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2 of the March 2026 homepage archives.
 In the mid- to late- 20th century,
300-ohm twin-lead cable served as the dominant transmission line for connecting
television antennas to receivers. This Popular Electronics magazine article
explains that the "300-ohm" rating represents the characteristic impedance of the
line, which remains constant regardless of length when properly terminated. When
matched at both the antenna and the TV, the cable functions as an "untuned" line,
ensuring maximum signal transfer. If the termination does not match the cable's
impedance, the line becomes "tuned," causing the input impedance to fluctuate wildly...
 Metal-encased vacuum tubes were such a big
deal when they arrived on the scene in the mid 1930s that two successive issues
of Radio-Craft devoted the majority of print space to them. Metal tubes,
as admitted by editor and author Hugo Gernsback, did not perform as well electrically
as glass tubes yet, but that was attributed to the infancy of the technology. Overwhelming
positives, including ruggedness, lower cost of production, longevity and other aspects
would ensure that metal tubes "are here to stay." They never did even come close
to replacing glass tubes. One of the most interesting statements in the article
has nothing to do with metal tubes, but Mr. Gernsback's understanding...
 "At MWC26 in Barcelona, SpaceX introduced
a new phase of its
direct-to-device
(D2D) satellite strategy, renaming the offering Starlink Mobile and outlining
plans to align it more closely with terrestrial 5G networks. The service will run
on the company's second-generation low Earth orbit satellites and is positioned
as complementary to ground-based infrastructure. Michael Nicolls, SVP at SpaceX,
said in a presentation at the event that the upgraded satellites represent a significant
technical step beyond the LTE-compatible messaging, voice, and video services supported
by the first-generation constellation - broadband capabilities to unmodified cell
phones..."
 Here is a brief synopsis on the main difference
between
glass and metal vacuum tubes - the metal case tubes generally
exhibit higher interelectrode capacitances. Unless successfully addressed, that
limits usefulness in high frequency circuits. One of the major advantageous features
of metal tubes is the built-in EMI/RFI shielding both for keeping desirable fields
inside the tubes and keeping undesirable fields from entering...
 This article, in addition to reporting on
early
push-push power amplifier configurations, demonstrates what a
mess AC and DC power distribution systems were in the early days of electric service.
Standardization and regulation was at a minimum, and the plethora of potential hazards
to life and property makes you wonder how more people were not killed, maimed, or
had houses and businesses burned down. You hear a lot about medical issues that
came from lead-based paint on window sills, but the electrical wiring and connected
equipment were a mess. Back to the push-push amplifiers, though. According to the
author, the primary difference from the more familiar push-pull amplifier is that
the configuration removes bias from...
 Crane Aerospace & Electronics' products
and services are organized into six integrated solutions: Cabin Systems, Electrical
Power Solutions, Fluid Management Solutions, Landing Systems, Microwave Solutions,
and Sensing Components & Systems. Our Microwave Solution designs and manufactures
high-performance
RF, IF and millimeter-wave components, subsystems and systems for commercial
aviation, defense, and space including linear & log amplifiers, fixed &
variable attenuators, circulators & isolators, power combiners & dividers,
couplers, mixers, switches & matrices, oscillators & synthesizers.
Thursday the 12th
 Teenage technophiles Carl Anderson and Jerry
Bishop were up to their old tricks again in this "The
Tele-Tattletale" episode of John Frye's monthly adventure in Popular Electronics
magazine. The boys were bitten by the Space Race bug that was in full swing at the
time (1958). Jerry cleverly built himself a telemetering device to mimic some of
the functions being employed on missiles and, soon to be, manned spacecraft (1961).
His setup involved a lot of different technologies and homemade electromechanical
sensors and electronic paraphernalia - all stuff that can be bought for peanuts
on Amazon for use with Arduino configurations. At first I thought maybe Mr. Frye
had slipped in his writing, because in the beginning Jerry had the remote sensor
unit inside a metal freezer...
 In 1936, a high school graduate could expect
to earn about $15 per week, or about 38¢ per hour (40-hour week), in the
nascent radio business. According to the U.S. Bureau of Labor Statistics' Inflation
Calculator, that is the equivalent of around $348 per week in 2026, which is not
much to live on these days. Today, many McDonalds burger flippers are being paid
$15 per hour ($600/40-hour week). That equates to a little over $26 per week in
1936 - nearly twice as much as an electronics technician who likely had military
and/or technical school training. This 1936 Radio-Craft magazine article discusses
the benefits of formal education in regard to potential earnings...
