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Homepage Archive - October 2023 (page 2)

See Page 1 | 2 | 3 | 4 | of the October 2023 homepage archives.
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Friday the 13th

10 to the Many

10 to the Many, August 1964 Radio-Electronics - RF CafeWhen in junior high, I never cared much for math, other than being able to do just enough to get by. In fact, I think I got a "D" in ninth grade algebra. My interest in all things mechanical and electrical for some reason never engendered an attraction to anything other than the simplest addition, subtraction, multiplication, and division. There were no electronic pocket calculators in the day, and I had never heard of a slide rule. Three years of an electrical vocational program in high school forced me to comprehend and use a bit more math for Ohm's law, Kirchhoff's law, some equations for magnetic induction, and a little graphing of data points (not equations, though). Sometime while in the USAF working as an air traffic control radar technician, I realized that in order to pursue an engineering degree, being good at mathematics would be a requirement. Beginning with a pre-algebra course in a community college, I worked my way through algebra, calculus, differential equations, linear algebra, and geometry courses...

Improved Earth Magnetic Field Map Needed

Improved Earth Magnetic Field Map Needed - RF cafeThis is interesting because the Earth's magnetic field is constantly changing, and might be on the verge of a pole reversal. "The World Magnetic Model is essential for navigation. The model, which compiles precise measurements of Earth's magnetic field at points across the globe into one map, provides data on the constantly shifting magnetic field. But the current system for collecting that vital data is getting old. Now, a U.S. intelligence agency is in the final stages of a competition to develop new technology to replace that aging system. The hope is to one day produce an even more accurate World Magnetic Model, which is critical given its use in cellphones, aircraft, and military applications. 'We're using this every day to figure out if we're going left or right,' says David Roy-Guay, CEO of SBQuantum, one company participating in the competition. 'The World Magnetic Model is the magnetic model used in any and all navigation systems,' says Mike Paniccia, the program manager for the model. The map is maintained by the National Geospatial-Intelligence Agency (NGA)..."

Majestic Model 25, 9-Tube Twin-Detector Radio

Majestic Model 25, 9-Tube Twin-Detector Radio Service Data Sheet, February 1932 Radio-Craft - RF CafeOnce again I have given selflessly and freely of my time and talent to make available resources to those seeking certain knowledge regarding vintage radio circuits ;-) This time it is the Radio Service Data Sheet for the Majestic Model 25, 9-Tube Twin-Detector. The info was published in a 1932 edition of Radio-Craft magazine, one of Hugo Gernsback's many endeavors. Also on the page is a complete list of all such schematics and tuning and repair data posted thus far. At the left is a very nice example of a Majestic Model 25 console radio, on the ebth.com auction website. Lots of great photos are posted with close-ups of the tuning dial and the electronics chassis. Since this will eventually disappear, I had Archive.org save a copy of the page.

X-Microwave Needs a Sr. RF Principal Engineer

/2023/X-Microwave-Sr-RF-Principal-Engineer-Manager-10-13-2023.htm"> X−Microwave Needs a Sr. RF Principal Engineer - RF CafeX-Microwave, a Quantic company, provides modular RF and microwave building blocks that allow designers to seamlessly design, evaluate, prototype, and produce high performance RF and microwave systems faster, easier, and at lower cost. Quantic X-Microwave is seeking an experienced and motivated /2023/X-Microwave-Sr-RF-Principal-Engineer-Manager-10-13-2023.htm"> Sr. RF Principal Engineer at X-Microwave to join our team to support design and development of complex radar, electronic warfare (EW) and airborne RF microwave assemblies and subsystems. Quantic X-Microwave is experiencing substantial growth at our facility in Austin, Texas and we are seeking skilled talent to join our Engineering and Manufacturing team. In this position you will design, develop, assemble, integrate, and test complex RF assemblies and subsystems. Perform component analysis, trade studies, simulations, modeling, to ensure compliance with our customers product specifications...

