|
 Charles Babbage, born on December 26, 1791, in London, England, was one of the foremost mathematicians and inventors of the 19th century, best known for his pioneering work on the concept of a programmable computer. He was the son of Benjamin Babbage, a banker, and Betsy Plumleigh Teape, who hailed from a relatively affluent family. His upbringing was comfortable, allowing him access to an education that would later foster his intellectual pursuits. His father's wealth enabled Charles to attend some of the finest schools of the time, although his formal education started somewhat later than usual due to early childhood illness.
Babbage's schooling began at a local academy in Alphington and later at the King Edward VI Grammar School in Totnes,
Devon. He was a highly curious child...
 "Yesterday, NASA successfully launched the
Europa Clipper, the largest spacecraft the agency has ever built for a planetary
mission. Clipper is now successfully on its multi-year journey to Europa, bristling
with equipment to study the Jovian moon's potential to support life - but just a
few months ago, the mission was almost doomed. In July, researchers at NASA found
out that a group of Europa Clipper's
transistors would fail under
Jupiter's extreme radiation levels. They spent months testing devices, updating
their flight trajectories, and ultimately adding a warning “canary box” to monitor
the effects of radiation as..."
 The October issue of Electronics World
magazine included many articles written by
printed circuit board (PCB) industry leaders regarding the state of the art.
Multi-layer PCB technology was still in its infancy at the time, with most prototype
and production boards being 1- or 2-sided. As with the switch from vacuum tubes
to transistors, there were hold-outs who resisted the change to PCBs - for good
reason in some cases. A list of advantages and disadvantages is presented both for
and against, respectively, use of printed circuit boards. One of the biggest advantages
to point-to-point wiring (i.e., in the PCB disadvantage list) was that circuit modifications
in production was more easily accommodated, unless the change was simply...
 Along with the advent of FM (frequency modulation)
radio came an entirely new variety of
antenna shapes and configurations, compared to primarily a simple long, straight
wire for AM (amplitude modulation) radio antennas. Amateur radio operators (Hams)
of course had been designing, tuning, and using such antennas (as FM) for decades,
but the average radio listener was facing a whole new world of options for getting
the most out of his receiver. It is not that AM radio cannot benefit by similar
antenna configurations, it is just that the relatively long wavelength of AM station
frequencies (540 to 1,700 kHz) compared to FM station frequencies (88 to 108 MHz)
represents a two-order-of-magnitude...
 "Researchers have developed a novel
graphene-germanium hot-emitter transistor using a new hot carrier generation
mechanism, achieving unprecedented performance. This advancement opens new possibilities
for low-power, high-performance multifunctional devices. Transistors, the fundamental
components of integrated circuits, encounter increasing difficulties as their size
continues to shrink. To boost circuit performance, it has become essential to develop
transistors that operate on innovative principles. Hot carrier transistors, which
harness the extra kinetic energy of charge carriers, offer the potential to enhance
transistor speed and functionality..."
 When this was originally published, it was
Labor Day in the USA, so most people were off work (which seems antithetical to
the "labor" part of the holiday name). For those unfortunate enough to be at work,
here is a bit of vintage electronic comic relief from a 1969 Electronics World
magazine for your office-bound condition. Actually, during my years of working for
someone else, I used to work the holidays (except Christmas) if I could get another
day off instead. With very few managers around, those of us at work would enjoy
what we termed "IPV," or "In-Plant-Vacation." Very little work got done on those
days, and lunches and break-times were pretty long. I was always surprised the scheme
never caught on more widely...
 Exodus Advanced Communications, is a multinational
RF communication equipment and engineering service company serving both commercial
and government entities and their affiliates worldwide. We are pleased to announce
the model
AMP2083P-2KW solid state pulse amplifier (SSPA) is designed for Pulse/HIRF,
EMC/EMI Mil-Std 461/464 and radar applications in the C-band, 4.0-8.0 GHz frequency
band. Providing superb pulse fidelity and up to 100 μsec pulse widths. Duty
cycles to 6% with a minimum 63 dB gain. Available monitoring parameters for
Forward/Reflected power in watts & dBm, VSWR, voltage, current, temperature
sensing for outstanding reliability and ruggedness in a compact...
 By the time most of us who even remember
cathode ray tubes (CRTs) were first introduced to them, the technology and manufacturing
processes had been pretty much perfected - especially for the standard 525-line
(or 625-line outside the U.S.) resolution type. The National Television System Committee
(NTSC) published a standard for black and white (B&W) television in 1941 and
then for color in 1953. This "Picture Tubes" article in a 1955 issue of Popular
Electronics provides a look inside a CRT manufacturing plant at General Electric.
