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 Electromagnetism is
the force that governs the behavior of charged particles and the propagation of
electromagnetic waves, forming the physical basis for nearly all modern
electronic and wireless communication systems. From the fundamental observations
of Oersted and Ampere to the elegant synthesis of Maxwell's equations, the field
describes the inseparable relationship between electric and magnetic fields.
Whether it is the Lorentz force propelling an electron beam in a vacuum tube,
the induction driving a power transformer, or the alternating fields that carry
radio signals across the globe, electromagnetism is ubiquitous. This
Electromagnetism Quiz explores the core concepts of this discipline...
 Popular comic strips (aka "funnies") in
the 1930s and 1940s featured numbskulls, ne'er-do-wells, and simpletons. There was
usually one character in the strip's cast that was smart - at least in a relative
way if not absolute. Being familiar with some of the old comics like Blondie, Barney
Google, Krazy Kat, Beetle Bailey, Gasoline Alley, etc., I can see a definite relationship
between the story line of "Entertaining
Uncle Oscar" and the comics of the era in this short story that appeared in
a 1939 edition of the ARRL's QST magazine. As you might guess, the
feller named "Ham" is the smart one. Q: Is it irony, coincidence, or premonition
on the author's part that the uncle's name is the same as...
 If you are going to write an article about
etching crystals for radio frequency circuits, having a last name
like Gene Brizendine's couldn't be much better. It just sounds like a mineral
or a compound (benzidine, etc.). Amateur radio operators have for a long time adjusted
the resonant frequency of their crystals by either grinding or chemical etching.
Mr. Brizendine recommends etching as a more controllable method that does not
reduce the quality of the crystal like improper grinding can do. Ammonium bifluoride
is mentioned as the etchant. It is said to have cost about $1/pound in 1954, and
sells on Amazon today for about $23/pound. According to the BLS Inflation Calculator,
$1 in 1954...
 Working crossword puzzles can be contagious.
This April 12, 2020,
tech-themed crossword puzzle may even go viral - the second in
a series. It contains only clues and terms associated with engineering, science,
physical, astronomy, mathematics, chemistry, etc., which I have personally built
over nearly two decades. That includes the cause for our planet's current dilemma.
Many new words and company names have been added that had not even been created
when I started in the year 2002. You will never find a word taxing your knowledge
of a numbnut soap opera star or the name of some obscure village in the Andes mountains.
You might, however, encounter the name of a movie star like Hedy Lamarr...
 Werbel Microwave is a manufacturer of
RF directional and bidirectional couplers (6 dB to 50 dB) and RF power
dividers / combiners (2- to 16-way) with select models operating up to 26.5 GHz
and 100 W of CW power (3 kW peak). All are RoHS and REACH compliant and
are designed and manufactured in our Whippany, NJ, location. Custom products and
private label service available. Please take a couple minutes to visit their website
and see how Werbel Microwave can help you today.
 Transformers are the workhorses of power
distribution and signal processing, utilizing Faraday's law of induction to step
voltages up or down while maintaining high efficiency. By coupling magnetic fields
between primary and secondary windings through a shared core, they provide critical
electrical isolation and impedance transformation between circuit stages. From massive
grid-scale power units to tiny high-frequency RF baluns, transformers must manage
complex phenomena such as magnetizing current, eddy current losses, hysteresis,
and parasitic leakage inductance. This quiz explores the core physics behind transformer
operation, including the “turns ratio” relationship, the role of core...
 A column entitled "Radio-Electronics Monthly Review" appeared in each issue of Radio-Craft
magazine. As now, things were moving quickly at the time. With WWWII recently ended,
a lot of the new technology developed to help beat back Nazism and Communism was
being transferred to peacetime uses. The May 1947 issue contained, amongst other
items, info regarding how radio servicemen were organizing efforts to get its ranks
educated on FM sets as AM was being replaced and/or supplemented with the new miracle
noise-free broadcast systems. It also reported that the IRS decided not to go forward
with earlier plans to tax television shows being displayed in public...
 Radio control (R/C) systems operating in
the 2.4 GHz ISM band, using one of or a combination of frequency hopping and
direct sequence spread spectrum scheme, have been in widespread use since the early
2000s. As with any new technology, there was a lot of reluctance to adoption of
the systems based on a few reports (valid or not) of performance issues - primarily
lack of control range where communications between the transmitter (Tx) and receiver
(Rx) with a pilot and aircraft was lost and a crash ensued. Tx power was already
at the FCC-mandated maximum, so manufacturers quickly improved receivers by adding
diversity with a second Rx antenna. The receiver...
