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dB Control dB-9006 Magnum Opus Synthesizer - RF Cafe Website

Littelfuse Advertisement

Littelfuse Ad, April 1954 Radio & Televsion News - RF Cafe WebsiteQuestion: If a fuse is rated at 3 amps, at what value of current should it "blow?" Answer: Not at 3 amps. As this Littelfuse company advertisement from a 1954 issue of Radio & Television News magazine informs us, fuse ratings do not indicate the current value at which a fuse opens to protect a circuits, but rather the maximum current level at which it will NOT blow (open circuit). The same goes for circuit breakers. Various types of fuses are available to handle certain types of applications. For instance, a highly capacitive load will according to the well-known equation iC(t) = C * dv/dt could draw a very large amount of initial (inrush) current if there is not enough series resistance to limit it to prevent...

RF Cafe Quiz: Ohm's Law

Quiz #90: Ohm's Law - RF Cafe WebsiteOhm's Law is the bedrock of electrical engineering. Formulated by Georg Simon Ohm in 1827, it establishes the fundamental linear relationship between voltage (V), current (I), and resistance (R) in an ideal conductor. This simple yet profound equation -- V = IR -- allows engineers to predict circuit behavior, design voltage dividers, calculate power dissipation, and troubleshoot complex systems with ease. While it holds true for most metallic conductors under constant temperature, real-world circuits often involve non-linear components and temperature-dependent materials where the law must be applied with nuance. This Ohm's Law Quiz covers the core mathematical relationships, units of...

On the Very Highs

On the Very Highs, July 1944 QST - RF Cafe Website"Our first complete column devoted to the subject [of v.h.f. and u.h.f. signal variation], presenting material similar to that which follows, was withheld from publication at that time in compliance with censorship." That is an amazing statement from a time when almost any form of technical information that was not already public knowledge was withheld for the sake of the war effort. Nothing that might even remotely give the enemy an edge, and consequently possibly harm our troops, got past the government censors at the War Department. Most citizens and even media editors willingly complied. Compare that with today's 5th column traitors at most of the media outlets that not only can't wait...

Early Digi-Key Advertisement

Digi-Key Advertisement, July 1974 Popular Electronics - RF Cafe WebsiteWaaaay back in the mid-1980s when I first became aware of Digi-Key, it was one of the relatively few electronics component suppliers that had a large on-hand stock of commonly used parts and provided fast shipping. Places like Newark Electronics and Allied Electronics also provided good service, but Digi-Key usually offered lower prices than the others. By the 1990s, I was placing orders at least weekly during circuit design projects. Digi-Key was founded in 1972 in Thief River Falls, Minnesota - the town that for many years often had the country's lowest recorded daily temperature. This 1/4-page advertisement appeared near the back of a 1974 issue of Popular Electronics magazine...

SimSmith / SimNEC Software

SimSmith Smith Chart Software - RF Cafe Cool ProductRandy Rogers, AD7ZU, mentioned in the May 2020 issue of QST magazine the Smith Chart software called "SimSmith," by Ward Harriman, AE6TY. SimSmith first appeared around 2011. Being written in Java, it will run on any operating system that supports Java. Recent versions incorporate Numerical Electromagnetics Code (NEC) code and bear the name "SimNEC." At present, several versions of SimSmith/SimNEC are available. If you are following a video and want to use the SimSmith release closest to that used in the video, look at the top of the screen to see the version of SimSmith being used and then choose between older versions. If you new to the software, he strongly...

The Maser & Sugar Scoop Antenna: Receiver for Signals from Space

The Maser & Sugar Scoop Antenna: Receiver for Signals from Space, November 1960 Electronics World - RF Cafe WebsiteWhen really good researchers set out to write books on history, they do not simply cull information from the publications of fellow contemporary authors; instead, they look for sources that were published during or around the time of the subject being covered. Doing so helps minimize the possibility that inaccuracies have crept into the knowledge pool and that information other authors might have either deemed insignificant or have missed can be recovered. That is part of my motivation for going to the trouble of buying these vintage magazines and posting articles like this one which reports on early maser developments. It delves fairly deeply into the solid state physics of rare earth...

Please Thank Werbel Microwave for Continued Support!

Werbel Microwave Passive RF Components - RF Cafe WebsiteWerbel Microwave is a manufacturer of RF directional and bidirectional couplers (6 dB to 50 dB) and RF power dividers / combiners (2- to 16-way) with select models operating up to 26.5 GHz and 100 W of CW power (3 kW peak). All are RoHS and REACH compliant and are designed and manufactured in our Whippany, NJ, location. Custom products and private label service available. Please take a couple minutes to visit their website and see how Werbel Microwave can help you today.

