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Today in Science History

Electronics-Themed Comics

Electronics-Themed Comics, January 1962 Radio-Electronics - RF CafeI have written before about the love-hate relationship a lot of the buying public had with television and radio repair shops and repairmen - similar to car owners and mechanics. Lots of jokes and skits (what today is termed a "meme") were created back in the heyday of in-home entertainment to make light of the situation. These four electronics-themed comics from a 1962 issue of Radio-Electronics magazine are typical examples. The one from page 111 alludes to an issue that would almost never be seen today on a TV, unless maybe the AC power supply was on the fritz. A composite analog broadcast signal contained vertical and horizontal sync[ronization] components which...

3D-Shield Electronics from ESD

3D-Shield Electronics from ESD"Electrostatic discharge (ESD) protection is a significant concern in the chemical and electronics industries. In electronics, ESD often causes integrated circuit failures due to rapid voltage and current discharges from charged objects, such as human fingers or tools. With the help of 3D printing techniques, researchers at Lawrence Livermore National Laboratory (LLNL) are 'packaging' electronics with printable elastomeric silicone foams to provide both mechanical and electrical protection of sensitive components. Without suitable protection, substantial equipment and component..."

TV and Radio Repair Featured in "Dragnet"

Television and Radio Repair Featured in "Dragnet" - RF Cafe Video for EngineersMr. Bob Davis, a seemingly endless source of little known and/or long forgotten historical radio and television technical trivia, apprised me of this short segment from the 1960s Dragnet television series, starring Sgt. Joe Friday. It features a guy, who turns out to be a ... well, I won't spoil it for you ... who proudly professes his thirty year career as a radio repairman. "...started back in the days of the old Crosleys, Atwater-Kents, Farnsworths. Those were real radios, well built, well designed. Nothing cheap about any of them. They didn't have transistors in those days, just tubes as big as light bulbs. That meant heavy chassis, heavy transformers, and we didn't fix them by simply slapping in a new part, either. We fixed the old parts. I wish...

Square-Corner UHF Reflector Beam Antenna

The Square-Corner Reflector Beam Antenna for Ultra High Frequencies, November 1940 QST - RF CafeA new word has been added to my personal lexicon: "sphenoidal." Author John Kraus used it to describe the wedge shape of a corner reflector. The Oxford Dictionary defines "sphenoid" thusly: "A compound bone that forms the base of the cranium, behind the eye and below the front part of the brain. It has two pairs of broad lateral "wings" and a number of other projections, and contains two air-filled sinuses." This "square corner" configuration - essentially a "V" shape, is shown to exhibit up to 10 dB of gain while being relatively (compared to a parabolic reflector) insensitive...

General Relativity

Spacetime Distortion General Relativity - RF CafeAlbert Einstein's general theory of relativity, published in 1915, fundamentally reshaped the way scientists understand gravity, space, and time. It extended his 1905 special theory of relativity, which described how the laws of physics are consistent for all observers in uniform motion and how light's speed is constant in a vacuum. However, the special theory did not address accelerating reference frames or gravitational forces. Einstein's general theory tackled these limitations by proposing that gravity is not a force in the traditional sense, but rather a curvature of spacetime caused by mass and energy. This profound insight would alter the course of 20th-century physics, influencing cosmology, black hole theory...

Memristor Analog Switching Neuromorphic Computing

Memristor Analog Switching Neuromorphic Computing - RF Cafe"The growing use of artificial intelligence (AI)-based models is placing greater demands on the electronics industry, as many of these models require significant storage space and computational power. Engineers worldwide have thus been trying to develop neuromorphic computing systems that could help meet these demands, many of which are based on memristors. Memristors are electronic components that regulate the flow of electrical current in circuits while also 'remembering' the amount of electrical charge that previously passed through them. These components could replicate the function of biological..."

Reflections on the News

Reflections on the News, February 1969 Electronics World - RF CafeReading through the news items in the vintage electronics magazines provides a mixture of important historical facts and figures along with some predictions on the future of the industry. Some of the predictions turn out to be amazingly accurate, even though in retrospect they might seem obvious. Take, for example, Sylvania VP Dr. Robert Castor's foresight about how, "the future growth of the semiconductor industry lies in a major switch from the production of individual components to solid-state subsystems that can be used as building blocks in electronic designs." "Well of course," you might be temped to say; however, at the time there were still significant hurdles to overcome related to material purity, wafer size, photolithography...

