I know a guy, a multi-decade-long Amateur
Radio operator, who at one time was a big participant in
TV DXing. For those who are not familiar with the techno-sport, TV DXing is
the hobby of receiving and identifying distant television broadcast signals from
far-off locations, often using specialized antennas and receiving equipment. Enthusiasts
seek to capture signals from stations hundreds or even thousands of miles away,
which requires advanced technical skills and sophisticated reception techniques.
Modern-day DX-ers typically document their reception achievements by capturing screenshots,
logging station details, and sharing their findings with other hobbyists through...
• FCC Toughens Stance on
Pirate Radio
• Mobile Operators Bemoan
$109B Infrastructure Cost
• 5G Adoption Grows,
LTE
Remains Strong
• China
to Host World Radio Conference?
• Intel
Delays Ohio Fab Till 2030
Most of us have heard of the National Association
of Broadcasters (NAB). Founded in 1922 at the dawn of commercial radio broadcasting,
it is still in existence today. When commercial television broadcasting "stepped
out" in a major way in the early 1940s, industry chieftains and station owners decided
that their new media paradigm was unique enough to warrant a separate union, so
the
Television Broadcasters Association (TBA) was formed. A lot of
effort went into establishing and building a coalition with enough influence in
the marketplace and with government regulators, independent of radio, to exist as
a force to be dealt with. Many people believed that radio as an entertainment and
news media source would decrease at a rate as great or greater than television was
increasing. Once again, experts were not successful at predicting behavior of the
citizenry, which was true both in the United States and around the world...
Windfreak Technologies designs, manufactures,
tests and sells high value USB powered and controlled radio frequency products such as
RF signal generators, RF synthesizers, RF power detectors, mixers, up / downconverters.
Since the conception of WFT, we have introduced products that have been purchased
by a wide range of customers, from hobbyists to education facilities to government
agencies. Worldwide customers include Europe, Australia, and Asia. Please contact
Windfreak today to learn how they might help you with your current project.
The December 1969 issue of Radio-Electronics
magazine's "New & Timely" column reported that at the National Electronic Association
conference,
technicians reported burns and eye damage caused by X-radiation from color TV sets
under repair. Night vision scopes for commercial use were introduced by Raytheon,
suitable for law enforcement, industrial security, and nature study. A joint U.S.-Indian
plan planned to beam TV directly to millions of Indian villagers via a stationary
applications satellite in 1972. The French Atomic Energy Commission used a superpowerful
laser to create minute thermonuclear explosions, fusing deuterium...
Anatech Electronics offers the industry's
largest portfolio of high-performance standard and customized
RF and microwave filters and filter-related products for military, commercial,
aerospace and defense, and industrial applications up to 40 GHz. Three
new filter models have been added to the product line in April, including a 5500
MHz WiFi cavity bandpass filter, a 3437-3537 MHz ceramic duplexer filter, and a
1425 MHz cavity bandpass filter. Custom RF power filter and directional couplers
designs can be designed and produced with required connector types when a standard
cannot be found, or the requirements are such that a custom approach is necessary...
This article published in a 1955 issue of
Popular Electronics magazine is a really good primer on the history and
working principles of the
electron microscope. It also explains why such a device is needed;
i.e., why an optical microscope cannot do the job when really high levels of magnification
are required. As object dimensions are spaced at distances near to or less than
the optical wavelength being observed, it becomes impossible to resolve into separate
features. Accordingly, when observing at the upper end of the visible light spectrum
at around 400 nm, under ideal conditions you would not be able to clearly discern
two feature less than about 800 nm apart. Current (2019) CMOS gate thicknesses
run about 5 μm, so visible light cannot be used to image those structures.
Another resolution limiting factor is aperture size, which, depending on the wavelength
causes diffraction patterns of two objects to overlap...
If you are a seasoned vintage electronics
equipment aficionado, restorer, hobbyist, etc., then you most likely already have
your own list of supply sources for vacuum tubes. Contrary to what others might
think, there is still a healthy stock of tubes available from private websites like
Pacific T.V. (hat tip to Bob Davis), as well
as collective sites like eBay, Facebook Marketplace, Craigslist, and vintage electronic
equipment forums. Prices for common tubes are surprisingly low if you shop around.