RF Cafe Quiz: Electromagnetism

Quiz #91: Electromagnetism - RF Cafe WebsiteElectromagnetism is the force that governs the behavior of charged particles and the propagation of electromagnetic waves, forming the physical basis for nearly all modern electronic and wireless communication systems. From the fundamental observations of Oersted and Ampere to the elegant synthesis of Maxwell's equations, the field describes the inseparable relationship between electric and magnetic fields. Whether it is the Lorentz force propelling an electron beam in a vacuum tube, the induction driving a power transformer, or the alternating fields that carry radio signals across the globe, electromagnetism is ubiquitous. This Electromagnetism Quiz explores the core concepts of this discipline...

Entertaining Uncle Oscar

Entertaining Uncle Oscar, August 1939 QST - RFCafePopular comic strips (aka "funnies") in the 1930s and 1940s featured numbskulls, ne'er-do-wells, and simpletons. There was usually one character in the strip's cast that was smart - at least in a relative way if not absolute. Being familiar with some of the old comics like Blondie, Barney Google, Krazy Kat, Beetle Bailey, Gasoline Alley, etc., I can see a definite relationship between the story line of "Entertaining Uncle Oscar" and the comics of the era in this short story that appeared in a 1939 edition of the ARRL's QST magazine. As you might guess, the feller named "Ham" is the smart one. Q: Is it irony, coincidence, or premonition on the author's part that the uncle's name is the same as...

Quartz Crystal Etching

Quartz Crystal Etching, May 1954 Radio & Television News - RF Cafe WebsiteIf you are going to write an article about etching crystals for radio frequency circuits, having a last name like Gene Brizendine's couldn't be much better. It just sounds like a mineral or a compound (benzidine, etc.). Amateur radio operators have for a long time adjusted the resonant frequency of their crystals by either grinding or chemical etching. Mr. Brizendine recommends etching as a more controllable method that does not reduce the quality of the crystal like improper grinding can do. Ammonium bifluoride is mentioned as the etchant. It is said to have cost about $1/pound in 1954, and sells on Amazon today for about $23/pound. According to the BLS Inflation Calculator, $1 in 1954...

Engineering & Science Crossword Puzzle

Engineering & Science Crossword Puzzle April 12, 2020 - RF Cafe WebsiteWorking crossword puzzles can be contagious. This April 12, 2020, tech-themed crossword puzzle may even go viral - the second in a series. It contains only clues and terms associated with engineering, science, physical, astronomy, mathematics, chemistry, etc., which I have personally built over nearly two decades. That includes the cause for our planet's current dilemma. Many new words and company names have been added that had not even been created when I started in the year 2002. You will never find a word taxing your knowledge of a numbnut soap opera star or the name of some obscure village in the Andes mountains. You might, however, encounter the name of a movie star like Hedy Lamarr...

Please Thank Werbel Microwave for Continued Support!

Werbel Microwave Passive RF Components - RF Cafe WebsiteWerbel Microwave is a manufacturer of RF directional and bidirectional couplers (6 dB to 50 dB) and RF power dividers / combiners (2- to 16-way) with select models operating up to 26.5 GHz and 100 W of CW power (3 kW peak). All are RoHS and REACH compliant and are designed and manufactured in our Whippany, NJ, location. Custom products and private label service available. Please take a couple minutes to visit their website and see how Werbel Microwave can help you today.

RF Cafe Transformer Quiz

Quiz #89: Transformers - RF Cafe WebsiteTransformers are the workhorses of power distribution and signal processing, utilizing Faraday's law of induction to step voltages up or down while maintaining high efficiency. By coupling magnetic fields between primary and secondary windings through a shared core, they provide critical electrical isolation and impedance transformation between circuit stages. From massive grid-scale power units to tiny high-frequency RF baluns, transformers must manage complex phenomena such as magnetizing current, eddy current losses, hysteresis, and parasitic leakage inductance. This quiz explores the core physics behind transformer operation, including the “turns ratio” relationship, the role of core...

Radio-Electronics Monthly Review

Radio-Electronics Monthly Review, May 1947 Radio-Craft - RF Cafe WebsiteA column entitled "Radio-Electronics Monthly Review" appeared in each issue of Radio-Craft magazine. As now, things were moving quickly at the time. With WWWII recently ended, a lot of the new technology developed to help beat back Nazism and Communism was being transferred to peacetime uses. The May 1947 issue contained, amongst other items, info regarding how radio servicemen were organizing efforts to get its ranks educated on FM sets as AM was being replaced and/or supplemented with the new miracle noise-free broadcast systems. It also reported that the IRS decided not to go forward with earlier plans to tax television shows being displayed in public...

