii, Guam, Saipan, Okinawa, and, as reported in this 1960 issue of Radio-Electronics magazine, Wake Island. The system was designed to be highly resilient, with redundant communication paths and backup power supplies to ensure that communication could be maintained even in the event of a nuclear attack. It played a critical role in supporting military operations during the Vietnam War and in maintaining diplomatic relations with allies in Asia. The PSCS was eventually superseded by more advanced satellite communication systems in the 1980s...

Noise Figure / Y-Factor Conundrum - Solved

Noise Figure / Y-Factor Disagreement Conundrum - Solved, Kirt's Cogitations #350 - RF CafeWebsite visitor Jared Finan contacted me a few days ago to ask whether I had any idea why noise figure and Y-factor measurements made with his HP/Agilent/Keysight 8975A Noise Figure Meter were not in agreement. The same measurements made with his HP/Agilent/Keysight 8970A - a much older piece of equipment - agreed very well. My suggestion turned out to not be the answer. Jared wrote back later saying he found the cause of the problem - a real exercise in troubleshooting! He gave his permission to post our dialog here so in case someone else might have been plagued with a similar issue. There are several methods for measuring noise figure, including the Y-factor method, the cold source method, and the hot/cold load method. The Y-factor method is the most widely used technique for noise figure measurement...

Admiral Model 7C64 Schematic & Parts List

Admiral Model 7C64 Schematic & Parts List, February 1948 Radio News - RF CafeThis "drive-by" schematic and parts list for the Admiral Model 7C64 vacuum tube console radio and phonograph appeared in the February 1948 issue of Radio News magazine. I refer to it as "drive-by" because there was no description or maintenance verbiage provided. You might not expect from the relatively simple circuit that the entire Model 7C64 was mounted in a multi-sectioned wooden cabinet that included a phonograph. The thumbnail at the left is from the RadioMuseum.org website - a great source for research on vintage vacuum tube radios. Admiral Radio is a brand of electronic products that was founded in Chicago in 1924. The company started out as a manufacturer of phonographs and radios. In 1971, Admiral Radio was acquired by Panasonic.

Shape-Shifting Antenna Arrays to Improve Sensing Technology

Shape-Shifting Antenna Arrays to Improve Sensing Technology - RF Cafe"Researcher Kaushik Sengupta is working to expand the capabilities of sophisticated antenna arrays paired with high-frequency wireless chips in his lab at Princeton. Sophisticated antenna arrays paired with high-frequency wireless chips act like superpowers for modern electronics, boosting everything from sensing to security to data processing. In recent years, Sengupta's lab has designed antenna arrays that help engineers make strides toward peering through matter, boosting communications in canyons of skyscrapers, putting a medical lab on a smartphone, and encrypting critical data with electromagnetic waves instead of software. In a new article in Advanced Science, Sengupta's research team presented a new type of antenna array based on the paper-folding art of origami. The shape-shifting array, designed like a folded paper box called a waterbomb, allows engineers to create a reconfigurable and adaptable radar imaging surface..."

How and Why of Frequency Modulation

An Engineer Analyzes the How and Why of Frequency Modulation, August 1941 Radio-Craft - RF CafeThis is the second and final installment of an article on the topic of frequency modulation (FM) that began with Part 1 in the July 1941 edition of Radio-Craft magazine. Author Raymond Guy, a radio facilities engineer at the National Broadcasting Company (NBC), covers all the fundamentals of FM (a relatively new concept at the time, invented by Major Edwin Armstrong) not just from a functional circuits perspective but also pointing out a broadcaster's concern for channel spacing and broadcasting ranges. Transmitter pre-emphasis, receiver de-emphasis, noise thresholds, and adjacent channel and co-channel broadcasting strategies are discussed here...

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

/jobs.htm">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 /jobs.htm">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...

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. 50 Ω and 75 Ω models are available, along with a full line of precision calibration and connector adaptors.

Wednesday the 15th

Walter Ashe Radio Company

Walter Ashe Radio Company, July 1955 Radio & Television News - RF CafeThe Walter Ashe Radio Company, featured in this 1955 issue of Radio & Television News magazine, was a British radio manufacturer that operated from the 1920s to the 1950s. The company was founded by Walter Ashe, who was an engineer and inventor. In the early days, the company produced crystal radios, which were simple radios that used a piece of crystal to detect radio waves. However, the company quickly expanded its product range to include valve radios, which were more advanced and offered better sound quality. During World War II, the company produced radios for the British armed forces, including the famous "Gibson Girl" portable radio, which was used by soldiers in the field. After the war, the company continued to produce radios for the civilian market, including the popular "Waverley" series of radios. In the 1950s, the company began to face increasing competition from foreign manufacturers, and it struggled to keep up with the rapidly changing technology in the radio industry...

