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 It appears that maybe Abraham Lincoln had
a son who was an electrical engineer working at Motorola Semiconductor back in the
1960's. Put glasses on Honest Abe (I did) and author Irwin Carroll's a spitting
image of the Great Emancipator. Seriously though, this article is a great introduction
to the fabrication and use of variable capacitance (aka varicap and varactor) diodes. They have
been - and still are - used widely for electrically tunable oscillator and filter
circuits. Topics such as temperature and figure of merit ("Q") are discussed as
well. This edition of Electronics World ran a series...
 Sam Benzacar, of Anatech Electronics, an
RF and microwave filter company, has published his July 2025 Newsletter that, along
with timely news items, features his short op-ed entitled "3GPP
Release 20 Gets Us Closer to 6G." In it, he states, "One of the most significant
areas of emphasis in Release 20 is integrating artificial intelligence (AI) and
machine learning into the radio access network (RAN) and the core network." I have
seen numerous news items in the last few months reporting on the melding of AI and
network communications. This type of AI "intelligently" controls the global and
local systems by optimizing traffic flow via real-time tower and control center
analysis. A major feature is device-to-device (D2D) communications that can bypass
the network...
 It is hard to imagine a time when integrated
circuit (IC)
comparators were a big deal, but as recently as 1973 when this
article appeared in Popular Electronics, they were new to a designer's
bag of tricks. Prior to an IC solution, comparators needed to be constructed from
opamps and a handful of peripheral biasing components. As with other integrated
circuits, not only does the overall price go down, but so does circuit board real
estate, cost, temperature variability, and electrical parameter variance between
devices. The first comparator circuit I remember designing was a temperature sensor
that went in an oven used for curing the potting...
 Here is an area of electronics that will
be foreign soil to most Gen-Xers and Millennials -
troubleshooting your malfunctioning radio, phone, television,
garage door opener, kitchen appliance, etc. Admittedly, most modern devices are
designed and priced to be replaced rather than repaired. Relatively cheap product
replacement and service plans keep them going for a year or three until they are
obsoleted by newer devices with whiz-bang additional features. However, there are
many of us still around who are born to tinker and are too cheap to bear the thought
of throwing something away before at least attempting to fix it. I have written
often about how many...
 "The low-cost, scalable technology enables
seamless integration of high-speed gallium nitride transistors onto a standard silicon
chip. Gallium nitride is an advanced semiconductor material that is expected to
play a key role in the next generation of high-speed communication systems and the
power electronics that support modern data centers. However, the widespread use
of gallium nitride (GaN) has been limited by its high cost to incorporate it into
standard electronic systems. To address these challenges, researchers from MIT and
collaborating institutions have developed a
new fabrication process that integrates high-performance GaN transistors..."
 At least 10 clues with an asterisk (*)
in this
technology-themed crossword puzzle are pulled from "Tech Industry
Headlines" column on the RF Cafe homepage (see the Headline Archives page for help).
For the sake of all the avid cruciverbalists amongst us, each week I create a new
technology-themed crossword puzzle using only words from my custom-created related
to engineering, science, mathematics, chemistry, physics, astronomy, etc. Enjoy...
 Innovative Power Products has been designing
and manufacturing RF and Microwave passive components since 2005. We use the latest
design tools available to build our baluns, 90-degree couplers, directional couplers,
combiners/dividers, single-ended transformers, resistors, terminations, and custom
products. Applications in military, medical, industrial, and commercial markets
are serviced around the world. Products listed on the website link to detailed mechanical
drawings, electrical specifications, and performance data. If you cannot find a
product that meets your requirements on our website, contact us to speak with one
of our experienced design engineers about your project.
 Just yesterday I posted an article titled
"Understanding Your Triggered Sweep Scope," that appeared in the May 1973 issue
of Popular Electronics, so I figured this "Scope-Trace Quiz" would make a good compliment. It is from a 1965
issue of Popular Electronics. Driver circuits all include a sinewave source
in parallel with a series resistor and diode, connected to the vertical and horizontal
o-scope inputs. The resulting Lissajous waveforms resemble hands on a clock face
thanks to the diode. Shamefully, I only scored 70%, but in my own defense I'll say
I didn't take the time to draw them out on paper. Pay careful attention to the scope...
