Today in Science History

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 280k per year (in eight locations on each page, with >17k pages)...

Basic Navy Training Courses - Electrical Meters

Electricity - Basic Navy Training Courses, NAVPERS10622, Chapter 18 Electrical Meters - RF CafeIn an electrical system, "how much?" is asked about four quantities - current, voltage, resistance, and power. And four kinds of meters measure these quantities - ammeters, voltmeters, ohmmeters, and wattmeters. Each meter's name indicates its use. Every conductor, every motor, every circuit of any kind has a rated current load. Exceed this rated load and you ask for trouble - heat develops, connections melt, and insulation burns. Ammeters tell you exactly how much current is flowing - they forewarn you of overload. Each insulation has a voltage rating. And 120-volt insulation will not stand 240 volts. It's like trying to put 70 pounds of air pressure in a bicycle tire rated at 35 pounds. Something lets loose. Motors are built to operate at a definite voltage of 110, 220, or 440 volts. If you try to operate a motor above or below its rated voltage, it either "burns out" or gives such poor service that it's useless...

Basic Navy Training Courses - Ohm's Law

Electricity - Basic Navy Training Courses, NAVPERS 10622, Chapter 6 - Ohm's Law - RF CafeDuring the late 1700's and early 1800's, three great electrical discoveries were made. An Italian, named Volta, discovered how to produce an EMF from a primary cell. He gave his name to the measuring unit of electromotive force - the VOLT. Ampere, a Frenchman, measured current flaw and gave his name to the measuring unit of current - the AMPERE. A German, named Ohm, measured the resistance of circuits and conductors and gave his name to the resistance measuring unit - the OHM. Ohm did more than experiment with resistance - he connected his own discoveries with those of Volta and Ampere. The result was OHM'S LAW. Make sure you understand each one of the three quantities in electricity - they make up Ohm's Law. On the following page is a table of these important quantities, their symbols, their units, their abbreviations, and their effects an a circuit...

What's Your EQ?

What's Your EQ?, April 1967 Radio-Electronics - RF CafeThis newest "What's Your EQ?" (Electronics Quotient) challenge appeared in the April 1967 issue of Radio-Electronics magazine. It only has two circuits to work out. The first is a fairly basic analysis problem where a voltage source and some resistors are connected. You need to solve for the value of one resistor, given the current through it. As it often the case, re-drawing the schematic to remove cross-connections clarifies the situation and makes the task much simpler. The other problem is a black box type, and it should not pose much of a problem. Not stated but implied is that the diodes within are ideal and do not have a junction voltage drop (sorry for the spoiler, but it really should have been included in the statement). Bon chance, viel Glück, 祝你好运, buena suerte, Удачи, καλή τύχη, がんばって, powodzenia, buona fortuna, and good luck...

An Accurate Voltage Divider

An Accurate Voltage Divider, May 1957 Radio & TV News - RF CafeIt took me a couple passes of the explanation to comprehend the advantage of a Thomson-Varley (aka Kelvin-Varley, since Thomson and Lord Kelvin are one and the same person) switchable voltage divider compared to a standard type. At first I thought the author, Edwin Bohr, was implying that the source and load impedances would not have as great of an effect on the accuracy of the divider (and to some extent it is less sensitive), but the main advantage is that the configuration permits simple cascading stages of decade dividers to achieve essentially any degree of resolution. Both a standard series-wired type voltage divider and the Thomson-Varley need ten resistors and eleven switch positions to provide 10 equal steps (plus bypass). However, using the same approach for 100 equal steps in the standard divider scheme would require 100 resistors, 1000 steps would require 1000 resistors, etc. The Thomson-Varley divider cascades decades of dividers so that 100 equal divisions requires only 20 resistors, 1000 divisions requires 30 resistors, etc. Such a 'breakthrough' idea was particularly significant in the days when large radial lead components and multi-layered wafer switches that were point-to-point hand-wired were all that were available, as compared to printed circuit boards that are automatically assembled with pick-and-place robots today. Obtaining large quantities of precision resistors is a lot easier nowadays as well. Metrology laboratories still use Thomson-Varley type voltage dividers for equipment calibration...

