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 The June 1949 issue of Radio & Television
News had four
television-themed comics. Television at that time was a relatively
new home appliance, so there was a huge amount of interest in the technology. It
hadn't really been all that long since the public got used to hearing sound (i.e.,
'talkies') in the movie theater, so the mystique that surrounded television made
it the subject of a lot of puns and jokes. 1949 was a mere four years after the
end of World War II, and the post-war economic boom was primed by a surplus
of left-over electronic components along with lots of available talent both in the
areas of design and assembly...
 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.
 Both my father and grandfather were
stamp collectors - philatelists is the technical word - who dabbled
in a recreational way with commemoratives from foreign countries. Nearly all were
canceled (used) stamps that today, as back in their
day, have no real value other than to someone interested in history. Of course none
are the rare types. I now possess many of those stamps in an album that was painstakingly
hand-illustrated and assembled to arrange each stamp according to its country and
issue date. At one time I, too, dabbled in the hobby, having collected many plate
blocks and special issue U.S. stamps in the 1970s and 1980s, along with purchasing
a few designs of special purpose such as those with aerospace and communications
themes...
 Exodus Advanced Communications offers a
scalable portfolio of
high-power solid-state RF amplifiers designed for electronic warfare, GPS/GNSS denial,
and counter-drone applications. These systems are engineered to support high-power
RF denial architectures capable of disrupting control, navigation, and payload links
across multiple frequency bands. Integrated into mobile, fixed, and expeditionary
platforms, Exodus amplifiers enable reliable, long-range electronic attack performance
in complex and evolving threat environments. These solutions are deployed within
high-power RF denial systems across mobile and fixed counter-UAS platforms, as illustrated...
 "Measuring low-frequency electric fields
with high precision remains a significant challenge. Existing sensing technologies
often cannot deliver traceability, compact design, and the ability to detect field
direction all in one system.
Rydberg atoms are gaining attention in electric-field quantum metrology because
they have large electric dipole moments and their behavior can be tied to well-defined
atomic properties. Most current methods for detecting low-frequency or DC electric
fields using Rydberg atoms rely on vapor-cell electromagnetically induced transparency
(EIT) spectroscopy. However, this technique is limited..."
 Here are the
Majestic Chassis Models 380 A.C. T.R.F., and 400 A.C.-D.C. Superheterodyne
and
Delco 32-Volt Radio Receiver Chassis Radio Service Data Sheets
as featured in a 1933 edition of
Radio-Craft magazine. As mentioned many times in the past,
I post these online for the benefit of hobbyists looking for information to assist
in repairing or restoring vintage communication equipment. Even with the availability
of SAMS Photofacts, there are some models that cannot be found anywhere other than
in these vintage magazines...
 For the sake of avid cruciverbalists amongst
us, each week I create a new
crossword puzzle that has a theme related to engineering, mathematics, chemistry,
physics, and other technical words. You will never be asked the name of a movie
star unless he/she was involved in a technical endeavor (e.g., Hedy Lamar). Clues
in this week's puzzle with an asterisk (*) are directly from this week's "High Tech
News" column on the RF Cafe homepage (see the Headline Archives page if necessary)...
 Please take a few moments to visit the
everythingRF website to see how they can assist you with your
project. everythingRF is a product discovery platform for RF and microwave products
and services. They currently have 354,801 products from more than 2478 companies
across 485 categories in their database and enable engineers to search for them
using their customized parametric search tool. Amplifiers, test equipment, power
couplers and dividers, coaxial connectors, waveguide, antennas, filters, mixers,
power supplies, and everything else. Please visit everythingRF today to see how
they can help you.
 In 1961, when these
tech-themed comics appeared in Electronics Illustrated magazine, the
"Space Race" was in full swing. That, along with home hi-fi stereo equipment, newfangled
color televisions, and - gasp - transistors, filled the headlines. They were also
the subject of many forms of humor. These four comics touch on many of those aspects,
all centered on the Space Race. Of course, everything is noticeably dated. "Flunking
the code test" means not much to Amateur radio licensees who earned their first
license (like me, in 2010) after the 5 WPM Morse code requirement was removed. Building
something in "kit form" was a good way to save some money and learn something...
