Homepage Archive - May 2026 (page 2)

Friday the 29th

Bell Telephone Laboratories - Circular Waveguide Invention

According to this full-page advertisement in the June 1955 issue of Radio & Television News magazine, Bell Telephone Laboratories was responsible for designing and fielding "waveguide pipe," aka flexible circular waveguides. According to other historical sources, both George Southworth of Bell Telephone Laboratories and Wilmer Barrow of the Massachusetts Institute of Technology (M.I.T.) independently and simultaneously developed circular waveguide, but the early devices were rigid pipe rather than being fabricated from tightly wrapped, insulated wire that permitted it to be bent rather than requiring separate corner and offset pieces. Insertion loss and VSWR is typically not as good as with rigid waveguide, but the ease of installation in many situations justifies the poorer electrical performance. Bell Telephone Laboratories was responsible...

Howard W. Sams and Co., Inc. Photofacts

Having recently struggled a little with re-stringing the dial cord on a vintage Realistic (Radio Shack) Patrolman-50 Radio, it really became apparent why the Sams Photofact Folders were of such value to electronics servicemen. Unlike the tangled mess of dial cord shown in the ad, I had the advantage of being able to carefully open the chassis and photograph the routing and wrapping of the broken dial cord around pulleys and shafts. Even so, a lack of experience required some trial and error to get the tensioning correct. No doubt many unqualified radio owners attempted to fix their own broken dial cords prior to breaking down and committing to spending a few bucks to have a pro do it correctly. The tight quarters in my portable radio had me using tweezers to do some of the routing...

Norman Rockwell Paintings with Radio Themes

My mother loved Norman Rockwell paintings for their ability to get to the heart of Americana. She was an avid collector of books on Rockwell and decorated plates for display - as avid as one can be on my newspaper classified ad manager father's feeble salary, anyway. I, too, have a great appreciation for Rockwell's great talent to choose his subject matter and models and to, when fitting, include a nearly photographic level of detail within. The Saturday Evening Post magazine featured many of his works spanning from 1916 until 1971 - from the middle of World War I and on through World War II, Korea, and Vietnam. Summer, spring, fall, and winter; Christmas, Easter, Veteran's Day, President's Day, Mother's Day, New Year's, and other annual events; experiences of love, happiness, joy, surprise, sadness, and a host of other emotions...

What's Your EQ?

Time to put on the thinking cap again for three more "What's Your EQ?" circuit challenges, compliments of Radio-Electronics magazine in May 1962. The first is a classic "black box" type problem which, from reading its description, involves some sort of resonant circuit. that's all I'll say on that. The next, called "An Easy One?" should, by the way it is drawn, be a clue that it might be easier to solve if you re-draw it to make a familiar-looking circuit. Hint: Summons the spirit of Sir Charles Wheatstone. Just the name of the last one, "Iterative Network," is enough to induce a cold sweat. As with most of these "What's Your EQ?" problems, successful completion of a first year college circuits course is plenty to get through them. A few are better attempted by people with hands-on experience troubleshooting circuits, but don't let that scare you off...

Please Thank KR Electronics for Their 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. Update: KR Electronics has been acquired by NIC, where KR Electronics' legacy of quality and innovation will continue to thrive, offering the same trusted products and services under NIC's leadership. For over three decades, NIC has delivered high-quality component performance and reliability, ensuring the successful deployment and operation of our clients' mission-critical solutions. Designed and manufactured in the USA. Please visit NIC today to see how we might be of assistance.

Thursday the 28th

Roger McCraw Check in w/MPN-14 Pics from Thailand c1973

Roger McCraw sent me these photos from his assignement in U-Tapao, Thailand, cicra 1973. I submitted a couple of the images to AI for colorization - amazing! Says Roger, "The pictures were taken at U-Tapao, Thailand and are dated April 1973. I was there from Jan 73 till Jan 74 and was a 30351 in the 1985th Comm Squadron. Since I was the newbie I was selected to change the light bulbs so I decided to give a Nixon peace sign for the photographer. The MPN was on a turntable so it could service both approaches to the runway. The ATC displays were in a trailer that was attached to a building, it was just to right of truck in picture. I only remember the name of one person because his name is listed on TWS website. He bought a four function calculator...