If you need an output power amplifier for a commercial radio station, be prepared
to shell out major wampum, though. Many NOS (new old stock) varieties in original
boxes can be had, as well as used tubes. Most have been tested for specification
compliance.
Westinghouse is yet another bulwark company
of America's foundational industrial age, beginning in the late 19th Century. George
Westinghouse founded eponymously-named company,
Westinghouse Electric & Manufacturing Company, in 1886, during the time
he was working with Nikola Tesla (I wonder whether any of the current-day anti-Tesla
nimrods are stupid enough to vandalize NT statues and monuments?) to institute a
commercial electrification infrastructure. Mr. Westinghouse began his life
of fame and fortune with a locomotive air brake design. During World War II,
Westinghouse's many locations designed and manufactured many types of products to
facilitate troops in all Theaters of Operation. This 1943 issue of Popular Mechanics
magazine carried a full-page...
This set of three circuit analysis challenges
appeared in the January 1963 issue of Radio-Electronics magazine. Readers,
staff, and even come companies submitted the "What's
Your EQ?" (EQ = Electronics Quotient) content. As an example of the latter,
Cleveland Institute of Electronics provided "Draw the Waveform." Don't let the diode
vacuum tube deter you from the puzzle. Just mentally replace the tube with a solid
state diode symbol with the anode at the top where the tube's plate (anode) is shown.
The negative element of a tube is called the cathode, same as the solid state diode.
"Capacitor Charge" is easy enough. "Another 2-Box Light"...
"Despite increasingly intense competition
for skills across all sectors of industry and a growing appetite amongst engineers
for a new challenge, engineering salaries appear to have stagnated over the past
12 months. This is just one of the key findings of The Engineer's tenth
annual salary survey, which is published in full on The Engineer's website
in a new interactive digital format. Attracting responses from 621 engineers working
across 12 different sectors, this year's survey was carried out between December
2024 and January 2025. As ever, the results provide a fascinating insight into
UK engineering salaries and how engineers are feeling about their careers..."
In this 1963 issue of Radio-Electronics
magazine, editor Hugo Gernsback reflects on the early days of television, noting
that the first regular daily TV broadcast began on August 13, 1928, over radio stations
WRNY and W2XAL, which were associated with his former publication, Radio News.
Initially, these
broadcasts were silent, featuring only moving images the size of a postage stamp,
and it wasn't until 1931 that TV broadcasts included sound. Gernsback critiques
the slow progress in improving the audio quality of television receivers, pointing
out that despite advancements in high-fidelity and stereo audio technology, most
TV sets still lacked these features due to regulatory restrictions by the FCC. He
expresses hope that recent petitions to the FCC...
Exodus Advanced Communications, is a multinational
RF communication equipment and engineering service company serving both commercial
and government entities and their affiliates worldwide. Exodus' model
AMP20081 high power solid state power amplifier (SSHPA) is ideal for broadband
EMI-Lab, communications, and EW applications. Class A/AB linear design accommodates
all modulations & industry standards. It covers 80-1000 MHz, producing
600 W nominal, with a 500 W P1dB and 56 dB minimum gain. Excellent
flatness, optional monitoring parameters for forward/reflected power, VSWR, voltage,
current & temperature sensing for superb reliability and ruggedness...
In that these
comics from Radio-Craft magazine have an electronics
theme, you can claim looking at them is work-related. The themes of the comics reflect
common scenarios of the 1944-1945 era in which they were published, but with not
much modification can be applied to today's environment. People will always expect
more features from products, will be critical of everything presented to them, and
will want to haggle for the best deal from the used camel salesman. You might consider
using one of them for your next conference or project status presentation. There
is a list of many more similar comics at the bottom...
In a groundbreaking announcement that will
forever transform global communications, QentComm®©™ (Quantum Entanglement Communications)
has unveiled the world's first
commercially viable quantum entanglement communication system. Dubbed QeG®©™
(Quantum entanglement Generation, pronounced kwee-gee), supplementing the traditional
4G, 5G, and 6G nomenclature, this revolutionary technology eliminates the limitations
of traditional radio-based systems, delivering instantaneous, unlimited connectivity
across any distance without reliance on satellites, cell towers, or fiber optics.
