The
bridged-T filter is a quick-and-dirty construct used to notch out a specific
frequency that is interfering with a desirable frequency or band of frequencies.
It is a resonant LC (inductor-capacitor) circuit consisting of a single inductor
"bridging" a pair of series capacitors having a resistor to ground between them,
or, if preferred, a capacitor bridging one or two inductors. A convenient
nomogram (aka nomograph) is provided by the author in this 1964
Radio-Electronics magazine article for quickly selecting values, which was
a very popular design aid in the pre-calculator era. A slide rule could be used
to calculate a range of values when only a single variable was in play, but
juggling more than one variable (component value) was greatly aided by a
multivariable nomograph. Truth is nomographs can still...
Television, in 1955, was still a relatively
new phenomenon to many - maybe even most - people. According to multiple sources,
the portion of American households with a TV set went from under 20% in 1950 to
nearly 90% ten years later in 1960. That was a meteoric rise, particularly considering
the expense of even a minimal TV. The technology was not even available commercially
when most people were born, so the rush to join in on the craze was akin to the
mass adoption of cellphones in the 1990s. "Carl &
Jerry" creator John Frye used his pair of electronics-savvy teenagers to help
make the "magic" behind recreating a moving picture on a CRT miles away from where
it was created. Water flowing through a garden hose has often been employed as an
analogy for current flowing through a wire to explain electricity to laymen and
beginning students of the craft. Here, it is not water flowing through the hose
but water leaving the hose and flowing through the air that serves to represent
an electron stream travelling from the electron gun to the phosphor-coated glass
front of a CRT. Frame rates, scan lines, deflection coils, and other relevant terms
are i
"The
RF front-end (RFFE) industry, valued at $21 billion, is expanding beyond its
traditional focus on mobile and infrastructure to drive innovation in the automotive
sector. Each segment within the industry presents unique dynamics and growth opportunities.
After a difficult 2022, the smartphone market is showing signs of recovery, with
expected year-over-year growth of 4%, projected to reach 1.2 billion units by 2024.
The mobile RFFE market is predicted to hit US$18 billion by the end of 2024, though
it may face stagnation due to market saturation and pricing pressures. This
market is expected to expand, with the 2027 launch of RedCap..."
I'm having a hard time writing this with
my eyes rolled back in my head. The last time I experienced this level of overwhelmedness
was probably the third or fourth week of my feedback and control class at UVM. Even
though
electricity and magnetism shares many complimentary and parallel concepts, for
some reason thinking in terms of magnetics when describing amplifiers, mixers, modulators,
etc., has always caused brain freeze. Maybe it has to do with an ingrained bias
due to my earliest dealings with circuits being from a technician background before
earning an engineering degree. The equations of electric fields and magnetic fields
are very similar so that helps lower...
Temwell is a manufacturer of
5G wireless communications filters for aerospace, satellite communication, AIoT,
5G networking, IoV, drone, mining transmission, IoT, medical, military, laboratory,
transportation, energy, broadcasting (CATV), and etc. An RF helical bandpass specialist
since 1994, we have posted >5,000 completed spec sheets online for all kinds
of RF filters including helical, cavity, LC, and SMD. Standard highpass, lowpass,
bandpass, and bandstop, as well as duplexer/diplexer, multiplexer. Also RF combiners,
splitters, power dividers, attenuators, circulators, couplers, PA, LNA, and obsolete
coil & inductor solutions.
Here we are with another set of three "What's
Your EQ?" circuit challenges, these from the February 1962 issue of Radio-Electronics
magazine. As usual, those challenges provided by Jack Darr are the purview of television
servicemen of the era. The photo shown of the problematic CRT display looks like
a chest x-ray or maybe hieroglyphics in the dark corner of a cave, but evidently
the artifacts are readily identifiable to an initiated few. The Forbidden Current
Path circuit answer is not what I thought it would be. I maintain that whether my
answer or the designer's answer is correct depends on the physical...
