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 A popular meme on chat websites these days
is the posting of some items or scenes indicative of times many moons ago, with
a comment something like, "If you know what this is, you are probably wearing reading
glasses." I recently saw one with a picture of an old cube type flash bulbs that
went on Kodak Instamatic cameras. In fact, I still have my Kodak Instamatic 40
camera and a couple of unused flashcubes. Those flashcubes were expensive for a
guy who never had much pocket cash; maybe that's why I have so few pictures from
back in the day. Anyway, I mention all that because some of the topics of these
electronics-themed comics from a 1962 issue of Electronics Illustrated
magazine would be likely candidates for the meme...
 A new word has been added to my personal lexicon:
"sphenoidal." Author John Kraus used it to describe the wedge shape
of a corner reflector. The Oxford Dictionary defines "sphenoid" thusly: "A compound
bone that forms the base of the cranium, behind the eye and below the front part
of the brain. It has two pairs of broad lateral 'wings' and a number of other projections,
and contains two air-filled sinuses." This "square corner" configuration - essentially
a "V" shape, is shown to exhibit up to 10 dB of gain while being relatively (compared
to a parabolic reflector) insensitive to physical size and driven radiator placement
across a wide band when made sufficiently large. No radiation pattern was...
 As you might know, particularly if you are
a frequent RF Cafe visitor, amateur radio operators (Hams)
were prohibited from broadcasting during the entirety of World War II,
(see
War
Comes) ostensibly as a security measure. The concern was that people
might unintentionally (or intentionally) convey information on troop positions and
family names, domestic factory locations and activities, and the general state of
the nation in regards to attitude and finance. Unlike today, that type of data was
not easily gathered even by a dedicated deployment of internal spies. In the early
1940s, the majority of amateur radio activity was carried out in the form of Morse
code, and operators were understandably concerned...
 Here is a fascinating story from a 1946
issue of the ARRL's QST magazine of the ordeal one Catholic priest
experienced while serving in the Philippines during the Japanese occupation in World
War II. Father Visintainer exploited his personal interest in
radio communications
to help keep local residents apprised of the war's progress and talk to the outside
world. Japanese troops confiscated all the existing shortwave radios and converted
them to their own frequencies. Some were re-converted by daring servicemen and then
hidden. Batteries were recharged using covert water wheel powered generators located
in the woods. Drama hit a peak one day when an attempt to formulate a make-shift
battery electrolyte resulted in an explosion that brought Japanese running to the
church lab...
 For decades, the engineering community has
viewed space as the ultimate frontier (Captain Kirk declared it) - a clean, vacuum-sealed
environment that offered a solution to the terrestrial limitations of bandwidth,
range, and latency. Nations and industries have long championed the
democratization of global communications, seeing Direct-to-Device (D2D) connectivity
as the next logical step in our technological evolution. But as we move from the
era of rare satellite backhaul to the age of the "mega-constellation," the engineering
paradigm has shifted. We are no longer just looking at the sky; we are beginning
to occupy it with such density that we risk creating a perpetual "noise floor" for
the rest of humanity. This article examines the thermodynamics, the mechanics of
orbital mesh nodes, and the sheer volume of material required to shift our compute
infrastructure into the heavens...
 Just the other day I saw a greeting card
with a sailboat on the front with the words "Anchors Away," on it. It was not meant
to be a pun on "anchors aweigh;" the card writer didn't know any better. This
episode of "Carl & Jerry" has our teenage Ham radio operators and electronics
hobbyists running a newly built model tugboat powered by a steam engine and navigated
via a radio control system. As is always the case, no activity of the pair goes
without drama of some sort. Author John T. Frye used his writings to present
technical topics within the storyline, both in the "Carl & Jerry" series here
in Popular Electronics magazine and his earlier "Mac's Radio Service Shop"
series that appeared...
 For the sake of all the avid cruciverbalists
amongst us, this
technical-term-themed
crossword puzzle contains only words and clues related to engineering, mathematics,
chemistry, physics, and other technical words. 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
(e.g., Hedy Lamarr or the Bikini Atoll)...
 Sam Benzacar, of Anatech Electronics, an
RF and microwave filter company, has published his May 2026 Newsletter that, along
with timely news items, features his short op-ed titled "The
Math of LEO No Longer Adds Up." Sam runs the numbers on Low-Earth-Orbit satellites,
and assesses future plans. "SpaceX now operates more than 10,000 Starlink satellites,
roughly two-thirds of everything in orbit. The next-largest operator, OneWeb, has
fewer than 700." They roam the nighttime sky, with small dots of light tracking
across our already light-polluted skies. The ITU coordination process now confronts
filings for more than a million LEO spacecraft, with half a million projected to
be in orbit by 2040. Now that Internet coverage and even Direct-to-Device (D2D)
networks...
