See Page 1 |
2 | of the April 2025 homepage archives. Wednesday the 30th
 The Non-Linear Systems, Inc. (NLS) X-3 Multipurpose
Digital Voltmeter is a rugged, early solid-state DMM from the mid-to-late 20th century,
developed by NLS -
founded by Andrew Kay, inventor of the digital voltmeter. Known for high precision
and a Nixie tube or LED display, it measured DC/AC voltage, resistance, and sometimes
current, with a high input impedance (1 MΩ+) to minimize circuit interference.
Designed for industrial and lab use, it was among the first digital meters to replace
analog counterparts, reflecting NLS's role in pioneering digital instrumentation.
Some models saw military/aerospace applications, underscoring their reliability.
Though obsolete, the X-3 remains collectible, especially among vintage electronics
enthusiasts, with functional units prized for their retro appeal...
 Maybe this is a job for
QentComm! "Project Eleven, a quantum computing
research organization, has announced the launch of the
Q-Day Prize, a global challenge offering 1 BTC to the first team able to break
an elliptic curve cryptographic (ECC) key using Shor's algorithm on a quantum computer.
The first team to successfully achieve this breakthrough before April 5, 2026, will
be awarded 1 BTC. The challenge directly targets the Elliptic Curve Digital Signature
Algorithm (ECDSA), which underpins bitcoin's security model. While theoretical discussions
about quantum threats have persisted for years, Project Eleven seeks to turn speculation
into measurable risk by encouraging practical demonstrations of cryptographic..."
 Yet three more puzzlers for the student,
theoretician and practical man appeared in the June 1963 issue of Radio-Electronics
magazine. These "What's Your EQ?" submissions may look simple, but double-check
your answers before you say you've solved them. If you've got an interesting or
unusual answer send it to us. We are especially interested in service stinkers or
engineering stumpers on actual electronic equipment. We are getting so many letters
we can't answer individual ones, but we'll print the more interesting solutions
(the ones the original authors never thought of)...
 Anatech 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 filter models have been added to the product line in April, including
a 1200 MHz LC bandpass filter with a 400 MHz bandwidth, a 737-707 MHz
ceramic duplexer, and a 9950 MHz cavity bandpass filter with a 200 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...
 Breaking news in the electronics realm in
1968 included Matsushita Electric unveiling a piezoelectric ceramic (PCM) transformer
for TVs, replacing bulky flyback transformers. Driven by 200V AC, it vibrates mechanically
to generate 10-12 kV, slashing size/weight by 80%. Meanwhile, the FDA moved
to
ban carbon tetrachloride (carbon tet) - a toxic chemical in fire extinguishers
and cleaners - citing fatal inhalation risks. Carbon tet was used widely for cleaning
grease and oil off electronics assemblies. In education, Tyler Junior College adopted
RCA's "Select-A-Lesson" dial-access system, letting students dial course numbers
to receive audio-visual lessons from centralized tapes. Defying tube obsolescence,
ITT Electron Tube Division...
 In July 1966, Radio-Electronics
magazine covered
Europe's efforts to standardize color-TV at the Oslo CCIR conference, where
three competing systems were under consideration: NTSC (the U.S. phase-modulated
system, cost-effective but prone to hue errors), SECAM (the French sequential system
using FM to eliminate phase distortion but requiring a delay line), and PAL (the
German system that corrected NTSC's phase errors by alternating signal polarity
each line). While SECAM offered simplicity (no user controls) and PAL provided better
color stability under interference, NTSC remained the cheapest option. A last-minute
Russian proposal, SEQUAM (a hybrid of PAL and ART)...
Tuesday the 29th
 I have to admit to never having heard of
three of the terms (5, 6, and 13) here in this "R-E Puzzler"
that appeared in the July 1967 issue of Radio-Electronics (R-E) magazine.
I provided definitions for each at the bottom of the page in the Answers area. These
R-E Puzzlers are a form of crossword puzzle, except no words cross. It is more
of a "crossletter" puzzle because at least one letter in each row is common to another
row. In some ways they are more difficult than a true crossword puzzle since not
as many letters can be filled in from other clues to help figure out the unknown
word. You'll need to print this out to fill in since web apps weren't a thing in
1967...
 The most interesting item in this half dozen
radio circuits from the April 1948 issue of Radio News magazine is the
Meck FM Converter. From the Cool386 website, "The Meck FM converter is like
other FM converters of the time, in that it is really just an FM tuner with an audio
output. It does not actually convert the FM to AM (like the later FM converters
used with AM car radios). This audio output is several hundred millivolts and is
meant to be fed into the audio stage of an existing radio, which typically consists
of a triode voltage amplifier and pentode output stage." Commercial FM radio broadcasts
in the U.S. began in 1941. The first licensed commercial FM station was W47NV in
Nashville, Tennessee...