"A new
world record
in wireless transmission, promising faster and more reliable wireless communications,
has been set by researchers from UCL. The team successfully sent data over the air
at a speed of 938 Gb/s over a record frequency range of 5–150 GHz. This speed
is up to 9,380 times faster than the best average 5G download speed in the UK, which
is currently 100 Mb/s or over. The total bandwidth of 145 GHz is more
than five times higher than the previous wireless transmission world record. Typically,
wireless networks transmit information using radio waves over a narrow range of
frequencies..."
Sputnik refers to the first series of satellites
launched by the Soviet Union. The word "Sputnik" means "satellite" in Russian. The
launch of Sputnik 1 on October 4, 1957, marked a monumental moment in human history,
heralding the dawn of the Space Age and sparking a fierce technological competition
known as the Space Race between the United States and the Soviet Union. This satellite,
the world's first artificial one, orbited Earth at an altitude of roughly 215 to
939 kilometers and broadcast a radio signal that astonished the world, particularly
in the United States, where it spurred rapid advancements in aerospace and scientific
research. The successful launch of Sputnik was an achievement that was years in
the making, involving a combination of visionary planning, political motives, and
intensive engineering by some of the Soviet Union's top scientists.
Blog: Air Quality
Measurements with Particle Counters
Transcat | Axiom Test Equipment, an electronic
test equipment rental and sales company has published a new blog post entitled "Provide
Essential Air Quality Measurements with These Particle Counters" that covers
how particle counters can provide essential measurement capabilities that can help
avoid contamination and support high manufacturing yields. These measurement tools
can detect and measure microscopic particles suspended in air that can contaminate
the most carefully planned manufacturing lines. Air particle counters can be designed
for various...
In 1958, most people were not accustomed
to seeing the now-familiar maps plotting
sinusoidal
courses of satellites across the face of the earth. It had only been in October
of the previous year that any object other than the moon was in orbit around our
home planet - that was U.S.S.R.'s Sputnik. Just as people of all ages and all backgrounds
enthusiastically joined in the newfangled phenomenon of aeroplanes after the Wright
Brothers flew their fragile craft at Kitty Hawk, electronics communications and
scientists worldwide hopped aboard the satellite train. This article from a 1958
issue of Radio & TV News magazine provided insight into the construction
and flight characteristics...
LadyBug Technologies was founded in 2004
by two microwave engineers with a passion for quality microwave test instrumentation.
Our employees offer many years experience in the design and manufacture of the worlds
best vector network analyzers, spectrum analyzers, power meters and associated components.
The management team has additional experience in optical power testing, military
radar and a variety of programming environments including LabVIEW, VEE and other
languages often used in programmatic systems. Extensive experience in a broad spectrum
of demanding measurement applications. You can be assured that our Power Sensors
are designed, built, tested and calibrated without compromise.
What were some of the
top issues of the radio and television industry half a century ago? In a lot
of respects, the same things that concern it today. A ready supply of service technicians
was a concern that was taken seriously by the Electronics Industry Association (EIA).
While there are not many local repair shops for electronics products nowadays, there
is still a huge demand to techs who are willing and able to do the hard work of
keeping the world's communication infrastructure operational - climbing towers,
repairing cell equipment. Now, as then, good pay, job security, benefits, and respect
for the job being done were at the top of...
In a parallel to the traditional test setup
of signal generation and signal acquisition, RIGOL Technologies announced today
the latest additions to its portfolio of
performance measurement equipment with the introduction of the DG5000 Pro Series
Generators and DHO/MHO5000 Series Oscilloscopes. The DHO/MHO5000 Series bring next-level
performance to RIGOL's respected line of high-resolution oscilloscopes, while the
DG5000 Pro generators do the same for the company's capable Pro Series arbitrary
waveform generators...
