Electronics-Themed Comics: Short Circuits

In 1961, when these tech-themed comics appeared in Electronics Illustrated magazine, the "Space Race" was in full swing. That, along with home hi-fi stereo equipment, newfangled color televisions, and - gasp - transistors, filled the headlines. They were also the subject of many forms of humor. These four comics touch on many of those aspects, all centered on the Space Race. Of course, everything is noticeably dated. "Flunking the code test" means not much to Amateur radio licensees who earned their first license (like me, in 2010) after the 5 WPM Morse code requirement was removed. Building something in "kit form" was a good way to save some money and learn something...

Mac's Radio Service Shop: Service Bench Chatter

In our present "No user serviceable parts inside" world of electronic products, it is easy to understand why very few people have an appreciation for the technical prowess needed to troubleshoot and repair them. When reading through these episodes of "Mac's Radio Service Shop" that appeared in mid last century editions of Radio & Television News magazine, I am inspired to envy the skills that small electronics repair shop owners had for working on the old vacuum tube based radio and television sets. Digital electronics has its own unique set of quirks and special knowledge requirements to troubleshoot, but when everything is analog rather than merely being required to be a "0" or a "1"...

FCC Seeks College Grads for Honors Program

"The U.S. Federal Communications Commission (FCC) has announced that it is once again accepting applications for its Honors Engineer Program. Initiated in 2018, the one-year development program gives selected candidates an opportunity to work with FCC personnel on innovative issues in the communications and high-tech arenas, including 5G communications technology, the national deployment of broadband services, and communications technologies intended to improve access to those with disabilities. Those selected to participate in the Honors Engineer Program will be eligible for continued employment at the agency. Application to the FCC's Honors Engineer Program is open to recent college graduates with an engineering degree..."

Amateur Radio Crossword Puzzle

This week's crossword puzzle theme is Amateur Radio. All RF Cafe crossword puzzles are custom made by me, Kirt Blattenberger, and have only words and clues related to RF, microwave, and mm-wave engineering, optics, amateur radio, mathematics, chemistry, physics, and other technical subjects. As always, this crossword puzzle contains no names of politicians, mountain ranges, exotic foods or plants, movie stars, or anything of the sort unless it/he/she is related to this puzzle's technology theme...

Submarines - Are We Open to Sneak Attack?

Submarines first proved their deadly capabilities during World War II when Adolph Hitler's navy used them to torpedo not just military ships but merchant ships in commercial trade routes between the Americas and Europe. Hideki Tojo's navy used subs to conduct surveillance prior to the deadly surprise attack on Pearl Harbor. Their naturally stealthy environment - underwater - proved to be a difficult realm both for detection and for attack. Fortunately, sensor technology developed quickly during the war, and soon a combination of air and sea based methods were in use and proved very effective. Submariners no longer sailed in relative security from being treated to a violent, icy burial at sea...

Thanks to PCB Directory for Continued Support!

The leading website for the PCB industry. PCB Directory is the largest directory of Printed Circuit Board (PCB) Manufacturers, Assembly houses, and Design Services on the Internet. We have listed the leading printed circuit board manufacturers around the world and made them searchable by their capabilities - Number of laminates used, Board thicknesses supported, Number of layers supported, Types of substrates (FR-4, Rogers, flexible, rigid), Geographical location (U.S., China), kinds of services (manufacturing, fabrication, assembly, prototype), and more. Fast turn-around on quotations for PCB fabrication and assembly.

Hide and Seek - Peenemünde to Canaveral

As the Soviet army closed in on the Peenemünde rocket base in March 1945, German engineers led by Wernher von Braun initiated a desperate evacuation of their revolutionary research. Tasked by von Braun, engineer Dieter Huzel organized the transport of tons of top-secret blueprints and records to avoid capture by the advancing Red Army. Amidst the chaos of collapsing lines and aerial warfare, Huzel successfully secured the documents in an abandoned, ironclad mine near Goslar, shielding them from Soviet hands. After dynamiting the entrance to seal the cache, Huzel and fellow scientists fled westward to surrender to American forces. Following their successful arrival in U.S. lines, the location was revealed...