 In our present "No user serviceable parts
inside" world of electronic products, it is easy to understand why very few people
have an appreciation for the technical prowess needed to troubleshoot and repair
them. When reading through these episodes of "Mac's Radio Service Shop" that appeared in mid last century editions
of Radio & Television News magazine, I am inspired to envy the skills
that small electronics repair shop owners had for working on the old vacuum tube
based radio and television sets. Digital electronics has its own unique set of quirks
and special knowledge requirements to troubleshoot, but when everything is analog
rather than merely being required to be a "0" or a "1"...
 "The U.S. Federal Communications Commission
(FCC) has announced that it is once again accepting applications for its
Honors Engineer Program. Initiated in 2018, the one-year development program
gives selected candidates an opportunity to work with FCC personnel on innovative
issues in the communications and high-tech arenas, including 5G communications technology,
the national deployment of broadband services, and communications technologies intended
to improve access to those with disabilities. Those selected to participate in the
Honors Engineer Program will be eligible for continued employment at the agency.
Application to the FCC's Honors Engineer Program is open to recent college graduates
with an engineering degree..."
 This week's crossword puzzle theme is
Amateur Radio. All RF Cafe crossword puzzles are custom made by me, Kirt
Blattenberger, and have only words and clues related to RF, microwave, and mm-wave
engineering, optics, amateur radio, mathematics, chemistry, physics, and other technical
subjects. As always, this crossword puzzle contains no names of politicians, mountain
ranges, exotic foods or plants, movie stars, or anything of the sort unless it/he/she
is related to this puzzle's technology theme...
 Submarines first proved their deadly capabilities
during World War II when Adolph Hitler's navy used them to torpedo not just
military ships but merchant ships in commercial trade routes between the Americas
and Europe. Hideki Tojo's navy used subs to conduct surveillance prior to the deadly
surprise attack on Pearl Harbor. Their naturally stealthy environment - underwater
- proved to be a difficult realm both for detection and for attack. Fortunately,
sensor technology developed quickly during the war, and soon a combination of air
and sea based methods were in use and proved very effective. Submariners no longer
sailed in relative security from being treated to a violent, icy burial at sea...
 The leading website for the PCB industry.
PCB Directory is the largest directory of
Printed Circuit Board (PCB)
Manufacturers, Assembly houses, and Design Services on the Internet. We have listed
the leading printed circuit board manufacturers around the world and made them searchable
by their capabilities - Number of laminates used, Board thicknesses supported, Number
of layers supported, Types of substrates (FR-4, Rogers, flexible, rigid), Geographical
location (U.S., China), kinds of services (manufacturing, fabrication, assembly,
prototype), and more. Fast turn-around on quotations for PCB fabrication and assembly.
 As
the Soviet army closed in on the Peenemünde rocket base in March 1945, German engineers
led by
Wernher von Braun initiated a desperate evacuation of their revolutionary research.
Tasked by von Braun, engineer Dieter Huzel organized the transport of tons of top-secret
blueprints and records to avoid capture by the advancing Red Army. Amidst the chaos
of collapsing lines and aerial warfare, Huzel successfully secured the documents
in an abandoned, ironclad mine near Goslar, shielding them from Soviet hands. After
dynamiting the entrance to seal the cache, Huzel and fellow scientists fled westward
to surrender to American forces. Following their successful arrival in U.S. lines,
the location was revealed...
 Sending telegraph messages, whether by wire
or wireless means, has always been expensive, particularly considering charges are
determined by the character (letter, number, symbol). Accordingly, the Shakespearean
line from Hamlet declaring that "brevity is the soul of wit" can be reworked to
"brevity is the soul of economy." A telegraph wire, unlike a telephone call, is
a legally binding communiqué, as is of course a written letter, but a telegram is
immediate transmission of information for time-critical messaging. A series of "commercial codes" were developed enabling senders to save often
significant money by sending multi-character codes that represented entire phrases
and/or sentences. What struck me about this article that appeared in a 1948 issue
of The Saturday Evening Post magazine...
 "With all the many pressures you have as
a product designer, does
electromagnetic
compliance (EMC) always seem like a stumbling block to delaying product sales?
Is your product exhibiting one of the top three failures: radiated emissions, electrostatic
discharge, or radiated immunity? Are you continually cycling between design/fixing
- running to the compliance test lab - failing again - and back to shot-gunning
more fixes? Wondering how to attack these issues earlier in the design cycle? Would
you like to learn how to characterize and troubleshoot simple design issues right
on your workbench? Then, this monthly column is for you..."