When selecting articles for posting here
on RF Cafe, I like to include ones that are directed toward newcomers to the field
of electronics as well as for seasoned veterans. This piece from a 1958 issue of
Radio & TV News magazine entitled "Basic Electronic Counting," is a
prime example in that it introduces the concept of binary numbers. We've all been
there at some point in our careers. A big difference between now and when this article
appeared is that in 1958, almost nobody was familiar to binary numbers, and fuggetabout
[sic] octal and hexadecimal. Only those relatively few people designing and working
with multimillion dollar, vacuum tube-based digital computers installed in universities,
megacorporations, and government research facilities had ever dealt with digital
numbers. The earliest example of powers of two I remember was back in junior high
school. It had to do with a
"Every invention begins with a problem -
and the creative act of seeing a problem where others might just see unchangeable
reality. For one 5-year-old, the problem was simple: She liked to have her tummy
rubbed as she fell asleep. But her mom, exhausted from working two jobs, often fell
asleep herself while putting her daughter to bed. 'So [the girl] invented a teddy
bear that would rub her belly for her,' explains Stephanie Couch, executive director
of the Lemelson MIT Program. Its mission is to nurture the
next generation of inventors
and entrepreneurs. Anyone can learn to be an inventor, Couch says, given the right
resources and encouragement. 'Invention doesn't come from some innate genius, it's
not something that only really..."
Mechanical filters of the type described
in this 1969 Electronics World magazine article are yet another example
of the genius of some people. They are actually a form of electromechanical device
in that the applied electrical signals are first converted into mechanical signals,
followed by resonant mechanical elements that discriminate according to frequency,
and finally a conversion back to an electrical signal is made. It is fundamentally
the same principal as a crystal, SAW, or BAW filter, albeit each with distinctly
different methods and topologies. Mr. Donovan Southworth, of Collins Radio, presents
the basics of mechanical filters in this brief write-up...
LadyBug Technologies was founded in 2004
by two microwave engineers with a passion for quality microwave test instrumentation.
Our employees offer many years experience in the design and manufacture of the worlds
best vector network analyzers, spectrum analyzers, power meters and associated components.
The management team has additional experience in optical power testing, military
radar and a variety of programming environments including LabVIEW, VEE and other
languages often used in programmatic systems. Extensive experience in a broad spectrum
of demanding measurement applications. You can be assured that our Power Sensors
are designed, built, tested and calibrated without compromise.
Attempts at making an
electronically printed facsimile (fax) of an original document at a location
distant from the source have been around for quite a while. As mentioned by
Radio-Electronics magazine editor Hugo Gernsback in this article, Samuel Morse
had a crude working device for printing messages on paper even before his eponymously
named code of dots and dashes became famous in 1837. A couple decades earlier, a
fellow named John Redman Coxe, of Philadelphia, Pennsylvania, devised a method of
electronically printing images and text on paper using a conductive solution and
a direct current pile (aka battery). Dr. Coxe, a physician, is not a well-known
figure in the electronics world, but in his day...
"Researchers have discovered how the 'edge
of chaos' can help electronic chips overcome signal losses, making chips simpler
and more efficient. By using a metallic wire on a semi-stable material, this method
allows for long metal lines to act like superconductors and amplify signals, potentially
transforming chip design by eliminating the need for transistor amplifiers and reducing
power usage. A stubbed toe immediately sends pain signals to the brain through several
meters of axons, which are composed of highly resistive fleshy material. These axons
operate using a principle known as the 'edge of chaos,' or semi-stability, enabling
the swift and precise transmission of information..."
The January 1969 issue of Electronics
World magazine published an extensive list of
Japanese company trade names and their addresses. Many of them went out of business
or were bought by other corporations long ago, as occurs in all countries. "Aiwa"
is listed twice, but that might have been a legitimate duplication due to separate
locations (BTW, I owned an Aiwa stereo at one time). My first "real" cassette tape
deck was made by TEAC (founded in 1953 as the Tokyo Electro Acoustic Company) and
my first "real" stereo receiver was made by Sansui. I remember the line in "Back
to the Future 3" where Doc Brown, having time-travelled from 1955, makes a
disparaging remark about a circuit in the DeLorean failing because of it being labeled
"Made in Japan." Marty counters...
• ARRL Defends
902-928 MHz Amateur Radio Band
• FCC's
Auto Safety Spectrum Rules
• $5M in U.S.
