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Circulators & Isolators Quiz

Quiz #76: Circulators & Isolators Quiz - RF CafeWelcome to the RFCafe Isolators & Circulators Quiz, a technical overview focused on non-reciprocal microwave components. These specialized devices are the primary tools used to protect sensitive signal sources from reflected power and to route signal flow in multi-stage RF systems. Whether you are isolating a high-power transmitter from a high-VSWR antenna, developing duplexers, or optimizing the signal isolation between cascaded amplifiers in a precision measurement setup, a solid grasp of circulator and isolator physics is essential. This assessment addresses the fundamental properties of ferrite-based non-reciprocal hardware, including insertion loss, port-to-port isolation, power...

What Does Your Daily Commute Cost You?

What Does Your Daily Commute Cost You? - RF Cafe SmorgasbordHow far do you commute each day for the privilege of doing your part to push back the frontiers of technical ignorance and to boldly go where no engineer - or technician - has gone before. Do you know what the cost equates for you each year? This handy-dandy infographic lays out some gruesome numbers. Those with a weak stomach probably should pass on viewing this one. Here's a hint at what you will see: See that big $795 in the thumbnail image? That's the average cost per year for commuting -- per mile! Yessiree, if you live just 10 miles from work, you're losing nearly $8,000 per year, depending on you automobile type, on gas, tires, maintenance, devaluation, and loss of your personal time (which is valuable, after all). Back in the early 1990s I drove about 45 miles each way...

Measuring Semiconductor Device Input Parameters with Vector Analysis

Measuring Semiconductor Device Input Parameters with Vector Analysis - RF Cafe WebsiteJoe Cahak, owner of Sunshine Design Engineering Services in Ramona, California, has written a white paper entitled, "Measuring Semiconductor Device Input Parameters with Vector Analysis." This article covers a recent test experience that utilized some thinking about the test fixture, the bias requirements and the device mounting and special calibration offsets needed to de-embed the test fixture response from the device response within the test fixture. The device also had to have bias on several ports simultaneously. We had to establish a "reference plane" within the fixture, from which we can use the Vector Network Analyzer's Port Extension or Phase Offset to dial out the distance from our 1 port calibration reference plane to the point of short reference within the fixture. With this phase offset compensation we can then measure...

Low-Pressure Modulation Facts

Low-Pressure Modulation Facts, July 1953 QST - RF Cafe WebsiteAuthor Howard Wright takes the opportunity here to distill the concept of modulation down to its basic operation while dispensing with the garbled mix of "graphs, formulas, charts, vectors, diagrams, and Greek letters which often enter into various discussions of modulation". Wright describes how to the uninitiated radio dial spinner, the culmination of events occurring behind the scenes in an AM reception is akin to knowing "that, to be reproduced, the picture [in a magazine] was broken down into its primary colors, if all we had to go by was the original print and the magazine?" That is a very apt comparison...

Many Thanks for Alliance Test Equipment's Support!

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

Mac's Radio Service Shop: A Little Lightning

Mac's Radio Service Shop: A Little Lightning, July 1948 Radio News - RF Cafe WebsiteBenjamin Franklin is famous for his kite-flying experiment whereby he "discovered" not electricity (as many people believe), but that lightning is a form of electricity (most people thought it was a jet of gas). A lesser known fact about Mr. Franklin is that he invented the lightning rod after realizing the electrical nature of lightning. His understanding of electric fields facilitated an implementation whereby hefty iron cabling interconnected a tall, pointed rod installed at the tallest point on a building and a spike driven into the ground. Lightning typically strikes the object that is the shortest distance (in terms of electrical field strength) from it because the discharge can begin at the lowest voltage. The presence of the grounded lightning rod above the highest point on a structure effectively brings that point all the way down to ground level...

Radio Terms Illustrated

Radio Terms Illustrated, August 1947 Radio-Craft - RF Cafe WebsiteThese "Radio Term Illustrated" comics from vintage Radio-Craft magazines are some of my favorite tech-themed comics. Most were drawn by Frank Beaven in response to suggestions / requests by magazine readers. The one here from page 80 entitled "Crystal Gazing" was done by Franklin Folger. If you didn't know that it appeared in a 1947 edition, you might assume it depicts a Steam Punk themed LCD computer monitor mounted atop a Morse code straight key, but of course it is not. At the time, cathode ray tubes (CRTs) were the only form of video display, and while small like the one in the drawing (and round, unlike the drawing), they were far from flat. Little did the artist suspect that his "Crystal Gazing" idea meant to imply a type of mystic's medium for seeing...