 "Advanced alien civilisations could discover
human life on Earth by picking up
technosignatures given off inadvertently by civilian and military radar, new
research shows. The study investigated how hidden electromagnetic leakage might
look to extraterrestrials up to 200 light-years away if they had advanced radio
telescopes like those on Earth. It also suggests this is how far humans would be
able to look to spot extraterrestrials who have evolved to use a similar level of
technology. Preliminary results revealed at the
Royal Astronomical
Society's National Astronomy Meeting 2025 in Durham show how aviation hubs such
as Heathrow, Gatwick and New York's JFK International Airport give off clues to
human existence..."
 Here is a unique type of article from a
1974 issue of Popular Electronics. Author Ralph Tenny presents a
poor-man's environmental test chamber constructed with a Styrofoam
picnic cooler, a dry ice sump, a heater, a thermocouple, and a bunch of input/output
ports for making electrical measurements. While working on my senior project at
college - an electronic remote weather station - I needed to verify functionality
up to 150°F and down to 0°F. Having the Torture Box would have been handy, but instead
I used the kitchen oven and freezer with the interconnect cable mashed between the
door gasket and frame. Unfortunately I don't have any...
 The transition from vacuum tubes to semiconductors,
and from black and white to color televisions was in full swing by 1973. Accompanying
the change in components was a re-thinking of the most effective and profitable
method of manufacturing and servicing the new equipment.
Modularization was thought to be key to future success even though
production costs were slightly higher. Reliability improvements were already reducing
the need for service calls and highly trained technicians who could troubleshoot
failures down to the component level. Swapping out suspect modules with known-good
modules, in Mac's words, results in "a quickly trained module swapper who knows
only 'how' and not..."
 The
first thing I learned (or re-learned) in reading this article is that in 1967, "Hertz"
had only recently been assigned as the official unit of frequency. According to
Wikipedia, International Electrotechnical Commission (IEC) adopted it in in 1930,
but it wasn't until 1960 that it was adopted by the General Conference on Weights
and Measures (CGPM) (Conférence Générale des Poids et Mesures). Hertz replace cycles
per second (cps). The next thing that happened was that I was reminded of how images
such as the op-art tracing of
antenna oscillation that are routinely generated today by sophisticated
software, required huge amounts of setup time and trials to yield just a single
useful and meaningful image using actual hardware...
 San Francisco Circuits has published a comprehensive
guide on the
8 most essential types of PCB vias, helping designers, engineers, and procurement
teams navigate the challenges of modern board manufacturing. This is a guide to
the 8 different via types. As electronic devices continue to shrink in size while
increasing in complexity, PCB vias play a critical role in enabling multi-layer
interconnections, high-speed signal integrity, and thermal performance. The 8 main
types of PCB vias each serves a specific function depending on the board's structure,
component density, and electrical requirements...
 This is Part 3 of a series of articles on
atomic radiation that appeared in Electronic World magazine
in 1969. It deals with measurement techniques and equipment. Shippingport Atomic
Power Station, the first full scale nuclear power plant in the U.S., went operational
in 1957. It marked the dawn of a new era of electric power generation that was filled
with grandiose predictions of limitless, non-polluting, dirt cheap power. Everything
was going to be powered by electricity - air heating and cooling, lighting, automobiles,
water heating. Atomic power was going to be a figurative and almost literal beating
of swords into ploughshares as the destructive energy...
• FCC
Power Shift Underway
• Global
Foundry Market Sees Milder Dip in 2025
• U.S.
Renegotiating Chips Act Awards
• Recalls Can Create a
Multitude of Legal Problems
• Why
ChatGPT's Essays Don't Fool the Experts - Yet
 TGIF, as the saying goes. Here are a couple
new vintage
electronics-themed comics for your enjoyment as you wind down
the work week. They appeared in a 1944 issue of Radio-Craft magazine. My
favorite is the one with the lady in the vacuum cleaner repair shop. Look at her
request! Her husband must have put her up to it. The other comic is pretty good,
too. Having lived toward the end of the vacuum tube era, my appreciation of the
equipment is more for the nostalgic quality than memories of having to wait for
the tubes to warm up and re-tuning the radio and TV set at intervals while listening
and/or watching...