 "NTT DOCOMO, a Japan-based mobile network
operator providing telecommunications services including mobile voice, data, 5G,
and digital solutions for consumers and enterprises and Keio University Haptics
Research Center have conducted a demonstration of high-precision
remote robot operation over commercial 5G. By combining Configured Grant, a
low-latency network slicing technology, with Keio's Real Haptics® technology, force
feedback and tactile sensations were transmitted stably. The demonstration marks
the first instance of Configured Grant being used to enable practical robot teleoperation
over commercial 5G..."
 Radio-Craft magazine ran a series
of feature articles on "Men Who Made Radio." The January 1930 edition honored Canadian
engineer
Reginald A. Fessenden, who is credited for making the first
wireless voice transmission. Mr. Fessended worked with both Thomas Edison and
George Westinghouse, eventually inventing the rectifying electrolytic detector,
which was the successor of the coherer and the precursor of the crystal and the
tube detectors. His interest in communications extended beyond radio to include
sonic devices like sonar, a field in which he also gained significant renown...
 What was considered in 1937 to be a breakthrough
feat for a full-size airplane is today accomplished regularly in model airplanes.
What took hundreds of pounds of generators, radio gear, sensors, and actuators to
perform the first-ever
fully automatic landing is now done with a few ounces of microminiaturized
GPS receiver, processor, MEMS sensors, servos, and a LiPo battery. The HobbyZone
Sportsman S+RTF (see video at bottom) is an example. Most modern commercial aircraft
are capable of landing themselves in an emergency situation. Just today there was
a news report of an American Airlines pilot that died in flight and the copilot
took over to land the airplane...
Wednesday the 11th
 Conceptual dilemmas in electronics (and
other fields) often arise from foundational misunderstandings that can be resolved
through rigorous analysis. This Popular Electronics magazine article addresses
three primary paradoxes that frequently confuse beginners. First, the "plus-and-minus"
debate regarding current direction is clarified as a semantic convention: while
electrons physically flow from negative to positive, the historical definition of
current often assumes the opposite direction, provided one remains consistent. Second,
the capacitor-charging paradox, which seems to contradict the near-light-speed transmission...
 Here are the schematics, chassis layout,
and service info for the
Howard Explorer Model W Deluxe 19 Tube All-Wave Superheterodyne
radio. The Radio Service Data Sheets that were published in Radio-Craft
magazine usually seem to have more information included than those published in
other magazines, at least in the same era (1940-ish). It might have to do with how
much material is provided by the manufacturer rather than a decision by the magazine
editors. Believe it or not, there are still people searching for such data...
 "SpaceX
satellite policy lead Udrivolf Pica told participants in the International Telecommunication
Union Space Connect webcast about the next-generation Starlink direct-to-device
(D2D) cellular service for smartphones. The revelation of the new service follows
SpaceX's October 2025 U.S. trademark filing for "STARLINK MOBILE" and comes as Elon
Musk has recently hinted at Starlink mobile ambitions. 'We are aiming at peak speeds
of
150 Mbps per user,' Pica said, adding, 'So something incredible if you think
about the link budgets from space to the mobile phone..."
 On a fairly regular occasion someone will
write to one of the QST magazine columnists or post on a forum asking about information
on a particular antenna configuration he recalled seeing printed many moons ago,
but can no longer find anything on it. Fortunately, the columnists are guys who
have been in the Ham game for a many decades and not only remember what the writer
references, but knows where to dig out the original info. Even with the plethora
of resources available on the Web, some things still cannot be found because nobody
yet has posted it. That is one of my prime...
 Hiram Percy Maxim is well-known by amateur
radio operators as the founder of the American Radio Relay League (ARRL). He died
in 1936 and was buried at Rose Hill Cemetery in Hagerstown, Maryland. A few years
ago while visiting relatives in Hagerstown, I went to the cemetery, took some photos,
got the exact GPS coordinates, and posted a short article on it (see
Hiram Percy Maxim's Gravesite in Hagerstown, Maryland). If
not for my documentation, there would be no way to know that the large grave marker
shown in this 1940 QST magazine article does not belong to the esteemed
Mr. Maxim, but to the matron of his wife's family...