Exodus LNA2006, 10 MHz-18 GHz, 23 dBm LNA

Exodus LNA2006, 10 MHz −18 GHz, 200 mW, LNA - RF CafeExodus Advanced Communications, is a multinational RF communication equipment and engineering service company serving both commercial and government entities and their affiliates worldwide. We are pleased to offer our low-noise power amplifier for 10 MHz to 18.0 GHz. The LNA2006 produces 23 dBm (200 mW) power with 23 dB gain. A small class-A benchtop linear design for optimum reliability & ruggedness for all EMC applications. Suitable for all single channel modulation standards. Built-in protection circuits.

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, and more. Page templates are provided with a preset scale (changeable) for a good presentation that can incorporate all provided symbols...

20-Year Tubes For Transatlantic Cable

20-Year Tubes For Transatlantic Cable, May 1957 Radio & TV News - RF CafeWho knew that the British General Post Office was once in the vacuum tube development business? This 1957 article about the world's first transatlantic telephone line (TAT-1) mentions that the amplifier and frequency equalizer repeater circuits and components for the Newfoundland and Nova Scotia section of line was their responsibility. Bell Telephone Lab handled the deep-sea portion of the system that ran between Newfoundland and Scotland. Everything was designed to have at least a 20-year service-free lifespan. TAT-1 was inaugurated September 25, 1956, and was decommissioned in 1978 without any technical failures (although a trawler did snag the cable once, causing a brief outage), thus achieving its designed longevity goal. An interesting solution was implemented to provide the high voltage requirements of the equipment while avoiding excessive dielectric thicknesses...

Tech Headlines  <Archives>

Electronics & Technical Headlines - RF Cafe• Today Is World Amateur Radio Day

• More Small 5G Towers Reduce Network Energy Requirements

• FCC to Online Retailers: Cease Selling Non-Secured IoT Devices

• How AI Could Have Prevented the Key Bridge Collision (or caused it) 

Energy Conversion Quiz

Energy Conversion Quiz, April 1963 Popular Electronics - RF CafeThis quiz from a 1963 issue of Popular Electronics magazine challenges (not too much, though) your knowledge of energy conversion in common devices. A few of them might be unfamiliar to people born after about 1990, but even so, you've probably seem them all at some point, especially if you are a regular RF Cafe visitor (meaning you're probably smart). It won't be giving anything away by telling you that item B is a heater that screws into a light bulb socket, and item F is a phonograph stylus. Robert P. Balin constructed many quizzes of this kind in the 1960s and 70s. A complete list of all the Popular Electronics Quizzes is lower on this page...

The Incredible Ovshinsky Affair

The Incredible Ovshinsky Affair, September 1969 Electronics Illustrated - RF CafeEven with having been granted more than 400 patents in his lifetime, and being a major player in the realms of energy, data storage, and semiconductor research and manufacturing, you - as well as most people - have probably never heard the name Stanford Ovshinsky. He was somewhat of a celebrity in the 1960s and 1970s when working hard to promote his concept of "glassy semiconductors," - aka Ovonic devices. Ovonics are amorphous materials that are used for making switches for digital logic and memory devices. Either the Ovshinsky process did not pan out for high volume commercial production or some other technology displaced the what it was hoped to dominate. Not too long ago when watching an episode of original The Man from U.N.C.L.E. TV series, the Ovshinsky Effect was mentioned by Illya Kuryakin when watching it after having read this article in a 1969 issue of Electronics Illustrated magazine...