After Class - Special Information on Radio, TV, Radar and Nucleonics

This installment of the After Class series in the December 1957 edition of Popular Electronics deals with inductors. It is a beginner-level introduction to how reactive components behave in circuits. For some reason the concept of magnetism's influence on electrical current (present with inductors but not capacitors) seems to be more difficult to comprehend than that of electrons, even though James Clerk Maxwell shows in the mid 1800s that the two phenomena are interrelated. I am tempted to say that back in the 1950s when this article appeared, people were less familiar with the relatively new concept of electronics, but in thinking about it, your typical 2019 reader is probably even less likely to know anything at all about electronics or the way basic components work. I would bet that maybe 1% could even tell you the difference between AC and DC current...

Jean Shepherd on Getting His Class A Amateur Radio License

Not very long ago I mentioned Jean Shepherd (original assignee of W9QWN and later K2ORS call signs) as being one of my favorite old-time radio broadcasters (1960s-1970s). Jean was famous for recounting stories of his own life and for reporting news of the time in a way that could hold you in rapt attention from beginning to end. His humor, wit, and command of the English language was acknowledged by his contemporaries. If you listen to enough of his broadcasts you will notice the frequent mention of electronics and his experiences as a licensed amateur radio operator beginning at a tender young age. Just recently I listened to him recount his first day in high school when a SNAFU in the computer-generated (must have been a UNIVAC) class schedule mistakenly had him reporting to the girls' swimming pool...

Watch That Fuse Replacement

I was born in the era of screw-in glass fuses in household electric service panels. There was always a supply of replacements in the cabinet above the stove. Sometime around 1978, prior to enlisting in the USAF, I replaced the fuse panel with a Square D circuit breaker panel - a skill learned through four years of electrical work. In the Air Force, I worked on a 1950s era air traffic control radar system which consisted of many chassis assemblies having fuse holders on their front panels. The racks themselves had a circuit breaker panel, but it was a retrofit from sometime in the early 1970s. That was my introduction into the wide variety of cylindrical glass fuses - high and low voltage, normal-, slow- and fast-blow, time delay, etc. I learned of the reason why circuit designers employed each type, and always used exact replacements when possible. Later, as a circuit and systems design engineer myself, I always was careful to specify the most appropriate fuse type. This 1960 article in Radio-Electronics magazine is a good primer on fuse handling...

Wednesday the 27th

Circuit Quiz

Being that this Circuit Quiz appeared in a 1966 issue of Radio-Electronics magazine, the amplifier components shown are transistors, rather than vacuum tubes. I have to admit to not doing very well on it. One of the challenges is first determining what the intended function of the circuit is supposed to be, then you figure out what is wrong with it. Spoiler alert: I'm going to use circuit A as an example. It is declared to be a voltage regulator circuit, and the deficiency is the lack of a stable voltage reference. The architecture is typical of a voltage regulator with the common base setup used to increase the current supply. However, there is no reason to necessarily assume the DC IN is not itself already regulated, and the function if merely to increase the current supply capacity. If that is the case, then the circuit seems sufficient as shown. Maybe the fact that there is no problem otherwise should tell you make an assumption about the designer's intention and look for something that would be suspect under that condition. Anyway, that's my excuse and I'm sticking with it ;-)

Element Spacing in 3-Element Beams

This rather extensive article from a 1947 issue of QST magazine describes the method used by author Philip Erhorn to experimentally determine optimum spacing for the parasitic elements of his antenna. Unless you have electromagnetic field simulation software available for designing antennas, the procedure typically involves beginning with published formulas for element length and spacing, then resorting to a cut-and-test method of finding a combination that works best for your installation and goals. Almost certainly no two Hams end up with identical configurations because differences in terrain...