 "A team of researchers at Q-CTRL, a quantum
infrastructure software-maker based in Sydney, Australia, has announced the successful
demonstration of its newly developed
quantum navigation system called 'Ironstone Opal.' The group has written a paper
describing how their system works and how well it tested against currently available
backup GPS systems and has posted it on the arXiv preprint server. With the advent
and subsequent reliance on GPS by private and military vehicles and aircraft for
navigation, governments have come to understand how vulnerable such systems can
be..."
 The June 1969 issue of Radio-Electronics
magazine features the following news items. University of Wisconsin engineers tested
cryogenic "neuristors" in liquid helium, mimicking brain neurons for ultra-dense
computing. Bell Labs developed a 600-component IC for Picturephone timing circuits.
A revised maritime signal code added medical terms like "Oo-nah-won" (broken thumb).
A study found 20% of U.S. color TVs leaked dangerous X-rays due to high voltage.
Japanese firms Matsushita and Mitsubishi demonstrated early flat-screen TVs, while
U.S. research shifted to plasma displays. NASA and India planned satellite TV for
remote villages, hinting at future U.S. educational broadcasts. FM radio, once written
off...
 Knowledge of the
meteorological microburst was a very new concept in 1960 when Radio-Electronics
magazine editor Hugo Gernsback penned this column. However, microbursts were not
formally identified until the 1970s by meteorologist Tetsuya Theodore Fujita, following
his investigation of the 1975 Eastern Air Lines Flight 66 crash. His research defined
them as dangerous, localized downdrafts, leading to improved aviation safety measures
like Doppler radar detection. In his noted fashion, Mr. Gernsback accurately
described the phenomenon and predicted the Doppler radar technology which would
be needed to forewarn pilots of impending danger. Microbursts are most threatening
near the ground where the airplane does not have...
Monday the 28th
 Start your week our right with a few electronics-themed
comics from these 1960's vintage Radio-Electronics magazines. The one on
page 108 is my favorite - by far the most clever. The artist had no idea that he
was drawing the
world's first e-cigarette, only not in its present-day form. The page 86 comic
invokes memories for just about everyone regarding some dummkopf neighbor or boob
in a car with the stereo volume level cranked way up. We hope they will all someday
go deaf from it, as a form of retribution. I had a neighbor one time who had a massive
stereo outdoor system around his pool, and he blasted the area all weekend long
during the summer. I finally got it under control after I would fire...
 These two puzzlers for the student, theoretician
and practical man, appeared in the October 1966 issue of Radio-Electronics
magazine. A wide variety of difficulty in problems exist. "Double-check your answers
before you say you've solved them," says editor Clark. Readers submitted most of
the "What's
Your EQ?" problems. The magazine paid $10 ($92 in 2025 money) for each one accepted.
"We're especially interested in service stinkers or engineering stumpers on actual
electronic equipment." See the huge list below of others I have posted over the
years...
 "Researchers have achieved a major leap
in quantum computing by simulating
Google's 53-qubit Sycamore circuit using over 1,400 GPUs and groundbreaking
algorithmic techniques. Their efficient tensor network methods and clever 'top-k'
sampling approach drastically reduce the memory and computational load needed for
accurate simulations. These strategies were validated with smaller test circuits
and could shape the future of quantum research, pushing the boundaries of what classical
systems can simulate. Simulating Google's Quantum Circuit..."
 This article on applications for the most
basic of adjustable electronic components - the
potentiometer (aka "pot") - will probably surprise a lot of readers with the
wide variety of configurations in which it can be used to perform much more than
a boring light bulb dimmer or motor speed control. In this 1966 issue of Radio-Electronics
magazine, Mr. F.H. Franz educates us on how to add components around the pot
to perform specialized linear and nonlinear responses, and even some wild curves
when a battery is inserted. Stereo systems have used logarithmic responses in speaker
circuits for more than a century using some of these tricks (audio taper potentiometer)...
 Breaking news from May 1969: Researchers
at Bell Labs and Japan's Kyodo Electronic Labs developed new IC fabrication methods
to cut costs and
shrink transistor sizes by 75%. Bell's collector-diffusion isolation eliminates
masking steps by using a p-type layer for insulation, while base-diffusion isolation
reduces power needs and enables sub-1-nsec switching. Kyodo's technique deposits
insulating polycrystalline silicon oxide, allowing denser circuits. These advances
could double or triple IC yields per silicon wafer. Meanwhile, Hughes Aircraft tested
retractable solar arrays for spacecraft, delivering 1,500 watts when unfurled. In
consumer tech, Motorola introduced a 20-cent audio...