Many Thanks to Reactel for Their Long-Time Support!

Reactel Filters - RF CafeReactel has become one of the industry leaders in the design and manufacture of RF and microwave filters, diplexers, and sub-assemblies. They offer the generally known tubular, LC, cavity, and waveguide designs, as well as state of the art high performance suspended substrate models. Through a continuous process of research and development, they have established a full line of filters of filters of all types - lowpass, highpass, bandpass, bandstop, diplexer, and more. Established in 1979. Please contact Reactel today to see how they might help your project.

Electronics in 2012 AD

Electronics in 2012 AD, October 1962 Radio-Electronics - RF Cafe2012 came and went more than a decade ago. The date was 50 years in the future back in 1962 when Radio-Electronics magazine editor Hugo Gernsback asked industry leaders to cogitate on possibilities of the state of electronics in 2012. Let's see how they did. One guy predicted our communications would be in the 100 THz to 1,500 THz band, using 2 decimeter antennas. Nope. Another believed we would be communicating with aliens on a regular basis. A military dude partly hit the mark by predicting 2- and 3-year-olds would be sitting in front of "televideo screens" (cellphones) learning Esperanto and "other basic studies." Bell Labs believed most audiovisual material, along with commerce, would be done electronically; i.e., the World Wide Web. I'm not quite sure how to interpret the IT&T guy's prediction of replacing microwave space transmission with light wavelength waveguide transmission. Seems bassackward to me...

The Phone Scam Gram

The Phone Scam Gram - RF CafeHere is a unique approach to discouraging scam callers. A lot of scam calls are themselves AI, so can one AI detect and aviod another? "Gangster Granny! Meet Daisy: O2's new weapon against scammers. O2 has unveiled its new, unique weapon in its fight against scammers: Daisy, an AI-powered assistant designed to keep fraudsters talking and waste their time. As part of Virgin Media O2's 'Swerve the Scammers' campaign, Daisy's mission is to distract scammers with realistic, rambling conversations, helping protect potential victims while raising awareness about fraud. Her lifelike conversations, peppered with stories about family or hobbies like knitting, have kept fraudsters on the line for up to 40 minutes..."

Special Relativity

Special Relativity - RF Cafe

Albert Einstein's special theory of relativity, a milestone in physics, transformed our understanding of space, time, and energy (mass). The theory, published in 1905, stemmed from Einstein's efforts to resolve inconsistencies in classical physics, specifically between Newtonian mechanics and electromagnetism as formulated by James Clerk Maxwell. By reconceiving space and time as interconnected and relative to the observer's frame of reference, Einstein established a framework that had profound implications for science and technology. To understand how this groundbreaking idea emerged, one must consider...

Werbel 2-Way Splitter for 500 MHz to 26.5 GHz

Werbel Microwave 2-Way Power Splitter for 500 MHz to 26.5 GHz - RF CafeWerbel Microwave's Model WM2PD-0.5-26.5-S is a wideband 2-way in-line power splitter covering of 500 MHz to 26.5 GHz with excellent return loss, low insertion loss, and high isolation performance. With ultrawideband performance, amplitude balance is typically 0.24 dB and phase unbalance is typically 2.6°. Insertion loss is low for the bandwidth, coming in at a typical 1.2 dB above 3 dB splitting loss. Return loss 16 dB typical. Isolation 18 dB typical. The device is precision-assembled and tested in the USA...

RCA Institutes Career Opportunity

RCA Institutes Ad, June 1969 Electronics World - RF CafeIf you wanted a career as an electronics technician at the end of World War II, the world was your oyster - so to speak. Electronics and communications trade magazines and publications like Mechanix Illustrated and Popular Science ran a plethora of ads monthly that offered unlimited opportunity to men seeking a career servicing the burgeoning market of postwar technological marvels. Even though the enclosures were not yet being marked with "No user serviceable parts inside," that fact was most people were not qualified - nor did they want - to monkey with the guts of radios, televisions, and other household appliances... (I provide a simulation to show the true zener diode circuit output)...