Chips Act Money to Metrology Projects
• U.S. State Department Approves
Surveillance Radar System Sale to Romania
•
5G Americas ITU IMT-2030 Vision for 6G White Paper
John Redman Coxe was a prominent American
physician, scientist, and innovator born on September 20, 1773, in Philadelphia.
Coxe's intellect and curiosity drove him toward an illustrious career in both medicine
and early scientific exploration, which included experimentation in electrochemistry.
He graduated with a degree in medicine in 1794, setting the course for his lifelong
journey into medicine and early scientific innovation. Coxe broadened his approach
to medicine and science, inspiring him to explore the convergence of scientific
methods and practical applications. John Redman Coxe is most remembered not only
for his contributions to medicine but also for his interest in experimental physics,
particularly in the field of electrochemistry...
TotalTemp Technologies has more than 40
years of combined experience providing thermal platforms.
Thermal Platforms are
available to provide temperatures between -100°C and +200°C for cryogenic cooling,
recirculating & circulating coolers, temperature chambers and temperature controllers,
thermal range safety controllers, space simulation chambers, hybrid benchtop chambers,
custom systems and platforms. Manual and automated configurations for laboratory
and production environments. Please contact TotalTemp Technologies today to learn
how they can help your project.
When I saw this 1966 Radio-Electronics
magazine article entitled, "Vibration
and Shock - Nature's Wrecking Crew," for some reason the first thing I thought
of was "The Wrecking Crew," that anonymously played the music for a huge number
of popular singers - mostly those without prominent bands of their own during the
1960s and 1970s rock-and-roll era. ...but I digress. My introduction to the potential
deleterious effects of vibration on electronics was in the 1970s, with airborne
receivers and servos in my radio controlled model airplanes. Even though they were
transistorized, vibration from glow fuel engines could wreak havoc with potentiometers
in servos and solder joints everywhere, including battery packs. I remember seeing
the control surfaces jitter...
You don't see jobs advertisements like this
anymore. Here is an ad that appeared in the the July 1944 edition of QST
(the American Radio Relay League's, ARRL's, monthly magazine), placed by Raytheon
Manufacturing Company (now just Raytheon Company), looking for
vacuum tube design, test, and processing engineers. Licensed amateur radio operators
were in high demand during the war years because of their knowledge and enthusiasm
for electronics and wireless communications. I hope you didn't come to this page
hoping to really find a tube designer job available. Of course, there are still
vacuum tubes being designed for TWTs and magnetrons, but those are few and far between...
The "carborundum"
signal detector, an innovative device developed by engineer General H. H. C. Dunwoody
in the early 20th century, represents a significant advancement in radio technology,
particularly in the context of crystal detectors used for receiving radio signals.
This device utilized the unique properties of silicon carbide, also known as carborundum,
which was synthesized in the late 19th century by Edward Goodrich Acheson. The connection
between Dunwoody and the material lies in the application of carborundum as a semiconductor
in radio signal detection. The operational theory of the carborundum signal detector
is rooted in its ability to rectify alternating current (AC) signals. When radio
waves, which are essentially electromagnetic waves...
"Researchers have created a cutting-edge
structure by placing a very thin layer of a special insulating material between
two magnetic layers. This new combination acts as a quantum anomalous Hall insulator,
significantly broadening its potential use in developing ultra-efficient electronics
and innovative solar technology. A Monash University-led research team has found
that a structure featuring an ultra-thin topological insulator, sandwiched between
two 2D ferromagnetic insulators, transforms into a large-bandgap quantum anomalous
Hall insulator. This heterostructure opens the door to ultra-low energy electronics
and even topological photovoltaics..."
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It's Election Day 2018, and depending on how the
voting goes, some of us (hopefully not me) are going to need some cheering up when it's
all over. If that includes you, then here is a dose of high tech
POPULAR ELEComics levity to help ease your
"My Side Lost and the World Is Going to End" blues. The first of this set of comics from
a 1967 issue of Popular Electronics magazine could serve as an ironic
tribute to the day. On the other hand, if your side wins and you're on cloud
nine, then I suggest you exercise caution when seeing these comics because the
added joviality might cause you to swoon from overstimulation. Of course if you
are not an American or do not care about elections or happen upon this page
after the 2018 mid-term elections, please enjoy these comics in the usual
manner...