Alaska Telephone Cable Opened for Use

Alaska Telephone Cable Opened for Use, March 1957 Radio & Television News - RF CafeAlaska and Hawaii were added to the Union as the 49th and 50th states, respectively, in 1959. Prior to that time, both were referred to as possessions or territories. This story from a 1957 edition of Radio & Television News refers to Bell Telephone Systems and the U.S. Army Signal Corps laying the first cable for opening commercial telephone service between Port Angeles (near Seattle), Washington, and Ketchikan, Territory of Alaska. The 900 mile, submarine cable carried 36 circuits, and took 2 years to install at a cost of $20 million ($226 million in 2024 money per the BLS). Work conditions for crews were nowhere near as accommodating or protected against accidents as they are today. As with so many things, our forebears sacrificed life and limb, literally, to bring us to the comfortable existence we enjoy today. The men in these and other vintage photos I post deserve your gratitude...

Thanks Again to everythingRF for Long-Time Support!

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

It's a Clumsy World for Lefty

It's a Clumsy World for Lefty, September 1961 Popular Science - RF CafePardon my self-indulgence here, but in this world where every idiosyncrasy of every person and/or special interest group and/or identity group must be accommodated - yea, even celebrated and accorded special privileges - why is it that we left-handers, south-paws, leftys, gawk-handers - call us what you may - to this day are forced to adopt the practices and implements of right-handers? If a left-handed version of a keyboard (number keys on left), a pair of scissors, notebooks with hinging on the right, mugs with handle to the right of design, tape measures that extend to the left with numbers right-side up, etc., it usually costs more. Speaking of reparations (were we?), while many of the aforementioned entities are claiming a right to reparations for past injustices regardless of whether the claimant ever personally suffered from it, why shouldn't leftys, who historically have been forced to adopt and adapt to the righty's world, and even punished for resistance or inability, also now be financially compensated for the indignances? A few years ago I would have asked for a cool million dollars, but with the hyperinflation of late, I need $1.19M today. In cash, and tax-free...

Understanding Error Vector Magnitude (EVM)

Understanding Error Vector Magnitude (EVM) - RF CafeRhode & Schwarz publishes a lot of very useful application notes that are particularly for newcomers to the field of RF and microwaves. All are forms of infomercials for their products, but than all companies do it. This new one entitled, "Understanding EVM," provides "...an introduction to error vector magnitude (EVM), which is the primary metric of modulation accuracy. This paper is divided into three sections. The first section discusses the fundamentals of the digital modulation schemes used in modern radio frequency communications systems, in particular, APSK and QAM. The second section discusses the fundamentals of error vector magnitude. This section not only defines EVM, but also discusses the most common sources of EVM, how EVM is measured, and the effects of EVM. The final section explains the basics of constellation diagrams and how constellation diagrams can often be used to diagnose or troubleshoot the common root causes of EVM. EVM is measured at each symbol time, and larger values of EVM indicate greater distance between the measured and ideal points..."

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 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...

3D Magnetic Recording for Ultra Storage HDDs

3D Magnetic Recording: Unprecedented Hard Drive Storage Density - RF Cafe"Research groups from NIMS, Seagate Technology, and Tohoku University have made a breakthrough in the field of hard disk drives (HDD) by demonstrating the feasibility of multi-level recording using a three-dimensional magnetic recording medium to store digital information. The research groups have shown that this technology can be used to increase the storage capacity of HDDs, which could lead to more efficient and cost-effective data storage solutions in the future. Enhancing Data Storage Capacity Data centers are increasingly storing vast amounts of data on hard disk drives (HDDs) that use perpendicular magnetic recording (PMR) to store information at areal densities of around 1.5 Tbit/in². However, to transition to higher areal densities, a high anisotropy magnetic recording medium consisting of FePt grains combined with heat-assisted laser writing is required. This method, known as heat-assisted magnetic recording (HAMR), is capable of sustaining areal recording densities of up to 10 Tbit/in². Furthermore, densities of larger than 10 Tbit/in² are possible based on a new principle demonstrated by storing multiple recording levels of 3 or 4 compared..."