 Amplifier Solutions Corporation (ASC) is
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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.
Friday the 25th
 Finish up your week by considering these
three "What's
Your EQ" circuit challenges that appeared in a 1964 issue of Radio-Electronics
magazine. They were submitted for consideration by readers, and sometimes by staff
writers. The first is yet another form of the Black Box mystery component. Kendall
Collins sort of gives away part of the answer in the problem statement. The second
is a fairly straight-forward switching circuit. You'll get it with no problem. The
third is most challenging. Don't be put off by the presence of a vacuum tube in
the schematic. Mentally replace it with a FET and go from there. Interestingly,
there is a lot of forum chatter about the Dynakit "Stereocator" feature regarding
stereo reception...
 "Japan-based Fujitsu Ltd has reported gallium
nitride (GaN) high-electron-mobility transistors (HEMTs) on free-standing GaN substrates
operating at 2.45 GHz in the industrial, scientific & medical (ISM, 2.4–2.5 GHz)
reserved band with
85.2% power-added efficiency (PAE) and 89.0% drain efficiency (DE) [Toshihiro
Ohki et al, Appl. Phys. Express, p18, p034004, 2025]. The team reports: 'To the
best of our knowledge, our device sets a new record for the highest power-added
efficiency and drain efficiency among discrete GaN HEMTs, highlighting the superior
potential of GaN-on-GaN HEMTs for highly efficient RF power amplifiers..."
 In his 1967 Radio-Electronics magazine
column, editor Forest Belt envisioned the 1970s as a decade of radical electronic
transformation, where homes would become
"total-electronic" environments controlled by advanced technology - from computer-assisted
cooking and video communicators to 3D television, laser communications, and even
sleep-enhancing atmospheric systems. He urged electronics professionals, experimenters,
and service technicians to prepare for this future, emphasizing that innovation
and broad technical expertise would be critical to meeting consumer demands for
ever-newer gadgets and conveniences. Belt warned that technicians who failed to
adapt would be left behind, while those mastering emerging fields like fuel cells
and heatless...
 At Tuskegee, Alabama, March 7, Colonel Frederick
V. H. Kimble, U. S. A., pinned wings on the blouses of five young Negro lieutenants,
members of the first
graduating class of the Army's first Negro air school. Since last July they
had undergone all the primary and advanced training to which white Army cadets at
Randolph and Kelly fields are subject. Now they are charter members of the Air Force's
99th (all Negro) Pursuit Squadron, established last summer at a $2,000,000 airdrome
near Alabama's famed Tuskegee Institute and now developing into one of the Army's
biggest training bases...
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• Deutsche Telekom
Quantum Internet Record
• Satellite-Hungry
Orange Taps Telesat
• UK Invests
£23M in Telecoms
R&D
 In August 1968, Radio-Electronics
magazine's "News Briefs" reported on RCA's groundbreaking development of liquid
crystal displays (LCDs), demonstrating how an electric field could turn transparent
liquid crystals opaque - a key step toward flat-panel TVs. The article explained
that these displays, just 0.001" thick and requiring minimal power, could be driven
by integrated circuits and were visible even in bright light, unlike traditional
CRTs. That "Radar
Colander" photo looks like an out-of-this-world being - the lady's hairdo that
is, not the metal hemisphere! Additionally, the Supreme Court ruled 7-0 that the
FCC had authority to regulate CATV systems, reversing a lower court decision and
impacting cable operations nationwide...
Thursday the 24th
 This 1964 Radio-Electronics magazine
article details the
operation of common electrical meters - voltmeters, milliammeters, and ohmmeters
- all based on Ohm's law (I = E/R). The core component is the d'Arsonval
movement, a DC-sensitive mechanism that can measure AC when paired with rectifiers.
Voltmeters use multiplier resistors for different ranges, while ohmmeters employ
an internal battery, producing a nonlinear scale. AC measurements rely on rectifiers
to determine RMS voltage (0.707 of peak sine wave), though this method only works
for pure sine waves. The article also explains practical circuits, including protection
features like fuses, and discusses voltmeter sensitivity (ohms/volt), emphasizing
that higher input resistance minimizes measurement errors by reducing circuit loading.
Full-wave rectification improves sensitivity compared to half-wave setups...