Electronics-Themed Comics

Electronics-Themed Comics, February 1962 Radio-Electronics - RF CafeTake time out of your busy workday to look at these three electronics-themed comics from the February 1962 issue of Radio-Electronics.. The page 32 comic reminds me of sometime in the late 1970s while working as an electrician (prior to enlisting in the USAF) when I was doing side jobs, and a guy had me wire up a receptacle for his big 25" screen (CRT) which he had mounted in a wall, with the chassis sticking out the back. It was in an upstairs room in a Cape Cod style house with lots of room behind the wall. He was a "man cave" pioneer with a full suite of high quality audiovisual equipment - even a Betamax machine! The page 81 comic exhibits the irony that would have existed in the day if American-made electronics equipment had been promoted in Japan, which they probably were not. In 1962, Japanese...

No Video for Satellite Direct-to-Cell

No Video for Satellite Direct-to-Cell - RF CafeAdmittedly, I mostly posted this because of the drawing. "While direct-to-cell (D2C) satellite communications were a big topic at the recent Brooklyn 6G Summit, the technology is already here, well before 6G's anticipated 2030 arrival. Apple and Google already offer D2C emergency messaging, and Starlink, T-Mobile and others are anticipated to follow. D2C satellite communications will be well established when 6G arrives. The 3GPP froze a 5G specification for Non-Terrestrial Networks (NTN) in Release 17 in March 2022, which means that NTN-compatible chips and components should be available now or soon. SpaceX has reduced the cost..."

Electricity & Physiology

Electricity & Physiology, January 1971 Popular Electronics - RF CafeThe subtitle of this article from a 1971 issue of Popular Electronics magazine, "From Quackery to Speculation to Programmed People," could to some extent still be applicable even though the author evidently meant to put an end to the "quackery" and "speculation" part of it. Indeed, a lot of advancement has been made in the fields of electrostimulation of weak or/or paralyzed muscles, healing of certain types of soft and hard tissues, suppressing sporadic muscle twitching and epileptic seizures, and other malady diagnosis and relief. Specifically tuned microwave frequencies have proven useful in healing and symptom relief as well. As with most articles on medical procedures, I cringe at some...

Anatech Intros 3 Filter Models for November

Anatech Electronics Intros 3 New Filter Models for November 2024 - RF CafeAnatech Electronics offers the industry's largest portfolio of high-performance standard and customized RF and microwave filters and filter-related products for military, commercial, aerospace and defense, and industrial applications up to 40 GHz. Three new C-band cavity bandpass filter models have been added to the product line, including a 4994 MHz BPF with a 50 MHz bandwidth, a 4950 MHz BPF with a 10 MHz bandwidth, and a 5785 MHz BPF with a 100 MHz bandwidth. Custom RF power filter and directional couplers designs can be designed and produced with required connector types when a standard cannot be found, or the requirements are such that a custom...

Engineering & Tech Headlines <Archives>

• 5G Is 42% of Fixed Wireless Access (FWA) in 2024

• Robert Dennard, DRAM Pioneer, Dies at 91

• TSMC's Energy Demand Drives Taiwan's Geopolitical Future

• Semiconductor Packaging Market on 5.6% CAGR 'Till 2028

• Altering Asteroid Trajectories with Nuclear X-Rays

Albert Einstein: A Short Biography

Albert Einstein: A Short Biography - RF CafeAlbert Einstein, one of the most renowned physicists in history, was born on March 14, 1879, in Ulm, in the Kingdom of Württemberg, part of the German Empire. His father, Hermann Einstein, was an engineer and salesman who ran an electrochemical factory, and his mother, Pauline Koch, managed the household and supported her son's education. Einstein had one sister, Maja, who was born in 1881 and with whom he had a lifelong close relationship. Einstein's extended family included several relatives who would play various roles in his life, both personally and professionally. His early family life was comfortable, though his parents moved frequently as they sought economic stability. Hermann Einstein's business ventures had varying success, and eventually, the family moved to Italy in 1894...

Rotary Stepping Switches

Rotary Stepping Switches - They're Everywhere, December 1967 Radio-Electronics - RF CafeHere is the second part of a series of articles about stepping switches appearing in 1967 issues of Radio-Electronics magazine. A standard (at the time) dial rotary phone was used as a familiar example in the part one. It delivers a single pulse for each number / letter set from 1, 2 (ABC), 3 (DEF), through 9 (WXY), 0 (Operator). On some phones, you can hear the clacking of the switch contacts as the spring-loaded dial rotates from the selected number back to home position. The stepping action as the result of dialing occurs at the telephone system switching and call routing equipment at central locations. There, stepping switches increment with each pulse received, and when the full number of pulse sets have arrived, the circuit is complete and the call put through to ring the phone...