 Meteor scatter communications is an excellent
example of where hobbyists - in this case amateur radio operators - have contributed
mightily to technology. It could be argued that a big part of the reason for such
occasions is that many people involved in science type hobbies are employed professionally
in a similar capacity, and their extracurricular activities are a natural extension
of what pays for the pastimes. It seems amazing to me that
meteor
scatter as a means of achieving upper atmosphere reflections of radio signals
went undiscovered until 1953, but evidently that is the case. Meteor scatter is
a very popular form of amateur radio challenge...
 "Make the most of your time at
Dayton Hamvention® with the free ARRL Events phone app. Hamvention is the world's
largest annual gathering of radio amateurs, and will be held May 15-17 in Xenia,
Ohio. There is a lot to do and see. Use the ARRL Events app to make sure you don't
miss a beat and plan out your visit now. The ARRL events app is produced by ARRL
The National Association® for Amateur Radio in partnership with Dayton Hamvention.
The app includes Hamvention's full program, so you can browse and schedule forums,
preview the extensive list of exhibitors, and find affiliated events. During the
event, attendees can use..."
 Here's a topic that never goes out of style.
Without bothering to worry about source and load impedances, this brief tutorial
on the fundamentals of
power supply filter design using series inductors and parallel
capacitor combinations. The author offers a rule-of-thumb type formula for guessing
at a good inductor value based on peak-to-average expected current. This is by no
means a comprehensive primer on power supply filter design and is directed more
toward someone new to the concept...
 Werbel's new
WMC-0.5-2-6dB-S, 6 dB directional coupler provides precision attenuation
where it matters most. It covers 500 MHz to 2 GHz with broadband flat coupling response,
high directivity, and excellent return loss performance. The device covers the upper
portion of the UHF band as well as L band in a single unit measuring just 3.60 x
0.60 x 0.38 inches. Minimized reflections increase accuracy of the measurement.
Mainline insertion loss of 1.2 dB (typical) includes coupling factor. The 6 dB coupling
ratio gives an approximate 75/25% splitting ratio and may be used as such to distribute
signals unequally where required, often to make up for asymmetrical losses elsewhere
in a system...
 Connecting a diode backwards across a solenoid
coil to shunt potentially damaging current and/or voltages when the supply is turned
off is a common trick for saving connected circuitry. Depending on the magnitude
of the magnetic field and how quickly the field collapses, some really high voltages
can be produced. In fact, the ignition coil and point (now
solid state) system in exploits exactly that principle to turn the 12 volts
from your car battery into 20-40 kV for firing the spark plugs. Engineers that
designed this early
cyclotron
had limited options for what to use given the state of the art in the early 1940s,
and chose to keep the generator permanently connected to the coil (no switch) so
that if the controller failed, the coil's energy...
 In the opening scene of "Gladiators," Quintus
remarks to Maximus (Russell Crowe), "A people should
know when they've been conquered." Such truth is applicable to society today regarding
ubiquitous surveillance. Less than two decades ago the media was
filled with stories of outrage over the discovery of some new form of monitoring
and reporting system having been installed on highways, in shopping malls, along
sidewalks, even bathrooms. Since the 9/11 terrorist attacks, anything goes with
government snooping. Count the numbers of freedoms you have lost and the inconveniences
suffered because of those 19 men with no identifiable common cause
(wouldn't want to profile). This story from 1956 shows
how long stealth installation...
 I wonder why today's editions of the ARRL's
QST magazine does not have a column dedicated to the "YL" (Young Lady,
or female in general) contingent of the amateur radio realm? Ham radio, as most
-if not all - historically male-dominated hobbies has fairly significant outreach
efforts to try attracting women into activities. My Model Aviation magazine
has a monthly column written by a lady whose enthusiasm for model airplanes equals
that of most males - and she's funny to boot! - but it is not dedicated to female
modelers. If there is a girl or woman present at a competition, she is almost guaranteed
to receive coverage...
 The December 1947 issue of Radio News
and the February 1954 issue of Radio & Television News published these
electronics-themed comics. Humor evolves over time, which is apparent when you
look over these and many of the other comics from these vintage electronics magazines.