Tuesday the 10th
 Here are a couple
high tech comics for your enjoyment from the pages of the July
1961 edition of Electronics World magazine. I'm guessing the joke in the
page 72 comic is that unknown parts were/are generically referred to as "Brand
X," so hopefully that would bring in customers who couldn't identify components
(which the repairman probably could). It could also be an unintended warning that
if "Brand X" (knockoff part) is sold there, then there is a good chance inferior
parts will be used in the repair. The page 94 comic is yet another play
on the huge popularity of home hi-fidelity (hi-fi) sound systems of the day. Amplifiers
still used vacuum tubes so building speaker driver circuits that could handle hundreds
of watts was easy to do...
 Fifth in the "Men Who Have Made Radio" series,
Heinrich Hertz is honored here for giving mankind what author Hugo Gernsback appropriately
termed "a sixth sense." Having earned his doctorate with a thesis on "the distribution
of electricity over the surface of moving conductors," Hertz proved through his
experiments the existence of electromagnetic waves - the aforementioned sixth sense.
During his short 37 years on Earth,
Heinrich Hertz accomplished an impressive amount of fundamental
research and discovery. He was remembered fondly as a kind man who placed advancing
the frontiers of science ahead of fighting for credit...
 Werbel Microwave began as a consulting firm,
specializing in RF components design, with the ability to rapidly spin low volume
prototypes. The
WMRD09-7.2-S is a 9-way resistive splitter that covers from DC to 7.2 GHz
with ultra-wide bandwidth. This unique design accomplishes extremely flat frequency
response in a small radial package. Our unique design approach provides higher than
expected isolation between outputs at far ports than would be achieved in a typical
star topology. It has applications in markets such as CATV, T&M, and military
radio...
 While
watching the Avengers: Age of Ultron movie, at some point when one of the
computer voices was speaking, a memory of the "This Is DigiTalker" voice
suddenly came to mind. Back in the mid-1980s while working at Westinghouse in Annapolis,
Maryland, a couple of the engineers brought a DigiTalker prototype experimentation
board into the super-classified area where I worked. According to National Semiconductor's
datasheet, it was introduced sometime around 1980. The programmable digital voice
IC was a big deal in that unlike other devices that had a fixed set of...
 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.
Monday the 9th
 Some things never change - at least at the
fundamentals level.
Electric circuits is one of those things. I don't remember when I first became
interested in electrical apperati, but it must have been due to a natural affinity
to the science because nobody in my family or my circle of friends expressed any
interest. I was the odd man (or boy) out on my street, because while all the other
kids were playing baseball, basketball, and football, I was sticking forks in electric
sockets and disassembling flashlights, battery-powered toys, and building Erector
Set contraptions using the included electric motor. That's not to say I ever got
really good at it, but significantly better than I ever got at playing sports...
 You would be forgiven in this era of ubiquitous
cellphone usage for thinking maybe
Citizen Band (CB) radios are only used these days by techno-throwbacks
like myself, but the fact is many truckers still use them for convenience as well
as to avoid having all their communications intercepted, monitored, and recorded
by government agencies. It can be a deceiving sense of privacy though, because police
officers often monitor CB radio transmissions while in patrol cars, and even solicit
the assistance of other CBers in identifying and apprehending suspected transgressors
- an advantage of public, unencrypted conversation afforded law enforcement which
is not available with cellphones. Also, CB transmission, even though usually regarded
as "hearsay" in legal venues, has many times been admitted as evidence in cases
where "present sense impression," "excited utterance," or some other special...
 I have experienced the problem with low
precision AI calculations; however, it will use high precision if specifically instructed
to do so. "AI has driven an explosion of
new number
formats - the ways in which numbers are represented digitally. Engineers are
looking at every possible way to save computation time and energy, including shortening
the number of bits used to represent data. But what works for AI doesn't necessarily
work for scientific computing, be it for computational physics, biology, fluid dynamics,
or engineering simulations. IEEE Spectrum spoke with Laslo Hunhold..."
 This week's
Science & Engineering Crossword Puzzle, as is the case with all RF Cafe
crossword puzzles, has only words and clues related to science and engineering.