2024 ARRL Field Day Results Published

2024 ARRL Field Day Results Published - RF Cafe"Results are published, and the numbers are in. They paint a picture of a very active 2024 ARRL Field Day. Nearly 1.3 million contacts were reported during the 24-hour event. That is up from 2023's 1.25 million contacts. That's likely indicative of the continued rise of Solar Cycle 25 leading up to the event, but more people also participated this year. Entries were received from all 85 ARRL and Radio Amateurs of Canada (RAC) sections, as well as from 27 different countries from outside the US and Canada. 'It is encouraging to see a rise in participation year to year,' said ARRL Contest Program Manager Paul Bourque, N1SFE. 'ARRL Field Day is amateur radio's premier event, and the hams turned out for it..."

Einstein Expounds on His New Theory

Einstein Expounds on His New Theory, 12/3/1919 The New York Times - RF CafeAfter searching for the first mention of Nikola Tesla in U.S. newspapers, I performed a similar search on Albert Einstein, again using editions available in the NewspaperArchive.com database. I was utterly surprised to find it in a 1919 issue of the The New York Times. His theory of Special Relativity was published in 1905 and his theory of General Relativity was published in 1915, so it took The NY Times four years to mention it. There is a reference to Dr. Einstein's' work on relativity in a 1915 edition of The Manitoban, from Winnipeg, Canada. The NY Times article is an actual interview with Albert Einstein, wherein at one point it is stated that there were perhaps only a dozen people in the world at that time who understood general relativity. Interestingly, Einstein uses the term "difform motion" to describe...

Exodus AMP2103P-LC, 0.5–3.2 GHz, 1 kW Pulse SSPA

Exodus AMP2103P-LC, 0.5–3.2 GHz, 1 kW Pulse SSPA - 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 announce the model AMP2103P-LC, dual-mode (CW & pulse) amplifier covering 800 to 3200 MHz. 1000 watt peak pulse power, or 500 watts CW. Ideal for automotive pulse/radar EMC-testing & commercial applications. Pulse widths to 560 μsec, duty cycle to 10%, 60 dB gain, and outstanding pulse fidelity. Monitoring parameters for forward/reflected power in watts and dBm, VSWR, voltage, current, and temperature, with unprecedented reliability and ruggedness in a compact 7U chassis...

Sally, the Service Maid

Sally, the Service Maid: The Case of the Silent Speaker, April 1944 Radio-Craft - RF CafeSally Mason was the soldering iron-wielding heroette (heroine sounds too much like the narcotic) of Nate Silverman's "Sally, the Service Maid" series that ran in Radio-Craft magazine during the years of World War II. As I noted in the previous episode, many of the nation's women were left behind to run their husband's, father's and/or son's electronics sales and repair businesses when they went off to save the world from aggressive Communists, Socialists, Maoists, Nazis, and other nasty types. Some of those ladies had already become very adept at troubleshooting, component replacement, and aligning radio and television sets, while some were left to learn at the School of Hard Knocks. Sally's father, Gus Mason...

Thanks to Crane Aerospace & Electronics for Their Support!

Crane Aerospace & Electronics - RF CafeCrane Aerospace & Electronics' products and services are organized into six integrated solutions: Cabin Systems, Electrical Power Solutions, Fluid Management Solutions, Landing Systems, Microwave Solutions, and Sensing Components & Systems. Our Microwave Solution designs and manufactures high-performance RF, IF and millimeter-wave components, subsystems and systems for commercial aviation, defense, and space including linear & log amplifiers, fixed & variable attenuators, circulators & isolators, power combiners & dividers, couplers, mixers, switches & matrices, oscillators & synthesizers.

Electronic Navigation in Flight

Electronic Navigation in Flight, August 1962 Radio-Electronics - RF CafeThe AN/MPN-13|14 mobile radar system I worked on while enlisted in the U.S. Air Force was designed and fielded around the time this Electronic Navigation in Flight article appeared in a 1962 issue of Radio-Electronics magazine. It had been upgraded a few times by 1979 when I was in Air Traffic Control Radar Repairman technical school at Keesler AFB, Mississippi; however, the original system did not featured a Doppler capability. The fully RF analog system could not provide air traffic controllers with speed data, but it did use physical mercury delay lines to provide a stationary target (ground, and to some degree, rain, clutter) cancellation by inverting and summing a real-time radar...