 "NASA has issued a formal request for information
from domestic and international companies on their capabilities to provide
satellite-based communication and navigation services near Earth. The effort
aims to transition space mission support from government-operated systems to commercial
satellite services. This call is part of the agency's broader Communications Services
Project, which seeks to develop partnerships with private industry to address the
needs of upcoming science and exploration missions. 'As part of NASA's Communications
Services Project, the agency is working with private industry to solve challenges
for future exploration,' said Kevin Coggins, deputy associate administrator of NASA's
SCaN Program..."
 A series of three articles appeared in 1973
issues of Popular Electronics that conducted a high-level review - or introduction
if you've never seen it before - of DC circuit analysis. In this first installment,
Professor Arthur Seidman, of the Pratt Institute, covers a variety of subjects starting
with
direct current (DC) circuit theory. Ideal current and voltage
sources, units and notations, Ohm's law, Kirchhoff's law, resistors, capacitor and
inductor charge and discharge curves, series and parallel circuits, power calculations,
conductance, and other good stuff is covered. There is even (gasp) a bit of calculus
presented...
 A decade after
tunnel diodes were first invented by Nobel Laureate Leo Esaki,
grand plans for the unique device never played out. Predictions included its use
for computer solid state memories to replace magnetic core arrays. Tunnel diodes
benefitted from the aura surrounding their exploitation of the quantum mechanical
tunneling phenomenon, which had a futuristic ring to it. Conventional diodes, having
a relatively wide depletion region, require the current carriers (electrons and
holes) to overcome a potential hill in traveling from the valence band to the conduction
band of energies. Since high doping levels are used in the tunnel diode, a narrow
depletion region is formed at the junction. This allows electrons...
 Amateur Extra-class teenagers Calvin Nolten
and Phineas Thorin embark on a mission to track down the source of spurious signals
in the 70 cm Ham band which threaten DX contesting on Field Day. The story
is
Saving Field Day, wherein, Calvin Nolten, a pint-sized shockwave of
teenage pandemonium, slammed open the front door of his home with a report that
could've been mistaken for a misfiring capacitor, the frame shuddering as if protesting
the assault. At fifteen, barely scraping five-and-a-half feet, Calvin was a bundle
of raw energy. His school backpack was a chaotic jumble of ham radio manuals, a
late-model Galaxy smartphone, and lunchtime leftovers. He stormed the kitchen, raided
the fridge for a quick snack, and before the light inside had a chance to go out,
Calvin was out the back door, bound for Phineas Thorin's basement "shack." Mrs.
Nolten, unperturbed by the familiar maelstrom, took solace in know that the chaos
meant her boy was home safe - and likely already plotting some radio mischief with
his partner in crime next door...
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The RF Cafe Homepage
Archive is a comprehensive collection of every item appearing daily on this
website since 2012 - and many from earlier years.
 Being an old-school old guy (turn 64 this
year), I still work the
crossword puzzle in the daily newspaper - surely you've heard of antiquated
print media form of which I am the only house on my street which has it delivered
daily. I also like the cryptogram type word jumble puzzles. Working the Sudoku puzzles
is also a pencil and paper exercise (as opposed to interactive online) because of
my method of figuring out the numbers. My older sister is a whiz at them, and she
does them on her iPhone. Old habits die hard, as the saying goes. But I digress.
In addition to the weekly RF Cafe Engineering and Science crossword puzzles I create
each week, I also like to post crosswords that appeared in the vintage electronics
magazines. This one appeared in the March 1962 issue of Popular Electronics...
 Lightning has not changed since the days
when Benjamin Franklin flew his special kite during storms. Contrary to some peoples'
belief, he did not "discover electricity;" rather, the experiment proved his theory
that lightning was a form of electrical discharge. Maybe someone has already
pointed this out, but in effect Franklin put into service the world's first
lightning rod. The conductive (wet with rain) hemp rope between the metal wire
spike on the kite and ground (the plate of a Leyden jar) performed the task a lightning
rod is meant to do - lower the difference of potential between the charged clouds
and ground, thereby reducing the likelihood of an electrical discharge. An induced
current traveled along the rope and charged the Leyden jar. If lightning had actually
struck the kite as fables suggest, Franklin would probably have been killed even
though he was holding on to a silk string attached to the bottom of the hemp string
to provide some insulation. Mr. Kirchhoff's current law would have apportioned
the lightning strike current at the knot joining the two strings according to the
respective...