Each week for two decades I have created a new technology-themed crossword puzzle
using only words (1,000s of them) from my custom-created lexicon related to engineering,
science, mathematics, chemistry, physics, astronomy, etc. You will never find among
the words names of politicians, mountain ranges, exotic foods or plants, movie stars,
or anything of the sort. You might, however, find someone or something in the otherwise
excluded list directly related to this puzzle's technology theme, such as Hedy Lamarr
or the Bikini Atoll, respectively. Avid cruciverbalists amongst us: the gauntlet
has been thrown down.
 "And there is nothing new under the sun."
- Ecclesiastes 1:9, NKJV (did you know that is the origin
of the saying?). This 1930 editorial by Radio-Craft editor Hugo
Gernsback describes a coordinated scam perpetrated by
radio manufacturers to compel consumers to buy new sets rather
than have their existing sets repaired. In short, retail prices were inflated to
accommodate a built-in 'trade-in' allowance that far exceeded the repair cost or
used radio cost. Radio service shops were getting the short shrift because many
people who might have otherwise elected to have repairs made would instead trade
in the old set for a new one...
 It really wasn't all that long ago when
most people worked on computers with Color Graphics Adapter (CGA) that had just
16 colors (4-bit pixels). In the late 1980s (wow, maybe it really was a long time
ago), the luxury of a 256-color (8-bit pixels) Video Graphics Adapter (VGA) monitor
and video card would cost you around $300 each. I recall seeing ads for "16 million
color" displays by ViewSonic that ran north of a kilobuck. My first "real" monitor
was bought in 1987 and was 4-bit monochrome.
Televisions, as you know, began as black and white (actually a
infinite number of gray levels between black and white). When TVs first arrived
in people's homes, they were glad for any kind of display, but it wasn't long before
marketing gurus convinced the masses that...
Friday the 6th
![To Be, Or Not to Be [a Metal] - Do Astrophysicists Know the Difference?: Kirt's Cogitations™ #374 - RF Cafe](images/big-bang-universe-creation-kirt-blattenberger-hp.gif) As a multi-decade-long amateur astronomer,
I have read countless articles written by
astronomers who refer to all elements heavier than helium (#2 on the periodic
table of the elements) as "metals." Ostensibly, the origin stems from early detection
of heavy elements in stars, based on heliographic spectrum investigations, where
iron - being the most abundant stable byproduct of supernova explosions - was most
readily observed. I wondered if the "metals" nomenclature came from the next heaviest
element, lithium (#3 in the periodic table), being a metal, thereby laying the foundation.
Not so, claims AI, since lithium is very rare overall in the universe, and not readily
observed. For clarity, I also procured the scientific distinction...
 I usually learn something new with each
episode of Mac's Radio Service Shop, but not necessarily related to electronics.
Such is the case this time where after Mac gives Barney a quick lesson in how to
determine a transformer's winding turns ratio when needing to create an impedance
match circuit. He then, while discussing whether "free" repair estimates are truly
free or of any real value at all, he uses the phrase "a horse on you." Maybe it is because I don't frequent bars that
I had never heard that, but after a little research I now know it refers to a bar
dice game called "'Horse." "A horse on you" is when you lose the final round of
a 2-out-of-3 challenge. "A horse apiece" is when you and your opponent each win
one round in a 2-out-of-3...
 "Data centers for AI are turning the world
of power generation on its head. There isn't enough power capacity on the grid to
even come close to how much energy is needed for the number being built. And traditional
transmission and distribution networks aren't efficient enough to take full advantage
of all the power available. According to the U.S. Energy Information Administration,
annual transmission and distribution losses average about 5%. The rate is much higher
in some other parts of the world. Hence, hyperscalers such as Amazon Web Services,
Google Cloud and Microsoft Azure are investigating every avenue to gain more power
and raise efficiency. The potential virtues of
high-temperature
superconductors..."
 Consumer grade
thermoelectric coolers have been around for so long now that most
people probably assume there is nothing wondrous about the discovery that makes
them possible. I still marvel at the process that allows the application of a current
through physical junction of two dissimilar metals (certain
types) to produce a cooling effect rather than the I2R heating normally associated
with conductors. This article from a scientist at Westinghouse Electric's research
laboratories provides a nice introduction to the subject of thermoelectricity from
both electric current generation based on the application of heat to a dissimilar
metals junction, and the aforementioned cooling effect possible from passing a current...