How Radio-Control Systems Work

How Radio-Control Systems Work, May 1974 Popular Electronics - RF Cafe WebsiteRadio control (R/C) systems operating in the 2.4 GHz ISM band, using one of or a combination of frequency hopping and direct sequence spread spectrum scheme, have been in widespread use since the early 2000s. As with any new technology, there was a lot of reluctance to adoption of the systems based on a few reports (valid or not) of performance issues - primarily lack of control range where communications between the transmitter (Tx) and receiver (Rx) with a pilot and aircraft was lost and a crash ensued. Tx power was already at the FCC-mandated maximum, so manufacturers quickly improved receivers by adding diversity with a second Rx antenna. The receiver...

Laser Modulators

Laser Modulators, April 1967 Electronics World - RF Cafe WebsiteAs reported in this 1967 Electronics World magazine piece, lasers were still the things of science fiction to most people. Real-world applications seemed to be far off in the future, but in fact, work was underway setting the stage for today's blazingly fast communications systems. The author here references attaining 5 THz optical transmission speeds through fiber and through the air. At the time, a laboratory filled with bulky prototypes chassis and optical tables were required to get those results. I can remember reading articles in the 1970s when laser power output was measured in "Gillette power," referring to the beam's ability to burn through a number of razor blades (a big deal...

Today in Science History - RF Cafe Website
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Homepage Archives - RF Cafe

The RF Cafe Homepage Archive is a comprehensive collection of every item appearing daily on this website since 2008 - and many from earlier years. Many thousands of pages of unique content have been added since then.

 

Acoustic Surface-Wave Devices

Acoustic Surface-Wave Devices, March 1971 Popular Electronics - RF Cafe Website"Praetersonic" - now that's a word you don't run up against very often. It is a combination of praeter* (beyond) and sonic (related to sounds), or what more familiarly is called ultrasonic. If fact, praetersonics was the early term given to surface acoustic wave (SAW) piezoelectric devices. Amazingly, even as far back as the early 1970s, SAW filters were being fabricated that worked in the 40 MHz realm. This Popular Electronics article does a really nice job of introducing the basics of SAW and BAW (bulk acoustic wave) technology at the time it was coming into the mainstream. Lots of hurdles still needed to be overcome, like high insertion loss, difficult to control impedances and internal signal reflections, etc. As with many new technologies, pundits cast hopeful prediction...

Television? ... It's a Cinch!

Television? ... It's a Cinch!, March 1953 Radio-Electronics - RF Cafe WebsiteIf television was "a chinch," in 1953 as this Radio-Electronic article claims, the world would have had it long before then. Just like looking up the work-out solutions to a physics problem in the back of a textbook, a lot of things look simple and obvious once someone else has already done it. I guess that's not really a fair criticism of this piece since author Aisberg's goal is to assuage some of the doubts and misconceptions a lot of people had about the relatively new technology. 1953 is the year that the NTSC formalized its color TV standard, which, BTW, was careful to accommodate B&W transmissions on the same channels - similar to how AM-FM stereo and stereo FM radio can coexist with monaural (mono) broadcasts. Television, in case you are not aware, began as an electromechanical system with picture frames and shutters, spinning discs, and other Rube Goldberg contraptions...

Stop Pay TV!

Just Say "No" to Pay TV - RF Cafe WebsiteThe more things change, the more they remain the same. People (including, admittedly, me) don't want to have to pay for any type of media delivery, especially when it arrives via air waves or the Internet. Six months before I was born, a reader of Radio-Electronics magazine wrote to declare his outrage at the fledgling industry of Pay Television. That a viewer would be expected to pay the broadcaster for a show that was being, in his opinion, amply subsidized by advertisers, was an outrageous concept, an unthinkable assault on all that is holy. While his indignation was probably shared by the majority of the television viewing public, evidently the maniacal scheme succeeded. In the 1950s and even through part of the 1970s, television shows typically included about 10-12 minutes of commercials and other non-show segments for each hour of broadcast. Season 1, Episode 1 of Star Trek, for example, ran for 50 minutes; that was in 1966...