Negative Feedback Transistor Amplifiers

Negative Feedback Transistor Amplifiers, May 1957 Radio & TV News - RF Cafe WebsiteThe big graphic with Figures 1 through 17 reminds me of the kinds of study sheets I used to make when cramming for exams in my college circuits courses. Did I ever tell you about the wise guy instructor I had for my first Circuits class at the University of Vermont? Anyway, this article provides an introductory level treatment of using negative feedback in amplifier circuits. Lots of illustration and formulas are included. Frequencies are at baseband, so you won't learn any secrets for high frequency amplifier stabilization, but then even RF and microwave circuits eventually need to convert down to baseband at some point for sampling or for use as audio or video...

QST Strays: Powder Puff Derby

Powder Puff Derby Peanuts July 6, 1975 - RF Cafe WebsitePrior to seeing this new tidbit in a 1976 issue of QST magazine, I had no idea that the wife of Peanuts comic strip creator Charles Schulz was an airplane pilot - and that is with having been a huge Peanuts fan for decades. Other than one of Snoopy's alter egos being that of a World War I flying ace, there is no other theme of airplanes in the strip, although according to this article, there was a 1975 Sunday comic strip with Peppermint Patty and Marcie flying atop Snoopy's doghouse, from California to Michigan. The Straits Area Radio Club (W8GQN) provided communications for the Powder Puff Derby, aka the Women's Air Derby, race in which Mrs. Jean Clyde Schulz took part in 1970, 1971, and 1975. It was a very long course - more than 2,000 miles as the crow flies...

SPURS Software - RF Design Magazine Software Contest

SPURS Software - RF Design Magazine Software Contest Winner (November 1992) - RF Cafe WebsiteWay...... back in 1992, RF Design magazine ran a software contest. Those were the days when most engineers and hobbyists wrote software in either Basic or Fortran. I happened to use Turbo Pascal, by Borland. At the time, I was working as an RF engineer for Comsat, in Germantown, MD. Having done a lot of frequency conversion designs in my previous work at General Electric, and even more there at Comsat, I had already written a crude program to calculate mixer spurious products, so this challenge gave me the excuse I needed to refine the user interface and add some creature comfort features like...

Time for Another Breakthrough

"It Seems to Us..." Time for Another Breakthrough, August 1976 QST - RF Cafe WebsiteAmateur radio operators - and all electromagnetic spectrum users for that matter - have always lamented crowded bands and interference (QRM and QRN). That goes for licensed and unlicensed bands. In 1976 when this editorial was printed in the ARRL's QST magazine, spectrum occupation within allocated bands was defined by commonplace analog AM and FM methods. Co-existence was generally not possible for operation within a common frequency range. Spread spectrum modulation / demodulation changed all that beginning in the 1990s, but prior to then such schemes were largely the exclusive domain of military communications, as were many other spectrum-saving methods which are commonplace today. A big part of the reason is the significant advances in digital processing hardware and software, along with declassification of some of the algorithms that eventually found their way into cellphone, WiFi, and other commercial applications. Given that many of the professional engineers...

They're Taking the Guesswork out of Scatter Communications

They're Taking the Guesswork out of Scatter Communications, September 1969 Electronics Illustrated - RF Cafe WebsiteAs with many areas of electronics communications, much of both the initial and continued research in atmospheric scattering of electromagnetic signals was/is done by amateur radio operators. The phenomenon is routinely used for accomplishing long distance communications (DX, in Ham terms) by exploiting the reflection property of ionized layers when radio signals impinge at a certain angle. The portion of the signal that returns to the transmitter location, when monitored, can provide information to the sender about the height, distance, and frequency range of the reflecting atmospheric layer. Some of the first indications of backscattering were noticed by radar operators who would receive echo returns from "phantom" targets that were really atmospheric reflections...

