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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There is little incentive to build your own
field strength meter these days when commercial instruments are readily available
and relatively inexpensive. For instance, you can buy an MJF-801 FSM with a 100 kHz
to 500 MHz spectrum coverage for just $45, brand new. More sophisticated, calibrated
instruments are available for a lot more, but this basic unit is dirt cheap. However,
if you want to read a little about the theory behind a field strength meter and
see how one goes together, this article from a 1960 issue of Popular Electronics
magazine provides that opportunity...
Selecting the proper antenna for a particular
application can mean the difference between success and failure when any combination
of signal strength and/or signal interference is involved. Modern spread spectrum
technologies has eased the job a bit, but there are still instances when high gain
and/or directivity is necessary. You might be tempted to say that gain and directivity
are essentially the same thing, and to some extent that is true. However, in the
case of needing to minimize signal interference from surrounding sources, a
directional antenna might be utilized not due to a need for increased
desired signal strength but to reduce the power of undesired emitters. Such was
often the requirement for television and FM radio reception. After years of needing
to reorient the folded dipole antenna for my FM radio because...
The old-time radio broadcasts available on
the Internet are obviously recorded version of shows made long ago. However, back
in the day those shows were
originally performed live in front of microphones and recorded
in a broadcast studio. With a cast of two or three or even more, the actors would
voice their lines with as much talent and effort as those performing for movies.
The crew usually included a group of people responsible for creating background
sound effects like horses running, car horns tooting, airplanes buzzing by, and
dogs barking. All was done real-time with split-second timing required to pull it
off and sound convincing. Radio audiences were unaware of all the work required
as they sat intently listening to the Adventures of the Lone Ranger and The Shadow.
Behind the scenes were dozens of engineers and technicians tending local radio broadcasting
equipment and all-important telephone landlines used for synchronizing stations
across the country...
Some of us like seeing the old advertisements
from vintage era magazines. This
Taylor Tubes advertisement from the February 1941 edition of the ARRL's
QST magazine is a prime example. Vacuum tubes had a high degree of automation
for stamping out internal components, forming the glass shells and evacuation of
the air, but they still required human production line operators for assembling
the components prior to being encapsulated and sealed. National Instruments hadn't
invented LabVIEW yet to run the testing station, so people manually placed the tubes
into a board full of sockets for burn-in and testing...
Here is a little technology humor to help
easy you into the week ahead. Ironically, the themes of the three
comics (by three separate artists) represent an evolution of the
electronics realm over the past few decades, although almost certainly not
planned by the editors. The first has to do with a couple TV servicemen
installing an antenna, the second is of an out-of-work TV repairman, and the
third is what might be considered a drone by today's norms. There is a huge list
of other comics at the bottom of the page...
Dr. Allen Du Mont played a huge role
in making television practical because of the improvements he made to the cathode
ray tube (CRT). Prior to his work, the lifespan of a CRT was measured in tens of
hours, and they were expensive, so their use was limited to special military and
research applications. Du Mont's interest in "wireless" began at an early age,
and he earned his commercial radio operator's license at the age of 14 (in 1915).
He designed and produced oscillographs (i.e., oscilloscopes) that incorporated his
CRTs. His involvement in the television industry was a natural evolution and extension
of the work done in related industries. The DuMont Television Network was formed
in 1942, rivaling the established CBS and NBC...
Prior to the availability of affordable
synthesized transceivers under microprocessor control, Ham radio operators needed
to tune a continuously variable local oscillator (internal or external) or have
a selection of crystals for specific frequencies. Even by 1982 microprocessors were
relatively expensive, so equipment incorporating them was also pricey. Heathkit's
model
SS-9000 transceiver claimed to be designed by amateurs for amateurs, and was
"so feature-conscious, it has no options." That's right, anything and everything
that could be imagined was included in the base model; there we no upgrades. It
used a high accuracy and stability internal 10 MHz reference oscillator for
the PLL synthesizer. Also incorporated was an RS-232 serial port for control via
computer (up to 9600 baud!), such as the Heathkit/Zenith personal computer (the
IBM PC had hit the market in the prior year, and the the Radio Shack TRS-80
and Apple II had been around since 1977). The SS-9000 was solid state throughout
(likely where the "SS" prefix originated)...
One aspect of advertising on the RF Cafe
website I have not covered is using
Google AdSense.