New Technology Sparks an Expansion for Germanium Transistors

New Technology Sparks an Expansion for Germanium Transistors, April 6, 1964 Electronics Magazine - RF Cafe WebsiteWhilst reading articles on semiconductor research and development in the era of this 1964 Electronics magazine, it often occurs to me that much of the terminology presented is new to most people in the electronics field, having been just recently coined by those developing the technology. To wit, here author Landress shows diagrams of planar and mesa structures for transistors. We are so familiar by now with those configurations that it hardly seems there was a time when engineers did not speak so matter-of-factly of them. Hole and electron mobilities were terms familiar to a niche group of atomic materials scientists a decade earlier, as were diffusion depth and doping concentrations. As the 1919 electronics practitioner would confabulate upon matters of thermionic emission and getter flashing in vacuum tubes...

RF Cafe Engineering & Science Crossword Puzzle for March 10

RF Cafe Engineering & Science Crossword Puzzle March 10, 2019Since 2000, I have been creating custom science-themed crossword puzzles for the brain-exercising benefit and pleasure of RF Cafe visitors who are fellow cruciverbalists. The jury is out on whether or not this type of mental challenge helps keep your gray matter from atrophying in old age, but it certainly helps maintain your vocabulary and cognitive skills at all ages. A database of thousands of words has been built up over the years and contains only clues and terms associated with engineering, science, physical, astronomy, mathematics, chemistry, etc. You will never find a word taxing your knowledge of a numbnut soap opera star or the name of some obscure village in the Andes mountains. You might, however, encounter the name of a movie start like Hedy Lamarr or a geographical location like Tunguska, Russia, for reasons which, if you don't already know, might surprise you...

Delco Radio Division of General Motors Employment Ad

Delco Radio Division of General Motors Employment Advertisement, March 6, 1964 Electronics Magazine - RF Cafe WebsiteI, along with probably most other people my age, habitually associate the brand name of Delco (Delco Electronics, technically) with General Motors (GM) electrical and electronic products such as radios, storage batteries, alternators, and spark plugs. Dayton Engineering Laboratories Co., of Dayton, Ohio, merged with GM's AC spark plug division in 1974 to become AC-Delco. I bought many sets of AC-Delco spark plugs for my cars over the years. Nowadays, GM's electronic products go by the name of ACDelco (no hyphen now). Attempting to research the full provenance of the modern-day AC-Delco is headache-inducing due to sell-offs to Delphi, Aptiv, and other entities. The best I can determine is that the contemporary ACDelco is a brand name for products that might be manufactured by many different companies. This advertisement searching for electrical and mechanical engineers...

Opportunity Awareness: Thoughtful Reflections on Your Future

Opportunity Awareness: Thoughtful Reflections on Your Future, April 1971 Popular Electronics - RF Cafe WebsiteThis 1971 article from Popular Electronics magazine was the twelfth in a long series of features reporting on electronics related college degrees, technical schools, on-the-job training, military training, areas of specialty, career planning and options, current hiring practices and companies doing the hiring, salaries and hourly rates, worker's compensation and insurance, etc. All the issues of importance today were being covered even half a century ago, although the names have been changed for some entities. For instance the state employment bureaus are now referred to as departments of labor and industry; e.g., here in Pennsylvania, the DLI supplies statistics on labor...

1953 Radio-Electronics Tech-Themed Comic

Electronics-Themed Comics, March 1953 Radio-Electronics - RF Cafe WebsiteIf you look through the hundreds of technology-themed comics that appeared various electronics magazines, many deal with the trials and tribulations of television repair and service. That is because in the introductory era of TVs, people were, understandably, infatuated with being able to not just hear but see what was happening in the broadcast. Radios and phonographs got a lot of coverage as well. Storylines involving a guy on the roof installing or repairing an antenna were considered particularly funny, especially if it depicted someone hanging precariously from a lead-in cable or a ladder rung. This comic addresses the all-too-common situation where sometimes a better picture was obtained using a makeshift antenna than with a bona fide, professionally designed antenna...

Vintage Watkins-Johnson Tech Notes Additions & Updates

Vintage Watkins-Johnson Tech Notes Additions & Updates - RF Cafe WebsiteThanks to Chuck U. for providing new Watkins-Johnson (WJ) Tech Notes v10-3 and v15-2, and an improved copy of v5-2. A lot (but not all) of the TNs that I had or other people sent to me are made from B&W copies from old scanners, so the quality is not super good. Chuck's versions appear to be scanned from the originals in color, so they're very good...