 As reported in this 1967 Electronics
World magazine piece, lasers were still the things of science fiction to most
people. Real-world applications seemed to be far off in the future, but in fact,
work was underway setting the stage for today's blazingly fast communications
systems. The author here references attaining 5 THz optical transmission speeds
through fiber and through the air. At the time, a laboratory filled with bulky prototypes
chassis and optical tables were required to get those results. I can remember reading
articles in the 1970s when laser power output was measured in "Gillette power," referring to the beam's ability to burn through
a number of razor blades (a big deal...
 If my counting is correct, by 1952 only
33 of America's 48 states (Hawaii and Alaska weren't admitted until 1959),
and Washington, D.C., had
television broadcasting stations. That most of the early television
experimentation occurred on the east coast is apparent by looking at the number
of stations there compared to the west coast. You might think California would have
the largest amount of TV stations, but it only had 11 located in 3 cities. New York,
on the other hand, had 13 in 7 cities. Ohio had 12 stations in 5 cities, and Pennsylvania
had 7 stations in 5 cities, one of which was my town of Erie. Vermont, New Hampshire,
Mississippi, Wyoming, both Dakota, and Oregon were among...
 By now, engineers and scientists have managed
to replace most vacuum tubes with solid state devices - at least for consumer products.
The one place tubes remain are in microwave oven. Those klystron tubes operate in
the 2.4 GHz band and typically output ranging from about 500 W to 2 kW.
No doubt materials and methods have changed since the 1950s, but fundamentally klystrons
of today are the same as klystrons then. Between this article and Part 1 that
appeared in the April 1952 issue of Radio & Television News magazine,
authors Joseph Racker and Lawrence Perenic provide a very nice introduction on the
topic. According to the Wikipedia entry, the name "klystron"...
 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 by providing en route weather information. Having already mastered the
state...
 I have never seen study-at-home audio-visual
(AV) physics courses offered by Albert Einstein or AV courses on chemistry promoted
by Ernest Rutherford, but I can now say I have seen study-at-home AV courses offered
by electronics pioneer Lee de Forest. This full-page advertisement for the
de Forest's Training, Inc., company of Chicago, Illinois,
appeared in a 1945 edition of Radio-Craft magazine. The vaunted (at least
by the company) "Syncro-Graphic" training was an early attempt at the paperless
classroom. The student watched films reels of instruction rather than "frequent
flipping of pages to refer back or ahead to illustrations mentioned in text." It
would be another 50 years before...
 The history of electrical current is replete
with tragic incidences of maiming and death caused by ignorance and/or inattention
to known danger. Having been involved in both the electrical wiring and the electronics
fields since the 1970s, I am quite aware of the legion of hazards present when current
flows. My tool box contains screwdrivers and lineman's pliers with notches of
melted metal from inadvertent contact between differences of potential in circuit
breaker panels and electrical wall boxes. Once you experience the thrill of a sudden
blinding flash, unique buzzing sound, and smell of burning hot steel, you'll
never forget it. A lot of people have been
electrocuted, though, through no fault...
 Less than half a decade had passed when
Radio & Television News editor Oliver Reed wrote this piece extolling the
virtues of the transistor and how "it may well revolutionize the
entire electronics industry." If you have followed a lot of my postings from the
vintage electronics magazines here on RF Cafe, you are well aware that there
was a lot of resistance to and doubt about the future of semiconductors. Naysayers
had the same kind of reaction to the advent of the horseless carriage (automobile)
and locomotive, relativity and quantum mechanics, and even curative medicines. Point
contact transistors were still largely in use, but were costly compared to the relative
simplicity and low...
 Please take a few moments to visit the
everything RF website to see how they can assist you with
your project. everything RF is a product discovery platform for RF and microwave
products and services. There are currently 374402 products from more than 2667 companies
in the database, and engineers can search using a customized parametric search tool.
Also 5482 technical articles. Amplifiers, test equipment, power couplers and dividers,
coaxial connectors, waveguide, antennas, filters, mixers, power supplies, and everything
else. Please visit everything RF today.
 Inductance is a fundamental property of
any conductor, representing its ability to store energy in a magnetic field when
current flows through it. From the simple air-core loop to complex multi-layer transformers,
inductors are essential for filtering, impedance matching, energy storage, and signal
processing. Unlike capacitors, which resist changes in voltage, inductors resist
changes in current, governed by the classic relationship of electromotive force
being proportional to the rate of change of current. This quiz delves into the behavior
of inductors in both AC and DC circuits, the variables that define their magnitude
- such as core material permeability, number of turns, and geometry...
 Albert Einstein published his paper on
Special Relativity in 1905 and on General Relativity in 1916.