The Ham Who Was President

Since this is a presidential election year, I figured it would be a good time to post a tongue-in-cheek- story that appeared in the November 1952 issue of QST magazine about a fictional American president J. Willoughby Winkelspoof. The American Radio Relay League (ARRL) always has been and still is apolitical, so don't take seriously anything you read here. If you are an astute follower of politics, you might pick up on the nuances woven into the story, and might even marvel on how much the political landscape has changed in the half century since Pres. Winkelspoof graced the Oval Office...

Magnetostriction Devices and Filters for RF: Part 2

This is Part II of a 3-part series of articles on magnetostriction devices. At audio and low IF frequencies, the use of ferrite elements to construct relatively high-Q resonant circuits for filtering was a big deal in the middle of the last century. Although not presented in this article, design formulas and tables were published to implement the familiar Butterworth, constant-k, Chebyshev, Gaussian, and other types. Tuning, particularly for higher order filters, could be a chore since it involved a cut--and-try method on the ferrite rods. However, that is what was available in the day, and it evidently worked well enough to be worth the trouble for desired...

Electronic Crosswords, May 1961 Electronics World

Electronics World magazine often published electronics-themed crossword puzzles. Unlike RF Cafe engineering crosswords I created for two decades that use only technical words and clues, this one does include some unrelated words. A couple clues I was surprised to see pertain to radar; e.g., 32A: Small visible mark on a radar or scope screen, and 44A: Identification Friend or Foe. Some words require a familiarity with technology of the era, but you shouldn't have much trouble. You'll need to print this out on paper to work it...

Tuesday the 26th

A New Look in Transformers

Advances in transformer technology are driven by the need for miniaturization and efficiency, particularly in airborne and high-frequency military equipment. By optimizing core materials and fabrication, engineers can significantly reduce the weight and physical dimensions of transformers. A major technical milestone highlighted in this 1964 Electronics World magazine article, was the development of grain-oriented silicon steel, which, through precise crystal alignment, offers superior magnetic properties and reduced energy losses compared to traditional soft iron. Modern design further mitigates power loss from hysteresis and eddy currents by employing thin, insulated laminations...

Radios with a "Mystic Hand" and a "Phantom Conductor"

It didn't take much in the early days of radio to capture the curiosity of consumers with buzz phrases like a "Mystic Hand" to keep the radio tuned properly - really just AFC control, and a "Phantom Conductor" circuit that boosted the volume of high level audio (a nonlinear amplifier). Here are 4 more Radio Service Data Sheets from Radio-Craft magazine. Crosley Model 1316 Radio Service Data Sheet, Westinghouse Model WR 207 & WR 208 5-Tube Dual-Band Superheterodyne Radio Service Data Sheet, RCA Victor "High-Fidelity Electrola," Model R-99 Radio Service Data Sheet...

Bud Radio Advertisement

Back in the days when I built a lot of prototype electronic gear, project enclosures were generically referred as a "Bud Box." Lab stock rooms always had a good variety of sizes and configurations of the soft aluminum and sometimes plastic boxes that were easily drilled, punched, filed, and painted to make professional looking equipment. Not all the project boxes were made by Bud Industries, but just as everyone knows you're talking about a cola when you say "Coke," it was understood that a "Bud Box" was a chassis for a home-brewed circuit. They are still seen in construction articles of electronics hobby magazines today. I have even seen test equipment and utility items for sale that are obviously in a Bud Box type of chassis. This full-page advertisement for Bud Radio appeared in a 1930 issue of Radio Craft magazine - a mere two years after opening their doors...

Radio & Radar Crossword Puzzle

This week's crossword puzzle sports a radar and radio theme. 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, mathematics, chemistry, physics, and other technical subjects. As always, this crossword 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...

Monday the 25th

Travelling Wave Tubes (TWTs)

The traveling-wave tube (TWT), invented by Dr. Rudolph Kompfner during World War II, revolutionized microwave amplification by providing exceptional bandwidth without the limitations of traditional resonant cavities. By utilizing an electron gun, a precision-wound helix, and a magnetic focusing circuit, the TWT transfers energy from an electron beam to a propagating signal wave. This design enables high-gain, low-noise performance essential for radar, missile guidance, and high-capacity telecommunications systems like the TH radio-relay. Although early production faced challenges regarding reliability and manufacturing complexity, ongoing engineering refinements achieved the stability necessary for critical applications, including the Telstar communications satellite...