Nine of the Latest New Developments from G-E Research

Nine of the Latest New Developments from G-E Research, March 6, 1964 Electronics Magazine - RF Cafe WebsiteHalf a decade after Texas Instruments (Jack Kilby, 1958) and Fairchild Semiconductor (Robert Noyce, 1960) produced the first semiconductor integrated circuits, General Electric must not have been too confident that the newfangled technology was going to take hold. This 2-page spread from a 1964 issue of Electronics magazine, promotes their "Compactron" integrated circuit vacuum tubes. The Compactron is a building block concept where standardized stages of diodes, triodes, pentodes, etc., are encapsulated in a single vacuum tube package with necessary input and output pins for connecting external components. The incentive was smaller volume, lower parts count, lower power supply current, simpler chassis wiring or circuit board layout, and greater ruggedness. One source I found showed the availability in 1962 of 24 distinct Compactron models...

Daylight Saving(s) Time - Again!

Graphical Look at Daylight Saving(s) Time - RF Cafe WebsiteCall me obsessive, but the switch to and from DST has bugged me not so much for its existence, but for butthead politicians that won't keep their hands off of it. A few years ago I wrote a piece titled, "A Graphical Look at Daylight Saving(s) Time," to deal with it, and then again last year with, "Daylight Saving(s) Time vs. Standard Time." Research the history of DST and you will see how often Congress has changed the days - always for good reasons, don't you know. In 1958, the year of my birth, DST began on April 27th 1958 Old Farmer's Almanac Daylight Savings Time - RF Cafe Website(vs. March 10th this year), and ended on September 28th (November 3rd this year) - See 1958 Old Farmer's Almanac pages. What else can I say on the matter?

Hitachi Nuvistor Advertisement

Hitachi Nuvistor Advertisement, March 6, 1964 Electronics Magazine - RF Cafe WebsiteAccording to the somewhat limited unique information available about the "nuvistor" vacuum tube amplifier, it was superior to many glass-encapsulated vacuum tubes. Lower noise figure, smaller size, greater ruggedness, intrinsically shielded, and relatively higher operating frequency were the main marketing standpoint. RCA introduced the nuvistor in 1959, and shortly thereafter GE, started making them, and then by 1964 Hitachi was offering nuvistors. The manufacturing process, where the entire assembly was performed in a vacuum chamber, made nuvistors more expensive than competitor glass tubes. The nuvistor concept might have been big if transistors had not been making such rapid progress in supplanting most vacuum tubes. In fact, nuvistors (a portmanteau of "new" and "transistor") were supposed...

Vector-Circuit Matching Quiz

Vector-Circuit Matching Quiz, June 1970 Popular Electronics - RF Cafe WebsiteThis vector circuit matching quiz will hurt the brain a little more than most of the ones that were printed in Popular Electronics. In order to score well, it helps to visualize the circuits relative to where they would appear on a Smith Chart. Capacitive impedances lie in the bottom half and have negative phases (-s, -jω). Inductance lie in the upper half and have positive phases (s, jω). The familiar 'ELI the ICE man' mnemonic helps, too. Be sure to pay attention to the color of the vector arrow heads. Example: In a purely inductive circuit like #4, voltage leads current by 90°. Since phase rotation is CCW, you need to look for lettered phase diagram where the white arrowhead (voltage) is 90° ahead of the black arrow head...

Introduction to Solid-State Devices and Power Supplies

Introduction to Solid-State Devices and Power Supplies (NEETS Module 7, pp1-10) - RF Cafe WebsiteThese NEETS training modules created by the U.S. Navy appear to have originally come out in 1990s and has been modernized a few times since then, so the information is fairly up to date. You will still find a lot of descriptions of vacuum tubes, but that is because even in 1998 the military still had a lot of legacy equipment that needed to be maintained. This particular module provides the student with an introduction to and history of semiconductor physics. The chapter runs a total of 62 pages so there's a lot of content...

RF Cafe Engineering & Science Crossword Puzzle for March 3

RF Cafe Engineering & Science Crossword Puzzle March 3, 2019Beginning in 2000, I have created hundreds of custom electronics-themed crossword puzzles for the brain-exercising benefit and pleasure of RF Cafe visitors who are fellow cruciverbalists. The jury is out on whether or not this type of mental challenge helps keep your gray matter from atrophying in old age, but it certainly helps maintain your vocabulary and cognitive skills at all ages. A database of thousands of words has been built up over the years and contains only clues and terms associated with engineering, science, physical, astronomy, mathematics, chemistry, etc. You will never find a word taxing your knowledge of a numbnut soap opera star or the name of some obscure village in the Andes mountains. You might, however, encounter the name of a movie start like Hedy Lamarr or a geographical location like Tunguska, Russia, for reasons which, if you don't already know, might surprise you...

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