Under the leadership of Kirt Blattenberger, QentComm (pronounced kwent-kahm) has
created a system that defies conventional physics by utilizing quantum entanglement
for real-time, secure communication between devices anywhere in the universe - including
here on Earth...
In this "Carl & Jerry" technodrama from
a 1957 issue of Popular Electronics magazine, the two boys start out enjoy a casual
day of kite flying, using a homebrew radio-controlled camera attached to the kite
to capture an aerial view of Round Island in a lake. After successfully taking a
picture, they develop the film and discover two men and an odd setup on the island.
Curious, they return the next day, find a hidden tunnel, and stumble upon an illegal
liquor still. As you might expect, the teens run into a heap of trouble when the
moonshiners nab them. Using their combined ingenuity and knowledge of communications
methods common to Ham radio operators of the era, contact was made and help was
on the way. Read about Carl and Jerry's exploit and exactly what it was that saved
the day - and their hides!
"In late January 2025, 17 students and staff
members from Las Animas High School (LAHS) in Colorado visited the
Deep Space Exploration Society Radio Telescope (DSES) located at the Plishner
Radio Astronomy and Space Sciences Center near Haswell, Colorado. They also got
an introduction to amateur radio. 'This first field trip visit of high school students
reflected the dreams of Michael Lowe, former DSES board president, who sought to
create a center for radio astronomy and space science education in southeast Colorado,'
said DSES President Myron Babcock, KL7YY..."
Making format changes to magazines after
many years of an established standard always ruffles the figurative feathers of
a significant portion of regular readers. Two magazines I read monthly, Model
Aviation and QST, recently underwent a format change - both of which
I considered very nice. However, reader comments in the aftermath showed a few who
were not impressed. Popular Electronics magazine in 1966 made announcements
regarding plans to adopt some of the
newer base units for physical measurements, including this one for beginning
to use "Hertz" (Hz), along various numerical prefix forms, instead of "cycles per
second" (cps). The editors give sound reason...
The
Beverage Antenna, very familiar to amateur radio operators, is
a simple but efficient, highly directional, non-resonant antenna that consists of
a single straight wire of one or more wavelengths that is suspended above the ground.
It is orientated parallel to the direction of intended reception. One end is terminated
to ground through a resistor, and the other is connected to the receiver. The following
quote comes from the patent (US1,81,089) text: "In accordance with theoretical considerations,
if an antenna were to be freely suspended and if the surface of the earth constituted
a perfectly conducting parallel plane, current waves would travel through...
This letter was sent to Hugo Gernsback,
publisher of Radio-Electronics magazine, in response to the "30-Day
Record Response" article penned by noted scientist and inventor Mohammed Ulysses
Fips. In it, Stephen A. Kallis, Jr. heaped laud upon the "Most Revered and Esteemed
Fips" for his long-term recording device (remember, 1961 was many decades before
microminiature terabyte memory and microprocessors) were available, and chastises
Mr. Gernsback for evidently calling into question the authenticity of the recorder.
Kallis, a self-proclaimed stereo enthusiast, bolsters Fips' case by citing "A Proposed
Listening Area," by the Institute of Synergistic Statics Proceedings...
Raise your hand if you're old enough to
remember doing printed circuit board layout using
Rubylith tape. My hand is up. Back in the early 1980s, I did prototype
PCB designs in an engineering development lab at Westinghouse Electric's Oceanic
Division. Most of it was for analog and RF substrates that would be photographically
reduced in size for use with bare integrated circuit die and surface mount passive
components (Rs, Ls, and Cs), upon which I would later epoxy-mount those components
and wire-bond everything using 1-mil gold wire. However, there were projects where
full-size leaded components were used on a through-hole PCB that used not only the
Rubylith tapes but also sheets with special electronics shapes for solder pads around
the holes for components leads, ground and power planes, board-edge connectors...
"Quantum systems don't just transition between
phases - they do so in ways that defy classical intuition. A new experiment has
directly observed these
dissipative phase transitions (DPTs), revealing how quantum states shift under
carefully controlled conditions. This breakthrough could unlock powerful new techniques
for stabilizing quantum computers and sensors, making them more resilient and precise
than ever before. A new frontier phase transitions, like water freezing into ice,
are a familiar part of everyday life. In quantum systems, however, these transitions
can be far more extreme, governed by principles like Heisenberg's uncertainty..."