After Class - Using Load Lines

After Class - Using Load Lines, January 1956 Popular Electronics - RF CafeUse of a load line chart is a fast way of selecting the bias (operating) point and the most linear operational range for nonlinear devices. Notice that I didn't specifically say for transistors because this particular article deals with load lines for vacuum tubes. Almost nobody has any need for tube load line charts anymore, but the skill needed to interpret load lines for transistors is fundamentally the same as for tubes. Substitute Vce (collector-to-emitter voltage) for Plate Volts and Ic (collector current) for Plate Milliamperes and you have equivalence. Popular Electronics magazine ran this "After Class" tutorial series covering a broad variety of topics for many years. There is a short Load Line Quiz at the end to measure how well you understand the lesson.

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 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.

Thursday the 12th

Hobnobbing with Harbaugh

Hobnobbing with Harbaugh, August 1961 Popular Electronics - RF CafeHobnobbing with Harbaugh was a fairly regular feature in Popular Electronics magazine in the 1950 and 1960s, compliments of Dave Harbaugh. His cartoon themes touched on issues and situations of the day, mostly dealing with, as you might expect, electronics. Many of them take place in an electronics service shop or a sales floor. Harbaugh was an equal opportunity exploiter of dumb acts by both workers and customers. My favorite of these four from the August 1961 issue is the guy servicing the Japanese chassis. A close second is the portable TV gag; it took a moment to realize what is going on in the comic. The short-order repair service is pretty clever as well. The forth comic is a little too inane to even be funny, but that's just me. I took the liberty of colorizing these comics, as I have been doing with many of them. Color in magazines was a rare commodity even in 1961.

Sustainable Semiconductors with Multielement Ink

Sustainable Semiconductors with Multielement Ink - RF Cafe"Semiconductors are the heart of almost every electronic device. Without semiconductors, our computers would not be able to process and retain data; and LED (light-emitting diode) light bulbs would lose their ability to shine. But semiconductor manufacturing requires a lot of energy. Forming semiconductor materials from sand (silicon oxide) consumes a significant amount of heat-intensive energy, at scorching temperatures of around 2,700 degrees Fahrenheit. And the process of purifying and assembling all the raw materials that go into making a semiconductor can take weeks if not months. A new semiconducting material called "multielement ink" could make that process significantly less heat-intensive and more sustainable. Developed by researchers from Lawrence Berkeley National Laboratory (Berkeley Lab) and UC Berkeley, "multielement ink" is the first high-entropy..."

The Man Before Marconi: Joseph Loomis

The Man Before Marconi: Joseph Loomis, August 1948 QST - RF CafeBlack Friday is known to most modern-day people as the frenzied first day of Christmas shopping season on the day after Thanksgiving (the 3rd Thursday of November). It is named so because supposedly on that day many retailers finally turn the ink in their accounting books from red to black (net loss to net profit, respectably). However, there was an infamous Black Friday that occurred in the Fall of 1869, when the U.S. stock market experienced a severe crash. Many know of the 1929 crash that precipitated The Great Depression, but the other Black Friday, per this historical article from a 1948 edition of QST magazine, caused its own "great depression" in wireless communications pioneer Dr. Mahlon Loomis. His reaction is understandable after reading this piece - which I highly recommend to you. Dr. Loomis was a dentist whose side profession was being an electrical experimenter. Decades prior to Guglielmo Marconi's world-changing wireless message between St John's, Newfoundland, and Poldhu, Cornwall, in 1901, Loomis publically demonstrated wireless communications between kite-borne antennas (metal wire between the kite and the ground, a la Benjamin Franklin). It occurred between two mountaintops separated by 18 miles. The high drama that occurred thence while attempting to secure sponsorship funding for further experimentation is utterly amazing...