The reason is that I never took the time to explore how - or even whether it is
possible - to target a specific website for displaying your banner ads. A couple
display opportunities have always been provided for Google Ads to display, but the
vast majority of advertising on RF Cafe is done via private advertisers. That is,
companies deal with me directly and I handle inserting their banner ads into the
html page code that randomly selects and displays them. My advertising scheme is
what the industry refers to as a "Tenancy Campaign," whereby a flat price per month
is paid regardless of number of impressions or clicks. It is the simplest format
and has seemed to work well for many companies. With nearly 4 million pageviews
per year for RFCafe.com, the average impression rate per banner ad is about 225,000k per
year (in eight locations on each page, with >17k pages)...
We
read a lot about the early
radar system that was in operation at Pearl Harbor in December 1941 when the
surprise attack by Japanese naval airplanes decimated the fleet with a 3-hour-long
raid beginning at around 8:00 on that sleepy Sunday morning. According to "The Untold
Pearl Harbor Radar Story," by C.P. West, the SCR-270B (Signal Corps radio #270,
rev B) radar system had a range of 250 miles at an altitude of 50,000 feet. Westinghouse
built the system in 1940 following a development contract issued by the Army Signal
Corps in 1936. Historical documents report of the three systems on the island, two
had been shut down and that with the remaining system, operators Joseph Lockard
and George Elliot detected a formation of aircraft about 137 miles out to sea. They
were told it was a squadron of B-17s and to not worry about it...
Randy Rogers*, AD7ZU, mentioned in the May
2020 issue of QST magazine the Smith Chart software called "SimSmith,"
by Ward Harriman, AE6TY. SimSmith first appeared around 2011. Being written in Java,
it will run on any operating system that supports Java (Win64, Win32, Apple Mac
OS X, Solaris, and Linux). If you are using Win64 as I am, you will want to download
the "windows64-with-JRE.exe" file. Windows security will try to block it, but it
is safe to run after your antivirus program scans it and gives a green light. AE6TY
recommends using the installation files rather than just downloading the "SimSmith.jar"
file even if you already have a version of Java installed. When launching the program,
the window might not be very large, so grab a corner and stretch it out so the components
are easier to see. After playing around with SimSmith for a while, you might want
to click on the "SimSmith->preferences" menu selection...
This is the final installment of an 11-part
series in Radio News magazine entitled "Theory
and Application of U.H.F.," written by Milton Kiver. It spanned from December
1943 to June 1945. Topics included basic electrical, magnetic, and electromagnetic
theory, cavity resonators as tuning units of klystron and magnetron oscillators,
waveguide, free space propagation, high frequency amplifiers, transmission lines,
and coupling energy to/from cavity resonators. As the list suggests, there was a
great concentration on field theory. Being that the Radio News readership covered
a broad range of experience and education, Mr. Kiver went light on use of equations
and heavy on use of diagrams, charts, and textual descriptions. Everything described
throughout the series is as valid and applicable today as it was 75 years...
A series of three articles appeared in 1973 issues
of Popular Electronics that conducted a high-level review - or introduction if you've
never seen it before - of DC circuit analysis. In this first installment, Professor Arthur
Seidman, of the Pratt Institute, covers a variety of subjects starting with
direct current (DC) circuit theory. Ideal current and voltage sources, units and
notations, Ohm's law, Kirchhoff's law, resistors, capacitor and inductor charge and discharge
curves, series and parallel circuits, power calculations, conductance, and other good
stuff is covered. There is even (gasp) a bit of calculus presented...
An article with instructions relating to
subjects like overthrow, balance, friction, and cleaning could very well be about
a country's revolutionary struggles. In this case, it is an article about how to
rejuvenate a persnickety or inaccurate mechanical (aka analog)
meter movement. W.R. Triplett, relative (I assume) of meter manufacturer Ray L.
Triplett, is the author (Triplett is now owned by Jewel Instruments). There are
a lot of analog meters around in labs, workshops, and garages. Unless they have
been burnt out, most probably still work like new. Occasionally, however, the movements
get sticky because of accumulations of dirt and dust, bug filth, or even from corrosion.
This article offers some great tips for making them serviceable again...