Help Needed with Capacitor Markings

RF Cafe visitor James G. sent me photos of some paper capacitors he plans to replace in a 1950s vintage radio set. It is a foreign job, most likely from France, based on the schematic. Some markings on the capacitors are not familiar; maybe you have seen them. The photos show things like "ESSAI 1.500 V.C.C." which I assume means 1,500 V (1.5 kV) working voltage, based on the European swapping of dots and commas for decimal points. "Essai" in French means "test," or "trial." "V.C.C." is probably a French marking for voltage similar to WVDC (DC working voltage). Another marking shows "100/1000 deF," which could be μμF, but unlikely given it is a paper capacitor. Maybe millifarad? Any insight will be appreciated.

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...

Rare Metals, Once Forgotten, Now in Production

Rare Metals, Once Forgotten, Now in Production, October 1949 Popular Science - RF CafeHere is a really good synopsis of "rare earth" elements that explains how they came to be known in that way. Hint: It is not that they are so rare, in fact per Wikipedia, Cerium is the 25th most abundant element on Earth. The issue is they are not in concentrated lodes, but spread out as components of other mineral compounds, so extensive processing is needed to isolate and purify them. One of the first post-war commercial level extraction processes was the result of experimentations during nuclear bomb research. As you might know, "holes" existed in the Periodic Table of the Elements when it was first constructed in 1869 by Dmitri Mendeleev, because not all predicted naturally occurring elements had been found. Helium, atomic number 2, was not found on Earth until 1895, after first having been observed in the sun's spectrum a few years earlier (hence its name, from Helios). Author Alden Armagnac provides a primer in the original 15 rare earths (now 17) in this 1949 Popular Science magazine article... 

Electronics: Washington Newsletter

Washington Newsletter, October 18, 1965 Electronics Magazine - RF Cafe1965 was the beginning of America's involvement in Vietnam. A mere decade had passed since the end of the Korean War (or "conflict" if you prefer), and the Department of Defense had not done much to modernize the military since then. Unlike with World War II when U.S. factories were turning out military aircraft, ships, and ground vehicles ahead of formal involvement, Congress was not interested in making headlines with news of war machines. When the first U.S. troops were sent in March of that year, things kicked into high gear. Lyndon Johnson was said to have tried to direct the war from the White House, but it was his Secretary of Defense, Robert McNamara, whose actions caused the Vietnam efforts to be nicknamed "McNamara's War." The "Washington Newsletter" feature of this October 1965 issue of Electronics magazine reported on, among other military-related items, the U.S. Air Force's plans to phase out the venerated (now, not then) B−52 Stratofortress bomber by sometime in the 1970s...

RCA Institutes Ad - A Prophecy

RCA Institutes Ad - A Prophecy, October 1961 Electronics World - RF CafeIn the original radio broadcast of Jean Shepherd's "A Christmas Story," which was set in the Great Depression era, he spoke of magazine advertisements promising rewarding careers in electronics for men of adventure. Over the last few years I have posted many such advertisements from vintage electronics magazines, but they were also commonly seen in women's magazines, Life, The Saturday Evening Post, and many others. This ad pitching the Radio Corporation of America's (RCA) home study courses for electronics technology ran in a 1961 edition of Electronics World. Chairman of the Board, David Sarnoff, sends the message to readers. Sarnoff was commissioned as a Brigadier General in the Army Air Corps during World War II. He orchestrated radio broadcasts for the D−Day invasion (June 6, 1944), and also the Radio Free Europe system for post-war years... 

Transistor Takes Advantage of Quantum Interference

Transistor Takes Advantage of Quantum Interference - RF Cafe"As transistors are made ever tinier to fit more computing power into a smaller footprint, they bump up against a big problem: quantum mechanics. Electrons get jumpy in small devices and leak out, which wastes energy while degrading performance. Now a team of researchers is showing that it doesn't have to be that way. With careful engineering, it's possible to turn electrons' quantum behavior into an advantage. A team of English, Canadian, and Italian researchers have developed a single-molecule transistor that harnesses quantum effects. At low temperatures, the single-molecule device shows a strong change in current with only a small change in gate voltage, nearing a physical limit known as the sub-threshold swing. Getting near or beyond this limit will allow transistors to be switched with lower voltages, making them more efficient and generating less waste heat. The research team, including physicists at Queen Mary University of London, achieved this by taking advantage of how quantum interference alters the flow of current in single molecules..."