One Problem in Choosing Test Leads

Authors Cohen and Hessinger warn about the need to consider the capacitive loading effects of shielded and closely-space test leads when measuring other than direct current or very low audio or line frequencies. Lead capacitance is especially likely to affect measured values when the frequency is high and/or the source and load impedances are high. As was common in the day, capacitance units of μμfd (micro-micro farads = 10^-6 x 10^-6 = 10^-12 F) are cited, which is equivalent to units of pF (10^-12 F)...

Ground Resistance and Its Measurement

An old electrician's saying goes "Ground is ground the world around," implying that every point on Earth's surface is at the same potential - specifically 0 volts. We know, of course, that it is not so. Maybe on average such a claim could be made, but just as "sea level" is not the same at all points on the ocean's surface (hence we speak of "mean sea level"), neither is the voltage potential the same everywhere. Further, just as the salinity of all points on the ocean surface do not have the same salinity (and thereby conductivity), the conductivity of various places on dry land vary - often significantly. Electric power systems are very concerned with soil electrical conductivity in the vicinity of power generation installations...

Diode Modulators

Byron Goodman published a very thorough diode modulator article in a 1953 issue of QST magazine. It was one of the first of such articles that used the very recently available semiconductor diodes rather than the previously used vacuum tubes. Single-balanced bridge and ring modulator circuits are presented, along with the theory behind their operation. It would be a few years more before double balanced mixers with their abilities to reject even intermodulation products, and triple balanced mixers with very high overall spurious product rejection, would become commonplace...

Friday the 22nd

Electronic Brain

Back in the 1960s, Electronics Illustrated magazine ran a series of monthly Q&A columns titled "Electronic Brain," where readers wrote in to query the staff on particular quandaries. Even if you have been in the electronics game for decades, there were plenty of questions that probably invoked the "I'm sure I could have answered that at some point, but it's been so long that I couldn't say for sure," thought. The magnetomotive force topic in this set of three items did it for me. I knew there was a magnetic flux equivalent of electric current flow, but I probably would not have been able to write the equation using the precise...

Mac's Radio Service Shop: A Breathing Spell

We are accustomed these days with stores having "no questions asked" return policies for just about anything. I once watched a guy successfully return a 4" PVC plumbing fitting that had clearly been smeared with glue in the coupling areas. Another time a guy returned a painting drop cloth that was full of paint, declaring that it wasn't what he wanted. The return counter bins of Walmart and other stores are always chock full of stuff. Such was not always the case, though. This episode of Mac's Radio Service Shop, mentions, among other thing, how busy he and sidekick Barney had been right after Christmas doing troubleshooting and repair on various electronic equipment that had been received as gifts. Imagine receiving...

SF Circuits Achieves CMMC Level 2 Certification

San Francisco Circuits, a leading printed circuit board fabrication and assembly supplier serving commercial and defense markets, today announced that it has achieved Final Cybersecurity Maturity Model Certification (CMMC) Level 2 Certification status following a successful independent assessment by an accredited Certified Third-Party Assessment Organization (C3PAO). San Francisco Circuits Achieves CMMC Level 2 Certification The certification confirms that San Francisco Circuits' enterprise information systems meet the cybersecurity requirements outlined in NIST SP 800-171 Revision 2, as codified in 32 CFR Part 170, for the protection of Controlled Unclassified Information (CUI)...

National Ad: World's 1st AC Power Strip?

Could this be the world's first publically documented rack-mounted AC power strip? The National Company of Cambridge, Massachusetts, which began life as the National Toy Company, ran a long series of advertisements in QST and other electronics magazines that were heavy on text and light on pictures - definitely not the norm in advertising. This one, number 62, from a 1939 issue describes, along with a reference frequency oscillator, how their engineering team fabricated what we now call an AC power strip for use in an equipment rack. According to the sketch provided, there does not appear to be an On/Off switch and almost certainly not any form of surge protection as is common (maybe even required by UL) for modern power strips. Someone at National should have patented the idea; their heirs would be rich today...