Lost Your Money? Wire KUBIT

Sending 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 magazine...

Just Starting in EMC?

"With all the many pressures you have as a product designer, does electromagnetic compliance (EMC) always seem like a stumbling block to delaying product sales? Is your product exhibiting one of the top three failures: radiated emissions, electrostatic discharge, or radiated immunity? Are you continually cycling between design/fixing - running to the compliance test lab - failing again - and back to shot-gunning more fixes? Wondering how to attack these issues earlier in the design cycle? Would you like to learn how to characterize and troubleshoot simple design issues right on your workbench? Then, this monthly column is for you..."

Radio Service Data Sheets for Vintage Radios

In 1938, the designers at Sears, Roebuck & Company's, Silvertone radio division were truly thinking "outside the box" when they came up with this "Rocket" model Models 6110. It is an ultra compact tabletop design with a unique rounded top and a huge tuning dial that comprised one entire end of the Bakelite cabinet, along with a set of six pushbuttons for station recall.  Also published were datasheets on the Allied Radio Knight Model E10913, the General Electric Model GD-52,, and the Zenith Models 6D302, 6D311, 6D326, 6D336, 6D360. An ever-growing list of models is at the bottom of every page...

Mallory Clutch-Type Potentiometers

What drew my attention with this P.R. Mallory & Company advertisement was not an actual electronic component that they are most noted for - potentiometers, capacitors, switches, metal alloys, and of course batteries (later renamed Duracell). Philip Rogers Mallory began his company manufacturing tungsten wire for lamps. Rather what interested me was the huge variety of standard potentiometer and rotary switch extension shafts. Unlike modern electronics where pots and switches are typically mounted to the enclosure with wires running to the circuit assembly, many...

Nathan B. Stubblefield - America's Marconi

The failure to recognize Nathan B. Stubblefield as the primary inventor of radio is a classic example of how institutional power, financial interests, and the legal machinery of the telecommunications industry tend to favor those with corporate backing over solitary, unconventional inventors. Stubblefield's technology, which he demonstrated as early as 1892, utilized induction and conduction through the earth and water rather than the electromagnetic wave propagation (Hertzian waves) that ultimately became the standard for modern radio. Because his method was effective only over relatively short distances and functioned on different physical principles, it was eclipsed by the work of Guglielmo Marconi. Marconi was the superior marketing force. He was backed by a massive corporate infrastructure and was savvy in securing international patents...

Standing Waves on Transmission Lines

Author T.A. Gadwa employs a standing wave mechanism analogy that I don't recall having read before - that of a dam on a river. The river is the transmission line with a lake as the source and then he imagines a dam load. The dam standing waves, per his description, have phase and amplitude characteristics that depend on how tall the dam wall is relative to the surface height of the dammed river. An extensive array of graphs is provided showing how the current of the dam standing waves react to the dam transmission line termination impedance...

Electronic-Themed Comics from 1951

Here are a couple more electronics-themed comics, this time ones that appeared in the October 1951 edition of Radio & Television News magazine. When is the last time you saw a comic in a technical magazine? Note the AC power cord attached to the "portable" television. Television was a big deal in the day (I assume the "His" on the guy's towel implies that "Hers" is at the other end of the power cord). Color TV was not commercially available until a few years later. Nowadays, a person would have a smartphone, tablet, or notebook computer while on the can. There is a huge list of other comics at the bottom of the page...

Reviving Teletext for Ham Radio

"Once upon a time in Europe, television remote controls had a magic teletext button. Years before the internet stole into homes, pressing that button brought up teletext digital information services with hundreds of constantly updated pages. Living in Ireland in the 1980s and '90s, my family accessed the national teletext service - Aertel - multiple times a day for weather and news bulletins, as well as things like TV program guides and updates on airport flight arrivals. It was an elegant system: fast, low bandwidth, unaffected by user load, and delivering readable text even on analog television screens. So when I recently saw it was the 40th anniversary of Aertel's test transmissions, it reactivated a thought that had been rolling around in my head for years..."