The AVC comic is the best, IMHO. For those of you not around in the olden days of
vacuum tubes, tapping on a tube would often make it work properly again, either
because of a dirty contact in the socket or crud that had accumulated on the screen
grid. I give this batch a score of about 7 out of 10, but you might think otherwise.
There is a growing list of other comics at the bottom of the page. Enjoy...
 How RF circuits work have long been referred
to as "black magic,... even sometimes by people who fully understand
the theory behind the craft. To me the ways in which a transmission line - be it
coaxial cable, microstrip, or waveguide - can be manipulated and controlled with
various combinations of lengths and terminations is what most qualifies as "magic."
Sure, I know the equations and understand (mostly) what's happening with incident
and reflected waves, etc., and how the impedance and admittance circles of a Smith
chart graphically trace out what's happening, but you have to admit there's something
wonderfully mystical about it all...
 I remember hearing a long time ago about
"The Thing"
- a passive bugging device discovered within a wooden Great Seal gifted to the U.S.
Embassy in Moscow. This 1962 Electronics Illustrated magazine feature explores
the ingenious, battery-less Soviet listening device. Far from a conventional electronic
bug, this passive device utilized a specialized resonant cavity and a diaphragm
that modulated an external 1600 MHz radio beam, essentially acting as an echo-based
microphone that was incredibly difficult to detect. While the article highlights
the device's diabolical simplicity and sensitivity, it contains no mention of the
U-2 incident or Gary Powers; notably, historical records clarify that Ambassador
Lodge displayed the device in 1960 to expose Soviet espionage...
 Based on beleaguered wife Sylvia Kohler's
mention of GE's Electronics Park in this story (surely a fable... or not), she and
unintentional antagonist, superheterodyne hubby (aka "Happy Boy," but we know him
as Popular Electronics cartoonist
Carl Kohler) probably lived in the Syracuse, NY, area. Electronics
Park existed during the hey days of General Electric when the sprawling campus ,
just north of I-90, designed and manufactured a plethora of both household and military
electronics products. GE's Electronics Laboratory ("E-Labs") was the company's pride
and joy. Today, a tiny portion of Electronics Park is still occupied by Lockheed
Martin, who bought that GE division in the 1990s, and the rest belongs the city.
But I digress... enjoy the story (her reason for referring to hubby as a Superheterodyne
is highlighted)...
 Multielement quad antennas are as popular
today as they were in 1967 when this article appeared in the ARRL's QST
magazine. That is not to say they are common. This particular design is for the
10-, 15-, and 20-meters bands, all three
of which are still in use today. If you build a multielement quad as shown here,
you might want to find a substitute for the bamboo frame members; aluminum tubing
is pretty cheap, but if you use metal, you'll need to use insulators at the connection
points. Formulas are provided for determining element lengths and director and reflector...
 There is something about these proposed
shorthand circuit symbols that reminds me of the IEEE digital
logic symbols using the distinctive shape (the traditional format) versus the newer
rectangular shape format. The set is quite extensive when all the different flavors
of combinatorial blocks - flip-flops, timers, counters, shift registers, encoders,
decoders, etc. - are included. My personal preference, you might guess, is the original
format with distinctive shapes. Although I do not do a lot of digital work, it is
easier for me to follow the signal flow and mentally perform the logic operations
with the distinctive shapes. But I digress. This article from a 1947 issue of
QST magazine introduces...
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 • Europe's
Electronics Sector Picks up Speed
• Top
5 Companies Granted U.S. Patents in 2025 (one American)
• Shape-Shifting
Semiconductors Activated by Light
• UK Teachers Say
AI Eroding Critical Thinking
• FCC
Approves Charter's $34.5B Acquisition of Cox
 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.
 Carl and Jerry were early adopters of the
near field communications (NFC) craze that is going full-swing today. As they often
do, the harmlessly mischievous teenage duo used their combined grasp of modern electronics
to pull off gags on unsuspecting friends ... and sometime adversaries. In this episode,
a near-field transmitter and receiver pair is designed to help Carl bedazzle a scientist
who was attempting to disprove the ability to use "Extrasensory Perception" (ESP)
- the title of this 1956 Popular Electronics magazine technodrama - to determining
what another person was thinking about. In this case it was detecting which playing
card was being displayed on an overhead projector. Of course Carl didn't really
have "the gift," but relied on his co-conspirator, Jerry...