Thomas Edison in John Hancock Ad in The Saturday Evening Post

Presenting yourself or your company as being modeled after a person of great accomplishment has been a common promotional tactic for as long as there has been print media. The John Hancock chose in this issue of The Saturday Evening Post to suggest, albeit by an indirect approach, to elicit the admiration Americans had for Thomas Edison's lust for innovation and desire to make people's lives better in hopes that readers would associate Edison with the insurance company. While the juxtaposition is strained, I do like one line in particular, "He lured electricity into a bottle and taught it to glow with good cheer." This short tribute to on of the world's greatest engineers is worth your a few moments of your valuable time...

One Problem in Choosing Test Leads

Authors Cohen and Hessinger warn about the need to consider the capacitive loading effects of shielded and closely-space test leads when measuring other than direct current or very low audio or line frequencies. Lead capacitance is especially likely to affect measured values when the frequency is high and/or the source and load impedances are high. As was common in the day, capacitance units of μμfd (micro-micro farads = 10^-6 x 10^-6 = 10^-12 F) are cited, which is equivalent to units of pF (10^-12 F)...

Friday the 22nd

RF Filter Quiz

Welcome to the RF Filter Quiz, an essential tool for radio enthusiasts and engineers dedicated to mastering frequency selectivity in complex signal chains. Whether you are troubleshooting signal interference, optimizing stopband rejection for a sensitive receiver, or designing your own ladder networks, a thorough understanding of passive and active filter synthesis is vital for achieving peak performance. This assessment tests your knowledge across ten fundamental concepts, including the practical trade-offs between Butterworth, Chebyshev, and Elliptic topologies, the impact of finite component Q-factors, and the critical relationship between group delay and passband ripple. By evaluating your grasp of these core principles...

Low Pressure Modulation

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

Folded and Loaded Antennas

Here is a fairly major treatise on folded and loaded antennas that appeared in a 1953 issue of QST magazine, with "Suggestions for Mobile and Restricted-Space Radiators." It is not for the faint of heart or anyone with mathphobia. Integral calculus is part of the presentation, although an understanding of calculus is not required to get the gist of the article. Equations for calculating the antenna configuration radiation resistances are given for the 3λ/4-wave folded dipole, the λ/8-wave folded monopole, the bottom-, center- and top-loaded λ/8-wave monopole, the bottom-loaded λ/16-wave monopole, and the λ/4-wave monopole folded twice, to name...

Balloon-Supported Antennas

Kite- and balloon-lifted antennas are very popular in the amateur radio realm. They are primarily used for short-term activity such as during a contest or during an emergency; however, some operators use them on a more extended basis. A really good series of articles on the use of balloons and kites for suspending antennas can be found here. Equations for calculating necessary balloon and kite sizes and predicting wind effects are included along with lists of "Dos" and "Don'ts." This is not a new phenomenon. A 1940 edition of QST magazine described how to employ weather and sounding balloons to provide needed antenna configurations...

Espresso Engineering Workbook - Free!

New: Frequency Planner. RF Cafe's spreadsheet-based engineering and science calculator, Espresso Engineering Workbook™, is a collection of electrical engineering and physics calculators for commonly needed design and problem solving work. The filter calculators do not just amplitude, but also phase and group delay (hard to get outside of a big $$$ simulator). It is an excellent tool for engineers, technicians, hobbyists, and students. Equally excellent is that Espresso Engineering Workbook™ is provided at no cost, compliments of my generous sponsors. 50 worksheets to date...

Electronics-Themed Comics

Take a quick break before - or while - hunkering down for a long day's grueling work. Most of the electronics-themed comics that appeared in QST magazine were associated directly with particular columns. For example, the cartoons featuring "Jeeves," the overtaxed manservant of a never-seen house master, was part of the "How's DX" feature. Drawn by artist Phil Glidersleeve (aka "Gil"), W1CJD, poor Jeeves was often found doing his boss's will in the most precarious situation with intemperate weather making his assignments tough to complete. Situations involving Podunk Hollow Radio Club were frequent subjects of Gil's drawing pen as well...