Admiral "Aeroscope" Midget Sets Radio Service Data Sheet

Admiral "Aeroscope" Models 161-5L, 162-5L and 163-5L Midget Sets Radio Service Data Sheet, August 1939 Radio-Craft - RF Cafe WebsiteFor many years I have been scanning and posting Radio Service Data Sheets like this one featuring the Admiral "Aeroscope" 161-5L, 162-5L, and 163-5L Midget Set models which appeared in a 1939 issue of Radio-Craft magazine. There are still many people who restore and service these vintage radios, and often it can be difficult or impossible to find schematics and/or tuning information. Some websites offer to sell this information, but often what is shown here is enough to get an old radio working again since most times both schematics and alignment steps are included. I keep a running list of all data sheets to facilitate a search... 

War Advertising Council

War Advertising Council, February 1944 Popular Science - RF Cafe WebsiteI'm probably one of the few people remaining who fairly regularly recite the World War II (WWII) era slogan of "Use it up. Wear it out. Make it do, or Do without." One of the primary killers of economies has been inflation, whatever the cause - usually deficit spending by government and/or printing of fiat money. Wartime typically produces high inflation levels due to the need to produce the equipment necessary to wage a battle. Supply and demand are another cause of inflation. If the demand is greater than the supply, prices go up because owners want to maximize profits. If the need for skilled labor is greater than what is available, workers demand higher pay, and the price goes up. During WWII, as the chart to the upper left shows, inflation rates were sky high, and the government propagandists called on the citizens to "do their part" to keep prices under control by not creating a higher demand then the supply chain could accommodate...

Many Thanks to San Francisco Circuits for Continued Support!

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

Antenna Theory Quiz

Quiz #77: Antenna Theory Quiz - RF Cafe WebsiteWelcome to the RF Cafe Antenna Theory Quiz, a specialized assessment designed to test your knowledge of the radiating structures that define the success of any RF communications system. From fundamental dipole operation and feedpoint impedance to the critical nuances of gain, polarization, and pattern formation, a deep understanding of antenna physics is essential for any serious radio enthusiast or professional engineer. This quiz challenges you on key concepts, including the characteristics of Yagi-Uda arrays, the significance of front-to-back ratios, the dynamics of ground planes, and the practical challenges of matching networks. By evaluating your grasp of these essential antenna principles...

Mathematical Puzzles, 1981 Old Farmer's Almanac

Mathematical Puzzles, 1981 Old Farmer's Almanac - RF Cafe WebsiteEach autumn I used to anxiously await the appearance of the newest edition of The Old Farmer's Almanac on the store shelf, and such was the case with this 1981 issue. It is not that I was/am an avid farmer, just that I enjoy reading the anecdotes, tales, and interesting historical tidbits included amongst the pages along with tables of high and low tides, moon and sun rising and setting times, astronomical events, and weather patterns expected for the year that lay ahead. Most of all, I liked working the puzzles and riddles. Over the years the difficulty levels gradually got lower and lower (aka dumbed down), to the point where for the last decade or so I have not even bothered buying the OFA. Now it is full of numbnut stuff...

Electronics-Themed Comic, Popular Electronics

Electronics-Themed Comic, February 1972 Popular Electronics - RF Cafe WebsiteThis is a great electronics-themed comic from a February 1972 issue of Popular Electronics. It encompasses the essence of the stereotypical salesman ruse, especially in that era when people were sure that electronics repair services were out to rip them off by selling unneeded services and replacement parts. Aspiring TV technicians who couldn't grasp the technology moved on to working as mechanics in a garage, poking tiny holes in brake lines to scare owners into paying for complete braking system rebuilds. I usually like to post multiple comics on each page, but at the moment only this one is available...

Frequency-to-Meter Conversion Chart for Hams

Frequency-to-Meter Conversion Chart for Hams & SWL's, June 1966 Popular Electronics - RF Cafe WebsiteAs with your school and college days where once there was no longer any reason to memorize physical constants, conversion formulas, and names of people, places, and things, much of the noggin's gray matter was repurposed to remember topics of more immediate need. You can always look up what you have forgotten. While studying for your Ham radio or FCC license, being able to be able to quickly convert between wavelength and frequency is essential. Recalling on demand frequency-wavelength pairs is a real time saver on a timed exam. Even being able to perform the conversion on a calculator during the test takes up valuable time that could be better used on other tasks. This handy-dandy chart for converting...