Wireless Engineering Crossword Puzzle

I have a confession to make regarding the puzzle titles. While all RF Cafe crosswords do in fact use only my hand-entered dictionary of terms and clues (literally thousands accumulated over the years) that pertain exclusively to science, engineering, chemistry, physics, mathematics, astronomy, etc., the choice for a particular title is to help attract search engines to the page. There is nothing deceptive going on, just an attempt to exploit the nature of search engine algorithms that rank pages based on meta tags coinciding with relevant...

Anatech Electronics April 2026 Newsletter

Sam Benzacar, of Anatech Electronics, an RF and microwave filter company, has published his April 2026 Newsletter that, along with timely news items, features his short op-ed titled "Bell Labs in Murray Hill Celebrates." Sam, whose company is located not far from Murray Hill, extolls the many discoveries and inventions that took place there since its founding in 1925 as Bell Telephone Laboratories. It was originally a subsidiary of AT&T and Western Electric, later becoming part of Lucent Technologies and Alcatel-Lucent before Nokia's acquisition in 2016. Sam reports on the facilities' recent 100th anniversary celebration. The list of accomplishments would will volumes...

Ferrites - The Mighty Midgets of Electronics

The transformative role of ferrites - crystalline structures composed of iron oxide and metallic additives - in advancing modern electronics, is reported in this 1961 Electronics Illustrated magazine article. Ferrites uniquely combine magnetic properties with electrical insulation, enabling high efficiency at frequencies where standard iron cores fail due to eddy current losses. This "electronic wonder material" proved critical for television development, allowing for larger picture tubes through efficient flyback transformers and deflection yokes. Furthermore, ferrites revolutionized computing by providing reliable, compact memory cells, replacing failure-prone vacuum tubes in machines like the Whirlwind I. Beyond these core applications, the material facilitates innovations such as ultrasonic ...

Engineers Kick-Started the Scientific Method

"In 1627, a year after the death of the philosopher and statesman Francis Bacon, a short, evocative tale of his was published. The New Atlantis describes how a ship blown off course arrives at an unknown island called Bensalem. At its heart stands Salomon's House, an institution devoted to 'the knowledge of causes, and secret motions of things' and to 'the effecting of all things possible.' The novel captured Bacon's vision of a science built on skepticism and empiricism and his belief that understanding and creating were one and the same pursuit. No mere scholar's study filled with curiosities, Salomon's House had deep-sunk caves for refrigeration, towering structures for astronomy, sound-houses for acoustics, engine-houses..."

Werbel 2-Way Power Divider for 1.5-20.5 GHz

Werbel's new WM2PD-1.5-20.5-S-ECO, 2-way power divider covers 1.5 to 20.5 GHz and is designed for engineers who need wideband performance in a compact, cost-efficient package. Optimized for size, bandwidth, and manufacturability, it is well suited for high-volume applications, lab use, and general-purpose signal distribution where extreme port match is not required. Designed, assembled, and tested in the USA. "No Worries with Werbel!"

The Electronic Mind - How it Remembers

The radar system I worked on in the USAF used two early memory types described in this 1956 Popular Electronics magazine article. In fact, the radar was designed during that era, so it is no surprise. Our IFF secondary radar had a whopping 1 kilobyte of magnetic core memory in its processor circuitry. It consisted of 1024 tiny toroids mounted in a square matrix with four hair-width enamel coated wires running through them as x and y magnetization current lines, sense, and inhibit functions. If my memory serves me (pun intended) after three decades away from it, the TTL circuitry (no microprocessor) stored range values to calculate speed and direction from sample to sample. The other memory type was a mercury acoustic delay line contraption having a piezoelectric transducer at one end to launch an electrical pulse along its length and another transducer at the other end to convert back to an electrical pulse...

Schematics and Parts Lists for Vintage Vacuum Tube Radio Models

These are the schematics and parts list for vintage vacuum tube radios Westinghouse Model H-133; Arvin Models 150TC, 151TC; and Admiral Model 7C63, Chassis 7C1 as they appeared in the December 1947 issue of Radio News magazine. I scan and post these for the benefit of hobbyists and historians seeking such information. As time goes by, there is less and less likelihood that records of these relics from yesteryear's archives will be made available. As with all historical information, it takes someone with a personal interest in preserving the memories in order to fulfill the mission...