Thursday the 21st

A Logic Named Joe : The Internet Foretold?

Somebody get Al Gore on the phone - preferably using Skype. It appears that maybe he did not invent the Internet after all. Sci-fi writer William F. Jenkins, who went by the pen name "Murray Leinster," wrote a short story entitled A Logic Named Joe, that appeared in March 1946 issue of Astounding Science Fiction. In the story, an amazingly prescient description of the modern Internet is laid out. The works is copyrighted so I will not replicate the entire thing here, but these are a few excerpts that sound a lot like Mr. Leinster was in cahoots with DARPA during the development*. Before I forget, thanks to RF Cafe visitor Terry W. for sending the link. My comments look like...

Editorial re FCC Potentially Shutting Down Amateur Radio During WWII

"Do you think that F.C.C. would be engaged in the present terrific expense and effort of getting our fingerprints and citizenship histories if there were intention of shutting us down shortly?" That statement was printed by the QST magazine editor in the issue that preceded the December 7, 1941, attack on Pearl Harbor by thirteen months. A few things about it are troubling. First, the FCC was collecting fingerprints of licensed amateur radio operators. Second, the FCC was assimilating information about licensed amateur radio operators' citizenship histories. Third, a combination of short-sightedness and apparent naiveté concerning the FCC's willingness to shut down amateur radio operations once...

Tesseract Antique Instruments

My introduction to a tesseract was during an episode of Carl Sagan's "Cosmos" series in the 1980s, where he was demonstrating how beings in of dimension N would perceive items of dimension N+1. The tesseract, Sagan explained, is a 3-dimensional projection of 4-dimension hypercube. Watch the embedded video for more information. The Tesseract website, which has nothing to do with a hypercube as far as I can tell, deals in some very cool antique scientific instruments. I learned of it from an article in Astronomy magazine where an editor recommended it when researching the potential value of a collectible telescope. Run by Drs. David and Yola Coffeen, Tesseract has a huge inventory of items...

Wednesday the 20th

Astronomy and Amateur Radio

It is always nice to read an article that encompasses more than one of my hobbies, whether it be amateur radio and amateur astronomy like this one, amateur radio and model rocketry, or amateur radio and radio controlled airplanes. I don't recall ever seeing an article that combined astronomy and model airplanes. In this 1943 QST magazine piece, author Hollis French expounds on the necessity for Hams to understand the effects that atmospheric phenomena, caused primarily by our sun's periodic and intermittent activity, have on radio signal propagation. Properties of the ionospheric layers had by 1943 been pretty well surmised based on cause and effect relationships through indirect observation since at the time no sounding rockets had been launched into the upper atmosphere to obtain in situ measurements of ionization, magnetic fields, and free electron activity...

Multi-Impedance Dipole Antennas

Maybe I suffer from cranial rectumitis at the moment, but I'm having a hard time with a statement made about coaxial feedline impedance, to wit, "102-ohm line (52-ohm lines in series)." I must be missing something because I don't understand how placing two 52-ohm transmission cables in series results in twice the impedance. Aside from that, author John Avery presents an interesting article on multi-impedance dipole antennas. Empirical data is presented on how the feedpoint impedance of a dipole varies with distance above the ground. His results are very close to theoretical values which assumes non-sagging elements, perfectly linear alignment, a perfectly conductive ground, etc. He then extended his investigation into 2-wire (4x impedance)...

The Wives and Mothers of Radio Amateurs

How well received do you think this social concept would be in today's easily offended world: "To bring together socially the Wives and Mothers of Dallas Radio Amateurs; to promote mutual sympathy, counsel, and interest in our husband's and our son's hobby; and with a realization that theirs is an outstanding, fascinating, far-reaching and educational hobby, it is our desire to further their interests in whatever way may present itself." It would be roundly criticized as a backward, misogynistic, 1930-era mindset intended to subject women to yet another form of domestic slavery beyond housekeeping and child rearing - no doubt thought up by a man. Anyone thinking so...