 In 1938, the designers at Sears, Roebuck &
Company's, Silvertone radio division were truly thinking "outside the box" when
they came up with this "Rocket" model
Models 6110. It is an ultra compact tabletop design with a unique
rounded top and a huge tuning dial that comprised one entire end of the Bakelite
cabinet, along with a set of six pushbuttons for station recall. Also published
were datasheets on the
Allied Radio Knight Model E10913, the
General Electric Model GD-52,, and the
Zenith Models 6D302, 6D311, 6D326, 6D336, 6D360. An ever-growing
list of models is at the bottom of every page...
 What drew my attention with this
P.R. Mallory & Company advertisement was not an actual
electronic component that they are most noted for - potentiometers, capacitors,
switches, metal alloys, and of course batteries (later renamed Duracell). Philip
Rogers Mallory began his company manufacturing tungsten wire for lamps. Rather what
interested me was the huge variety of standard potentiometer and rotary switch extension
shafts. Unlike modern electronics where pots and switches are typically mounted
to the enclosure with wires running to the circuit assembly, many...
 The failure to recognize
Nathan B. Stubblefield as the primary inventor of radio is a classic example
of how institutional power, financial interests, and the legal machinery of the
telecommunications industry tend to favor those with corporate backing over solitary,
unconventional inventors. Stubblefield's technology, which he demonstrated as early
as 1892, utilized induction and conduction through the earth and water rather than
the electromagnetic wave propagation (Hertzian waves) that ultimately became the
standard for modern radio. Because his method was effective only over relatively
short distances and functioned on different physical principles, it was eclipsed
by the work of Guglielmo Marconi. Marconi was the superior marketing force. He was
backed by a massive corporate infrastructure and was savvy in securing international
patents...
 Author T.A. Gadwa employs a
standing wave mechanism analogy that I don't recall having read
before - that of a dam on a river. The river is the transmission line with a lake
as the source and then he imagines a dam load. The dam standing waves, per his description,
have phase and amplitude characteristics that depend on how tall the dam wall is
relative to the surface height of the dammed river. An extensive array of graphs
is provided showing how the current of the dam standing waves react to the dam transmission
line termination impedance...
 Here are a couple more
electronics-themed comics, this time ones that appeared in the October 1951
edition of Radio & Television News magazine. When is the last time
you saw a comic in a technical magazine? Note the AC power cord attached to the
"portable" television. Television was a big deal in the day (I assume the "His"
on the guy's towel implies that "Hers" is at the other end of the power cord). Color
TV was not commercially available until a few years later. Nowadays, a person would
have a smartphone, tablet, or notebook computer while on the can. There is a huge
list of other comics at the bottom of the page...
 "Once upon a time in Europe, television
remote controls had a magic
teletext
button. Years before the internet stole into homes, pressing that button brought
up teletext digital information services with hundreds of constantly updated pages.
Living in Ireland in the 1980s and '90s, my family accessed the national teletext
service - Aertel - multiple times a day for weather and news bulletins, as well
as things like TV program guides and updates on airport flight arrivals. It was
an elegant system: fast, low bandwidth, unaffected by user load, and delivering
readable text even on analog television screens. So when I recently saw it was the
40th anniversary of Aertel's test transmissions, it reactivated a thought that had
been rolling around in my head for years..."
|
 • AI
and Geopolitics Forge Memory Market Crisis
• European
Electronics Distribution Gains Momentum
• UK
Secure Quantum Communications Boost
• 2026
PC Sales down 11.3%, Tablets down 7.9%
• Starlink
Becoming Mainstream Option
 The
RF Cafe Homepage Archive
is a comprehensive collection of every item appearing daily on this website since
2008 - and many from earlier years. Many thousands of pages of unique content have
been added since then.
 Modulating a
light beam for secure communications was not a new concept is 1939 when Gerald
Mosteller invented his device, but doing so with inexpensive equipment, using "outside-the-box"
thinking, was new. Exploiting the relatively recently discovered physical phenomenon
of "skin effect," his system used a specific range of frequencies to modulate the
filament of a standard flashlight type incandescent light bulb that could effect
temperature changes - and therefore intensity changes - rapidly and of significant
amplitude to transmit information in the audio frequency range. Mr. Mosteller's
contraption evolved as the result of a college thesis project. There does not exist
a plethora of modern-day modulated light communications systems using incandescent
bulbs as the source, so it is safe to assume insurmountable physical and/or financial
obstacles prevented it from going mainstream. There are, of course, many modulated
light communication devices in use...