Why Color-TV Makers Worry

Anxiety Amid Affluence: Why Color-TV Makers Worry, December 27, 1965 Electronics Magazine - RF CafeDecisions, decisions, decisions. As the title states, color television manufacturers were, in 1965 when this Electronics magazine article was published, finding themselves between a rock and a hard place, as the saying goes, regarding a change from vacuum tubes to transistors. The buying public (aka consumers) had mixed emotions about the newfangled semiconductors based at least partly on bad information about transistors. Transistors had been designed in various circuits for a decade and a half and were gaining rapidly in performance and reliability. The price was coming down, but as reported here, still cost $5 to $10 apiece compared to a $1 vacuum tube. Company management needed to decide whether to delay implementing the new engineering and production methods required to deal with transistors...

The 1st Virtual Meeting Was in 1916

The 1st Virtual Meeting Was in 1916 - RF Cafe"At 8:30 p.m. on 16 May 1916, John J. Carty banged his gavel at the Engineering Societies Building in New York City to call to order a meeting of the American Institute of Electrical Engineers. This was no ordinary gathering. The AIEE had decided to conduct a live national meeting connecting more than 5,000 attendees in eight cities across four time zones. More than a century before Zoom made virtual meetings a pedestrian experience, telephone lines linked auditoriums from coast to coast. AIEE members and guests in Atlanta, Boston, Chicago, Denver, New York, Philadelphia, Salt Lake City, and San Francisco had telephone receivers at their seats so they could listen..."

Understanding Wave Physics

Understanding Wave Physics - RF CafeHere is the electromagnetic wave section of the "Wireless Networking in the Developing World," book (open source). "Wireless communications make use of electromagnetic waves to send signals across long distances. From a user's perspective, wireless connections are not particularly different from any other network connection: your web browser, email, and other applications all work as you would expect. But radio waves have some unexpected properties compared to Ethernet cable. For example, it's very easy to see the path that an Ethernet cable takes: locate the plug sticking out of your computer, follow the cable to the other end, and you've found it! You can also be confident that running many Ethernet cables alongside each other won't cause problems, since the cables effectively keep their signals contained within the wire itself. But how do you know where the waves emanating from your wireless device are going..."

Electronics Technician Training Part 1: Resident Schools

Electronics Technician Training Part 1: Resident Schools, September 1965 Popular Electronics - RF CafeThe decade of the 1960's was an exciting and fast-moving time for electronics, being that it was the beginning of a major paradigm change from vacuum tubes to transistors, from discrete circuit components to integrated circuits, and from point-to-point wiring to printed circuit boards. Computers were on the verge of moving out of university labs and corporate research and development centers to small businesses and retail headquarters. Electronic calculators were replacing mechanical calculators. Digital systems were replacing analog systems. Electronics training schools were in their collective heyday. Training prospects lined up in droves and competed to gain acceptance into the institutes. Home-study courses provided theory and hands-on building and troubleshooting...

Electronics-Themed Comics, June 1951 Radio-Electronics

Electronics-Themed Comics, June 1951 Radio-Electronics - RF CafeWhen looking a these vintage electronics-themed comics from Radio-Electronics magazine (and others), it probably is a case of "you had to have been there" to appreciate the humor in them. In a world of 24/7 broadcasting of every TV channel, the first comic wouldn't even make sense to someone who was born after about 1990, after which time most local over-the-air broadcast stations signed off at 1:00 or so, played the National Anthem, and then displayed a test pattern until about 6:00 am. The second comic is from the era of high voltages inside radio and TV chassis for vacuum tube plates and CRT accelerator grids. That big bulky thing the guy in the last comic is carrying is a thing called a cathode ray tube (CRT), which old people used to use...

European Electronics Market - The Boom Continues

European Electronics Market - The Boom Continues, December 27, 1965 Electronics Magazine - RF CafeThe final 1965 edition of Electronics magazine produced reports on the status of electronics markets in Western Europe and Russia. This is the opening statement proclaiming "The boom continues." Separate reports are included for West Germany (the Berlin Wall was still up then), the United Kingdom, France, Denmark, Austria, Sweden, Belgium, Switzerland, the Netherlands, and Italy are covered in separate sections. Russia, although obviously not part of Europe, is also covered. All will be posted within the next couple weeks for the benefit of historians...

How to Target RFCafe.com for Your Google Ads

Google AdSense - it makes good sense - <em>RF Cafe</em>One 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 225,000k per year (in eight locations on each page, with >17k pages)...