IMS 2026 Coverage by everything RF!

everything RF IMS 2026 Event Coverage - RF Cafe WebsiteIMS 2026 (IEEE MTT-S International Microwave Symposium) is the world's premier RF and microwave conference, bringing together thousands of industry professionals from around the globe to explore the latest technologies, tools, and technical developments. IMS2026 will feature the RFIC Symposium, the new RFSA and RFTT Symposia, and conclude with the ARFTG Microwave Measurement Conference. everything RF website's medai team is providing full coverage of the event. Stop by Booth 24048 to meet the crew.

The Man Who Pinned Wings on the Navy

The Man Who Pinned Wings on the Navy, July 1961 Popular Science - Airplanes and RocketsIn 1961, the United States Navy commemorated the fiftieth anniversary of the A-1 Triad, the service's first aircraft. This milestone honored Glenn Hammond Curtiss, the father of naval aviation, who designed the versatile machine capable of operating on land, water, and air. Born in Hammondsport, New York, in 1878, Curtiss possessed an innate obsession with speed and mechanical ingenuity. Before revolutionizing aviation, he dominated motorcycle racing, famously earning the title of the fastest man on Earth. His transition to flight led to landmark achievements, including winning the Gordon Bennett trophy in France and executing the first successful U.S. intercity flight...

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.

 

Lee de Forest - Father of Radio

Lee de Forest - Father of Radio, January 1947 Radio-Craft - RF Cafe WebsiteLee de Forest, upon whom was conferred the honorary title "Father of Radio" by Radio-Craft editor Hugo Gernsback (and others), exemplifies personal traits of most great inventors: high intelligence, stick-to-itiveness, courage, passion for his subject, determination, and a willingness to endure a lot of personal and financial abuse. The January 1947 issue of Radio-Craft magazine celebrated the 40-year anniversary of Mr. de Forest's invention of the Audion vacuum tube by including a large number of articles by various authors who knew him personally and attest to his greatness. I will be posting a few of those pieces, and you will probably be shocked at some of the shenanigans that went on by conniving people and naysayers who tried to deny de Forest due credit. For example, based on his work to make more sensitive receivers a judge in a lawsuit brought by Marconi strictly enjoined him "to forever desist from the manufacture, sale or operation of any system of wireless telegraph...

A Portable Thyratron Tester

A Portable Thyratron Tester, February 1957 Radio & Television News - RF Cafe WebsiteThe thyratron is not necessarily a familiar type of vacuum tube to most RF and microwave electronics practitioners unless they happen to be involved in radar, imaging (x-ray), particle accelerators, etc.† It is basically a high speed, high current switch used in pulse forming networks for firing magnetrons (via a high-voltage transformer). Both the S-band airport surveillance radar and the X-band precision approach radar I worked on in the USAF employed thyratrons. The X-band radar had been modified by the time I came on the scene to use a solid state thyratron (one of the earliest adaptations), but the S-band radar still used its original vacuum tube thyratron. While I don't recall for certain, I believe the thyratron in the thumbnail image is the one it used. The accompanying ruler...

Bargains by the Bagful

Bargains by the Bagful, February 1964 Popular Electronics - RF Cafe WebsiteThis Popular Electronics article by at-the-time editor Oliver Ferrell offers recommendations on how to spot a good deal in grab-bag assortments of electronics components when shopping for good deals, whether it be at a retail outlet, flea market, or Hamfest. The advice is a useful today as it was then. Little did anyone know that half a century later there would be another source for cheap parts that would dwarf what had previously been available - the Internet, and in particular, eBay. Mr. Ferrell mentions the term "radio row," which was a downtown area in many cities where surplus equipment dealers peddled their wares. In the 1950's and 60's, a lot of it was left over from wars, and included not just electronics parts but also mechanical gear. Two of the more famous "radio row" areas were in New York City and Tokyo, which were covered in two other articles entitled "Radio a la Cortlandt Street!," and "Akihabara Tokyo's 'Radio Row'," respectively...

Problems in Metropolitan TV Reception

Problems in Metropolitan TV Reception, March 1957 Radio & Television News - RF Cafe WebsiteMultipath signal interference is as prevalent today as it was at the beginning of radio communications - maybe more so since there are typically more reflective obstacles between the transmitter and the receiver. The evidence of multipath with digital communications, be it voice, Internet page viewing, or movies, is slowness in transmission as opposed to the analog case where garbled speech on radio and ghosting pictures on television are the evidence. High data rates with digital transmissions typically mask the packet errors and their necessary re-transmission; it all happens before the buffered information is presented to the listener / viewer. However, there is no such buffering of over-the-air radio or TV transmissions so evidence of multipath is immediately noticeable. I remember how sometimes...