In
this November 1940 issue of the Boy Scouts Boys' Life magazine, amateur
radio operators, or "hams," are described as having the ability to communicate across
vast distances, connecting far-flung locations such as Goulds, Florida, Cali, Colombia,
Cairo, Kenilworth, England, Bombay, and Brisbane. These operators, licensed by the
Federal Communications Commission, engage in various activities such as talking
to distant stations, participating in contests, and providing emergency communication
during natural disasters. With call letters assigned by international treaty, these
stations use a combination of code and phone to make contact, exchanging reports
and QSL cards. The
Radio merit badge was first offered in 1918 and has been...
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and phased matched VNA applications as well as standard & precision RF connectors.
Over 1,000 solutions for low PIM in-building to choose from in the iBwave component
library. They also provide custom coax solutions for applications where some standard
just won't do. A partnership with Newark assures fast, reliable access. Please visit
ConductRF today to see
how they can help your project!
The date approacheth when, according to
Western customs, every body needs to stand a vigil against the attempt of another
body to make him or her a fool. That date is of course April 1st, aka, April
Fools' Day. Many of the technical magazine we grew up with - and some still today
- engage in the ruse. Innovator and publisher Hugo Gernsback, who's long list of
accomplishments includes this Radio-Electronics magazine, often contributed
his own wit to the April editions. The usual scheme is to make the article just
authentic enough to be possibly real, while including features outrageous enough
to clue the read that he is being "had." Experienced subscribers knew that the Mohammed
Ulysses Fips byline was sure to deliver an April Fools delight. Here, Mr. Fips
expounds on the newfangled "Electronics
Razor..."
Here is a chart you don't see every day
- "Temperature Rise in Rigid Waveguide." The company, Engineering
Antenna Systems, of Manchester, New Hampshire, that published the chart in a 1965
edition of Engineering magazine, does not exist anymore. They were probably
bought by someone else, but I could not even find an honorable mention of them in
a Google search. Given the very low attenuation of properly sized and installed
waveguide, it is hard to imagine a temperature rise of 500°F; however, when megawatts
are pumped into it even a couple tenths of a decibel of attenuation per 100 feet
results in a lot of power loss. Noted is how attenuation - and therefore temperature
rise - is greater for frequencies at the lower end of the waveguide's operational
range. Temperature rise numbers are for natural convection in free air...
|
');
//-->1821: Linus Yale, inventor and manufacturer of locks, including the cylinder or pin-tumbler lock known by his name, was born. 1826: Zenobe-Theophile Gramme, inventor of the Gramme dynamo, was born. 1850: The city of Los Angeles was incorporated. 1876: Alfred Nobel... more
"Why the Tube Shortage" was not a question
being asked by Radio-Craft magazine editor Hugo Gernsback, it was an explanation.
It is similar to the present day situation with the "Global Chip Shortage" in all
the headlines being blamed on the Wuhan Flu plandemic (sic) causing a worker shortage.
It has affected everything from the production of smart watches to kitchen appliances
to cars and trucks. In 1946, however, the cause of the
vacuum tube shortage was a multi-faceted ordeal according to investigative work
by Mr. Gernsback. Service shops were accusing tube manufacturers of favoring
radio production companies while radio production companies accused the tube manufacturers
of favoring service shops. The truth, ostensibly, was that the federal government
still laid claims to a large portion of tube manufacturing for post-war defense
needs, and at the same time labor strikes were crippling production lines...
Amateur radio operators (Hams) and electronics
hobbyists are always on the lookout for a good deal on a good piece of test equipment
(TE). One way to accumulate a budget minded bench of TE is to find a way to combine
the functions of separate pieces to effect a new instrument. This
RF wattmeter was R.A. Thomason's method. It uses a simple application of
Ohm's law for converting electrical current into power values using a bank of
high power resistors and an external ammeter. Hand-dandy conversion charts are
provided for two different values of detector resistors, but the scales could
easily be changed to accommodate any resistor value. Note that the power
dissipating resistor bank is composed of two series-connected sets of eight
parallel-connected...