World DX Chart

World Distance Chart No. 1 & No. 2, July & August 1934 Radio News & The Short-Wave - RF CafeBefore the Internet, cellphone apps, and personal computers, many calculations began with a lookup table, chart, or nomograph. In the case of long distance radio operators [Ham, Short Wave Listener (SWL), and professional types] seeking distance and direction information for pointing antennas, it took a map like this one published by Radio News & Short-Wave magazine in 1934 to estimate an optimal configuration. Such tools were essential in order to determine the best direction to point the antenna, which over a long distance is usually much different than what might be assumed by looking at a flattened projection map of the earth (see "Distance Lends Enchantment" below). Distances in Chart No. 1 are all relative to New York, so operators in other locales need to compensate...

RCA's Cone of Silence

Radio Corporation of America - Cone of Silence, August 1949 Popular Science - RF CafeWhen most people of my era (born 1958) see or hear something about a Cone of Silence, they immediately think of the old Get Smart sitcom that ran in the middle through late 1960s (we have the DVD set). Don Adams, aka Maxwell Smart, aka Agent 86, and Barbara Feldon, aka Agent 99 (no name actually used), were the top operatives within the good-guy international crime fighting organizations known as CONTROL*. Their arch enemy was KAOS*. One of the gags used in the show was the Cone of Silence, meant to ensure a conversation between two CONTROL agents would not he heard by anyone else. The problem was that it never worked properly and the people ended up yelling to each other and/or holding up handwritten notes - both of which negated the need for a Cone of Silence. The users were most often Max and The Chief. The Get Smart series was a spoof of James Bond and The Pink Panther...

Overcoming Heisenberg Uncertainty

Overcoming Heisenberg Uncertainty in Quantum Measurements - RF Cafe"Chasing ever-higher qubit counts in near-term quantum computers constantly demands new feats of engineering. Among the troublesome hurdles of this scaling-up race is refining how qubits are measured. Devices called parametric amplifiers are traditionally used to do these measurements. But as the name suggests, the device amplifies weak signals picked up from the qubits to conduct the readout, which causes unwanted noise and can lead to decoherence of the qubits if not protected by additional large components. More importantly, the bulky size of the amplification chain becomes technically challenging to work around as qubit counts increase in size-limited refrigerators. Bolometer-Based Qubit Measurement Cue the Aalto University research group Quantum Computing and Devices (QCD). They have a hefty track record of showing how thermal bolometers can be used as ultrasensitive detectors, and they just demonstrated..."

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+ 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...

Heathkit HW−5400 HF SSB/SW Transceiver Update

Heathkit HW−5400 HF SSB/SW Transceiver Update - RF CafeThis good bit of personal insight into the Heathkit HW−5400 high frequency transceiver for Ham radio was offered by website visitor Paul A., of Long Island, New York. Lots of Heathkit builders made modifications, some necessary to achieve advertised performance, and others for improved performance. Paul's efforts are quite impressive. I made the comment that since Heathkit products were not built and tested in-house in large volumes, they did not have the benefit of feedback on performance of systems and components that would otherwise be gained from a production line. Prior to making new products available, Heathkit designers had a number of fellow employees build the kits at home using parts and instructions intended for customers. Changes were made based on that information, but that is nowhere near the quality of feedback provided on an assembly line. He begins: "Back in November of 2023 you had an article about the Heathkit HW5400. It included some photos of an unbuilt kit. This brought back many memories. I'm the original owner of an HW5400 that I purchased in 1985 from the Heathkit store in Northern Virginia. I bought the transceiver, speaker/power supply, keypad and the accessory IF filter. I had no idea what was in store for me! The transceiver worked the first time I turned it on, but after putting it on the air, I began to get reports of distorted or unnatural transmit audio. Thus began a two year long project to fix the bad audio..."