Axiom Blog: Essentials of DC Power Supplies & Loads

Axiom Test Equipment Blog: Essentials of DC Power Supplies & Loads - RF CafeAxiom Test Equipment, an electronic test equipment rental and sales company has published a new blog post that covers how important DC power supplies and loads are to control energy on the workbench and often serve as starting points for new product development. DC loads and power supplies work together to define the behavior of a device under test (DUT) in response to applied energy, not just in performance but in reliability and compatibility with other electronic devices. Power supplies are haunted (get it - Halloween coming?) by two forms of noise: normal-mode output noise and common-mode output noise. Normal-mode noise is generated by a power supply's internal circuitry while common-mode noise is earth-referenced noise originating from the power line or source. On the other hand, DC loads help evaluate power conversion devices and systems, including power supplies and rechargeable batteries for electric vehicles (EVs). The simplest starting point when searching for a DC power supply is the amount of energy it supplies...

Canada Puts Limit on R.F. Interference

Canada Puts Limit on R.F. Interference, February 1960 Electronics World - RF CafeAudio noises have been well tabulated in the past but how does one set a tolerable limit for radio-frequency noise? A recent Canadian Department of Transport regulation (known officially as SOR 59-116 by the Queen's Printer, Ottawa, Canada) has defined radio-frequency noise as any electrical disturbance "produced by any mechanical, electrical, or other device" and capable of being received on a radio receiver. The regulation refers specifically to r.f. generators in the ISM industrial bands, in which the amount of r.f. energy produced is without limitation. However, any r.f. generator in those bands must not have any emission outside of the band in excess of 25 microvolts-per-meter at a distance greater than one-thousand feet from the r.f. generator. A provision is also made that if r.f. generators are operated on any frequency outside the ISM bands the limit shall be 15 microvolts-per-meter at 1000 feet. Allowance is also made for higher power industrial equipment...

RF & Electronics Stencils for Visio

RF & Electronics stencils for Visio r4 - RF CafeWith more than 1000 custom-built stencils, this has got to be the most comprehensive set of Visio Stencils available for RF, analog, and digital system and schematic drawings! Every stencil symbol has been built to fit proportionally on the included A-, B-, and C-size drawing page templates (or use your own page if preferred). Components are provided for system block diagrams, conceptual drawings, schematics, test equipment, racks (EIA 19", ETSI 21"), and more. Test equipment and racks are built at a 1:1 scale so that measurements can be made directly using Visio built-in dimensioning objects. Page templates are provided with a preset scale (changeable) for a good presentation that can incorporate all provided symbols...

Please Thank RF & Connector Technology for Their Support

RF & Connector Technology - RF CafeProviding full solution service is our motto, not just selling goods. RF & Connector Technology has persistently pursued a management policy stressing quality assurance system and technological advancement. From your very first contact, you will be supported by competent RF specialists; all of them have several years of field experience in this industry allowing them to suggest a fundamental solution and troubleshooting approach. Coaxial RF connectors, cable assemblies, antennas, terminations, attenuators, couplers, dividers, and more. Practically, we put priority on process inspection at each step of workflow as well as during final inspection in order to actualize "Zero Defects."

Wednesday the 11th

America Listens In - German War Propaganda Radio

America Listens In - German War Propaganda Radio, June 1941 Popular Science - RF CafeJune of 1941, when this "America Listens In" article appeared in Popular Science magazine, was half a year before the Japanese Imperial Navy launched its surprise attack on the U.S. Navy at Pearl Harbor. We had been unofficially providing England, France, and a handful of other western European countries with intelligence data and even some military hardware and troop training, but had no Congressionally declared entrance into what would become World War II. Described here are methods and equipment used to listen in on, translate, and study foreign broadcasts, mostly from Germany. Use of wax cylinders for recording voice broadcasts was state of the art at the time, since magnetic tape technology was still in its infancy. Maybe we should have been putting as much effort into monitoring Japanese broadcasts; we might have averted the attack. BTW, if you think the current state of affairs regarding strife engendered between people groups being the work of media, dig this from the article: "Ill feeling of another kind is the aim of the propaganda of dissension. By recalling dissatisfactions...