 "A team of researchers from Arizona State
University, the U.S. Army Research Laboratory (ARL), Lehigh University, and Louisiana
State University has developed a groundbreaking high-temperature copper alloy with
outstanding thermal stability and mechanical strength. Their study, published in
the journal Science, presents a novel bulk nanocrystalline alloy,
Cu-3Ta-0.5Li, that demonstrates exceptional resistance to grain coarsening and
creep deformation, even at temperatures approaching its melting point. 'Our alloy
design approach mimics the strengthening mechanisms..."
 Three more problems await your attention
here to challenge your
Electronics Quotient (EQ), compliments of the February 1963 issue of Radio-Electronics
magazine. First in line is figuring a way to determine which of five boxes of resistors
contains mismarked components. It's a variation on a fairly common way to test components.
The second is another Black Box; it's a bit simpler than usual. Hint: WWTD? (What
would Thévénin do?). The third is a typical method of wiring a series of switches
so that a device can be turned on or off from any number of locations. I recently
implemented such a wiring job to control basement lights from four doorways - no
big deal. Have fun...
 Dr. Allen Du Mont played a huge role
in making television practical because of the improvements he made to the cathode
ray tube (CRT). Prior to his work, the lifespan of a CRT was measured in tens of
hours, and they were expensive, so their use was limited to special military and
research applications. Du Mont's interest in "wireless" began at an early age,
and he earned his commercial radio operator's license at the age of 14 (in 1915).
He designed and produced oscillographs (i.e., oscilloscopes) that incorporated his
CRTs. His involvement in the television industry was a natural evolution and extension
of the work done in related industries. The DuMont Television Network was formed...
 The leading website for the PCB industry.
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Wednesday the 23rd
 These two
electronics-themed comics appeared in a 1966 issue of Radio-Electronics
magazine. The page 40 comic is especially funny, IMHO. The term that best fits this
scenario is "anachronism," which is an object or concept that is out of its proper
historical time period. You'll concur once you see the comic. In 1966, real-world
lasers - as opposed to those found in science fiction - had output powers in the
range of watts or tens of watts. Maybe a hundred watts from a CO2 laser in a laboratory
setting like in the page 93 comic. Still, the concept of a laser powerful enough
to be used as a weapon - capable of vaporizing an enemy - was reality in most people's
minds...
 "DNA
strand displacement circuits are inching closer to becoming cellular machines.
Scientists are finding ways to make these programmable nanodevices stable and functional
inside living cells. If successful, they could revolutionize how we interface with
and control biology at the molecular level. A recent review published in Intelligent
Computing, titled 'From the Test Tube to the Cell: A Homecoming for DNA Computing
Circuits?' outlines major advances in the effort to bring DNA computing circuits
into living cells. The authors describe how dynamic nanodevices powered by DNA strand
displacement reactions could soon perform..."
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making them ideal for detecting hidden objects without revealing detailed body contours,
thus addressing privacy concerns. This makes them ideal as security scanners in
Airports and other venues like stadiums, train stations and other high-traffic venues.
mmWave security scanners from the leading manufacturers are listed here.
 A pair of items from this June 1963
Radio-Electronics magazine "News Briefs" column stands out: "Born 15 years
ago this month were the transistor, June 30, and the long-playing record, June 21."
Hard to imagine being there to reading that back in the day. Also noted was the
world's first IEEE convention, held March 25-28 in New York City. Subjects presented
250 papers at 54 session. This online document discusses the IRE's award recipients
to be honored at that March 1963 meeting. This doc is typical of the extremes corporations
go to in order to specify and control their "brand," in this case the simple IEEE
"kite" logo and text - sheesh! More TV sets were then in use abroad than in the
U.S., reported Television Factbook. At the end of 1961, there were 54 million sets
in foreign countries. By October, 1962, the total was 65 million, as compared to
60 million in the U.S. That, of course, is the sum of all countries other than the
U.S.
 Ask and ye shall receive... at least sometimes.
I posted a request for an article by science fiction writer Arthur C. Clarke, of
2001: A Space Odyssey fame, describing a
geostationary satellite system that was published in the October
1945 edition of Wireless World magazine. Thanks to RF Cafe visitor Terry
W., from the great state of Oklahoma, it is now available for everyone to enjoy.
Clarke was not just a sci-fi writer, but also an educated visionary and card-carrying
member of the British Interplanetary Society, who proposed many technological solutions
to issues of his day. In this instance, the challenge was developing an efficient
means to distribute TV signals across Europe and the world. Clarke's calculations
for the necessary number of repeater towers proved that concept impractical, so
he proposed using modified surplus German V2 rockets to launch Earth-orbiting "artificial
satellites," powered...