Electronics- Our Growing Industry

Electronics- Our Growing Industry, August 1958 Radio-Electronics - RF CafeToday's consumer electronics (CE) industry has an estimated value of $354 billion per a Statista report (a high number compared to others I located). In 1957, according to this article in Radio-Electronics, the market value was reported to be $13.7B ($121B in 2014 dollars per the BLS inflation calculator). The world population in 1957 was 2.89B and grew to 7.10B by 2013 (per Census.gov). That means population increased by a factor of 2.45 while the CE industry grew by a factor of 3.05. Within the margin of error of marketing expert estimates, that represents essentially flat growth. Fret not, though, because while the total spending on consumer electronics per capita might have been flat over a span of nearly 60 years, the effective cost per electronics product and the vastly improved functionality and reliability of electronics products has increased by a much larger factor ...

Measurements with Scattering Parameters

Measurements with Scattering Parameters - RF CafeJoe Cahak, owner of Sunshine Design Engineering Services, has submitted another fine article for posting here. Joe has many years of automated RF testing experience to leverage when writing this paper on making measurements with scattering parameters (S-parameters) involved. He begins, "In many RF and Microwave measurements the S-Parameters are typically expressed in dB (decibels) Magnitude units and Degrees in the polar coordinate system. Network and Vector Network Analyzers and Spectrum Analyzers all measure with voltage ratio measurements, so to convert to dB in terms of volts we must use the following equation. The Spectrum Analyzer is a frequency discriminating detector that detects the voltage for the signal. It will give the amplitude of signal as a function of frequency. It is scalar in measurement dimension magnitude vs. frequency. Displayed units are typically expressed in units of power (dBm). The Vector Network Analyzer measures complex magnitude and angle of RF signals vs. frequency. By using reference signals to calibrate the test system response and setting up a reference frame for the measurements, the instrument can measure the amplitude and phase angle of the AC-RF signal for each frequency it is tuned to. Displayed units are typically expressed..."

Get Your Custom-Designed RF Cafe Gear!

Custom-Designed RF-Themed Cups, T-Shirts, Mouse Pads, Clocks (Cafe Press) - RF CafeThis assortment of custom-designed themes by RF Cafe includes T-Shirts, Mouse Pads, Clocks, Tote Bags, Coffee Mugs and Steins, Purses, Sweatshirts, Baseball Caps, and more, all sporting my amazingly clever "RF Engineers - We Are the World's Matchmakers" Smith chart design. These would make excellent gifts for husbands, wives, kids, significant others, and for handing out at company events or as rewards for excellent service. My graphic has been ripped off by other people and used on their products, so please be sure to purchase only official RF Cafe gear. I only make a couple bucks on each sale - the rest goes to Cafe Press. It's a great way to help support RF Cafe. Thanks...

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 225,000 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...

The Conical Monopole Antenna

The Conical Monopole Antenna, November 1966 QST - RF CafeIt is important to concentrate your transmitter power into the proper beam if you wish to deliver the best signal to the other fellow's receiving antenna. This has logically led to the popularity of the Yagi beam antenna on the higher-frequency amateur bands. A beam antenna for the 80-meter band should have a 140-foot reflector and a 77-foot boom on a 250-foot tower. This makes the beam antenna impractical for the 80-meter band, and even for 40-meter operation a full-size Yagi is a forbidding structure to the neighbor's narrow-minded view - even a well-trained XYL might view such a monster beam with alarm. There is no easy solution to the need for a good DX antenna at low frequency, but the conical monopole antenna may be of interest to the more eager radio amateur as a more practical solution. The conical monopole antenna is a base-fed vertical antenna that has an omni-directional pattern in azimuth but with an elevation...

Uncommon Ground Difficulties

Uncommon Ground Difficulties, April 1958 Radio-Electronics - RF Cafe"Ground is ground the world around," is an oft repeated saying when talking about making electrical connections to Earth ground. In a general sense that is true, especially when referring to electromagnetic radio signals and antenna systems that are in some manner dependent on the common connection. However, when you are working within the confines of a localized electronic circuit such as on a printed circuit board or inside a chassis, there is no guarantee that without proper precautions ground is not at the same potential everywhere. Poor (high impedance) soldered, crimped, and bolted connections are among the prime offenders that cause voltage differentials to arise between points intended to be equipotential. RF frequency signals are particularly sensitive to even a minor divergence ...

What Is It?