Special Information on Radio, TV, Radar and Nucleonics

After Class: Special Information on Radio, TV, Radar and Nucleonics, November 1957 Popular Electronics - RF CafeBy 1957, when this article appeared in Popular Electronics magazine, betatrons, cyclotrons, cosmotrons, synchrocyclotron, bevatrons, and other forms of "trons" had the physics world all agog with anticipation of the next big discovery. Quarks were still a decade away from being discovered and something as exotic as the Higgs boson (aka god particle) hadn't entered anyone's mind. The news media was agog with reports of the world possibly coming to the end as a result of those experiments sparking a nuclear reaction chain that would cause the whole world to explode. Today, the news media is no smarter, because nowadays they fret over the Large Hadron Collider (LHC) generating a black hole that will implode the whole world. What a ship of fools...

Antennas Go into Hiding

Antennas Go into Hiding, October 1949 Popular Science - RF Cafe1949 wasn't all that long of a time since airplane antennas consisted of a hundred feet or more of wire that was spooled out in the air to trail behind the craft, servicing a CW type radio. The pilot tapped out Morse code on a key strapped to his knee and wrote down the received code as it came in. Prior to landing, the pilot wound the trailing wire antenna back in - which sometimes was forgotten and got ripped off by trees. By the time World War II came around, operating frequencies had moved up in the electromagnetic (EM) spectrum and antennas were accordingly shortened. Still, a review of airplanes at the time showed wire antennas strung from somewhere in the forward region of the airplane (over or under the cockpit) or from the wingtip(s), back to the tip of the vertical fin or tip of the horizontal stabilizer. That was all OK when airspeeds were south of 200 mph or so, but higher speeds caused excessive drag in the air requiring more rugged components, which added to weight. An exposed antenna also was subject to risk of damage from ice, strikes by foreign objects, and oscillation. This Popular Science article reports on some of the many advances made in embedding antennas...

Werbel  9-Way Resistive Power Splitter for DC-7.2 GHz

Werbel Microwave 9-Way Resistive Power Splitter for DC to 7.2 GHz - RF CafeWerbel Microwave, one of the world's premier RF and microwave components manufacturer, is proud to introduce the WM9RD-7.2-S, a 9-way resistive power splitter / combiner that covers DC to 7.2 GHz with ultra-wide bandwidth. This unique design accomplishes extremely flat frequency response in a small radial package. Our unique design approach provides higher than expected isolation between outputs at far ports than would be achieved in a typical star topology (>28 dB between Groups A-B-C, see datasheet). It has applications in markets such as CATV, test and measurement, and military radio. Its small size makes it easy to integrate into compact systems. Designed, assembled, and tested in the USA...

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 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...

Thanks Again for RIGOL Technologies' Continued Support!

RIGOL Technologies (electronics test equipment)RIGOL Technologies is transforming the Test and Measurement Industry. Our premium line of products includes digital and mixed signal oscilloscopes, spectrum analyzers, function / arbitrary waveform generators, programmable power supplies and loads, digital multimeters, data acquisition systems, and application software. Our test solutions combine uncompromised product performance, quality, and advanced product features; all delivered at extremely attractive price points. This combination provides our customers with unprecedented value for their investment, reduces their overall cost of test, and helps speed time to completion of their designs or projects.

Lee de Forest, Father of Radio, 1873-1961

Lee de Forest, Father of Radio, 1873-1961, September 1961 Radio-Electronics - RF CafeThe price of fame and fortune is often fraught with great tribulations and trials - literally. This eulogy of Audio vacuum tube inventor Lee de Forest which was written in 1961 by Radio-Electronics magazine editor Hugo Gernsback, summarizes many of the great accomplishments of the inventor / engineer, but does not mention the battles he fought both to protect his work from misappropriation by others and to defend himself from accusations of the same. All the industry greats - Edison, Armstrong, Tesla, Westinghouse, Noyce, Sarnoff, even Einstein - suffered similar experiences. Mr. Gernsback, a prolific inventor and publisher himself - was a good personal friend of Dr. de Forest, and featured his work often over more than three decades through his (Gernsback's) many trade magazines. A list of many of the articles is at the bottom of this page. If you are not familiar with the story of how de Forest arrived at his amplifying Audion tube, please read "How the Audion Was Invented. The journey began with the use of an open candle flame as a signal detector for CW (continuous wave) signals in wireless telegraphy. Interestingly, Mr. Gernsback deemed having a close-up photo of Dr. de Forest's hands was in important piece of the historical record...