 Please take a few moments to visit the
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Tuesday the 22nd
 Here are two more circuit problems for you
from the August 1966 issue of Radio-Electronics magazine. The first is
a fairly familiar tapered resistance network where you are asked to determine the
input resistance of the infinite network. Out of curiosity, I asked Arya, ChatGPT
4.1, Grok 3, and Gemini 2.5 Pro, to calculate the given formula to 75 decimal places.
I received four different answers. All agreed to 33 decimal places, and three
of them agreed to 51 places, then everything fell apart. Once again I warn: Do not
blindly trust the results of AI clients. Verify everything important!!! The other
problem is to determine the output waveform of a duo-diode vacuum tube circuit.
The semiconductor equivalent is a pair of PN junction diodes with the anodes at
the top.
 "It seems AI jobs are here to stay, based
on the latest data from the 2025 AI Index Report. To better understand the current
state of AI, the annual report from Stanford University's
Institute for Human-Centered
Artificial Intelligence (HAI) collects a wide range of information on model
performance, investment, public opinion, and more. Every year, Spectrum summarizes
our top takeaways from the entire report by plucking out a series of charts, but
here we zero in on the technology's effect on the workforce. Much of the report's
findings about jobs..."
 In the mid 1960s, Radio-Craft magazine
ran a series of articles on "Inventors of Radio." This April 1966 issue featured
Boris Lvovitch Rosing (1869–1933), a Russia-born physicist and pioneer of television
technology. Rosing was born in St. Petersburg, where he studied under Heinrich
Friedrich Emil Lenz and later taught at the Technological Institute. Beginning in
1902, he experimented with cathode-ray tubes for image transmission, developing
the first electronic television device by 1907, which used rotating drums and a
modulated electron beam to produce images. His breakthrough came in 1911 when he
successfully displayed simple images, earning him recognition and awards. Despite
interruptions from World War I and the Russian Revolution, Rosing continued refining
his designs, achieving higher-resolution scans...
 What's the big deal about
multicolor radar, you might ask? Not much today, but in 1955 color
displays were in their infancy. The earliest color cathode ray tubes (CRTs), developed
by John Logie Baird in the early 1940s, used just two phosphor colors (magenta and
cyan), illuminated by two separate electron guns, to produce a limited color display.
Ernest Lawrence came along later in the decade with his tri-color Chromatron CRT,
which had separate red, blue and green phosphor dots deposited in a triangular pattern
across the inner face of the tube. That is the scheme employed in this first multicolor
radar system. It was a major improvement for air traffic controllers since it facilitated...
Monday the 21st
 Success won in the realm of
space-based communications has been fraught with many failures.
As with most endeavors, it is thanks to the relative few who have sacrificed and
endured against overwhelming odds to bring significant technological advances in
communications to the many. Space presents a particularly difficult venue because
of the harsh deployment and operational environment, and inaccessibility after deployment.
Personal sacrifice has taken the form of depression, financial ruin, lost opportunity
for other endeavors, broken families, sickness, substance abuse, and other maladies
brought on by an obsession with success. Take a good look at the people in these
photos, and remember they are the ones who laid the foundations for the modern world
we take for granted. Such sacrifice has built the modern world...
 "For decades,
Geostationary Earth Orbit (GEO) operators were in the communications catbird's
seat 22,000 miles above the Earth, but the arrival of Low Earth Orbit (LEO) networks,
like Elon Musk's Starlink, is bringing the Old Guard in satellite com down to terra
firma. 'The proprietary and specialized GEO infrastructure of the past is now weighing
down space industry incumbents that find themselves needing to rapidly innovate
against mounting competition,' ABI Research Senior Analyst Andrew Cavalier wrote
in a recent research report. An indicator that innovation..."
 If it seems like I've been posting a lot
of these "What's
Your EQ?" features, there's a good reason... I have been posting a lot of them
lately. I had created the pages long ago, and somehow I forgot to go back and complete
them with the drawings. Expect to see a dozen or so more in fairly short order.
The circuit challenges are usually submitted by Radio-Electronics magazine's
readers, but occasionally one of the columnists will contribute. "How Wide?" seems
like you would need the value of L to calculate, but given that the problem is presented
without it, there must be a way, right? With the Series-Parallel circuit, I got
as far...