 FM radio has been in the news fairly frequently
in the last couple years as phone manufacturers and the
National Association of Broadcasters lobby the FCC and politicians
to mandate the inclusion of FM radio capability into every phone manufactured. In
a ploy to exploit the gullibility and egos of said bureaucrats and pols, their primary
argument that FM radio is a "first informer in times of crisis," assuming of course
that people will miss news of "the big one" when and if it occurs. To my knowledge,
successful reception of FM radio on a cellphone requires the listener wear a set
of wired ear buds since the wire from the phone to the ear buds functions as the
antenna. What percentage of cellphone users would bother to carry a set of ear buds?
I, of course, am a huge proponent of...
Thursday the 5th
 Arthur Brach created many
crossword puzzles for Popular Electronics magazine in the 1950s and
1960s. Unlike the hundreds of RF Cafe Crossword Puzzles I designed over more than
two decades, the PE puzzles usually have a few words that are not specifically related
to electronics and/or technology. Still, they are a good source of a brief break
from the day's business. You will need to print out this crossword puzzle to work
it, since it is not interactive. Have fun.
 "Fair
Trade" was a policy established in the post-WWII era in response to what consumer
retail groups considered business-ruining cost cutting by dealers who offered to
sell products at or barely above cost in order to steal profit from other stores.
So-scheming stores planned to make up for the low profit margin with high sales
volumes. Doing so drove a lot of the local competition out of business, leaving
the crafty dirty dealers to later raise prices. Stores that had manufacturer-sanctioned
service shops often got screwed because they were obligated to repair items like
TVs and radios that were bought from another dealer who did not do service work.
Profit margins on repair work - at least from honest shops - were typically very
low, so the owners depended on new product sales...
 Yowza, yowza, yowza
(The Jazz Singer),
QentComm's stock will be rising soon! "Quantum technology is already alive and
well in telecom networks, and although security is the top-of-mind use case, telcos
are also looking at quantum to make networks more resilient and transmit information
more quickly. Comcast announced this week it completed a trial with AMD and Classiq
that leveraged quantum software to find independent backup paths for network sites.
Elsewhere, Deutsche Telekom and Qunnect successfully demonstrated
quantum teleportation over an existing fiber network in Berlin..."
 The persona of Scott Adams' "Dilbert" is
described exactly in the opening sentence of this article in a 1930 edition of
Radio-Craft magazine. It is amazing - if not frustrating - to realize how
long the perception of science-minded people being introverts has been around. Dilbert's
"pointy-haired-boss" is nailed in the second sentence.
Georg von Arco is celebrated here as a major contributor to the
advancement of early radio, particularly wireless telegraphy equipment development.
Interestingly, as brought to my attention by Melanie as she did the text clean-up
after OCRing the magazine page, von Arco worked at the Sayville radio transmission
station on Long Island, New York, where the Telefunken Company's Dr. K.G. Frank
was arrested and interred for the duration of the World War I for sending out
"unneutral messages...
 Lots of Hams still use this tried-and-true
system for
tuning antennas for efficient operation on a variety of bands.
There are plenty of multi-band designs that rely on traps to reactively isolate
portions of the antenna that properly resonate at the desired frequency, but there
is usually a price to be paid in VSWR. Poor VSWR; i.e., higher mismatch loss, can
be overcome with higher transmitter output power, but the real sacrifice for poor
matching is loss of receiving range. The utter simplicity of using an insulated
cord to vary the physical length of the antenna element(s) for tuning is hard to
beat. It could be impractical on a setup where access to the antenna mount is difficult,
but my guess is most people can make good use of it...
Wednesday the 4th
 In this 1958 Popular Science magazine
article titled "Russian
Proposes Global TV," Soviet engineer V. Petrov proposed a global TV relay using
three geosynchronous satellites at 35,800 km altitude, launched 120° apart from
the equator at ~6,000 mph to match Earth's 24-hour rotation. Fixed over sites like
the USSR, China, and USA, they would relay signals - uplink on meter waves, downlink
on microwaves - via inter-satellite links, enabling worldwide broadcasts beyond
line-of-sight limits with directional antennas mitigating solar interference. Each
would require 10-kW antenna power, potentially reduced via pulsed transmission (note
digital waveforms in the drawing). This closely mirrored Arthur C. Clarke's 1945
Wireless World article "Extra-Terrestrial Relays," which...