August 16th's custom
Electrical Engineering themed crossword puzzle contains only 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. The technically inclined cruciverbalists amongst
us will appreciate the effort.
Lots of old-time sci-fi movies and TV shows liked
to display
Lissajous patterns on oscilloscopes when an authentic high tech look was
needed in a scene. Every engineer, technician, and physicist in the world - me
included - roll his or her eyes at the sight of such a lame attempt to impress
the public. Of course the truth is the first time I saw a Lissajous pattern
gyrating on an o-scope screen, I was mesmerized. The need to crank on the signal
generator knobs and take control of the electroluminescent object d'art was
overwhelming. Now, in the same manner that watching the first couple Space
Shuttle launches was a thrill not to be missed and then became just another
launch, so, too, is watching a live Lissajous pattern on a scope - it's just
another Lissajous. Except, well, that's not quite so - at least for me. I always
eagerly viewed Shuttle launches...
When most people are asked to name
prolific inventors, people like Thomas Edison and George Westinghouse, with
1084 and 361 each, respectively, come to mind - at least for the United States.
As of this writing, Kangguo Cheng of IBM holds the record with 2039 U.S. patents
assigned. Nikola Tesla had about 300 patents. Lee de Forest, the subject of
this 1937 Radio-Craft article, had a little over 180 patents. That still
qualifies as prolific by my estimation. However, there is more to ranking a person's
inventive worth than the number of patents awarded - like how profoundly his or
her invention(s) impacted the world. For instance, Alexander Graham Bell had a mere
18 patents awarded in only his name, with 12 more shared patents. If you look through
Wikipedia's "List of Prolific Inventors," you will see a lot of names with a lot
of patents assigned, but most of those names are probably unfamiliar. Have you noticed
how many of the old patent art looks like..."
There is an old adage that goes thusly: "If
you want to build an
oscillator, design an amplifier. If you want to build an amplifier, design an
oscillator." Its basis is the difficulty that can be experienced in obtaining the
right combination of feedback phase and amplitude. Of course experience, use of
simulators, and careful circuit construction minimize the opportunity for validating
that saying. The basic requirement for an oscillator is feedback from the output
to the input that is in-phase and great enough in amplitude to maintain, via the
amplifier's gain factor, a constant output level. Tuned L-C (inductor-capacitor)
tank circuits are often used as simple frequency-determining elements because of
their combined resonance characteristics. Phase shift oscillators are a type of
oscillator that can be built without inductors...
When you hear or read "satellite television," you naturally think of a service like DISH
Network or DIRECTV. When encountered in a 1956 Radio & TV News article, you
know "satellite" must mean "(3) someone or something attendant, subordinate, or
dependent." Such was the case for satellite TV locations in areas where, without
a network of microwave relay towers, communities situated where geography inhibited
standard VHF and UHF broadcast signals from reaching sets with sufficient power
were left with no or frustratingly poor reception. Home-based satellite TV as we
know it today began in the mid 1970s with Pat Robertson's Christian Broadcasting
Network broadcast. Artifacts of that ancient time can still be spotted in rural
areas: 10-foot-diameter dishes with eyeballs, smiley faces, or camouflage patterns
painted...
Germanium was "the" semiconductor of
choice in 1959 even though advances were being made with silicon. Most of the newer semiconductor
devices were being fabricated with germanium as the central transducer element. Temperature
sensors, strain gauges, "sensistor" variable resistance units, Hall effect sensors and
gyrators and circulators, torsional (twist) transducers, displacement sensors, and even
neutron detectors were done in germanium. Even though silicon is referenced as being
applicable to all the devices, it was not until the 1960s that silicon began to dominate
semiconductor fabrication. This paper titled ,"From Germanium to Silicon, A History of
Change in the Technology of the Semiconductors...