 Nobody younger than about 35 years old was
alive when the "Iron Curtain" was still in place. That was where the Communist countries
were able to keep outside information from the rest of the free world from getting
to their oppressed citizens. The Soviet Union, China, North Korea, and other regimes
had a vested interest in keeping people from learning that not everybody lived in
squalor as they did. Maybe you remember the tales of Sears Roebuck and Montgomery
Ward catalogs needing to be secreted into the countries because the Communists feared
their influence. The type of
radio signal jamming mentioned in this 1959 issue of Popular Electronics
magazine was common during the Cold War era. Modern communications has made information
dissemination ubiquitous, even in the still-Communist countries - like Russia, China,
and North Korea...
 Windfreak Technologies is proud to announces
the availability of our
FT108, an innovative
programmable bidirectional filter bank spanning a frequency range of 5 MHz
to 8 GHz in 15 bands. Band selection can be controlled through USB, UART or
at high speeds through powerful triggering modes. Each unit is factory tested via
network analyzer with unique data stored in the device to help with its use. Crossover
frequencies are stored so the user can send a frequency command and the FT108 will
utilizes Intelligent Band Selection logic to automatically toggle the optimal
filter path based on minimum insertion loss. Readback of FT108 insertion loss at
any frequency between crossover points allows for easy amplitude leveling...
Longtime RF Cafe visitor, electrical engineer, and occasional contributor Alan H.
Dewey sent me a note yesterday saying a book for which he helped provide a large amount
of research data has been published by authors Iain Dey and Douglas Buck. "The Cryotron Files:
How the Inventor of the Microchip Put Himself in the KGB's Sights," is an
extensive delve into the background of Dr. Dudley Allen Buck, whose son,
Douglas, conducted an extensive investigation into his father's mysterious death
that happened to coincide with the death of his colleague and two other
scientists just days after being visited by Soviet computer experts. Dr. Buck
was a superconductivity researcher during his short, highly productive life. A
cryotron, BTW, is a superconducting switch that would make for very low power
supercomputers if it could be made practical in IC form...
 Do you own one of those RFID-blocking wallets
to keep your credit cards from being read unawares? If so, you are engaging in electronic
countermeasures. Anyone interested in the history of
electronic countermeasures (ECM) and electronic counter-countermeasures (ECCM) will
benefit from this 1959 Electronics World article. ECM has been
practiced as early as World War I when wireless communications was first used
for military purposes. ECCM, of course, followed immediately on its heels.
Electronic countermeasures range from simple jamming of receivers to emitting
spoofing signals that fool receiver. In extreme cases ECM can destroy receiver
front-ends by overdriving and burning out circuitry. ECM and ECCM...
 It took me way too long, but I finally got
the June 1945 issue of Radio News magazine with Part 1 of the "Practical
Radar" series of articles by Jordan McQuay. The opening sentence said a lot
to the readers of the day: "The veil of secrecy has been lifted." Radar technology
was a highly guarded science during World War II, and, along with its related
technology, sonar, is widely credited with providing Allied forces the tools needed
to eventually emerge victorious against Axis forces on land and sea. Yes, Germany
and Japan (and Italy, but they didn't produce any systems) also had radar and sonar,
but American and British engineers managed to keep a step ahead, providing a major
advantage. The same goes for countermeasure techniques. This very extensive introduction
to radar was followed by four more equally lengthy articles. By the time this edition
of Radio News was published, the war in Europe and Africa was over, and would soon
be ended in Japan, so divulging "secrets" approved by the Department of War was
not a big deal. There were, however, many readers of this and other publications
that were upset...
 As with my hundreds of previous
engineering and science-themed crossword puzzles, this first one
of the new decade, January 5, 2020, contains only clues and terms associated with
engineering, science, physical, astronomy, mathematics, chemistry, etc., which I
have built up over nearly two decades. Many new words and company names have been
added that had not even been created when I started in the year 2002. You will never
find a word taxing your knowledge of a numbnut soap opera star or the name of some
obscure village in the Andes mountains. You might, however, encounter the name of
a movie star like Hedy Lamarr or a geographical location like Tunguska, Russia...
 In his usual manner, John T. Frye uses
tech-savvy teenage experimenters Carl Anderson and Jerry Bishop to teach a lesson
while writing a compelling saga. In this case Jerry gets "bitten" by house current while fiddling with a receiver chassis.