 Frequency crowding has evidently been an
issue since the early days of radio according to this 1930 article in Radio-Craft
magazine. The situation was really bad in the earliest times when unfiltered spark
type transmitters were the norm. Those pioneers could be credited, I suppose, with
being the first users of wideband communications, but it was not because they chose
to do so. Here author Clyde Fitch discusses the debate over whether there really
were such things as sidebands from modulation and makes an argument for their existence
based on analysis of various types of modulation. In particular, he predicts the
coming popularity of single sideband receivers with crystal-filtered channels, and
the need for matching SSB transmitters with... wait for it... carrier and sideband
suppression...
 "A new transceiver developed by electrical
engineers at the University of California, Irvine boosts radio frequencies into
140-gigahertz territory, unlocking data speeds that rival those of physical
fiber-optic cables and laying the groundwork for a transition to 6G and FutureG
data transmission protocols. To create the transceiver, researchers in UC Irvine's
Samueli School of Engineering devised a unique architecture that blends digital
and analog processing. The result is a silicon chip system, comprising both a transmitter
and a receiver, that's capable of processing digital signals significantly faster..."
 Somehow, after being in the RF business
for four decades, I have to admit to not being familiar with the term
"acceptance angle" for antennas. That is after having read scores
of articles on antennas. Maybe I did and just don't remember - embarrassing. Acceptance
angle is mentioned and explained in this article during the description of rhombic
antenna characteristics versus dipoles and multi-element designs. Although the author
focuses on television installations, information provided on signal reflections,
shadowing, ghosting, multipath, etc., is applicable to radio as well...
 Electrolytic capacitors have long been the
components that provide the highest capacitance density factor, that is, they have
the highest capacitance value for a given volume of space occupied. Anyone familiar
with electrolytic capacitors is aware of the polarization indicated on the package
(a marking or unique physical feature), indicating that there is required direction
for hookup; in fact, a backwards connection can lead to an explosive failure. While
physical construction of electrolytic capacitors have evolved over the decades since
this article was published, the fundamental operation has not. It is interesting
to note the reference to capacitors as "condensers," a name still commonly used
with internal combustion engine ignition systems and with some AC motors that use
them at turn-on for providing a starting coil phase shift...
Tuesday the 3rd
 This 1959 Popular Science magazine
reprint of a 1925 Radio News magazine article focused is on visionary physicist
Robert H. Goddard's proposed Moon Rocket as a means to test
whether radio waves can traverse interstellar space, potentially enabling communication
with other planets. Amid recent radio achievements, including mysterious signals
during Mars' approach and solar disturbances recorded on Earth, the piece challenges
Oliver Heaviside's theory that radio waves are confined by Earth's atmosphere. Goddard's
innovative rocket, propelled by successive explosive charges to escape gravity and
reach the Moon, would carry a compact radio transmitter in its nose cone, broadcasting
signals throughout its flight. Astronomers would track...
 This week's
crossword puzzle, as with all RF Cafe puzzles, uses only words
pertaining to engineering, science, mathematics, mechanics, chemistry, astronomy,
etc. You will never find a reference to some obscure geological feature or city,
or be asked to recall the name of some numbnut movie star or fashion designer. You
will, however, need to know the name of a famous RF filter design software author.
Enjoy...
 "Broadband achromatic wavefront control
plays a central role in next-generation photonic technologies, including full-color
imaging and multi-spectral sensing. A research team led by Professor Yijun Feng
and Professor Ke Chen at Nanjing University has now reported a significant advance
in this field in PhotoniX. The researchers introduced a hybrid-phase cooperative
dispersion-engineering approach that combines Aharonov-Anandan (AA) and Pancharatnam–Berry
(PB) geometric phases within a single-layer metasurface. This strategy enables
independent achromatic control of wavefronts for two different light spin states..."
 As with the article in this month's issue
of Radio-Craft magazine (December 1937), the reference to a 200th anniversary
is understated by 88 years for 2025.
Luigi Galvani was sort of the Benjamin Franklin of biology in
that just as Franklin demonstrated that lightning was a form of electricity, Galvani
showed that signals sent from the brains to the appendages of animals were electrical
in nature. In my high school days in the 1970s, we duplicated his experiment by
making deceased frogs' legs twitch when motivated by a D cell. Today, such an exercise
would likely be met with demonstrations by animal rights people (whose lives, BTW,
have probably in some way been improved as a result of previous such experiments).