Always a good way to end a busy week, here
is a collection of
electronics-themed comics that appeared in a 1967 issue of
Popular Electronics magazine. A few of the artists you will recognize if you
are a regular reader. Some drawing styles are immediately identifiable, such as
those by Dave Harbaugh (of "Hobnobbing with Harbaugh" fame). Others, at least to
me, are not quite so familiar. Frank Tabor, George White, Stan Fine, and JAS (I'm
sure I know those initials, but can't place them) are amongst the others. I have
to admit to not really knowing what the gag is in the comic with the guy in his
pajamas. The party guy is cutting a wire to his ear buds ...
"On the
way back to your home state, don't let the door hit ya' where the good Lord split
ya'. Oh, and we'll be sending you a tax bill in appreciation for your selfless sacrifice
in caring for our citizens." That is basically the sentiment of New York's governor,
who after literally begging
out-of-state healthcare workers to come to NY City amongst the Chinese COVID-19
breakout, has declared that his financially mismanaged and cash-strapped state
is going to collect income tax from the aforementioned good Samaritans.
Call me obsessive, but the switch to and
from DST has bugged me not so much for its existence, but for butthead politicians
that won't keep their hands off of it. A few years ago I wrote a piece titled, "A Graphical
Look at Daylight Saving(s) Time," to deal with it, and then again last year
with, "Daylight Saving(s) Time vs. Standard Time." Research the history
of DST and you will see how often Congress has changed the days - always for good
reasons, don't you know. In 1958, the year of my birth, DST began on April 27th
(vs. March 10th this year), and ended on September
28th (November 3rd this year) - See 1958 Old Farmer's Almanac pages. What else can
I say on the matter?
Isaac Newton famously said, "If I have seen
farther it is from standing on the shoulders of giants." His statement was figurative,
of course, but I can now say literally that I have stood on the shoulders of a giant.
Somewhere recently, I don't recall where, I read that although American Radio Relay
League (ARRL) founder
Hiram Percy Maxim was born in New York and spent most of his adult life in Connecticut,
he was buried in Rose Hill Cemetery located in Hagerstown, Maryland. That just happens
to be where Melanie and I stop a couple times each year to visit her mother. We
lived there ourselves for about three years in the early 1990s. That day, I surely
stood if not exactly atop Mr. Maxim's shoulders, then very nearly so as I maneuvered
to take this picture of his grave marker. Why is he buried in Maryland, you might
ask? That is where his wife's family's burial plot is located. Mrs. Maxim was the
daughter of former Maryland senator and governor William T. Hamilton. Hamilton,
in fact, helped establish the Rose Hill Cemetery in the mid 1880s...
It's the Friday before Christmas vacation
and nobody is thinking about work. If you are stopping by RF Cafe to kill time until
the boss lets you go home (early, preferably), thanks for thinking of us. Not that
you really need something to get you in a festive mood, but here are a few funny
amateur radio-themed comics from a 1966 issue of Popular Electronics
magazine, compliments of artist Buz Holland. When I saw the comic with the parrot
squawking CQ while including his call sign - WA4YKK - my first thought was to check
the FCC's Universal License System (ULS) to see to whom it belongs, and then I realized
it was the artist's...
Meteor scatter (aka meteor burst) communications
is today largely the domain of amateur radio operators in their ongoing attempts to set
records for making long distance (DX) contacts with a minimum amount of transmit power.
When this article was written by U. California's Victor Latorre, transcontinental fiber
optic cables did not interconnect the world with high speed, phase stable media that
meets the exacting needs of precise time synchronization. Radio astronomy, quantum physics
experiments, and even stock market trading depends on microsecond or finer timing. Mr. Latorre
mentions here about using
meteor scatter communications' unique phase-stable characteristic to send
synchronization signals between scientific and navigation facilities. Of course
meteor scatter has the severe disadvantages...