Memristor Breakthrough Transforms Analog Computing

Memristor Breakthrough Transforms Analog Computing - RF CafeRuh-roh, here is another science news item sure to memristor denier and über nimrod Tim H., who for years sent me harassing e-mails to inform me of how memristors are only theoretical entities. He got downright abusive and threatening. Maybe someday I'll reveal his identity ... but I digress. This article from the SciTechDaily website reports on work done at the University of Southern California. It begins: "Researchers have made significant advances in memristor technology, enhancing its precision and efficiency. This innovation promises to bridge the gap between analog and digital computing, offering faster, more energy-efficient processing suitable for AI, machine learning, and beyond..."

Espresso Engineering Workbook™ for Excel

RF 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 Butterworth Bandpass Calculator, and a Highpass Filter Calculator that does not just gain, but also phase and group delay! 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...

Bell Telephone Labs - Circular Waveguide

Bell Telephone Laboratories - Circular Waveguide, June 1955 Radio & Television News - RF CafeAccording to this full-page advertisement in the June 1955 issue of Radio & Television News magazine, Bell Telephone Laboratories was responsible for designing and fielding "waveguide pipe," aka flexible circular waveguides. According to other historical sources, both George Southworth of Bell Telephone Laboratories and Wilmer Barrow of the Massachusetts Institute of Technology (M.I.T.) independently and simultaneously developed circular waveguide, but the early devices were rigid pipe rather than being fabricated from tightly wrapped, insulated wire that permitted it to be bent rather than requiring separate corner and offset pieces. Insertion loss and VSWR is typically not as good as with rigid waveguide, but the ease of installation in many situations justifies the poorer electrical performance. Bell Telephone Laboratories was responsible for a huge number of breakthrough and paradigm-changing discoveries prior to being broken into parts (Regional Bell Operating Companies, aka Baby Bells) in 1984 due to an antitrust lawsuit...

Mac's Service Shop: Customer Cues

Mac's Service Shop: Customer Cues, October 1958 Radio & TV News Article - RF CafeIn 1958 when this "Customer Cues" installment of John T. Frye's "Mac's Service Shop" series of technodramas in Radio & TV News magazine, color television was a relatively new phenomenon. The first commercially sold color TV set - the Admiral C1617A - went on sale at the very end of 1953. The NTSC approved the first standardized specification for a composite color television composite signal (color, gray scale, audio, brightness, synchronization) earlier that year. It allowed the same signal to work with both black and white (B&W) and color receivers. A lot of research went into making sure the viewing public was happy with their sets, using polls, hands-on instruction and publications on how to properly adjust tuning and picture controls, plus tips on installing outdoor antennas and running the twin lead transmission cable down to the set. Of course the proper way to fiddle with the built-in "rabbit ears" antenna was covered as well. I don't think any official pamphlets included mashing tinfoil onto the rabbit ears in complex patterns as many people did - truth is, it must have worked in some cases. In the story, Mac schools Barney on the situation.

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 magazine 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 go. A great collection of old time radio broadcasts can be heard on the Old Radio World and Old Radio Programs websites...

Quiescent Autonomous Magnification Superintendence

Quiescent Autonomous Magnification Superintendence, April 1933 QST - RF CafeMoral standards seem to rigidly obey the second law of thermodynamics, which states that entropy (disorder) increases in a closed system. Most people would say society is more rude and corrupt today than in days gone by - count me among them. However, believing so does not obviate or excuse acts of deviance in the past. Indeed, even esteemed organizations like the American Radio Relay League (ARRL) seems to have been guilty of promoting dishonest acts. To wit, consider this offer appearing in the "Strayed" column of the April 1933 issue of QST magazine, "For Sale: QSL Cards of any country. Win your WAC without delay. Name your spot. We'll send the card." It also describes a scheme for ripping off electronics supplies stores. Shameful!