 This
Engineering-Theme Crossword Puzzle for March 21st has many words and clues related
to... you guessed it... engineering - including RF, microwave, 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
(e.g., Hedy Lamarr or the Bikini Atoll). The technically inclined
 This "Introduction
to Ultrasonics" article from a 1960 issue of Radio-Electronics magazine
does not necessarily directly apply to RF and microwaves, but there are similarities
in the circuitry and theory of generation and propagation. I was surprised to learn
that ultrasonics even back then went into the low GHz realm. Any mechanical vibrations
about about 20 kHz are regarded as ultrasonic. Ultrasonics can preform some
of the functions of x-rays in material inspection, without the danger of ionizing
radiation and extremely high voltages required to generate the rays. While working
in the 1980's as an electronics technician at the Westinghouse Oceanic Division
in Annapolis, Maryland, I often used an ultrasonic cleaner like the one shown here
for removing flux from printed circuit board assemblies (PCA's), cable connectors,
and other objects. The heated methyl-based bath solution produced a PCA with shiny
solder joint totally devoid of flux residue. We were still using 60/40, Sn/Pb rosin
core solder back then. We built sonar systems and components for the U.S. Navy,
including transducer-equipped torpedo nose cones, sonar transducer arrays for ship
hulls, and towed sonar systems...
 In the run-up to World War II and during
the battle, a lot of
plastics
research and production was considered classified defense information. Poly(methyl
methacrylate) (PMMA), also know by the trade names of Plexiglas, Lucite, Crystallite,
and others, was a crucial component for aircraft where the weight and brittleness
of regular glass made it practically useless (and dangerous). A full-page ad by
Shell Oil in this 1942 issue of Life magazine promoted plastic used in a bomber.
When I see this, it reminds me of "It's a Wonderful Life," where Sam Wainwright
offers George Bailey a position in his fledgling soybean-based plastic canopy factory
in Buffalo, New York. Being primarily a petroleum product, plastic was promoted
heavily by oil companies like Shell Oil, Standard Oil, American Oil, partially due
to patriotism, but no doubt also for the profits. Those places, of course, were
part of the "Military-Industrial Complex" identified by President Dwight Eisenhower.
In fact, an Internet search turns up many claims that those same companies conspired
to sell oil to Axis powers prior to America's official entry into WWII on December
7, 1941, when the Japanese bombed Pearl Harbor...
 Well... anyway it was 50 years ago referenced
to the year this story was published in the 1937 issue of Radio-Craft magazine.
That makes it 138 years ago referenced to 2025. The story's point is that half a
century had passed already since the confirmation of existence of electromagnetic
(EM) waves as proposed by James Clerk Maxwell.
Heinrich Hertz's "Funken-Induktor" (spark inductor) and his "Knochenhauershen
Scheiben" (Karl-Wilhelm Knochenhauer's disk-type capacitors) were key to Hertz's
ability to generate, transmit, and receive EM energy. The work originated from attempts
to prove that light was a form of electromagnetic waves...
 Here is another exciting episode of the sleuthing
adventures starring Popular Electronics' tech savvy teenagers,
Carl and Jerry. The Hardy Boys of electronics are the creation of author John
T. Frye, who created short story adventures for many years - long enough to at one
point require a major modification in the boys' appearances to reflect more modern
attire and eyewear (Carl's "The Far Side"-style glasses had to go). This particular
adventure begins with Carl considering whether his ham radio hobby is more useful
from the standpoint of its technical aspects or of its social aspects.
 Sometimes finding an existing instance of
one of the vintage radios is difficult or impossible. The
RCA Victor Model 54Bx portables are an exception. Plenty can be found for purchase
on eBay as this is written, as was a 54B1, 54B3, and a 54B4. I did a capture of
some of the listing images for a Model 54B2, and had Archive.org story a copy for
once the eBay site deletes it. In the internal photos, all four miniature vacuum
tubes (3S4, 1S5, 1R5, 1T4) can be clearly seen. Note also in the photos you can
see where, per the alignment procedure, rubber bands have been place around the
tubes in order to keep them from moving. The extremely cramped space required particular
attention to the routing of interconnect wires...
 This is the electronics market prediction for
Italy, circa 1966. It was part of a comprehensive assessment by the editors of
Electronics magazine of the state of commercial, military, and consumer
electronics at the end of 1965. Computers, military communications, numerically
controlled factory automation, and consumer electronics drove the Italian
markets, as was the case for every first-world nation. A bigger concentration on
exports was becoming an important part of the equation. Unless you can find a
news story on the state of the industry, detailed reports must be purchased from
research companies. Their websites have a lot of charts on Italy's current
electronics market showing revenue...