 RF Cafe's spreadsheet-based engineering
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 I have noted in the past how humor in the
days of yore was somewhat, shall we say, different, than what it is today. My vintage
aviation, mechanics, and electronics magazine from the early to middle part of the
last century contained
comics and humor pieces
that in a lot of cases were not very funny because of a lack of cleverness, and
in some cases were downright stupid. A search of both RFCafe.com and AirplanesAndRockets.com
will bear out my assertion. Look at the stuff from before 1950. This 1933 QST
magazine, flagship publication of the American Radio Relay League (ARRL), is a good
example. It was the April edition, which means it was chock full of puns, comics,
gags, and faux articles and news bits. Some of them are pretty good, but you might
need to adopt an alternate frame of mind to "get" them...
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Friday the 18th
 It's Friday afternoon as I prepare this
trio of
vintage electronics-themed comics for posting. They all appeared in the October
1964 issue of Radio-Electronics magazine. All three reflect the home entertainment
craze of the era, in particular TV. Color TV was making inroads into homes, despite
the relatively high cost, and in 1964, many programs were still being broadcast
in black and white (B&W). Stereo systems were huge as well, and you will find
many comics depicting stereo themes in the large list at the bottom of the page.
The love-hate relationship the public had with electronics equipment repairmen (it
worked both ways) is evident here. Millennials will never be able to relate to the
slings and arrows suffered by those of us who lived during the CRT TV times, but
then we Boomers...
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 "In
particle physics, the smallest problems often require the biggest solutions. Along
the border of France and Switzerland, around a hundred meters underneath the countryside,
protons speed through a 27-km ring - about 7x the length of the Indy 500 circuit
- until they crash into protons going in the opposite direction. These particle
pileups produce a petabyte of data every second, the most interesting of which is
poured into data centers, accessible to thousands of physicists worldwide. The
Large Hadron Collider (LHC),
arguably the largest experiment ever engineered, is needed to probe the universe's
smallest constituents. In 2012, two teams at the LHC discovered the elusive Higgs
boson, the particle whose existence confirmed..."
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 This item from a 1968 issue of Radio-Electronics
magazine's "Looking Ahead - Current Happenings with Future Overtones" feature might
have been in one of those lists of notable quotes from tech industry leaders that
are ridiculous in retrospect. It was written by editor David Lachenbruch. The
R-E staff is not populated with people who tenaciously hold on to established
technology while shunning new concepts. He cites industry experts who projected
that at the time 83% of new color TV sets were of all-vacuum-tube construction,
with only 3% being all-transistor, thus the claim, "Life
in the Old Girl Yet." While I don't have the numbers, I've read enough magazines
of the era to know that a very rapid transition to semiconductors...
 An April 1942 issue of Life magazine,
just four months into WWII, carried this full-page advertisement celebrating the
Lockheed P-38 Lightning, a revolutionary fighter aircraft hailed as the world'
s fastest - nearing the speed of sound - with unmatched maneuverability, outclassing
enemy planes in combat. Built by Lockheed for the U.S. Army and British RAF, the
P-38 embodied American ingenuity and freedom, flown by daring pilots defending democracy.
The ad positions the Lightning as a symbol of U.S. air supremacy, critical to Allied
victory in WWII, while promoting Lockheed's role in advancing aviation for both
wartime protection and postwar progress. The closing tagline, "Look to Lockheed
for Leadership," reinforces the company's wartime prestige and vision for the future...
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.
Thursday the 17th
 These challenges appeared in a 1961 issue
of Popular Science magazine. They are more reminiscent of what would be
found in The Old Farmer's Almanac; however, that dose not mean they are
easy. A variety of geometric, mathematic, and logic puzzles are included. Some,
you might have seen proposed in a different format, like the Chief Koko dilemma
of transporting objects across a weight-limited bridge. The division problem is
of the ilk still found in some Sunday newspaper editions. The Long Gun shipping
problem requires thinking "inside the box." Consider that a hint. The Puzzle of
the Month is a variation on an old magic trick. I remember my father having a bunch
of those wire loop things...
 "There's an effort underway to save some
of
Marconi's original towers, and an online poll is open for people to vote on
it being a restoration project through the 'Next Great Save' project from the National
Trust for Canada. Some of Marconi's first messages were received and transmitted
using the Battle Harbour Marconi Towers, thought to be the last of their kind standing
in North America. News of Admiral Robert Peary's 1909 North Pole expedition was
transmitted by these towers. After 100 years, the twin towers are in need of repair.
To honor 150 years since Marconi's birth, there are a number of events..."