China Plans 12k Satellite Constellation to Beat SpaceX

China Plans 12k Satellite Constellation to Beat SpaceX - RF CafeEarth-based astronomy continue on a path of doom. "China is pushing ahead with the construction of a second satellite megaconstellation to provide broadband internet services and compete with SpaceX's Starlink. G60 Starlink, which is backed by the Shanghai municipal government, will eventually comprise more than 12,000 satellites in low earth orbit. Its potential size is similar to Guo Wang, or National Network, a separate constellation consisting of some 13,000 satellites and commonly known as China's answer to Starlink. It is now under construction by the state-owned Guo Wang company. Last month, a delegation led by Cheng Xiangmin, party secretary of Shanghai's Songjiang district, inspected a new centre in western Shanghai that was dedicated to the massive production of G60 satellites, according to the district's official website. They also met representatives of the project's industrial partners, including Shanghai Alliance Investment and Shanghai Spacecom Satellite Technology..."

Magnetic Ceramics: Ferrites

Magnetic Ceramics: Ferrites, February 1953 QST - RF CafeMagnetic ceramics have been with us for a long time - probably forever as far as most people that use them these days are concerned. When this article was published in a 1953 issue of QST magazine, ferrites for use at RF frequencies were a new, breakthrough phenomenon. Take a look at inductors used in vintage radio equipment and you will find either air or solid iron as the permeable filler elements in most instances. Whereas iron might have a permeability of 100-150, the new magnetic ceramics exhibited permeabilities up to 4,000 at 1 MHz, and even higher for lower frequencies. Modern alloys and compounds provide permeabilities of more than 50,000 for special applications. Such high values allow physical size and weight of inductors and transformers to be greatly reduced. Also, since high permeability does a better job of constraining magnetic fields within their geometries, less shielding is required to prevent crosstalk. A plethora of resources are available on the Internet for design guidelines.

X-Microwave Needs a Radio Frequency Technician

/2023/X-Microwave-Radio-Frequency-Technician-10-10-2023.htm"> X−Microwave Needs a Radio Frequency Technician - RF CafeX-Microwave, a Quantic company, provides modular RF and microwave building blocks that allow designers to seamlessly design, evaluate, prototype, and produce high performance RF and microwave systems faster, easier, and at lower cost. Our Culture Dream Big. Have Fun. Get Stuff Done. As a /2023/X-Microwave-Radio-Frequency-Technician-10-10-2023.htm"> RF Technician at X-Microwave, you will work with innovative team to support product development and manufacturing for a wide range of customer applications. You will be a key team member in the delivery of our modular design platform that streamlines the design, prototyping, and production process of RF and Microwave systems. You must be responsive, flexible, and able to succeed within a fast-paced environment. In this role you will build test benches from DC to 110 GHz, interpret component datasheets and read schematics, and utilize level 3 soldering and rework skills. Electronics, RF hardware, or related discipline, or 5+ years of equivalent experience is required. Contact us today if you are interested...

Electronic Crosswords

Electronic Crosswords, May 1967 Electronics World - RF CafeThis Electronic Crosswords puzzle appeared in the May 1967 edition of Electronics World magazine. Most of the words are related to electronics and science (unlike my RF Cafe crossword puzzles, in which ALL words are pertinent. I will admit though, that I use software to help fill in the matrix (using a database of thousands of hand-entered words and definitions), whereas Mr. Kimsey had to do this one all by himself. If you happen to be an avid cruciverbalist, then you might want to try a few of the RF and microwave engineering themed crosswords that I have been publishing weekly for two decades...

RF Cascade Workbook

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

Thanks to Wireless Telecom Group for Their Support!

Wireless Telecom Group (RF power and noise measurement) - RF CafeThe Wireless Telecom Group, comprised of Boonton, Holzworth, and Noisecom, is a global designer and manufacturer of advanced RF and microwave components, modules, systems, and instruments. Serving the wireless, telecommunication, satellite, military, aerospace, semiconductor and medical industries, Wireless Telecom Group products enable innovation across a wide range of traditional and emerging wireless technologies. A unique set of high-performance products including peak power meters, signal generators, phase noise analyzers, signal processing modules, 5G and LTE PHY/stack software, noise sources, and programmable noise generators.