This entire page has been reworked to make
the denormalization
of prototype lowpass filter component values much easier to understand. I have received
numerous questions about the process over the years, particularly regarding the
swapping of capacitor and inductor values for highpass transformations. Bandpass
and bandstop transformations can be equally confusing. The original page pretty
much regurgitated the kind of presentation made by many textbooks, but this new
format should make amply clear the transformation from normalized lowpass component
values ...
In all-too-typical style, the Federal Communications
Commission (FCC) decided to look for a scapegoat it could not just blame for but strong-arm
a solution for claimed problems plaguing
Citizen Band (CB) radio as it was rapidly becoming a popular hobby in the
1960s. In the same manner in which bureaucrats blame gun and steak knife
manufacturers for the abusive actions of a minority of their products' users,
the FCC sought to curtail improper (maybe even illegal) operation of CB radios
by imposing type certification and feature restrictions on equipment
manufacturers. To demonstrate its magnanimity , though, the FCC offered to give
companies half a year to deplete their existing inventories. At the time and
through 1977, CBs had 23 channels, after which time 40 channels became the new
mandate... Friday 17
Dang, I swapped two answers and scored an
80%. Haste makes waste, as the saying goes. Don't rush through this 1967 Popular
Electronics "Electronic Angle Quiz" like I did and you'll probably ace it with
the greatest of ease - especially if you have been in the electronics realm at least
since the 1980s. Generation X'ers can have a two-question handicap (might never
have seen real-life example of drawing "A" or "E") and Millennials (might never
have seen drawing "A," "B," "D," or "H") get a four-question handicap...
There was a time that selecting a
television antenna was as important to the quality of life as buying the right
smartphone is today. There were probably as many choices in antennas then as there
are phones now. You might think, especially if you are not an amateur or military
radio operator, that nobody worries about antennas anymore, but as I've written
before there is a slight resurgence in people installing the old fashioned multi-element
antennas for receiving local television and radio stations. The market's not huge,
but seems to be keeping companies like Channel Master in business. Incidentally,
in contrast to my aforementioned comment, dig the opening sentence of the article:
"Virtually no one in this day and age goes about discussing the reception quality
of his telephone."
By the beginning of 1945 when most people
believed the War was all but won, the national and global attitude began to shift
from a wartime footing back to a commercial and domestic mindset. For the Axis powers
the prospect was one of shame and contrition, while knowing that unlike if they
had been the victors, Allied nations would deal harshly only with the leaders of
the aggression and destruction while showing mercy, humanity, and graciousness to
the general populations. In fact we became very good friends with Germany, Italy,
and Japan in the years immediately following their respective unconditional surrenders.
As the end of hostilities neared, information began being released by the government
about some of the previously closely guarded secrets of technical developments in
the previous half decade - such as the
radar systems covered in this October 1945 issue of Radio-Craft magazine...
Here for your New Year's Eve entertainment
is a new-old adventure story of "Carl & Jerry" titled, "Stereotaped New Year." In the same
manner that author John T. Frye's highly regarded "Mac's Radio Service Shop"
technodramas had themes echoing the time of year they were published, this appeared
in the January 1963 issue of Popular Electronics magazine, which would
have arrived in subscribers' mailboxes in December. Carl & Jerry, if you are
not familiar with the dynamic duo of the teenage electronics and Ham radio enthusiasts,
routinely got themselves involved in police investigations, creature comfort inventions,
and practical jokes involving tape recorders, disembodied spirits, and remote controlled
models. By 1963, they were out of high school and matriculating at "Parvoo University,"
which many people believe is a reference to Purdue University, given the boys' Midwestern
locale. Admittedly, this plot...
Dr. Scott Best, of SiberSci RF
engineering services, sent information about the FREE general purpose
DISLIN scientific
and engineering plotting software library that includes Smith Chart support.
The graphics library was initially created at the Max Planck Institute for Solar
System Research beginning in 1985 by Mr. Helmut Michels. Its continual series
of upgrades is as recent as May 2020. The DISLIN library is available for Unix,
Linux, FreeBSD, Windows, Mac OSX, and MS-DOS systems. It supports a variety of public
domain and commercial compilers for Go, Perl, Python, Java, Ruby, TCL, Julia, FreeBASIC,
Free Pascal, R, C/C++, and Fortran (77, 90, and 95). If you are a software developer,
you probably know that most development platforms are supplied with either no plotting
components or very rudimentary versions of for-purchase products. Many cost hundreds
or even thousands of dollars... |