Micro-Modules

Micro-Modules, September 1958 Radio & TV News - RF Cafe Website"Micro" as applied to electronics is relative, depending on which decade you reference. In the 1940s, a micro-size electronic assembly might have included "peanut" vacuum tubes and even some sort of printed circuit board. That was a huge step down in size from standard size tubes with point-to-point wiring between tube sockets and solder lugs on switches, potentiometers, variable capacitors, etc. Fixed value leaded resistors, capacitors, and inductors, and transformer wires connected to those lugs as well as to many terminal strips installed specifically for making connections. Once transistors came on the scene in the 1950s, a new round of miniaturization took place based on not just a significantly smaller size of solid state transistors and diodes, but their lower voltage and current requirements meant ancillary components could be made smaller as well due to lower voltage...

Father of Radar Gets His Reward from Patent Office

Father of Radar Gets His Reward from Patent Office, December 1957 Popular Electronics - RF Cafe WebsiteWell, this might get some dander up amongst the believers that Sir Robert Watson-Watt is "the Father of Radar." In the December 1957 edition of Popular Electronics magazine, Colonel William R. Blair was given that honored designation based on his work on a pulse-echo method of direction finding in the 1920s. The Wikipedia entry for Col. Blair refers to him more specifically as the "Father of American Radar." William R. Blair was awarded U.S. patent #2,803,819, titled "Object Locating System," on August 20, 1957 - a full 13 years after the patent application was submitted. Watson-Watt was issued a patent in 1935 on a radio device for detecting and locating an aircraft. His research was born out of an investigation into a "death ray" which had reportedly been invented by the Germans.

The Japanese Morse Telegraph Code

The Japanese Morse Telegraph Code, September 1942 QST - RF Cafe WebsiteLess than a year had passed since the surprise attack on Pearl Harbor by the Japanese navy when this article was published in QST. America had sprung into high gear to help the war effort - both as civilians and as military members. A vital part of the strategy was to educate as many people as possible regarding the tactics and habits of the enemy. Media of all sorts were used to help get the word out. QST did its part, probably more so than most forms of media, by appealing to those people capable and willing to contribute to the vitally important task of communications. How many hobbies could be directly applied to the needs of the military and homeland defense? Precious few, other than radio design, assembling, testing, and operation. I suppose to be fair I would have to mention a few other hobbies like vehicular maintenance, firearms marksmanship, and model building...

Engineering & Science Crossword Puzzle for February 9

Engineering & Science Crossword Puzzle February 9, 2020 - RF Cafe WebsiteAs with my hundreds of previous science and engineering-themed crossword puzzles, this one for February 9, 2020, contains only clues and terms associated with engineering, science, physical, astronomy, mathematics, chemistry, etc., which I have built up over nearly two decades. 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 or a geographical location like Tunguska, Russia, for reasons which, if you don't already know, might surprise you.

Milestone in Space Communication

Milestone in Space Communication, February 1973 Popular Electronics - RF Cafe WebsiteIn 1971 the International Telecommunications Union (ITU), convened a meeting dubbed the World Administrative Radio Conference for Space Telecommunications (WARC-ST). The ITU was a specialized agency of the United Nations for telecommunications, with a membership of 140 nations. Satellite communications was barely a decade old, but already the need for international agreements on spectrum usage had become very apparent. Prior to the 1971 meeting, there was the 1963 Extraordinary Administrative Radio Conference held in Geneva, Switzerland. Amateur radio had its presence in the game acknowledged with further allocations for its members' OSCAR birds; six had been flown already. As of this writing there are about 20 OSCAR satellites still in operation. Amateur satellites take many forms these days, including the newest trend in CubeSat platforms with a well-defined set of specifications on dimensions and mass per cube. Launches are provided on a space available basis at a substantially discounted cost...

Hams in Combat -One Life to Give

Hams in Combat - One Life to Give, July 1944 QST - RF Cafe WebsiteQST did a regular series of articles titled "Hams in Combat" during World War II. This story is unique in nature in that it tells of a newspaperman-turned-soldier who, in the story writer's mind, would have been the most suited for the job of author. It tells a far different story of the South Pacific than we were treated to in weekly episodes of McHale's Navy! "Had this story been written by the man who should have written it - Capt. William H. Graham, W9BNC - it would have been one of the greatest "Hams in Combat" yarns ever told in these pages. But Bill Graham never got around to writing his story. He was too intensely occupied with the living of it - too keenly aware of the new paragraph... Note the letter I received from Capt. Graham's great grandson.