Tuesday the 10th

What's Your EQ? (Electronics Quotient)

What's Your EQ?, September 1963 Radio-Electronics - RF CafeThree new circuits challenges await you from this "What's Your EQ?" feature in the September 1963 issue of Radio-Electronics magazine. "EQ," by the way, stands for Electronics Quotient (a la "IQ"). The first one is a relatively simple solving of two equations in two unknowns. Yes, I worked it out; in fact, my solution is via the "complete the square" method, whereas the author's solution plugs the coefficients in the quadratic equation. "Why No Voltage" is not too hard, and is easily understood based on the author's explanation. "Where's the TVI?" is more of a case study of an actual experience in locating the source of television interference. The culprit ends up being similar to the source of AM radio interference I got on my car radio in a certain area on my drive to work. It was worst on high humidity mornings. Turns out the problem was that same as the author's situation, only the damaged component in my case was a result of wear and tear - not sabotage.

ARRL 2023 Online Auction

ARRL 2023 Online Auction - RF CafeThe American Radio Relay League (ARRL) is holding its ARRL 2023 Online Auction from October 13th through 19th. A preview of auction items begins on October 10th. "Proceeds from our yearly Online Auction go directly to ARRL's education programs, including promoting activities to license new hams, strengthening Amateur Radio's emergency service training, offering continuing technical and operating education, and creating instructional materials. We would like to express our sincere appreciation to our corporate partners and members for your generous donations." There are currently 74 items available, including radios, antennas, power supplies, tuners, noise cancellers, test equipment, cable, books, microphones, and even "Mystery Boxes." If you have something for the auction, now is the time to get it listed.

VLF Loop Antenna

VLF Loop Antenna, January 1963 Electronics World - RF CafeIf you have been searching for a do-it-yourself VLF loop antenna that can be resonated from approximately 14 to 25 kHz, then look no more. This article from a 1963 edition of Electronics World magazine presents a relatively simple to build job that reportedly provides excellent reception. At these frequencies a wavelength is measured in miles, which makes even a simple dipole antenna impractical, so the multi-turn loop is the only reasonable alternative for most people. It is the same principle that allows the little ferrite-core antenna inside your AM radio to work so well when the shortest wavelength in the commercial AM broadcast band (535 - 1700 kHz in the U.S.) is nearly 600 feet.

RIGOL Intros DHO800/DHO900 Ultraportable Oscilloscopes

RIGOL Intros DHO800/DHO900 Ultraportable Oscilloscopes - RF CafeRIGOL Technologies has added to its line-up of high resolution oscilloscopes with the introduction of the DHO800/DHO900 series. These new oscilloscopes have a compact, portable design which is flexible to use for both on-site and desktop testing. DHO800/900 oscilloscopes feature true 12-bit resolution with low noise for excellent signal fidelity and analysis. DHO900 oscilloscopes are available in 125-250 MHz bandwidths, 4 channels, 1.25 GSa/sec sampling, 1,000,000 wfms/s waveform capture rate, and 50 MPts of memory standard. DHO800 scopes offer 70-100 MHz bandwidths, 4 channels, 1.25 GSa/sec sampling, 1,000,000 wfms/s waveform capture rate, and 25 MPts of memory standard. Both series feature 12 bit resolution, a 7" intuitive touch screen display and support type-C power. They are powered by the new UltraVision III platform featuring a custom ASIC chipset, which also provides for dramatically lower front-end noise. The higher resolution and lower noise enable users to analyze much smaller signal artifacts with greater speed and accuracy. "The new DHO800 and 900 series scopes are an excellent extension...