Echo 1 was put into orbit on August
12, 1960. This article was written 2½ years earlier in 1958 by Radio-Electronics
editor Hugo Gernsback. A technology visionary and prolific inventor and writer,
Mr. Gernsback astutely outlined the vast number of advantages that had already been
and would in the future be afforded the science community by virtue of a satellite's
perspective from space. Two of the Soviet Union's
Sputnik satellites had revealed the surprisingly irregular shape and gravitational
influence of the Earth, information about the upper atmosphere, and aspects of space
environment effects on radio communications. America was scrambling to catch up.
Gernsback and others postulated the configuration of active relay transceivers powered
by solar cells and storage batteries, satellite-based television and radio...
Listen to the RF
Cafe Podcast! A November edition of "Mac's
Radio Service Shop" is appropriate given today's date, especially since author
John T. Frye nearly always had the story's setting coincide with the month
in which it appeared in Radio & Television News magazine; the year
was 1951. The unspecified dateline is somewhere in the upper Midwest, most likely
Indiana. Mac's mention of converting a black-and-white television set to color by
installing a "color wheel" really betrays the era. The NTSC (National Television
System Committee) had not yet adopted an industry standard for color TV, and the
various manufacturers were selling a mix of mechanical, electro-mechanical and all-electronic
sets. In 1953, the NTSC settled on a 525-line interlaced scan (only 468 lines are
part of the visible scan). Knowing that a better color system would be available
soon due to massive public demand, Mac put his efforts into talking customers out
of a color conversion...
Today, if Rohde & Schwarz, Keysight,
or some other major test equipment manufacturer announced during a trade show presentation
a new oscilloscope model with a "Breakthrough!" featured dubbed "Cali-Brain®," they would be laughed off the stage. The technology
truly was a breakthrough in terms of displaying peak-to-peak waveform measurements
in a numerical presentation along with a cursor line indicating the pk-pk extent
from the display. It was not as convenient as next-generation scopes that provided
a movable horizontal pair of lines with a direct digital voltage difference readout,
but it did take some of the guesswork and potential error out of readings on complicated
waveforms. Of course modern microprocessor-based measurements...
The high-tech vehicle you see here was state-of-the-art
in 1935 when engineers at the
Cruft Laboratory at Harvard University outfitted it to do radio
research. The story appeared in QST magazine. The mission of the mobile unit is
to enable laboratory equipment to be carried into the field to make observations
on various radio phenomena. Clad with copper and chromium fittings, the vehicle
contained transmitting and receiving equipment along with various test equipment
that included a high stability frequency reference. In the article a "tungar" charger
is mentioned. A tungar vacuum tube is a high current rectifier with a tungsten element
and an argon gas filler...
For the sake of all the avid cruciverbalists
amongst us, each week I create a new
technology-themed crossword puzzle using only words from my custom-created
list related to engineering, science, mathematics, chemistry, physics, astronomy,
etc. At least 10 clues with an asterisk (*) in this technology-themed
crossword puzzle are pulled from the past week's (7/30 - 8/3) "Tech Industry Headlines"
column on the RF Cafe homepage. 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, see someone or something in the exclusion list directly related
to this puzzle's theme, such as Hedy Lamar or the Bikini Atoll, respectively. Enjoy!...
By now, most people involved with spread spectrum
communications are (or should be) aware that Hollywood starlet
Hedy Lamarr is credited
for being the first to suggest a frequency hopping scheme for secure communications.
If you do a Google search on Hedy Lamarr and spread spectrum, you see that except for
a few mentions on tech websites, it has only been in the news since the end of the last
decade. Scientific American magazine ran an article titled, "Hedy Lamarr: Not
Just a Pretty Face," in 2008. Google honored her in 2015 with a Doodle on their homepage.
"The most beautiful woman in the world," with the assistance of her co-inventor-composer
George Antheil...