Voices in the Mail

This article reports on the very earliest form of voice mail - recording a message on a reel-to-reel tape deck, placing it in an envelope, and snail mailing it to its recipient. Sure, it was slow, but unless you were under surveillance for some suspected crime, there was just about zero chance that some government agency was going to hear your private message. I had forgotten about it until reading this, but I remember that back in the 1960s, my father bought an el cheapo tape deck for our family and one for his parents, who lived in Buffalo, New York. My parents and four sisters and I had a pretty good time hamming it up on the tape, and looked forward to receiving a reply tape a month or two later. "Grandpa B," as we kids called him, was a real funny guy...

Tuesday the 19th

RF Attenuator Quiz

Welcome to the RF Attenuator Quiz, a technical resource specifically designed for engineers and radio hobbyists who demand precision in their signal chain analysis. Whether you are troubleshooting high-frequency systems, optimizing cascaded RF stages for improved impedance matching, or developing custom measurement tools like RF Cascade Workbook, a thorough understanding of passive attenuation is essential for maintaining signal integrity. This assessment challenges your knowledge across ten critical areas, including power handling limits, thermal derating, noise figure degradation, and the strategic use of attenuators to enhance system IP3...

Flexible Coaxial Cable

If anything qualifies for meeting the criteria of the old adage that says "Necessity is the mother of invention," it is coaxial transmission cable. Wireless communications during World War II was the necessity that drove the rapid development and continuous improvement of coax. Other than materials technology for wire, dielectric, protective jacket, etc., the basics of coax cable have not changed. It was during the war that polyethylene was developed and adopted as a dielectric material much superior to previously used copolene. Understanding of how electromagnetic fields propagate within and, under non-ideal conditions - on the outside of the cable has increased significantly...

How's Your Math?

If you are just starting out in the realm of electronics or maybe just need a little freshening up of your basic math skills, this rather extensive article from a 1942 issue of QST magazine is just what you need. Author Dawkins Espy does a really nice job of laying out the basics of algebraic operations, Ohm's law, trigonometry, and logarithms. Examples are provided for each category. In this day of calculators doing all the hard work of calculating logs, antilogs, and trig functions, it does even seasoned veterans at electronics calculations a bit of good to do a quick read-through to knock off cobwebs in the gray matter. How long has it been since you have seen tables of sine, cosine, and tangent values and/or tables of logarithms? Not long enough, you say?

All Elements Heavier Than Helium Are Metals?

Astronomers consider all elements heavier than helium to be metals. That definition obviously does not jive with the standard chemical definition of a metal as an element that readily conducts electricity, but a concept called "metallicity" argues that from a star (and therefore the universe) formation perspective, extremely high temperatures and pressures in first generation stars (like our sun) preclude the identification of distinct elements other than hydrogen and helium. Heavier elements, such as lithium (#3 on the periodic chart and a major component in LiIon batteries, is classified as a metal in chemistry) are overwhelmingly created after a massive enough hydrogen star collapses and begins fusing H and He into heavier elements. The relative abundance of hydrogen in the universe is deemed to be about 92%, and helium is 7.1%, so together they comprise about 99% of all elements...

Many Thanks to Amplifier Solutions Corporation for Continued Support!

Amplifier Solutions Corporation (ASC) is a manufacturer of amplifiers for commercial & military markets. ASC designs and manufactures hybrid, surface mount flange, open carrier and connectorized amplifiers for low, medium and high power applications using Gallium Nitride (GaN), Gallium Arsenide (GaAs) and Silicon (Si) transistor technologies. ASC's thick film designs operate in the frequency range of 300 kHz to 6 GHz. ASC offers thin film designs that operate up to 20 GHz. ASC is located in an 8,000 sq.ft. facility in the town of Telford, PA. We offer excellent customer support and take pride in the ability to quickly react to evolving system design requirements.

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