Since that time, many experiments have been performed worldwide by scientists intent
on both proving and disproving Mr. Einstein. Laser and nuclear based timepieces
have been improved for precision and calculations refined to aid in the task. This
1959 Popular Electronics magazine article reports on one of the first atomic
clock experiments used to test General Relativity. After more than 100 years, General
Relativity stands as originally presented. Even the rigors of quantum mechanics,
which Einstein did not embrace until much later in life, has not toppled its precepts...
 Even in this time of readily available computers
(including your smartphone) and printers, having a set of
rubber stamps for common electronics symbols would be pretty handy;
there are some Neanderthals among us who still use pencil and paper on occasion.
Simpler symbols like resistors and capacitors are easy enough to sketch by hand,
but something like a dual gate MOSFET with diode protection can take some time to
produce legibly. Common connector types like the DB signal/power series and some
RF kinds (BNC, SMA, etc.) would be useful, as would a set of oft-used logic gates
for the digital designers. The set shown here in a 1953 edition of Radio-Electronics...
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 How many of us have any idea what a
magnetic amplifier is or how they work? Very few, I would guess. This article
from a 1960 issue of Popular Electronics magazine is a good introduction.
Magnetic amplifier have been around since the beginning of the 20th century and
have been used extensively in heavy industrial and military equipment controls.
Their appearance is very similar to a typical electrical transformer, but the function
is completely different. Basically, the magnetic amplifier is a current-controlled
impedance changer. The current applied to the primary winding controls the degree
of saturation in the secondary, which in turn causes the impedance of the...
 Dry cell chemistry has come a long way since
this article appeared in the April 1959 edition of Popular Electronics
magazine. Yes, you can still buy a basic carbon battery, but much superior cells
are available now that perform over much wider temperature ranges, have nearly flat
discharge curves throughout their rated range, and offer standard chemistries with
voltages other than 1.5 volts per cell (nominal). For example, nickel metal hydride
(NiMH) cells exhibit 1.2 volts nominally, and lithium polymer (LiPo*) cells have
a nominal voltage of 3.7 volts. As a kid in the 1960s and 70s, I spent a lot of
time struggling to make Eveready flashlight "D" cells from my father's...
 A recent headline announced where a guy
hacked his
hearing aid to enable listening to Wi-Fi signals as he walked around
town. Why would a person do that? I suppose now that the audible digital handshaking
tones of telephone modems and fax machines are all but gone from everyday life,
he must have really been missing the nerve-grating melodies. I don't recall ever
seeing a story about anyone picking up Wi-Fi signals from a faulty metal tooth filling
like used to occur occasionally in the presence of high power AM transmitter towers.
This article from a 1956 edition of Popular Electronics reminded me of
it. I think I've told the story of how while working as an electrician in...
 Before a suitable manufacturing process
was developed for synthetic quartz, the mineral (silica, or silicon dioxide - SiO2)
was mined from the ground in various parts of the world. The primary source for
electronics grade quartz came from Brazil. It was not until 1921 that Walter Cady
developed the first quartz crystal oscillator, and George Pierce came up with his
eponymously named Pierce oscillator circuit in 1923. It was not until the1950s that
a commercial-scale process was developed for hydrothermal processing of synthetic
quartz. This 1938 Radio News magazine article describes the manufacturing
steps required for making
radio-quality natural quartz...
 CQ magazine is a great monthly
publication for the electronics hobbyist and professional. Each month it is chock
full of amazingly informative articles covering circuit design, system design, antenna
design, product reviews, electronics theory, prototyping and kit building, industry
news, and more. Being primarily an amateur radio publication, CQ also contains many
pieces on equipment setup and use, operational suggestions, contest coverage, ARRL
events, FCC regulatory news, reports on personal accomplishments, etc. As part of
his "Haywire State" article, Eric highlights the venerable
Bob Pease (sadly no longer with us) with his famously messy workbench and...
 One of my favorite old-time radio personalities,
Paul Harvey, had a trademarked feature titled The Rest of the Story. For those of
you not familiar with the format, Mr. Harvey would begin his story talking about
particular life aspects of a person that, while remarkable, usually had no connection
with the person's eventual claim to fame. The listener's challenge was to guess
who the person was before it was revealed at the very end, followed by, "... and
now you know --- the rest [emphasis] of the story." As far as I know the story of
FM radio inventor
Edwin H. Armstrong was never a subject, although it certainly met the criterion.
I've already let the figurative cat out...