Prior to the invention of gas (CO2,
HeNe) and chemical (iodine, hydrogen fluoride) lasers in the early to middle 1960s,
lasers (light amplification by stimulate emission of radiation) were made using
rare earth gems (ruby). Evolution occurred rapidly in power output, wavelength (color),
stability, purity, and lasing source type.The concept of lasers were introduced
in science fiction, but believe it or not the first recorded instance of the term
"LASER" was in a paper written in 1959 by Gordon Gould. Development flowed from
the preexisting maser (microwave amplification by stimulate emission of radiation)
knowledge. This 1960 news item in Electronics World magazine reported on
Dr. Theodore H. Maiman's work at Hughes Research Laboratories. Nowadays lasers are
ubiquitous in our lives (DVD players, automotive LIDAR, cat toys) and we have lasers
integrated into semiconductor substrates for intra-chip signal communications...
This quiz is based on the information presented
in Introduction to Antenna Analysis Using
EM Simulation, by Hiroaki Kogure, Yoshie Kogure, and James C. Rautio, published
by Artech House. It is written for novice engineers and engineering students. This
easy-to-comprehend resource offers readers thorough introductory-level treatment
of antenna analysis using electromagnetic (EM) simulators. This richly-illustrated
book shows how to use EM software to analyze and tune wireless antennas to meet
specific requirements. Readers learn important wireless antenna design terminology
and gain a detailed understanding of how antennas work. Moreover, the book offers
guidance in troubleshooting problems with wireless antenna designs...
Banner Ads are rotated in all locations
on the page! RF Cafe typically receives 8,000-15,000 visits each
weekday. RF Cafe
is a favorite of engineers, technicians, hobbyists, and students all over the world.
With more than 17,000 pages in the Google search index, RF Cafe returns in
favorable positions on many types of key searches, both for text and images.
Your Banner Ads are displayed on average 225,000 times per year! New content
is added on a daily basis, which keeps the major search engines interested enough
to spider it multiple times each day. Items added on the homepage often can be found
in a Google search within a few hours of being posted. If you need your company
news to be seen, RF Cafe is the place to be...
Once World War II was over and the
peoples of the world could breathe and start enjoying life again, television, which
had just begun to take off before the war, quickly gained widespread adoption in
homes. As with so many areas of technology and science, advancements in electronics
and wireless communications during the war years redounded very beneficially to
the
TV industry. Early schemes for television combined both electronics and mechanical
elements using rotating discs, vibrating mirrors, and other far-out schemes to convert
electrical signals to moving pictures. Due to the small size of the first cathode
ray tubes (CRTs), commonly called kinescopes at the time, light beams were launched
toward physically maneuvered mirrors to steer the image onto the back of a larger
glass screen - basically the first projection screen televisions ...but I digress.
TV's popularity grew so fast in the late 1940s and early 1950s that the Federal
Communications commission (FCC) issued a moratorium on the building of new broadcast
stations until a scheme could be devised to deal with signal overlap (interference)
from too closely spaced stations...
The study of
parallel circuits typically follows on the heels of series circuits
because at least for resistance and inductance, the math is easier. Capacitance
in parallel, on the other hand, use the equations and methods of resistance and
inductance in series. Unfortunately, though, for newcomers, series capacitance
uses the equations and methods of resistance and inductance in parallel. Sure,
most RF Cafe visitors covered all that stuff years ago, but as I've mentioned
before, there are always new people coming into the electrical and electronics
craft. These NAVPER Basic Navy Training Courses were and still are heralded as
being excellent introductory material for students entering the realm. I don't
know if it's still so, but back in the post World War II era and up through the
1980s civilian employers assigned great regard to and preference to for U.S.
Navy (and, ahem, Air Force) electronic technicians when hiring...
Quite a few articles on
color television were published in trade and hobby magazines in
the 1950s and 1960s as the technology was adopted and fine tuned. The electronic
circuitry aspect of transmitting and receiving chromaticity, intensity, synchronization,
and audio was impressive, but the science that went into color research was equally
amazing. As with so many things we take for granted because someone else did all
the hard work of figuring out how to make something work and then making it available
to us at an affordable price, the physics of human color perception needed intense
study in order to produce a pleasing image on the cathode ray tube (CRT). The key
to understanding color is the chromaticity diagram, based in the human tristimulus
color space, which is described in detail herein...
Banner Ads are rotated in all locations
on the page! RF Cafe typically receives 8,000-15,000 visits each
weekday. RF Cafe
is a favorite of engineers, technicians, hobbyists, and students all over the world.
