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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..."

Channel Master Antenna Advertisement

Channel Master Antenna Advertisement, October 1959 Electronics World - RF CafeA few months ago I posted a write-up on the vintage Alliance Model U-100 Tenna-Rotor that I installed in the garage attic with a Channel Master CM5020 VHF / UHF / FM antenna atop it. There are not many television antenna manufacturers around anymore; their numbers have been decreasing continually due first to the advent of cable-delivered TV and now with Internet-delivered TV. The "cord-cutter" movement is helping to give over-the-air television broadcasting a rebirth due to the outrageous cost of subscription programming. Anyone contemplating installing a television antenna today has the same concerns as those back in 1959 when this Channel Master advertisement appeared in Electronics World magazine - gain, directivity, bandwidth, ruggedness...

Electronic Sticklers

Electronic Sticklers, May 1959 Popular Electronics - RF CafeHere are a few more electronics conundrums with which to exercise the old noodle. These are puzzlers from a 1959 issue of Popular Electronics magazine, but at least one of them (#4) will likely prove to be a real stickler unless you have seen a similar resistor mesh problem before (see my solution for the resistor cube equivalent resistance). There are no tube circuits to use as an excuse for not attempting them - just resistors, batteries, switches, meters, a motor, and a couple light bulbs. All four would be fair game to present to an interviewee to see where he/she stands on basic circuit analysis...

Bargains by the Bagful

Bargains by the Bagful, February 1964 Popular Electronics - RF CafeThis 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...

Electronics-Themed Comics from Popular Electronics

All on Quarter-Inch Mylar, December 1966 Popular Electronics - RF CafeHere for your enjoyment during another workweek are three more vintage electronics-themed comics - this time from a 1966 issue of Popular Electronics magazine. The "quarter-inch Mylar" referenced in the title is recorder tape used in the very popular machines of the day. Not only were serious" music aficionados huge proponents of the medium, but so were the many recreational users. There was a sort of mystique involved with being able to record and instantly play back even normal conversations - sort of like with videos these days, except there is no mystique anymore because most users couldn't care less about the technology which enables their proclivities. The magazines of the era were full of stories on tape recorders and advertisements for buying them ...

Automatic Antenna Switching

Automatic Antenna Switching, April 1945 QST - RF CafeIn this article from a vintage issue of QST magazine, the author describes the automatic antenna switching system which was developed for controlling the forty-odd receiving antennas at the FCC's Grand Island Monitoring Station (Nebraska). With this system it required only a matter of seconds for the operator to select any desired antenna by simply pushing a couple of buttons on the control panel. A similar system could easily be designed for a lesser number of antennas either for a test range or an amateur radio operation. Of course modern-day antenna switching equipment does the job handily and at a good price ...

ABC's of Transistors

ABC's of Transistors, January 1969 Radio-Electronics - RF CafeSylvania was yet another bedrock American technology innovation company that in the last few decades has been bought by foreign concerns*, while retaining at least some semblance of its original identity - mostly for brand loyalty purposes. Along with pioneering lighting products, Sylvania produced vacuum tubes and semiconductors for use in its line of radios and televisions. Sylvania engineers published a lot of articles in electronics magazines introducing transistors and early integrated circuits to laymen, hobbyists, and professionals, some of whom were fledglings to the field and others who were transitioning tubes types. This particular article suggests methods for verifying operation of PNP and NPN bipolar junction transistors (BJTs) and for troubleshooting basic circuits ...

How Far Can You Go in Electronics Without a Degree?

How Far Can You Go in Electronics Without a Degree?, September 1957 Popular Electronics - RF CafeThis story reads like an infomercial for IBM, which it probably is. Of course infomercials had not been invented by 1957, so IBM was ahead of its time. The answer to the article's title, "How Far Can You Go in Electronics Without a Degree?" was the same 55 years ago as it is today: As far as your intellect and ambition will take you. Back then, as with today, few people could rise to the level of design engineer without a college degree. However, there are many aspects of electronics that requires no formal education at all if you possess the requisite skills. I never have bought into the feel-good lie about anyone being able to be whatever he or she wants to be. Some people simply cannot achieve the mastery necessary to do a particular job...

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)...

Belmont Model 408 "Farm" Superhet Radio Service Data Sheet

Belmont 4-Tube Model 408 (Series A) Battery "Farm" Superhet Radio Service Data Sheet, October 1938 Radio-Craft - RF CafeFor the last few years I have been scanning and posting Radio Service Data Sheets like this one featuring the Belmont 4-Tube Model 408 (Series A) Battery "Farm" Superhet radio in graphical format, rather than run OCR on them to separate the textual content. It appeared in the October 1938 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. No example of this radio could be found on the WWW. I keep a running list of all data sheets at the bottom of the page to facilitate a search...