But, I digress. Mr. Galvani's name is...
 Superheterodyne receivers were originally
the sole domain of the Radio Corporation of America (RCA), which owned the patents
and refused to license them until around 1930. Hugo Gernsback, a contemporary editor
of the era, provides a little insight into the superregenerative receiver circuits
superheterodyne was about to replace, and why it was an important improvement in
technology. Sidebar: The question often
arises regarding the difference between a "heterodyne" circuit and a "superheterodyne"
circuit. The most popular answer that "super" refers to the IF being located above
the range of human hearing, which peaks at about 15 kHz. Doing so assured that
any IF leakage into the audio circuits would not be discernable by a radio...
Monday the 2nd
 Carl and Jerry stories are usually a good
mixture of teenage curiosity, adventure, and electronics technology, but this "Out
of the Depths" episode is a bit too far-fetched. The first ninety percent of
this 1957 Popular Electronics magazine tale fulfills expectations, with
the boys applying their shared interest in technology while attempting to learn
and apply the technique of luring elusive fish from their safe dwelling places and
onto the ends of their hooks. A car battery, DC-to-AC inverter, tape recorder, and
high-gain microphone are the basis for the scheme. Things were going well, and I
expected the normal hard-fought victory with big, fat bass in their creels - and
then something only slightly more believable than finding a crashed alien spaceship...
 RCA, the
Radio Corporation of America was not merely a manufacturer of
radio, television, and phonograph equipment for home entertainment. The company
also made vacuum tubes for all sots of electronic equipment, and produced a weekly
radio broadcast called "Magic Key" on the NBC Blue Network. Sticking to their communications
roots, RCA today markets televisions, microwave ovens, Android-based tablet computers,
DVD / Blu Ray drives, telephones, 2-way radios, radios, clocks, antennas, and many
other devices - with no tubes in sight, not even in their TV displays...
 "Scientists at the University of New Hampshire
are using artificial intelligence to dramatically speed up the search for
new magnetic materials. Their approach has produced a searchable database containing
67,573 magnetic materials, including 25 previously unknown compounds that retain
their magnetism at high temperatures, a key requirement for many real-world applications.
'By accelerating the discovery of sustainable magnetic materials, we can reduce
dependence on rare earth elements, lower the cost of electric vehicles and renewable
energy systems, and strengthen the U.S. manufacturing base,' said Suman Itani, lead
author of the study..."
 Breaking News!
Espresso Engineering Workbook™ v3.2.2026 has just been released. This makes
the 49th worksheet added. It calculates magnitude, phase, and group delay for Butterworth
and Chebyshev lowpass, highpass, bandpass, and bandstop filters. Outside of the
kilobuck simulators, finding a calculator for phase and group delay is extremely
difficult - believe me, I've searched extensively for years. Espresso Engineering
Workbook™ can be downloaded free of charge. All you need is Excel™ v2007 or newer.
It is provided compliments of my advertisers. Contact me if you would like your
company added to the next release.
 Disneyland opened its gates in Anaheim,
California on July 17, 1955. It was billed as the most high-tech theme park in the
world, with a "wow" factor on par with the World's Fair extravaganzas. One of its
much-ballyhooed features was the "realistic" jungle safari tour with life-like animal
automatons and authentic 3-D jungle sounds. This article, published less than a
year after opening day, highlights some of the equipment and methods used by artists
and engineers to achieve the effects...
 Established in 1990,
dB Control supplies mission-critical,
often sole-source, products worldwide to military organizations, as well as to major
defense contractors and commercial manufacturers. dB Control designs and manufactures
high-power TWT amplifiers, microwave power modules, transmitters, high- and low-voltage
power supplies, and modulators for radar, ECM, and data link applications. Modularity
enables rapid configuration of custom products for a variety of platforms, including
ground-based and high-altitude military manned and unmanned aircraft...
These archive pages are provided in order to make it easier for you to find items
that you remember seeing on the RF Cafe homepage. Of course probably the easiest
way to find anything on the website is to use the "Search
RF Cafe" box at the top of every page. Some quoted items have been shortened
to save space. About RF Cafe.
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