With more than 17,000 pages in the Google search index, RF Cafe returns in
favorable positions on many types of key searches, both for text and images.
Your Banner Ads are displayed on average 225,000 times per year! New content
is added on a daily basis, which keeps the major search engines interested enough
to spider it multiple times each day. Items added on the homepage often can be found
in a Google search within a few hours of being posted. If you need your company
news to be seen, RF Cafe is the place to be...
Here is another of the "Electronic Sticklers" challenges from Popular Electronics
magazine - good for ratcheting down at the end of the week. These are fairly basic
circuit analysis problems that often can be solved by inspection, but sometimes
a pencil and paper are necessary. Re-drawing the circuit in a different configuration
to make the connections more obvious often helps when solving total resistance,
capacitance, inductance, etc., as in question #1. In this case, though, you need
to be able to recognize a common configuration to be able to simplify the circuit;
otherwise, you'll be writing and solving mesh equations. #2 has a simple answer
and a more elaborate possibility. #3 and #4 are simple inspection problems...
Founded in 1921 in Salem, Massachusetts,
Hytron Corporation started out making vacuum tubes, then after being bought by CBS
in 1951 they moved into the realm of semiconductor production. This story from a
1944 issue of Radio News magazine extolled the virtues of
Hytron's Master Test Station for its ability to quickly and accurately measure
a wide variety of tubes. Auto-ranging voltage regulators, parallax-free meters with
auto-ranging scales, safety fusing, and easy servicing were among it notable features.
To me, a parallax-free meter is one with a mirror behind the needle used to assure
the operator is looking straight-on at the scale, but in this case it meant the
array of meters was arranged in a semi-circle so that the operator was naturally
looking perpendicular to the meter faces from a fixed vantage point. The level of
automation no doubt reduced measurement errors...
This is another Radio Service Data Sheet
that appeared in the May 1936 edition of Radio-Craft magazine. I post this
schematic and functional description of the
Arvin Model 35, 8-Tube Car-Radio Receiver manufacturers' publications for the
benefit of hobbyists and archivists who might be searching for such information
either in a effort to restore a radio to working condition, or to collect archival
information. A WWW search for an Arvin Model 35 Car Radio did not turn up any
results, but I did see the unknown model shown here on an expired eBay auction.
It has a speaker front that looks like the Model 35. Installing and servicing
the earlier heavy, bulky car radios was the source of many electronic-themed comics
and articles. Some of the very earliest two-way radio sets (of which this is not)
had massive transformers, needed to generate power for the transmitter...
In this episode of John T. Frye's "Carl &
Jerry" series, the intrepid pair of teenage electronics hobbyists and Ham radio
operators are experimenting with an audio amplifier rig that uses a parabolic dish
for concentrating sound waves at a focal point where they have a microphone mounted.
Aside from picking up bird noises and a neighbor lady scolding her husband for not
properly washing the windows during a round of Spring cleaning, Carl imposes upon
Jerry for a lesson in
feedback techniques - both positive and negative - and the reasons one is preferred
over the other. The story winds up with a clever double entendre comment referring
to osculation...'
On a whim, I did a search for the earliest
appearance of Nikola Tesla's name in U.S. newspapers included in the NewspaperArchive.com
database. This story from Mr. George Grantham Bain appeared in multiple newspapers
within a few days of this March 5, 1896 edition of The Warren Times in
Warren, Pennsylvania, which coincidentally is only a few miles from me here in Erie.
The article reports on the role that Tesla's high voltage generators played in the
development of x-ray images on fluorescent displays and on film (which Tesla termed
"cathode photography"). It mentions how the term "cathode" is relatively new to
the general public even though it had been around since 1832 when Michael Faraday
introduced it in his work. Wilhelm Röentgen made the world's first x-ray image ...
With more than 1000
custom-built stencils, this has got to be the most comprehensive set of
Visio Stencils
available for RF, analog, and digital system and schematic drawings! Every stencil
symbol has been built to fit proportionally on the included A-, B-, and C-size drawing
page templates (or use your own page if preferred). Components are provided for
system block diagrams, conceptual drawings, schematics, test equipment, racks, and
more. Page templates are provided with a preset scale (changeable) for a good presentation
that can incorporate all provided symbols... |