Many Thanks to KR Electronics for Long-Time Support!

KR Electronics has been designing and manufacturing custom filters for military and commercial radio, radar, medical, and communications since 1973. KR Electronics' line of filters includes lowpass, highpass, bandpass, bandstop, equalizer, duplexer, diplexer, and individually synthesized filters for special applications - both commercial and military. State-of-the-art computer synthesis, analysis, and test methods are used to meet the most challenging specifications. All common connector types and package form factors are available. Designed and manufactured in the USA. Please visit NIC today to see how we might be of assistance.

Lamp Brightness Quiz

Here is another electronics quiz for you to try. Intuition from experience goes a long way here, but if all else fails you can work out the details of the rectifier circuits to determine which lamp received the most current. Keep in mind that the diode symbols are not LEDs; it is the "A," "B," and "C" symbols inside circles that are the lamps whose brightnesses are being considered. LEDs did exist at the time this quiz was created in 1969, but the circuits would perform differently if in fact LEDs were used for double duty of rectification and illumination...

Good Operating Pays Off

The more things change, the more they stay the same. That saying applies to many recreational activities. Pick up a copy of QST magazine that was published in the last year and look at reader comments and you will find laments about the dwindling participation of youngsters, an increased degree of incivility and rule breaking during engagement, the high cost of getting into the hobby, yadda yadda yadda. I witness it regularly in the model aircraft world, too. That is not to say the issues are not true or irrelevant, just that they are persistent. Each generation, it has been said, tends to think...

ButtonWorx Pressure-Sensitive Switch Replacements

I have long-maintained that the vast majority of electrical problems on consumer products can be attributed to bad connector or switch contacts. Just yesterday, I restored a 1970's-era TI talking kids' toy to working order just by cleaning the plug-in program module and mating motherboard contacts. RF Cafe website visitor / contributor Bob Davis sent this suggestion for curing intermittent or non-responsive front panel buttons on test equipment and other electronic gear like radios, remote keypads, games, tools, vehicles, keyboards, locks, etc. His problem was with a R&S spectrum analyzer. He found a solution from ButtonWorx, who manufactures replacement pressure contacts for a large range of products. Some are entire arrays to replace original parts, and others are individual switches for custom requirements.

Coronet Model C-2 Schematic & Parts List

You wouldn't know it from the schematic, but this Coronet Model C-2 tabletop radio has a very unique feature: The tuning scale/pointer, and volume and tuning knobs are on the top of the case, that is, the face of the radio points upward when properly displayed. When searching for photos of the Coronet C2, I found a few examples where the radio was sitting on a surface with the face situated vertically like a standard model, but the feet are clearly on the side opposite the face. The schematic and parts list for the Coronet C2 radio appeared in the February 1947 issue of Radio News 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. I keep a running list of all data sheets to facilitate a search...

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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.

Windfreak 5 MHz-8 GHz, 15-Band RF Filter

Windfreak Technologies is proud to announces the availability of our FT108, an innovative programmable bidirectional filter bank spanning a frequency range of 5 MHz to 8 GHz in 15 bands. Band selection can be controlled through USB, UART or at high speeds through powerful triggering modes. Each unit is factory tested via network analyzer with unique data stored in the device to help with its use. Crossover frequencies are stored so the user can send a frequency command and the FT108 will utilizes Intelligent Band Selection logic to automatically toggle the optimal filter path based on minimum insertion loss. Readback of FT108 insertion loss at any frequency between crossover points allows for easy amplitude leveling...

Electron Shadows Map Force Fields

When I saw the images in this "Electron Shadows Map Force Fields" article from a 1949 issue of Radio-Electronics magazine, the first thing I though of was how as kids back in the 1960s we would hold magnets against the front of the television cathode ray tube (CRT) to see how they distorted the picture. If I still had a CRT TV or computer monitor around, I'd take some photos of it for the sake of those who have never seen what happens. The difference between that and the images formed here is that the professionals inserted the object of interest directly in the electron beam, between the cathode and the fluorescent glass grid. As with the images in the article, magnets of various shapes created unique responses. If you drag the magnet across the face of the CRT...