 Major Edwin Armstrong, whose first name
is Edwin but is often assumed to be Major (which used to be a not-so-rare man's
first name), was endowed with many awards, patents, titles, and honorary distinctions
during his amazing career. He served in the Signal Corps during World War I,
where he attained the rank of Major. Having already achieved notoriety for his work
prior to being commissioned, he entered as military service as a Captain (RCA's
David Sarnoff was initially commissioned as a General during World War II).
Being highly patriotic, Armstrong granted the U.S. government free use of his patented
material during both wars. As with many other...
 Even in the late 1930s when this article
appeared in Radio News magazine, factory automation had made significant
progress from the times when nearly every step of the process had to performed by
hand by workers. However, as components became smaller, more delicate, and precision
assembly was essential to assure acceptable performance and reliability, direct
human interaction was the only available means for getting the job done. As can
be seen in this array of photos from the
DuMont company's television cathode ray tube (CRT) production line, simple monochrome
tubes required the precision and in-situ decision making of many kinds of skilled
craftsmen...
 My civilian career began at
Westinghouse's Oceanic Division in Annapolis, Maryland. It was long ago bought
out by Northrop Grumman and re-named Undersea Systems. Their AQS-24 towed sonar
system looks outwardly very much like the AQS-14 that I worked on while there in
the 1980s. Our parent organization was the Westinghouse Electronics Systems Division
in Baltimore, MD, adjacent to the Baltimore-Washington International Airport (BWI)
tarmac so that military aircraft could fly in and out to be retrofitted with radar
systems. Headquarters for Westinghouse was (and still is) in Pittsburgh, Pennsylvania,
where progenitor George W. founded it. Having had...
 In the late 19th century, 1877 to be precise,
Italian astronomer Giovanni Schiaparelli determined by observation and logical deduction
that the maze of dark lines seen on the surface of Mars had to be of intelligent
design (i.e., Martian beings) because no known natural process could possibly create
such complex patterns. He called them "canali," meaning channels, or canals. This
type of proclamation seeded the concept of
extraterrestrials
(ETs) being "out there" and most likely visiting Earth. American astronomer
Percival Lowell (of Lowell Observatory renown) picked up on and amplified the
Mars canals and oases theme through the early 20th century. In fact, it was...
 Dave Harbaugh did a number of different
humorous features for Popular Electronics magazine back in the 1960s and
'70s (see list at bottom of page). "Hobnobbing
with Harbaugh" was one of the more popular comic series he did. Article topics
ranged from husband-wife relationships where the husband is an über-enthusiastic
technophile of some sort and the wife has to put up with his crazy schemes and inventions.
These comics poke fun at technical schools and colleges, and their alumni. My favorite
is the "suicidal" waveform...
 Prior to around 1960, the nature of electromagnetic
radiation outside the Earth's atmosphere was entirely a matter of scientific conjecture.
As is evidenced by this 1961 Popular Electronics magazine article, at the
time it was still not known for certain whether electromagnetic energy outside the
bands transmitted through the
ionosphere existed for sure. There was of course no reason to believe that low
frequency, long wavelength radio waves were not present along with the rest of the
spectrum, but experiments needed to be developed that would launch satellites above
the atmosphere to detect probable out-of-band signals and then re-transmit them
on...
 Arithmophobia (a real word) is likely
the root cause of of decibelphobia (that one's made up), a condition that causes
some otherwise rational people to curl in the fetal position in an attempt to
avoid the topic. As with most subjects, the more often you engage in using a
term, the more comfortable you become with it. Technicians and engineers who
deal in voltage and power levels in terms of dividing quantities or transmitting
them from one location to another would find conversation and writing without
the use of decibels quite inconvenient. It is tempting to point out that using
decibel units to express ratios or relative levels, thereby permitting use of
simple...
 As is often the case with some of these
vintage electronics-themed comics, you need to be privy to the mindset of the
readership of the era. The 1948 Radio News magazine audience of electronics
technicians and servicemen had a wide variety of experiences dealing with finicky
customers and equipment. In-home service calls were as commonplace as family doctors
making house calls (I'm old enough to remember both doctor and TV repair visits
to our house in the 1960s). 1948 was only a couple years past the end of World War II,
a time when the electronics field was burgeoning with new technology and domestic
products that seemed magic and miraculous to...
 I've always disliked book and article titles
containing the word "Modern" because the word is utterly ambiguous and usually downright
misleading more than a few years past the original publication date. What at publication
time was modern is usually obsolete merely a decade later, especially in the realm
of high technology. Sometimes, however, as with this 1932 Radio News magazine
article on
insulation (dielectric) breakdown voltages, bringing the information up to date
requires only the addition of an extra couple decimal points of precision and/or
the substitution of a few words. For instance, replace "condenser" with "capacitor"
and units of "mfd" with "μF" and... |