This week's
wireless engineering-themed crossword puzzle, as is the case every
week, contains only words pertaining to science, engineering, amateur radio, physics,
mechanics, mathematics, etc. Making a special appearance is the name of the most
recent company to support RF Cafe through advertising. You will see their banner
graphical ad appearing in the right page border sometime this week ...
Electronics magazine editor Lewis H.
Young dedicated a series of issues in 1965 to reporting on the state of
electronics research and production in Japan. The December 13
edition had many articles on the subject. The world was still in the early phase
of a major transition from vacuum tubes and discrete components to transistors and
integrated circuits. Japan was at the leading edge of that effort - and it was very
successful. Ample evidence of the not-quite-there-yet status of the transition is
all the advertisements in this edition of the magazine. Products showcased by manufacturers
were discrete, not integrated - that applies to both electronic and mechanical subjects.
When you look at those components and assemblies, you get feel for what made them
work because the individual parts are in view. Many modern products are integrated
into packaged and tested subassemblies that are ready to be integrated...
Beginning in 2000, I have created hundreds
of custom technology-themed crossword puzzles for the brain-exercising benefit and
pleasure of RF Cafe visitors who are fellow cruciverbalists. The jury is out on
whether or not this type of mental challenge helps keep your gray matter from atrophying
in old age, but it certainly helps maintain your vocabulary and cognitive skills
at all ages. A database of thousands of words has been built up over the years and
contains only clues and terms associated with engineering, science, physical, astronomy,
mathematics, chemistry, etc. 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 start like Hedy Lamarr or a geographical
location like Tunguska, Russia, for reasons which, if you don't already know, might
surprise you...
If there was another episode of
Mac's Radio Service Shop where Barney was the primary teacher
and Mac was the student, I don't remember what it was. In fact, this is about as
total of a role reversal as there can be. First, Mac admits to having chased a presumed
oscilloscope issue down the proverbial rabbit hole only to realize the cause of
the problem was totally unrelated. Then, Barney produces a nifty device meant for
recording telephone conversations and demonstrates to Mac a couple ingenious applications
he discovered that were handy for troubleshooting television sets. When reading
Mac's description of using a magnet to alter the electron beam in a CRT, it reminded
me of how cool it was on the CRT displays to run a magnet ...
Sometimes, component datasheets can be pathetically
lacking in detail for parameters that you might think would be a minimum amount
of information needed in order to integrate the device into a circuit or system.
Or, it may be that you found a part in a spare parts box and can't find a datasheet
for it. When those times come, it is necessary to characterize the part yourself.
Relay control really isn't rocket science when it comes to electrical
circuits, but there are a few rules of thumb that should always be observed, the
most important of which (other than not exceeding voltage and current maximums)
is to wire a diode reverse biased across the coil terminals so that the
voltage/current induced due to the field collapse during de-energizing does not
smoke the driver circuit...
Radio-Craft magazine solicited inputs
from its readers for a series of 'WittiQuiz'
questions and answers related to radio and electronics, with a stipulation being
that there had to be some aspect of humor included. That meant that some of the
multiple choice answer options needed to be inane. For most of the questions, the
process of elimination is pretty easy, but a couple could cause some head scratching
- especially if you are not really sure of the answer. This group starts at number
28, so obviously preceding issues had questions 1 through 27. At some point I will
probably acquire them and post other WittiQuizzes.
Until the last couple decades, people of
the world recognized and called out evil by name when it reared its ugly head. Except
for subversive imbedded agents, media outlets - radio, television, print, speeches,
etc. - openly and vigorously condemned and attacked the enemy of its country's traditional
way of life. The theme ran deep and wide in news reports and in magazine features.
This advertisement for Air Adventures magazine which appeared in early 1940s
Radio News magazine is an example. In the place of politically correct
speech that doesn't dare to offend an entity which openly and maniacally seeks to
kill you we had the vast majority of media promoting nationalism and patriotism
in order to defeat the enemy. As with just about everything, eBay is a good source
of these vintage Air Adventures magazines. This particular publication only
ran for three editions. However, there were plenty of other titles that featured
stories of heroic adventures against the Nazi scum ;-) Flying Aces magazine... |