Please Welcome Temwell as an RF Cafe Sponsor!

Temwell (filters) - RF CafeTemwell is a manufacturer of 5G wireless communications filters for aerospace, satellite communication, AIoT, 5G networking, IoV, drone, mining transmission, IoT, medical, military, laboratory, transportation, energy, broadcasting (CATV), and etc. An RF helical bandpass specialist since 1994, we have posted >5,000 completed spec sheets online for all kinds of RF filters including helical, cavity, LC, and SMD. Standard highpass, lowpass, bandpass, and bandstop, as well as duplexer/diplexer, multiplexer. Also RF combiners, splitters, power dividers, attenuators, circulators, couplers, PA, LNA, and obsolete coil & inductor solutions.

Tiny Chip Generates High-Quality Microwave Signals

Tiny Chip Generates High-Quality Microwave Signals - RF Cafe"Columbia Engineering researchers have built a photonic chip that can produce high-quality, ultra-low-noise microwave signals using only a single laser. The compact device - a chip so small, it could fit on a sharp pencil point - results in the lowest microwave noise ever observed in an integrated photonics platform. The achievement provides a promising pathway towards small-footprint ultra-low-noise microwave generation for applications such as high-speed communication, atomic clocks, and autonomous vehicles. Electronic devices for global navigation, wireless communications, radar, and precision timing need stable microwave sources to serve as clocks and information carriers. A key aspect to increasing the performance of these devices is reducing the noise, or random fluctuations in phase, that is present on the microwave. 'In the past decade, a technique known as optical frequency division has resulted in the lowest noise microwave signals that have been generated to date,' said Alexander Gaeta, David M. Rickey Professor of Applied Physics and Materials Science and professor of electrical engineering at Columbia Engineering..."

Testing RF Amplifiers

Testing RF Amplifiers by Rhode & Schwarz - RF CafeRhode & Schwarz publishes a lot of very useful application notes that are particularly for newcomers to the field of RF and microwaves. All are forms of infomercials for their products, but than all companies do it. This new one entitled, "Testing RF Amplifier Designs," "...offers an overview from electronic design automation to real RF devices while focusing on verification, characterization, repeatability, and throughput. It explains the important characteristics and how they can be verified. In addition, it sheds light on the specialties along the value chain from development, validation and characterization to production." Here is a link to Testing RF Amplifier Designs that doesn't require registration...

Promote Your Company on RF Cafe

Sponsor RF Cafe for as Little as $40 per Month - RF CafeBanner Ads are rotated in all locations on the page! RF Cafe typically receives 8,000-15,000 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. Your Banner Ads are displayed on average 280,000 times per year! 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...

Army/Air Force Rotary Beam Parasitic Array Antenna

U.S. Army and U.S. Air Force Rotary Beam Parasitic Array Antenna, March 1948 Popular Science - RF CafeThe U.S. Air Force became a separate branch of the armed forces on September 18th, 1947, almost exactly two years after Japan unconditionally surrendered to Allied Forces (Germany had unconditionally surrendered back in May). This recruitment advertisement appeared in the March 1948 issue of Popular Science magazine, a year after the Selective Training and Service Act of 1940 expired on March 31st, 1947. It was a joint appeal by the Army and the Air Force for men seeking careers in communications - particularly targeting, it seems, amateur radio operators, by touting a steerable beam antenna. I could not find numbers on how many conscripted and volunteer troops left the service immediately after the war. Many articles reported a big force drawdown in personnel, which combined with massive layoffs in war equipment industries, led to employment problems. It did not last for long, as the Military Selective Service Act of 1948 reinstated draft registration again. After all, the Military Industrial Complex, as 5-star General/President Eisenhower would eventually call it, needed work.