 You just never know what names you will find
in vintage electronics magazines. Incredibly - assuming of course that this is who
it likely is - I ran across
Steve Wozniak (aka "Woz"), later to be co-founder of Apple Computer, in this
November 1966 issue of Popular Electronics. "Woz" first met Steve Jobs
five years later in 1971 while working at Hewlett Packard. If this is "Woz," he,
having been born in 1950, would have been a 16 year-old high schooler when his entry
was published. The article does not specify who is responsible for which quote.
Woz was a Ham radio guy, so maybe one of the Off the Air comments was from him.
My favorite implausible comment from Sequel 2 is this one: Don't waste money
on 5 amp fuses - buy 15 or 20 amp fuses - they cost the same and you get more fuse
for your money...
 There are few better ways to wind down
a work week than with some good old-fashioned (literally)
technology-themed comics. This three fifths of a handful of comics
appeared in a 1944 issue of Radio News magazine. You need to know when looking at
these scenarios that people in the 1940s cherished and revered their radio sets
like people today do with their cellphones. Magical and supernatural attributes
were assigned to them by some, especially the non-technically inclined. Entire families
gathered around the radio in eager anticipation of the latest episode of "The Shadow,"
The Lone Ranger," "Little Orphan Annie," "Jack Benny," and "Inner Sanctum Mystery."
BTW, if you want to experience the aura of old time radio shows, many of them are
available for listening online on the Old Time Radio Catalog website and others...
 Belmont Radio Corporation was located in
Chicago, Illinois. Founded independently sometime the 1920s, it became a subsidiary
of Raytheon Manufacturing after World War II in an effort to quickly launch
the Raytheon into nascent consumer FM radio and television markets. Belmont advertisements
were prominent in electronics trade magazines throughout 1940 to promote their war
efforts. A schematic and parts list for this
Belmont
Model 5240 vacuum tube radio appeared in the July 1948 edition of Radio
News magazine. I could not find an example of the radio anywhere. Based on
the schematic, my guess is it was a tabletop model. Please let me know if you know
where there is a photo of one...
 This week's engineering crossword puzzle
features the names of some of the
world's oldest electronics companies. Many of them began life
with a primary business focus other than electronics, then ended up being known
universally for their high tech products. If you're like me, until now you had no
idea that one of the world's leading cellular equipment makers originally was a
wood pulp mill, and another made playing cards. Clues with asterisks (*) are the
featured companies...
 With more than 1000
custom-built stencils, this has got to be the most comprehensive set of
Visio Stencils
available for RF, analog, and digital system and schematic drawings! Every stencil
symbol has been built to fit proportionally on the included A-, B-, and C-size drawing
page templates (or use your own page if preferred). Components are provided for
system block diagrams, conceptual drawings, schematics, test equipment, racks, and
more. Page templates are provided with a preset scale (changeable) for a good presentation
that can incorporate all provided symbols...
 The newest release of RF Cafe's spreadsheet
(Excel) based engineering and science calculator is now available -
Espresso Engineering Workbook™. Among other additions, it now has a Butterworth
Bandpass Calculator, and a Highpass Filter Calculator that does not just gain, but
also phase and group delay! Since 2002,
the original Calculator Workbook has been available as a free download.
Continuing the tradition, RF Cafe Espresso Engineering Workbook™ is
also provided at no cost,
compliments of my generous sponsors. The original calculators are included, but
with a vastly expanded and improved user interface. Error-trapped user input cells
help prevent entry of invalid values. An extensive use of Visual Basic for Applications
(VBA) functions now do most of the heavy lifting with calculations, and facilitates
a wide user-selectable choice of units for voltage, frequency, speed, temperature,
power, wavelength, weight, etc. In fact, a full page of units conversion calculators
is included. A particularly handy feature is the ability to specify the the number
of significant digits to display. Drop-down menus are provided for convenience...
RF Cascade Workbook is the next phase in the evolution of RF Cafe's long-running
series, RF Cascade Workbook. Chances are you have never used a spreadsheet
quite like this (click
here for screen capture). It is a full-featured RF system cascade parameter
and frequency planner that includes filters and mixers for a mere $45. Built in
MS Excel, using RF Cascade Workbook is a cinch and the format
is entirely customizable. It is significantly easier and faster than using a multi-thousand
dollar simulator when a high level system analysis is all that is needed...
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