What Is It?, February 1943 QST - RF CafeIf subjects pertaining to electronics - particularly vacuum tubes - are like music to your ears, then this poem entitled "What Is It?," from the February 1943 edition of QST, should suit you just fine. The rhyming words are supplied by author Frank Judd; you just need to supply the harmony. You might recognize paraphrasing of other familiar works such as Longfellow's "Paul Revere's Ride." Poems like this one were actually quite common back in the day. In fact if you look through the list of articles that I have posted from vintage QSTs, you will find about a dozen...

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...

Google Technology & Science Doodles

Google Technology & Science Doodles - RF CafeDo you remember seeing a cool Doodle on the Google search page and would like to find it again? Would you like to see not only the Doodle that piqued your interest, but ALL of the Doodles that Google has ever published? You can do that, but what might be more useful would a page full of all the technology- and science-related Doodles (click large image below) or some other specific topic. Fortunately, there is an easy way to find what you want by going to the Google website and typing "google doodles" into the search box, or just go to www.google.com/doodles. Once you get there, enter the specific event that interests you. Since some events have Doodles in more than one year, add a year to your search to narrow down returns...

Mathematics in Radio, Calculus and its Application in Radio

Mathematics in Radio, Calculus and its Application in Radio, July 1932 Radio News - RF CafeI challenge you to find a calculus lesson in a modern-day electronics magazine. In 1932, not all that long after Isaac Newton developed differential calculus (that's a joke), Radio News magazine ran a series of "Mathematics in Radio" articles that included, among other topics, a few lessons in calculus. Anyone who has taken college-level science or engineering courses knows how indispensible calculus is in working out many circuit, physics, and chemistry problems. My appreciation for calculus came when I realized that it actually allowed me to derive the kinds of standard equations that are commonly seen in lower level applications. For instance, if you needed to know the volume of a sphere, you could look up the familiar Volume = 4/3 π r3 formula, or you could write the equation...

Beware! The Serviceman!

Beware! The Serviceman!, September 1945, Radio-Craft - RF CafeThe battle between the serviceman and the customer is epic. The serviceman knows the customer is out to cheat him of his rightful due for expertise and availability, and the customer knows the serviceman will try to inflate the bill to finance his exorbitant lifestyle. This story from a 1945 edition of Radio-Craft is a humorous take on the subject at first glance from the customer's perspective, but after reading it you might ascertain that it is really from the serviceman's perspective. An article from a 1957 edition of Radio News magazine titled "Strategy for C.O.D. Service" was written as serious advice to servicemen to avoid being ripped off by customers typified by the one ostensibly penning this article...

Engineering & Science Crossword Puzzle for August 4

Engineering & Science Crossword Puzzle August 4, 2019 - RF CafeThis RF Cafe Engineering & Science Crossword Puzzle contains at least 10 words from headlines posted on the homepage during the week of July 29 - August 2, 2019 (marked with an asterisk*). These custom-made engineering and science-themed crossword puzzles are done weekly for the brain-exercising benefit and pleasure of RF Cafe visitors who are fellow cruciverbalists. Every word and clue - without exception - in these RF Cafe puzzles has been personally entered into a very large database that encompasses engineering, science, physical, astronomy, mathematics, chemistry ...

Electrical Shock: Fact and Fiction

Electrical Shock: Fact and Fiction, May 1959 Electronics World - RF Cafe"The Far Side" Doctors Poke Brain - RF CafeAny time I see an article that references causing limb movements by poking the brain with electrical signals, I think of the old The Far Side comic. Artist Gary Larson drew quite a few hilarious operating room scenarios. Electrocution is of course not a laughing matter - unless it happens to someone else and it is not serious and no harm is done. Then - and only then - can it be funny. I've laughed at myself many times after receiving a good jolt due to stupidity. Sometimes after such an experience I wonder how I never killed myself from getting zapped as the result of being too lazy to turn off a circuit breaker before servicing a light switch or receptacle. The sad thing is that I'll probably do it again some day...

How the J-K Flip-Flops

How the J-K Flip-Flops, January 1969 Radio-Electronics - RF CafeAn alternate title for this article that appeared in a 1969 issue of Radio-Electronics magazine could have been, "How to Build a J-K Flip-Flop." Author Leonard Geisler takes the reader through a step-by-step assembly of a functional J-K flip-flop using a collection of 1- 2- and 3-input NAND gates. The 1-input NAND, in case you are wondering, is used as an inverter. The piece reads like an in-depth first-semester electrical engineering technician course textbook. In the process of building the J-K, an R-S (reset/set) flip-flop is described. Nowhere does Geisler offer an explanation of from where the "J" and the "K" input labels come. According to electrical engineer Sourav Bhattacharya blog, it was Dr. Eldred Nelson of Hughes Aircraft who first coined the term J-K flip-flop...