 Comic strips used to be a popular venue for
instruction as well as for humor. Early editions of QST and many other
magazines often had many small comics scattered throughout. The one featured here
came from the May 1941 QST. Amateurs were and still are a vital part of
disaster response efforts. In fact it is pretty much inarguable that a big part
of why the FCC has not stripped away a larger portion of the allocated Ham bands
is due to the thousands of operators who volunteer their time and equipment to assist
government and private agencies with communications during times of duress. Some
have argued that the "amateurs" often do a much better job at disseminating time-critical
information that the "professionals."
 Joe Cahak, owner of Sunshine Design Engineering
Services in Ramona, California, has written a white paper entitled, "Measuring
Semiconductor Device Input Parameters with Vector Analysis." This article covers
a recent test experience that utilized some thinking about the test fixture, the
bias requirements and the device mounting and special calibration offsets needed
to de-embed the test fixture response from the device response within the test fixture.
The device also had to have bias on several ports simultaneously. We had to establish
a "reference plane" within the fixture, from which we can use the Vector Network
Analyzer's Port Extension or Phase Offset to dial out the distance from our 1 port
calibration reference plane to the point of short reference within the fixture.
With this phase offset compensation we can then measure...
 The advent of
metal-encapsulated vacuum tubes was supposed to be the death knell for traditional
glass tubes. This 1935 article from Radio-Craft spelled out the many virtues of
"metal" tube and how in short order their superiority would obviate the need - even
desire - for "glass" tubes. I'll let you read the article for the details, but want
to make note of an evidently archaic term used that could potentially be really
popular in today's manufacturing world if duly resurrected - "quantiquality" (aka
"quanti-quality" or "quanti quality"). The connotation is a process of high quantity
in conjunction with high quality. The only references I could easily find to quantiquality
was from late-19th-century newspaper archives. If sometime within the next few years
you start seeing some form of quantiquality appear in marketing copy and scholarly
papers, remember that you heard it here first...
 Repair service businesses have always gotten
a bad rap for deliberately inflating part and labor costs - often deservingly so
- but it's a shame the honest brokers are dragged down by the scum (or "gyps" as
this article calls them). Come to think of it, the word "gyp" is likely short for
"gypsy," which is sure to offend someone these days. Along with admonishing customers
to beware of shyster servicemen, there is an example of an orchestrated "sting"
operation whereby a radio set was intentionally "broken" in a certain way with witnesses
as to the fault, and then a couple dozen repair services were called upon to troubleshoot
and fix it, then present a bill for their work. The result is interesting, and even
resulted in one guy being prosecuted. The story reminds me of a similar much-publicized
sting that was done back in the 1990s against car repair services that were creating
leaks in brake lines and then charging customers to fix them...
 Here is a very useful article on the benefits
and technical challenges of
stacking antennas; it appeared in a 1958 issue of Radio-Electronics magazine.
It avoids rigorous mathematical analysis and instead presents recommended guidelines
and includes some very nice measured antenna patterns (no computer-generated predictions
in 1958) of the various configurations. The authors discuss radiation pattern changes
based on horizontal versus vertical stacking, and a combination of both. Plotting
all the vertical and horizontal radiation patterns would have take a lot of time
with a slide rule back in the day. This is the first of a series written by engineers
at the Scala Radio Company...
 It is common in electronics courses for
an analogy to be drawn between electrical and mechanical phenomena. In fact, a lot
of circuit analysis methods and equations apply directly to mechanics, and vice
versa. An LC (inductor-capacitor) oscillating tank circuit is akin to a spring and
dashpot. Resistance of a wire is likened to skin friction of water flowing through
a hose. Who among us can forget those lessons? This
Electronic Analogy Quiz from the November 1961 edition of Popular Electronics
magazine presents a challenge both because some not-so-familiar examples of analogies
are offered, and because some are a real stretch. Therefore, don't feel too bad
if you don't get a few. That's my way of saying that I didn't get all of them right
;-) Answers and explanations are at the bottom of the page...
 In our continuing saga Wireless Networking
in the Developing World, we now turn our attention to
transmission lines and coaxial connectors, where we find: The transmitter that
generates the RF power to drive the antenna is usually located at some distance
from the antenna terminals. The connecting link between the two is the RF transmission
line. Its purpose is to carry RF power from one place to another, and to do this
as efficiently as possible. From the receiver side, the antenna is responsible for
picking up any radio signals in the air and passing them to the receiver with the
minimum amount of distortion and maximum efficiency, so that the radio has its best
chance to decode the signal. For these reasons, the RF cable has a very important
role in radio systems: it must maintain the integrity of the signals in both directions...