Nanowire Lasers in Hybrid Polymer-SiN Waveguides

Integrating Nanowire Lasers in Hybrid Polymer-SiN Waveguides - RF Cafe"Northwestern Polytechnical University in China and Australian National University report on progress in integrating on-chip nanowire (NW) laser sources in passive photonic integrated circuits (PICs). The researchers implemented a straightforward strategy to embed the NWs in a waveguide. First, indium phosphide (InP) nanowires were transferred to a 3μm-thick silicon dioxide (SiO2) substrate with a thin 300nm silicon nitride (SiN) top layer. Gold markers were incorporated into the substrate to aid nanowire placement with a tungsten probe. The quantum-confined nanowires themselves can be produced in processes with high quality. The team used nanowires from metal-organic vapor-phase epitaxy on a (111)A InP substrate. The researchers comment: 'This integration strategy of an on-chip laser is applicable to other PIC platforms, such as silicon and lithium niobate, and the top cladding layer could be changed by depositing SiN or SiO2, promising its CMOS compatibility.' They add: 'Nanowire lasers have the merits of an ultracompact footprint, low threshold, and low energy consumption..."

Antennas for CB'ers and Hams

Antennas for CB'ers and Hams, September 1973 Popular Electronics - RF Cafe"Does a choice transmitting antenna always constitute the best receiving antenna?" That question alone, by author Carl Eller in this issue of Popular Electronics magazine, piques my interest and gives confidence that this article is the type I have long said is lacking in the amateur antenna system design realm. Most treatises, it seems, address only the transmit half of the operation. Just as with the old aviation adage that with enough power you can make a brick fly, in the non-professional world the attitude is often that a really crappy base antenna / transmission line / power amplifier mismatch is fine as long a tuner is capable of bringing the VSWR into an acceptable range (2:1 or better is preferred). That translates into a lot of loss from the sky to the equipment. All transmission line loss (attenuation), while theoretically reducing impedance mismatch issues, adds directly to the noise figure of a receiver, and therefore to the reduction of minimum discernible signal (MDS) level. Radiating peak envelope power (PEP) from your antenna so that someone on the other side of the world can hear you does not do much good if your antenna-to-receiver loss is so great that the response signal gets buried in the noise...

Elastic Polymer Dielectric Stretchable Transistors

Elastic Polymer Dielectric Stretchable Transistors - RF Cafe "Over the past few years, material scientists and electronics engineers have been trying to fabricate new flexible inorganic materials to create stretchable and highly performing electronic devices. These devices can be based on different designs, such as rigid-island active cells with serpentine-shape / fractal interconnections, neutral mechanical planes or bunked structures. Despite the significant advancements in the fabrication of stretchable materials, some challenges have proved difficult to overcome. For instance, materials with wavy or serpentine interconnect designs commonly have a limited area density and fabricating proposed stretchable materials is often both difficult and expensive. In addition, the stiffness of many existing stretchable materials does not match that of human skin tissue, making them uncomfortable on the skin and thus not ideal for creating wearable technologies..."

Written in the Stars

Written in the Stars, September 1953 QST - RF CafeRod Newkirk (credited with coining the term "Elmer") was a frequent contributor to the ARRL's QST magazine. In addition to writing the "How's DX?" column from 1947 to 1978, he occasionally had humorous short stories related to Hamdom. "Written in the Stars" and "How Christmas Came to S. McSquegg" are two examples. Here, Ms. Susie Sopenwater (a sort of "soap and water" portmanteau; i.e., pure and clean) gets interested in amateur radio after winning the Miss America pageant and finds plenty of volunteers to help her earn her license and set up a "shack." Susie's call sign was, WN5P!P. My guess is that the WN5 part is an allusion to wideband phone (5 kHz) and P!P is for her being a "pip." Of course the P!P could be a text/graphical reference to her physical qualities (look at it). Let me know if you have a better (or different) interpretation. You might need to know that a "lid" in amateur radio is a poor or inconsiderate operator...

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!

Many Thanks to Anatech Electronics for Long-Time Support!

Anatech Electronics logo - RF CafeAnatech Electronics (AEI) manufactures and supplies RF and microwave filters for military and commercial communication systems, providing standard LP, HP, BP, BS, notch, diplexer, and custom RF filters, and RF products. Standard RF filter and cable assembly products are published in our website database for ease of procurement. Custom RF filters designs are used when a standard cannot be found, or the requirements dictate a custom approach for your military and commercial communications needs. Sam Benzacar's monthly newsletters address contemporary wireless subjects. Please visit Anatech today to see how they can help your project succeed. 

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RF Cascade Workbook 2018 by RF Cafe

ConductRF Phased Matched RF Cables - RF Cafe