How to Derive -40°F = -40°C

How to Derive -40°F = -40°C - RF Cafe UniversitySome of what you and I consider common knowledge is largely unrealized by most people. Call me a geek, but I take pleasure in pointing out to people that the Fahrenheit and Centigrade scales are equal at -40°, and I especially enjoy working out the simple proof for them. Most people appreciated the effort and are amazed, claiming to have never seen that before. When I read the following in Smithsonian magazine, "Winter temperatures here, some 250 miles northeast of St. Petersburg, sometimes plunge to minus 40 degrees Fahrenheit," I wondered whether the author knew that -40°F = -40°C. Maybe he just didn't want to confuse his readers by omitting the redundant superfluous 'F' or 'C,' and it couldn't be 'K' because there are no negative Kelvin degrees. It could also be that he knew but figured most people do not...

A New Approach to Beam Antennas

A New Approach to Beam Antennas, February 1950 Radio & Television News - RF Cafe WebsiteThis article describes a method for tuning beam antennas from the ground rather than needing to experiment with matching capacitors and/or inductors at the antenna end of the transmission line. The scheme uses a separate length of transmission line attached to the reflector element at a length an integer number of half-wavelengths as required to reach the ground. That way, tuning elements can be installed and adjusted for one or more bands without needing to climb up to the antenna. The method can be used for any number of elements, but of course it could get a bit messy with more than a couple. The author, Major Charles E. Spitz (W7JHS), describes using a field strength meter to verify tuning correctness. Having read many QST magazine articles on antennas over the past decade or so...

Jury Told of Fraud in Radio Telephone (1917 NYT)

Jury Told of Fraud in Radio Telephone (New York Times - Thursday, November 27, 1913) - RF Cafe WebsiteMotivated by the series of articles about Lee de Forest in the January 1947 issue of Radio-Craft magazine, I did a search of U.S. newspapers from 1905 through 1947 looking for news items on him. In particular, I was hoping to find something about the lawsuit levied by the Marconi Company against Lee de Forest wherein the judge was reported to have told him, "...to forever desist from the manufacture, sale or operation of any system of wireless telegraph." Alas no such information was discovered, but the search will continue. I did find this piece and many other interesting items that will be posted as time permits. Here, Mr. de Forest sued, with the assistance of the U.S. Government, an investment company for defrauding investors in regard to company stock sales, using a charge of mail fraud to assist in prosecution. Mail fraud, tax evasion, interstate commerce and other such non-state related charges were (and still are) routinely used by the Feds...

Electronic Wrist-Watches

Electronic Wrist-Watches, February 1973 Popular Electronics - RF Cafe WebsiteTry as I did, I could not find any instance of the Ness Clocks all-digital liquid crystal display (LCD) desktop clock which appeared in this 1973 Popular Electronics article. There must not have been many produced. LCDs had only been commercially available for a year or so when this went on sale. Of the relatively few digital display clocks and watches available in the 1970s, the vast majority used light-emitting diodes (LEDs), and most sold for north of $100 (~$600 in today's money). Portable devices with digital displays really began to flourish with the advent of both CMOS circuitry and LCD displays; i.e., low current devices that extended battery life. Wrist watches, which could only accommodate very small batteries with limited energy storage capacity, were amongst the greatest beneficiary...

Curiosa in Radio

Curiosa in Radio, June 1935 Radio-Craft - RF Cafe WebsiteI usually try to post something a little less serious and technical on Fridays to help everyone wind down from the long week just passed. It could be a Carl & Jerry or a Mac's Radio Service Shop story, an electronics quiz, or even something I found out on the Internet. This time it is a "believe-it-or-not" type feature entitled "Curiosa in Radio," about radio manufacturing, operating, and infrastructure. One factoid claims "Only 1.1% of set manufacturers in business in 1924 are building sets today." It could due to being in the middle of the Depression Era so almost nobody was making / buying radios, but more likely it reflects the reality of the many people who jumped into the fledgling radio industry early on and then could not gain market share. Enjoy.

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