Heath Company: Heathkit Advertisement

Heath Company Heathkit, July 1955 Radio & Television News - RF CafeHeathkit's claim to fame was that it was able to offer user-assembled kits of high quality electronic products at a price lower than what equivalent factory assembled equivalents would cost. While that is probably generally the case, it is difficult to gauge what the relative quality really is. Some of the kits were easy to assemble for even people with little experience, but a good portion of them required familiarity with soldering and how electronics were put together. The instructions provided were very thorough, complete with photos and drawings of how each step should look. In fact, according to a 1972 installment of Mac's Service Shop entitled "Philosophy of a Kit Manufacturer," every Heathkit kit instruction booklet goes through a rigorous cycle of writing, testing, and rewriting before being released for production...

B&K Dyna-Quik Tube & Transistor Tester

B&K Dyna-Quik Tube & Transistor Tester, February 1958 Radio & TV News - RF CafeWay back in the 1980s while working at Westinghouse Oceanic Davison in Annapolis, Maryland, an engineer who knew I had recently obtained a 1941 Crosley Model 03CB console style radio generously gave me his B&K Dyna-Quik Model 650 Vacuum Tube Tester. It is a very comprehensive portable tester used by many professional radio and television servicemen. My tester also had the Model 510 Accessory Socket Panel that added an ability to test 50% more tube types. One indication that it is one of the later model tube testers is the inclusion of a transistor testing socket. Unlike testing vacuum tubes, all of which plugged into sockets to make them easily replaceable, testing a transistor or solid state diode required unsoldering or clipping the device out of the circuit and then soldering back in either the verified still good device or a replacement. It was one of the reasons electronics servicing people eschewed the adoption of semiconductors...

Heathkit Test Equipment: IM-17 Solid-State VOM

Heathkit Test Equipment: VOM's IM-17 - RF CafeWhen preparing this webpage from the 1982 Heathkit Christmas catalog, I decided it was a good excuse to clean and re-calibrate my personal IM-17 Utility Solid-State Voltmeter. It is still in good-as-new condition. The accuracy and precision is very good, with consistent meter readings when changing scales. The manual suggests using a 1.5 V dry cell battery for the DC calibration and the 120 V wall socket for the AC calibration, if no better sources exist. A kit-built 10 MHz bandwidth oscilloscope I assembled many moons ago specified the same two types of calibration sources. Fortunately, I had sources a little better than a battery and a wall socket, and unlike the earlier exercises, I now have a good quality digital multimeter to verify the voltage levels (and better sources). The IM-17 is a strange beast in that the AC and resistance measurements...

Engineering & Science Crossword for June 9

Engineering & Science Crossword Puzzle June 9, 2019 - RF CafeSince 2000, I have been creating custom engineering- and 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 ...

RF Cafe Engineering Crossword Puzzle w/Weekly Headlines February 25

RF Cafe Engineering Crossword Puzzle w/Weekly Headlines February 25, 2018At least 10 clues with an asterisk (*) in this technology-themed crossword puzzle are pulled from this past week's (2/19 - 2/23) "Tech Industry Headlines" column on the RF Cafe homepage (see the Headline Archives page for help). For the sake of all the avid cruciverbalists amongst us, each week I create a new technology-themed crossword puzzle using only words from my custom-created related to engineering, science, mathematics, chemistry, physics, astronomy, etc. Enjoy...

RF Cafe Engineering Crossword Puzzle w/Weekly Headlines for July 15

RF Cafe Engineering Crossword Puzzle w/Weekly Headlines July 15, 2018At least 10 clues with an asterisk (*) in this technology-themed crossword puzzle are pulled from this past week's (7/9 - 7/13) "Tech Industry Headlines" column on the RF Cafe homepage. For the sake of all the avid cruciverbalists amongst us, each week I create a new technology-themed crossword puzzle using only words from my custom-created related list to engineering, science, mathematics, chemistry, physics, astronomy, etc. You will never find among the words names of politicians, mountain ranges, exotic foods or plants, movie stars, or anything of the sort. You might, however, see someone or something in the exclusion list who or that is directly related to this puzzle's theme, such as Hedy Lamar or the Bikini Atoll, respectively. Enjoy!...

$5.00 for Best "YL" Photos

$5.00 for Best "YL" Photos, May 1935 Short Wave Craft - RF CafeNews headlines are filled with stories about how certain segments of the society are routinely excluded from participation in activities which have been historically 'dominated' by adult white males. Not only have 'outsiders' been prevented from engagement, but, you would likely conclude based on the invective words that drip from the pens and/or mouths of those reporting, tireless campaigns have been mounted to see to it that exclusiveness continues. I will agree that there have been instances of preferential treatment by some groups and people, but I also know many attempts have been made over the decades to attract other than white males into all kinds of activities normally associated with white males. In fact, it is not a stretch to say many specialty groups go out of their way to make a big deal out of non-typical persons interested in joining. Here is one of many examples that appeared in a 1935 (yes, 1935) edition of Short Wave Craft where the editor, Hugo Gernsback, encouraged women and girls to get involved in amateur radio...