Before certain safety measures were required by law, many electrical devices - radios,
televisions, vacuum cleaners, shop tools, kitchen appliances, etc. - were sold with
with either existing shock hazards or the potential for (no pun intended) a shock
hazard in certain usage or failure modes. Before the advent of polarized two-pronged
plugs and grounded 3-prong plugs, some devices presented hazardous voltage levels
to the user by virtue of a direct connection to exposed conductive (metal) surfaces.
In this instance, under normal operational conditions with the chassis installed
in its wooden case and plastic or phenolic control...
 "PCBs? We ain't got no PCBs in our TV sets†...
We don't have to give you no stinking PCBs." That is effectively what the Zenith
television advertisement from a 1958 edition of Radio-Electronics told its potential
customers. According to the Zenith communications department, even though their
head R&D guy, Dr. Alexander Ellett, was "the
daddy of printed circuit boards," they stuck with the traditional point-to-point
wiring in all their TV chassis. I have to agree with them from a troubleshooting
and component replacement perspective. There's nothing easier than heating a solder
lug or terminal post to unwrap a leaded R, L, or C either to measure its value,
isolate it from the rest of the circuit for making tests, or to replace it. There
is no worry about solder splatter or bridges, overheating the PCB material to cause
delamination, or lifting metal traces from the surface. There is also no issue with
getting a component lead out of a plated-through hole. Yes, of course modern circuits
need multilayer, high density circuit boards...
 By now, most people involved in science and
engineering have seen the iconic photos of cosmic rays and other
subatomic particles leaving a signature of their presence as streaks in a cloud
chamber. Invented by Scottish physicist Charles Wilson, the cloud chamber is a sealed
volume containing super-saturated water vapor that can be ionized by energetic particles
passing through it. The result is a tell-tale whitish line that can be straight
arced, or even a spiral, depending on the nature of the particle. First developed
in the early part of the 20th century, many particles predicted by researchers were
detected and identified. Many unexpected particles were also encountered that gave
physicists reasons to sharpen their pencils and develop new theories to explain.
Similar research and discoveries occur today using super-sensitive electronic detectors
instead of cloud chambers. CERN's Large Hadron Collider (LHC) is currently the world's
grandest particle collider for performing atomic and subatomic particle research...
 "Compactness distinguishes the Western Electric
8A airplane receiver." That statement describes a 160-pound system that included
a wind-driven electricity generator for the equipment used by Captain Frank M. Hawks
when setting coast-to-coast time records in the year 1929 using his Lockheed Air
Express airplane, dubbed "Texaco 5." A simple
4-tube AM radio, its chassis measured a whopping 6" x 10" x 12". There were
no radio direction finding stations enroute at the time, so the radio's usefulness
was limited to being "comforting to listen in every half-hour and be advised of
general conditions throughout the United States." Daring pilots of the day risked
life and limb to push forward the frontiers of technology by testing and proving
airframes, engines, electronics, navigation methods, and, almost as importantly,
building confidence and a sense of awe and urgency on the part of the public so
that continued development would be assured and encouraged...
 A well-laid-out and routed chassis, control
panel, equipment rack, or circuit breaker panel has always invoked the same sort
of appreciation and awe in me that a Rembrandt painting invokes in an art cognoscente
or a Beethoven concert invokes in a music aficionado. Many moons ago when I worked
as an electrician, I prided myself in obsessively neat and orderly runs of conduit
and Romex™ cable (with no twists), squarely mounted receptacle and switch boxes,
and rigid compliance with NEC requirements. Once I entered into the RF and microwave
realm, an entirely new kind of eye candy appeared in the form of
semi-rigid coaxial cable and waveguide runs. Knowing the technical (electrical)
requirements and limitations based on power, wavelength, and VSWR concerns served
to enhance the appreciation. Electrical wiring has its own unique requirements for
bend radii, enclosure fill, and voltage levels, due to heating, mechanical stress,
and voltage induction issues. RF transmission media adds to that signal reflections
due to contamination and cross-section perturbations, dissimilar junction spurious
mixing products, microphonics, common mode currents...