Summer Radio

Summer Radio, July 1934 Radio News and The Short-Wave - RF CafeReceiving information wirelessly or even over a wire is taken for granted today, but 80 years ago it was considered a "miracle of God" - that's what Alexander Graham Bell called it. Some regarded radio as being of the devil. The same is true of today's omnipresent communications - some consider it a blessing while others call it a curse. I'm somewhere in the middle. In 1934 when this Radio News & Shortwave magazine was published, the telecommunications world was in its heyday of growth with a reported 17 million listeners of AM radio (no FM yet). Radio dealers and servicemen were gearing up for customers with unbridled enthusiasm for the fledgling commercial broadcast industry's offerings. Even in the midst of the Great Depression, people were joining in on the wireless craze in large numbers, and amateur radio operators were almost feared for their awesome ability to comprehend and practice the black art of antennas and radio receivers...

How to Target RFCafe.com for Your Google Ads

Google AdSense - it makes good sense - RF CafeOne aspect of advertising on the RF Cafe website I have not covered is using Google AdSense. The reason is that I never took the time to explore how - or even whether it is possible - to target a specific website for displaying your banner ads. A couple display opportunities have always been provided for Google Ads to display, but the vast majority of advertising on RF Cafe is done via private advertisers. That is, companies deal with me directly and I handle inserting their banner ads into the html page code that randomly selects and displays them. My advertising scheme is what the industry refers to as a "Tenancy Campaign," whereby a flat price per month is paid regardless of number of impressions or clicks. It is the simplest format and has seemed to work well for many companies. With nearly 4 million pageviews per year for RFCafe.com, the average impression rate per banner ad is about 220,000 per year (in six locations on each page, with >17,000 pages). That's pretty good exposure for $300 per month. Some companies have expressed an interest in being able to manage their advertising accounts themselves a la the Google AdSense program...

Many Thanks to KR Electronics for Long-Time Support!

KR ElectronicsKR Electronics has been designing and manufacturing custom filters for military and commercial radio, radar, medical, and communications since 1973. KR Electronics' line of filters includes lowpass, highpass, bandpass, bandstop, equalizer, duplexer, diplexer, 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.

Monday the 9th

International Correspondence Schools

International Correspondence Schools, August 1937 Popular Mechanics - RF CafeThis International Correspondence Schools ad in a 1937 issue of Popular Mechanics magazine made me laugh when I saw it, so I figured it was worth posting to see how you react to it. As a lifelong consumer of technical and do-it-yourself type magazines, I remember always seeing advertisements for at-home learning courses, as well as many campus-based training for fields that require hands-on work with engines, machinery, boats, trains, airplanes, etc. Local, state, and federal code books were not bursting at their bindings with rules and regulations on every aspect of business from initial registration to specific kinds of goods and services you were permitted to ply your trade toward, and for whom you might be willing to work. A man could fairly easily gain enough knowledge through self-study to start his own business and/or qualify for an apprenticeship with experienced operators - often without a large investment in equipment. Interestingly, there do not seem to be any courses offered in areas like...

Espresso Engineering Workbook™ for Excel - 10.9.2023

RF Cafe Espresso Engineering Workbook™ for Excel - RF CafeRF Cafe Espresso Engineering Workbook™ for Excel - RF CafeThe newest release of RF Cafe's spreadsheet (Excel) based engineering and science calculator is now available - Espresso Engineering Workbook™.  Among other additions, it now has a Spurious Product Calculator with a graphical display. Since 2002, the original Calculator Workbook has been available as a free download. Continuing the tradition, RF Cafe Espresso Engineering Workbook™ is also provided at no cost, compliments of my generous sponsors. The original calculators are included, but with a vastly expanded and improved user interface. Error-trapped user input cells help prevent entry of invalid values. An extensive use of Visual Basic for Applications (VBA) functions now do most of the heavy lifting with calculations, and facilitates a wide user-selectable choice of units for voltage, frequency, speed, temperature, power, wavelength, weight, etc. In fact, a full page of units conversion calculators is included. A particularly handy feature is the ability to specify the the number of significant digits to display. Drop-down menus are provided for convenience. Now that a more expandable basis has been created, I plan to add new calculators on a regular basis...