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...

Computers Yesterday and Today

Computers Yesterday and Today, February 1960 Popular Electronics - RF Cafe60 years ago, when this article was originally published in Popular Electronics magazine, most computers were constructed either of gears or of vacuum tubes. The Univac in the photo below was a breakthrough for having been built entirely of transistors. Even with its "compact" size compared to is successor the ENIAC, the total computational power and programmability was orders of magnitude less than that of my handheld calculator, whose size is largely dictated not by the volume of the electronic circuits, but by the size of the display and the need for input keys larges enough to press reliably. Doesn't the photo of Pascal's calculator of 1642 look like it could be a modern 19" rack-mount chassis, complete with handles?

Lost Your Money? Wire KUBIT

Lost Your Money? Wire KUBIT, November 6, 1948, The Saturday Evening Post - RF CafeSending telegraph messages, whether by wire or wireless means, has always been expensive, particularly considering charges are determined by the character (letter, number, symbol). Accordingly, the Shakespearean line from Hamlet declaring that "brevity is the soul of wit" can be reworked to "brevity is the soul of economy." A telegraph wire, unlike a telephone call, is a legally binding communiqué, as is of course a written letter, but a telegram is immediate transmission of information for time-critical messaging. A series of "commercial codes" were developed enabling senders to save often significant money by sending multi-character codes that represented entire phrases and/or sentences. What struck me about this article that appeared in a 1948 issue of The Saturday Evening Post is how, following a court case involving how the inadvertent swapping of two character positions in a code...

RF Cafe Quiz #45: Dielectric and Thermal Properties of Materials at Microwave Frequencies

RF Cafe Quiz #45: Handbook of Dielectric and Thermal Properties of Materials at Microwave FrequenciesThis quiz is based on the information presented in Handbook of Dielectric and Thermal Properties of Materials at Microwave Frequencies, by Theodore Anderson. This book is a wealth of information of dielectric characteristics of biological tissues in plants, animals, as well as for ceramics, soils and minerals. Particular attention is paid to properties in the ISM frequency bands. Extensive sources for similar studies are provided. All RF Cafe quizzes would make perfect fodder in employment interviews for technicians or engineers - particularly those who are fresh out of school or are relatively new to the work world. Come to think of it, they would make equally excellent study material for the same persons who are going to be interviewed for a job.

QST Cruises with the Maritime Service

QST Cruises with the Maritime Service, July 1944 QST - RF CafeAre you between 16 and 17½ or between 26 and 35 and not in uniform? Are you 1-C or mildly 4-F or otherwise ineligible for military service? Are you interested in a radio operating job in direct support of the war effort? Then there's a place for you in the U. S. Maritime Service. If you hold a commercial radio-telegraph second or higher-grade license, so much the better. But you don't need a ticket to start with; in fact, you don't need any previous radio training whatsoever. The Maritime Service will train you. It will make a proficient merchant marine radio operator out of you at one of the nation's finest operator schools - with pay! This is an opportunity described several times before in QST. It is time now for the story to be told again...

Calls Home from Auto by Short Wave

Calls Home from Auto by Short Wave, August 1935 Short Wave Craft - RF CafeThis could be one of the earliest reports of mobile communications between a private automobile and a home base station. Using a personally designed and installed 5-meter transceiver both at home and in his car, Mr. Wallace is able to talk to his 12-year-old son on the way from work. My guess is that in 1935 there were not too many traffic jams, even in Long Beach, California, so it is doubtful that was the cause for his announced expected later-than-normal arrival home. The article states the automobile power supply needed to produce 300 mA of current at 525 V, which is ~160 W per Ohm's law, which seems unlikely considering car batteries were 6 V at the time, and that would work out to ~26 A. My question is whether little Billy possessed a license permitting him to talk back to dear old dad from the home station? If not, it really doesn't matter at this point since there is probably some statute of limitations that absolves him from prosecution...

Engineering & Science Crossword Puzzle for February 17

RF Cafe Engineering & Science Crossword Puzzle February 17, 2019Beginning in 2000, I have created hundreds of custom technology-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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