 This advertisement in a 1966 issue
of Radio-Electronics magazine promotes RCA Institutes' home training and
classroom programs, emphasizing the booming demand for electronics technicians due
to advancements in automation, space technology, and nuclear energy. These courses
were numerous and popular in the day. It highlights the
"AUTOTEXT" Programmed Instruction Method for faster learning, includes free
equipment like a breadboard, multimeter, and oscilloscope kit, and offers flexible
tuition with no long-term commitments. Career programs cover fields like TV servicing,
FCC licensing, industrial electronics, and computer programming, with placement
assistance boasting a 90% job placement rate at top companies like IBM...
 Sam Benzacar, of Anatech Electronics, an
RF and microwave filter company, has published his April 2025 newsletter that, along
with timely news items, features his short op-ed entitled "Separating
5G Hype from Reality," in which he says in his 40+ years in microwave tech,
he's seen real innovation vs. hype - and 5G leans toward the latter. Despite its
vastly more complex 3GPP standards, six years in, it's still unfinished, with carriers
overselling it early. Most "5G" is just 4G with minor upgrades, as true standalone
5G remains delayed by cost, complexity, and regulatory hurdles. Now, with 6G already
in development for the 2030s, the cycle risks repeating. Unless next-gen networks
deliver...
 Before there were
clocks that synchronized themselves to a wireless low frequency
(LF) time standard emanating from one of NIST's broadcast towers, a different method
was used to keep all the clocks in a building (like a school) reading the same time.
Many of the AC-powered mechanical master-slave clock systems are still in use today.
This episode of Carl and Jerry has them teaming with a contract repairman to figure
out why seemingly random clocks in their high school failed to synch with the master
overnight. Author John T. Frye provides a pretty thorough overview of how the
system operates using a power line carrier scheme. Of course the boys' keen troubleshooting
skills...
Please take a few moments to visit the
everythingRF website to see how they can assist you with your
project. everythingRF is a product discovery platform for RF and microwave products
and services. They currently have 333,423 products from more than 2198 companies
across 460 categories in their database and enable engineers to search for them
using their customized parametric search tool. Amplifiers, test equipment, power
couplers and dividers, coaxial connectors, waveguide, antennas, filters, mixers,
power supplies, and everything else. Please visit everythingRF today to see how
they can help you.
Wednesday the 16th
 In a 1966 issue of Radio-Electronics
magazine, several technological advancements were highlighted: A consulting economist
suggested that booming color TV sales - requiring significant consumer spending
- might be diverting funds from automobile purchases, potentially reducing car sales
by an estimated 800,000 units that year. That brings to mind the old saying "Correlation
does not imply causation," but maybe so in that case. RCA Laboratories had developed
a practical vapor-phase growth technique for gallium arsenide crystals, enabling
breakthroughs like room-temperature semiconductor lasers, high-frequency Gunn-effect
microwave sources, and ultra-bright electroluminescent diodes. Philco introduced
a visual tuning eye for color TVs, aiding precise channel...
 "Quantum information scientists at the Department
of Energy's Oak Ridge National Laboratory have successfully demonstrated, for the
first time, a device that combines key quantum photonic capabilities on a single
chip for the first time. Published in Optica Quantum, the study centers on a form
of
quantum computing that uses photons, particles of light, to create qubits and
to transmit and store information. Unlike classical bits, which represent either
0 or 1, qubits can exist in multiple states at once through a phenomenon known as
quantum superposition. This enables more complex and powerful information encoding.
The research..."
 The importance
of the Hall effect is
underscored by the need to determine accurately carrier density, electrical resistivity,
and the mobility of carriers in semiconductors. The Hall effect provides a relatively
simple method for doing this. Because of its simplicity, low cost, and fast turnaround
time, it is an indispensable characterization technique in the semiconductor industry
and in research laboratories. In a recent industrial survey, it is listed as one
of the most-commonly used characterization tools...
 The world's most effective
Drone Detection Systems from leading companies are conveniently
listed on the everything RF website. Current drone detection and mitigation
systems employ a combination of radar, RF scanners, EO/IR sensors, and acoustic
detection to identify unauthorized or hostile drones. Once detected, mitigation
techniques include RF jamming to disrupt control signals, GPS spoofing to misguide
the drone, directed energy weapons (e.g., lasers or high-powered microwaves), and
kinetic interceptors such as net guns or trained birds of prey. Counter-drone solutions
are widely used by military, critical infrastructure, and law enforcement to protect
against espionage, smuggling, and potential terrorist threats posed by sUAS...
 Fred Shunaman, Managing Editor of Radio-Electronics
magazine, wrote the editorial column in this 1966 issue entitled, "Electromagnetic
Interference... The Future's Greatest Communication Problem." Boy, was his prediction
right on the money. The ambient electromagnetic energy noise floor in the radio
communications realm was many decibels below what it is today, particularly in urban
areas, and Mr. Shunaman saw it coming; he just couldn't have known how intensely.