What You Should Know About Film Resistors

What You Should Know About Film Resistors, January 1965 Electronics World - RF CafeMetal oxide resistors have been around since the early 1960s. We take them for granted now, but prior to their appearance on the market the mainstays of electronics resistance elements were carbon composition and wirewound resistors. Carbon compound types are very inexpensive and are acceptable for a wide range of applications, but they have a bad habit of shifting value over time, particularly when subject to repeated heating and cooling cycles. Wirewounds (WW) are a good alternative when cost and physical space are not issues, but WW's can be tricky or even impossible to use when frequencies get above a few tens of megahertz because of inductance limitations. Metal film resistors exhibit much better long term stability than carbon composition types, and can operate well at frequencies in the hundreds of megahertz while dissipating a few watts of power. The television industry benefitted greatly...

Recessing Metal Contacts for GaN Transistors

Recessing Metal Contacts for GaN Transistors - RF Cafe"Researchers based in Sweden report low ohmic contact resistance (Rc) for recessed titanium/aluminum (Ti/Al) metal electrodes with a view to deployment in gallium nitride (GaN) high-electron-mobility transistors (HEMTs) and other transistors. Rc values as low as 0.14Ω-mm were achieved with a low annealing temperature of 550°C. The team from SweGaN AB, Chalmers University of Technology, Linköping University, Terahertz Materials Analysis Center, and Lund University, comment that their approach 'provides a large process window without the requirement of precise control of the recessed etching depth.' Lowering Rc for HEMTs should reduce power losses, making for less heat and noise generation, while increasing power output and efficiency. The team sees their electron-beam evaporation process as being less complex than other recessed contact structures that regrow doped III–nitride material in metal-organic chemical vapor deposition (MOCVD) in the recess. Electron-beam evaporation is more favored in industrial production..."

RCA Victor Portable Phonograph Electrola Model R-95

RCA Victor Portable Table Phonograph Electrola Model R-95 Radio Service Data Sheet, July 1936 Radio-Craft - RF CafeThe RCA Victor Portable Table Electrola Model R-95 is a record player / turntable / phonograph (choose your terminology) with a built-in audio amplifier and voice coil speakers speakers. Many portables of the day were all mechanical with hand cranks for power and one of the big horn sound amplifiers like on the Victrolas (note the R-95 is called an "Electrola"). Little information is available for it on the Web, and I could not find any photos. "Portable" back in 1936, when this schematic and datasheet appeared in Radio-Craft magazine, meant it might be possible for a person of moderate strength to lug it around and set it up on a table. An accompanying hernia was often involved. There are still many people who restore and service vintage radios and phonographs, so I post these when run across. A growing list of all data sheets can be found at the bottom of the page...

RF Cascade Workbook

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

Many 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.

Sunday the 8th

Engineering Theme Crossword for October 8th

Engineering Theme Crossword Puzzle for October 8th, 2023 - RF CafeThis custom RF Cafe engineering-themed crossword puzzle for October 8th contains words and clues which pertain exclusively to the subjects of electronics, science, physics, mechanics, engineering, power distribution, astronomy, chemistry, etc. If you do see names of people or places, they are intimately related to the aforementioned areas of study. Being that "H" is the 8th letter of the alphabet, it is used as the first and/or last letter of many words in today's crossword puzzle - as well as in-between. Those clues are marked with an asterisk (*, or **, depending on the number of them in the word). 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, Baseball Caps, and more, all sporting my amazingly clever "RF Engineers - We Are the World's Matchmakers" Smith chart design. These would make excellent gifts for husbands, wives, kids, significant others, and for handing out at company events or as rewards for excellent service. My graphic has been ripped off by other people and used on their products, so please be sure to purchase only official RF Cafe gear. I only make a couple bucks on each sale - the rest goes to Cafe Press. It's a great way to help support RF Cafe. Thanks...

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.

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.

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KR Electronics (RF Filters) - RF Cafe
Innovative Power Products Passive RF Products - RF Cafe

Windfreak Technologies Frequency Synthesizers - RF Cafe

ConductRF Phased Matched RF Cables - RF Cafe