Electronics-Themed Comics

Electronics-Themed Comics, January 1940 Radio News - RF CafeHere are a couple more electronics-themed comics from a 1940-era issue of Radio News magazine. The scenarios depicted in these old comics are often based on the real-life experiences of radio and electronics servicemen. No doubt many guys got clobbered by high voltage or deafening audio when a customer decided to power up a television or radio while being worked on in the home. When this comic with the police car radio appeared in 1940, it had only been a decade since the first 2-way radios were being installed in patrol cars (see "A New Arm of the Law"). A huge list of technology-themed comics is listed at the bottom of the page. Enjoy!

The Operational Amplifier - What It Is & How It Works

The Operational Amplifier, September 1971 Popular Electronics - RF Cafe, September 1971 Popular Electronics - RF CafeHere is the second of a two-part article on operational amplifiers (opamps). Part 1 appeared in the August 1971 issue of Popular Electronics, which I have and will post soon (it still needs to be OCR'ed). Fortunately, you don't need it to find Part 2 useful. Barely half a decade had passed since Bob Widlar introduced his μA709 integrated circuit operational amplifier. Clunky attempts at vacuum tube operational amplifiers were introduced in the 1950's, but they were not overly popular. Early bipolar junction transistor opamps offered a significant reduction in size, weight, and power consumption over tubes, but did not have as high of an input impedance, had a lower gain-bandwidth product, and handled much lower power levels, which relegated their use to IF and baseband circuits...

Hams in Combat -One Life to Give

Hams in Combat - One Life to Give, July 1944 QST - RF CafeQST 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.

2 Halos Stacked for 2 Meters

2 Halos Stacked for 2 Meters, January 1965 Popular Electronics - RF CafeThe stacked halo antenna is a compact configuration for obtaining a nearly omnidirectional radiation pattern with nearly 8 dB of gain. An ideal half-wave dipole antenna provides 2.15 dB, so adding 5 to 6 more decibels by merely stacking two halo antennas (which are essentially curved half-waves) might seem like getting more than the sum of the parts. That extra gain is obtained by concentrating the vertical radiation pattern lower to the horizon as compared to a straight half-wave, even though the horizontal pattern loses a bit of gain contribution from the translation to a nearly omnidirectional nature. There is nowadays a plethora of information available on the Internet regarding stacked halo antennas, but in 1965, this Popular Electronics article...

Lee de Forest and the Navy

Lee de Forest and the Navy, January 1947 Radio-Craft - RF Cafe This is another of the articles written about Lee de Forest that appeared in the January 1947 issue of Radio-Craft magazine, in celebration of the 40-year anniversary since the industry-changing Audio vacuum tube was invented. Author George H. Clark, a member of the first "radio-man" to be graduated from the Massachusetts of Technology (MIT), was, in addition to working for Marconi Wireless Telegraph Company, RCA, and the Telegraph and Telephone Company, the U.S. Navy's "Sub-inspector of Wireless Telegraph Stations." He dealt extensively with de Forest regarding installation and operation of radio systems both on ships and on shore. Interestingly, he mentions that the first Audions were used as detectors more so than as signal amplifiers, which in fact was de Forest's original goal (a more sensitive detector) in his experimentation...

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...

Sangamo Electric Company

Sangamo Electric Company, May 1950 Radio & Television News - RF CafeRemember the Sunday comics feature for kids where there was a picture drawn with things wrong in it, and you had to find them all? This 1950 advertisement for the Sangamo Electric Company's line of capacitors, which appeared in Radio & Television News magazine, could server as a modern-day version for the Cancel Culture "woke" crowd that believes it has a duty to criticize and impugn everything it happens to fear, not like, or not understand. My list is at the bottom of the page if you want to compare it to yours. On other Sangamo ad post pages I have provided a bit of research on the background of "Samgamo" to try to determine whether the use of Native Americans (aka "indians" at the time) was based on a local tribe. No link has ever been found. Below the ad are a few of the items discovered...

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...

After Class: Some Facts on Quartz Crystals

After Class: Special Information on Radio - Some Facts on Quartz Crystals, TV, Radar, and Nucleonics, January 1957 Popular Electronics - RF CafeAccording to a 2001 paper published by the National Institute of Standards and Technology (NIST, formerly National Bureau of Standards, NBS), "The end of the era of quartz frequency standards began in 1949 with the development at NBS of the world's first atomic frequency standard based on an ammonia absorption line at 23.87 GHz." Further, "The Bureau supported work on both technologies for the next decade, but the rapid advances in the accuracy of atomic frequency standards could not be matched by quartz devices, and the work on quartz frequency standards was stopped in 1959." This article from a 1957 edition of Popular Electronics claims that the "master of all master-clocks" resided at the U.S. Naval Observatory at the time - not quite accurate from what my research indicates ...

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Rigol DHO1000 Oscilloscope - RF Cafe