Rural regions had practically no noise issues at the time other than interference
with AM radios from dirty motor brushes, sparking transformers, and a few towers
for local television...
 Lots of
RF transmission cable parameter charts are available on the Internet,
but what sets this one apart is that is has entries for some of the popular 300 Ω
twin-lead cables of the rooftop television antenna era. It appeared in a 1956 issue
of Radio & Television News magazine. Mentioned in the article is the
reason most TV lead-in cable was colored brown was to help keep the sun's ultraviolet
rays from penetrating and deteriorating the plastic. Author Robert Gary claims silver
coloring was also used to reflect the UV, but I don't recall ever seeing silver
twin-lead - maybe it was a regional thing like for in the southwest. At the time,
μμfd (micro-microfarad) was commonly used rather than pF (picofarad). He also mentions
the G-Line transmission cable used by many of the...
Tuesday the 15th
 Are you in a mood to take this "What's
Your EQ?" (Electronics Quotient) challenge from E. D. Clark? Appearing
in the September 1964 issue of Radio-Electronics magazine, it is one of
dozens he conjured up with the assistance of readers. "What's in the Box" is pretty
straight-forward if you take the designer's advice and not try to over-think the
problem. I was easily able to come up with a circuit for explaining the changes
in capacitance and resistance, but didn't think of the additional mechanism to cause
the change to occur as specified. You'll probably do better. There are people in
the RF Cafe audience that can resolve the "Reverse Polarity" problem, but they are
very few and very far between...
 Here is a really nice write-up on electrical
noise, both how it originates and how it affects receiver systems. Although vacuum
tubes were still the predominant active amplification components in 1965 (the date
of this article), semiconductors were already solidly ensconced in the signal detector
role. I have to confess to learning a new term that I probably should be familiar
with:
Equivalent-Noise-Sideband-Input, or ENSI. It appears also in
Reference Data for Engineers: Radio, Electronics, Computer, and Communications.
Interestingly, this is the first time in a long time I have seen noise referred
to as "grass;" the drawings make it clear why the moniker was created. We were taught
to use "grass" in USAF...
 I am working on an update to my
RF Cafe Espresso Engineering Workbook project to add a couple calculators about
FM sidebands (available soon). The good news is that AI provided excellent VBA code
to generate a set of Bessel function
plots. The bad news is when I asked for a
table showing at which modulation indices sidebands 0 (carrier) through 5 vanish,
none of the agents got it right. Some were really bad. The AI agents typically explain
their reason and method correctly, then go on to produces bad results. Even after
pointing out errors, subsequent results are still wrong. I do a lot of AI work and
see this often, even with subscribing to professional versions. I ultimately generated
the table myself. There is going to be a lot of inaccurate information out there
based on unverified AI queries, so beware.
 "Since the discovery of graphene in 2004,
research into two-dimensional (2D) materials has advanced rapidly, opening new frontiers
in both fundamental science and technological development. While nearly 2,000 2D
materials have been theoretically predicted and hundreds successfully synthesized
in laboratories, the vast majority are limited to
van der Waals (vdW) layered crystals. A major goal in the field has been the
development of atomically thin 2D metals, which would significantly broaden the
scope of 2D materials beyond vdW structures. These ultrathin metals could also unlock
new physical phenomena and enable novel device architectures..."
 From the beginning of the electronics era
in the early 20th Century and continuing throughout, technical magazines like this
1969 issue of Radio-Electronics contained many articles and advertisements
purposed to attract people into the field. The military has always been an excellent
way to get both
classroom and hands-on training on sophisticated equipment, the price paid being
one or more terms of enlistment. A plethora of civilian schools offered classroom
and home-study courses, but could seldom provide the practical experience that could
give a job applicant a boost in qualification over a "fresh-out" candidate. Many
people, including yours truly, combined both military and civilian educations to
achieve the desired career options. According to a Grok 3 AI query...
 A while back, I posted information on a
vintage General Electric (GE) analog
AM/FM clock radio that I bought on eBay. It is a model I had as
a teenager while living at home. As with most, if not all, AC clocks of the day,
it used a
synchronous motor to drive the clockworks - in my case a set of rotating numerals
for displaying the time in increments of minutes (no seconds display). Synchronous
motors, as the name implies, rotates at a rate proportional to the frequency of
the alternating current that drives it. In the United States the AC line frequency
is 60 Hz. In the United Kingdom, the frequency is 50 Hz. Consequently,
a clock designed to work at 60 Hz...
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