 Simpson Electric is a name most RF Cafe
visitors are probably familiar with as being the maker of high quality analog multimeters,
with the Simpson 260 line being the most famous (it is still manufactured today).
Not as many people, however, know that Simpson also used to make oscilloscopes.
This article from a 1957 issue of Radio & TV News magazine was written
by a Simpson Electric engineer whose job was, in part, to respond to questions asked
by users. It covers basic operations like how to calibrate the display, adjust the
horizontal time base and vertical amplitude scales, and how to synchronize the display
with the input signal. Some explanation of
how to interpret periodic and pulse type waveforms is provided as well as tips
on how to avoid overloading and possibly damaging the instrument...
 The U.S. Army's Signal Corps was set up to
"exercise supervision over signal communications literally from the Pentagon to
the foxhole." Created in 1860 at the suggestion of a military doctor, the
Signal Corps originally used a system of flag waving for messaging dubbed
"wigwag" and graduated to overseeing the nationwide telegraph network six years
later. By 1870, members were tasked with establishing and operating a weather
forecasting service, so in 1907 when they created an aeronautical division it
was just in time for facilitating the nation's rapidly growing cadre of aircraft
pioneers (recall the Wright brothers had flown four years earlier at Kitty Hawk)
by providing en route weather information. Having already mastered the state of
the art that was radio and telephone...
 Some people like to demean engineers and
scientists for their propensity to want to conduct experiments and obtain measured,
empirical data rather than "winging it" and being satisfied with intuitive knowledge
or the contemporarily popular term "gut." If mankind had not adopted scientific
methods and ventured beyond the so-called cradle of civilization on the African
continent, we would all still be living in grass huts, hurling rocks at prey, and
foraging for berries.
Quantifying and categorizing all things in nature helps inventors create new
and improved implements that help make life better. Early on it was mostly individuals
like Archimedes, Euler, Newton, and Edison who built the pool of knowledge that
fed and evolved into corporations, governments, and universities doing the vast
majority of the work. Bell Laboratories is probably one of the most recognizable
names for a group of people that collectively produced an immense amount of data
and products...
 This
vector circuit matching quiz will hurt the brain a little more
than most of the ones that were printed in Popular Electronics. In order to
score well, it helps to visualize the circuits relative to where they would
appear on a Smith Chart. Capacitive impedances lie in the bottom half and have
negative phases (-s, -jω). Inductance lie in the upper half and have positive
phases (s, jω). The familiar 'ELI the ICE man' mnemonic helps, too. Be sure to
pay attention to the color of the vector arrow heads. Example: In a purely
inductive circuit like #4, voltage leads current by 90°. Since phase rotation is
CCW, you need to look for lettered phase diagram where the white arrowhead
(voltage) is 90° ahead of the black arrow head...
 Just as the title of this installment of
Mac's Service Shop, "A Typical Day in the Shop," suggests, the story is a
recollection of the kinds of scenarios that would found in an ordinary shift in
an electronics service business in the mid 1950's. Vacuum tubes were the norm of
the day, as were discrete leaded components and a rat's nest of wires running
from solder lug to solder lug. Printed circuit boards were beginning to appear
in commercial products, but mostly existed in specialty defense and aerospace
applications. You might wonder how many different ways could there be for simple
circuits like biasing and heater element lighting, but some pretty imaginative
variations made their way into radios, television, record players, and tape
decks, and often times that made a serviceman's life heck. Such was the case
here as über-owner-technician Mac admonishes sidekick Barney for not taking
time...
 Jules Antoine
Lissajous was a French mathematician who in the days before oscilloscopes concerned
himself with patterns (waveforms) that would be generated as the result of two separate
functions (signals) driving both the x- and y-axes. Lissajous used mechanical vibration
devices connected to mirrors to bounce light beams onto a projection surface, so
his results were not merely hand-drawn plots on graph paper. He was probably as
mesmerized with them as we are today when they appear. Sci-fi movies have used Lissajous
patterns in the background to 'wow' the audience into thinking it is witnessing
futuristic, cutting-edge technology. When troubleshooting analog circuits, it is
very advantageous to have seen and recognize many different types of waveforms so
that you have a better chance of picking out patterns ... |