 A
well-laid-out and routed chassis, control panel, equipment rack,
or circuit breaker panel has always invoked the same sort of appreciation and awe
in me that a Rembrandt painting invokes in an art cognoscente or a Beethoven concert
invokes in a music aficionado. Many moons ago when I work as an electrician, I prided
myself in obsessively neat and orderly runs of conduit and Romex™ cable (with no
twists), squarely mounted receptacle and switch boxes, and rigid compliance with
NEC requirements. Once I entered into the RF and microwave realm, an entirely new
kind of eye candy appeared in the form of semi-rigid coaxial cable and waveguide
runs. Knowing the technical (electrical) requirements and limitations based on power,
wavelength, and VSWR concerns served to enhance the appreciation. Electrical wiring
has its own unique requirements for bend radii, enclosure fill, and voltage levels,
due to heating, mechanical stress, and voltage induction...
 Usually an article about
clean layout techniques would be about printed circuit board layout; however, this
one refers to chassis layout. Having built many electronics chassis in my days as an
electronics technician (prior to earning an engineering degree), I have a great appreciation
for a professional-looking job. Some of the work done by hobbyists that appear in magazines
like QST, Nuts & Volts, and the older titles like
Poplar Electronics looks pretty darn nice - both for kits and homebrews. It's a
short article, but worth a quick look...
 Don't let the title fool you. This is not
a "bees-birds-and-flowers
routine" being provided to Barney by his boss, Mac. It turns out to be a brief
introduction into the fine art of troubleshooting intermittent problems in radio
and television circuits. As is usually the case, while the specifics of the scenarios
Mac describes might not apply to your challenge at hand, the general philosophy
always does. It is basically the old process of elimination where after rapping
components mechanically and/or heating or cooling them in hopes of observing a tell-tale
change in performance, the next step is to divide the suspected circuit portion
in half (electrically, but sometimes also physically) and look in one direction.
If the problem isn't there, then divide the circuit in the other direction in half
and go there. Repeat until the problem is found. One of my personal favorite first
steps is to verify all mechanical connector interfaces (if any) are contacting properly.
Clean with alcohol if possible, and burnish with sandpaper if appropriate, then
plug and unplug the connections a few times, just to make sure proper seating...
 This is part 4 of the "All About IC's" series that
appeared in Radio-Electronics magazine in 1969, where author Bob Hibberd
discusses the various types of integrate circuit (IC) families. He is not
referring to TTL and CMOS with divisions into small scale integration (SSI),
medium scale integration (MSI), large scale integration (LSI), and very large
scale integration (VLSI) like we have today. Back in 1969 the IC world was still
evolving through basic circuit structures like diode-diode logic (DDL),
diode-transistor logic (DTL), resistor-transistor logic (RTL), direct-coupled
transistor logic (DCTL), etc. What seems obvious now needed to be learned and
dealt with then. It is like struggling with a homework problem and being able to
look at the answer worked out in the back of the book where the solution then
looks obvious...
 Many people have provided resources on the
Internet that made my life easier, and I have been amazed at being able to find
photos and descriptions of very esoteric subjects for which I figured there was
no chance of finding anything. In appreciation, there are times I post stuff that
probably almost nobody will ever need, but maybe there is one guy (or gal) out there
who will breathe a sigh of relief when finally finding the needed data. This list
of
radio trade names and model numbers appeared in a 1933 edition of Radio-Craft
magazine. Page scans are provided at the top, and since search engines do not
yet OCR images to be able to index their textual content, I have also included my
OCR results at the bottom. Because the list is so extensive, no attempt has been
made to clean it up...
 Satellite evolution occurred at a rapid pace once
Sputnik and Echo were successfully launched in the late 1950s. Sputnik was a simple beacon
transmitter whose signal was used to measure orbital and atmospheric properties and their
effects on radio signals. Oh, and also to announce to the world that the USSR had accomplished
the world's first satellite mission - I'd brag, too. Explorer 1, the first
U.S. satellite, launched the following year, measured and broadcast Van Allen Radiation
Belt data. This Electronics World article appeared about a decade into the satellite
aspect of the "Space Race." By then...
 Feedback circuits seem simple enough intuitively,
at least for simple systems. It is easy, though, for someone not comfortable with
algebraic manipulations to arrive at the wrong conclusion for how a given
feedback constant figures into the calculation. Such was the case with an article
published in the July 1937 issue of ARRL's QST magazine, when many readers
wrote to the author accusing him of making an erroneous claim in an earlier article
(April) regarding using feedback to cancel out an unwanted harmonic in an amplifier.
The criticism turned out being justified. Here is a statement of the error and an
explanation of the proper approach which was printed a couple months later... |