For some reason the photos in the magazine were very poor quality (maybe for secrecy).
If you want one of the best explanations I have ever seen on how a TV picture scan
is implemented, check out this video entitled
What is 525-Line Analog Video? If you don't understand raster scanning after
watching it, you never will. You might be surprised to learn that there were not
actually 525 lines of picture information...
 The March 1962 "News Briefs" feature in
Radio-Electronics magazine was chock full of interesting developments.
Space flight was a big deal in the day, not that it isn't today, but the difference
is everything about it was new then. Fundamental technology was in the process of
being developed, and then continual improvements would be made during the ensuing
decades until we get to where we are today with a permanent presence of men in orbit,
interplanetary science probes, space-borne telescopes, Earth environment sensors,
and space weapons, and thousands of active
communications satellites. The sky is awash with manmade objects. In other news,
satellite TV was quickly gaining in capability (including live transmissions and,
gasp, "Living Color" per NBC)...
 The distinction between
direct conversion, heterodyne, and superheterodyne receivers represents a significant
evolution in radio technology. Each type of receiver plays a crucial role in the
development of modern communications, and their invention marks important milestones
in the history of radio engineering. To understand these differences, we will explore
the invention history, technical descriptions, and practical implementations of
each type, including their inventors, patents, and notable applications. A direct
conversion receiver (also known as a "zero-IF receiver") represents the simplest
type of radio architecture. It was first conceptualized in the early 20th century
as a way to simplify radio designs by eliminating the intermediate frequency (IF)
stage...
 Dealing with the problem of
lightning strikes was of concern long before electronic equipment needed to
be protected from its effects. Fires that were the result of lightning have always
been a problem in nature, but they were really catastrophic to civilization once
cities crowded with close-quartered wooden buildings became the norm. Benjamin Franklin
observed that when the many lightning-induced fires of Philadelphia were sparked
(pun intended), it was almost always the tallest structures in the area that were
hit. Those fire often spread to neighboring buildings and burned down entire city
blocks. It was a devastating and frequency...
 "By observing
spintronic magnetic tunnel junctions in real-time, researchers found these devices
fail at unexpectedly low temperatures, offering valuable insights for improving
future electronic designs. Next-Generation Electronics Degradation A new study led
by researchers at the University of Minnesota Twin Cities is providing new insights
into how next-generation electronics, including memory components in computers,
breakdown or degrade over time. Understanding the reasons for degradation could
help improve efficiency of data storage solutions. The research is published in
ACS Nano, a peer-reviewed scientific journal and is featured on the cover..."
 Arthur C. Clarke's writings and contributions
to science are vast and influential, intertwining his imaginative narratives with
profound scientific concepts. Clarke is credited with proposing the idea of
geostationary
satellites in a paper he published in the October 1945 issue of Wireless World
magazine. Titled "Extra-Terrestrial Relays: Can Rocket Stations Give Worldwide Radio
Coverage?," he described the concept of using a network of geostationary satellites
to provide global radio coverage. Geostationary satellites are satellites that orbit
the Earth at the same rate as the Earth rotates, so they appear to stay in the same
place in the sky relative to a fixed point on the Earth's surface. This makes them
ideal for telecommunications and broadcasting, as they can provide constant coverage
of a particular area without the need for multiple satellites or complicated ground
infrastructure...
 Here we go with three new "What's
Your EQ?" challenges from the July 1961 issue of Radio-Electronics
magazine. Readers submit the problems, which typically involve creating a circuit
to perform a specified function, or determining how a given circuit works. The first
of these is more of a puzzle, since the author shows you how to go about arriving
at the answer. Since incandescent light bulbs are not overly familiar to a lot of
people these days, it might be to the advantage of pre-Millennials who grew up using
them and are acquainted with their properties. The second is an old-fashioned Black
Box challenge that some readers will solve without much...
 "Japanese operator SoftBank announced that
the Sunglaider, its large-scale solar-powered uncrewed aircraft system (UAS) designed
for
High Altitude Platform Station (HAPS) stratospheric telecommunications, was
utilized in a field trial conducted by AeroVironment and the U.S. DoD in New Mexico,
the U.S. During the trial, carried out in early August, Sunglider succeeded in achieving
stratospheric flight, the Japanese operator said. With a wingspan of 78 meters and
the capability to carry payloads weighing up to 75kg, the Sunglider is larger than
other publicly announced HAPS UAS..."
 Monday (any day, for that matter) is a good
day for Carl and Jerry stories, Mac's Electronics Service Shop sagas, Hobnobbing
with Harbaugh, electronics-themed comics, electronics quizzes, and other forms of
nerd entertainment. Here is another of Robert P. Balin's great challenges titled,
"Diagram
Quiz," this one from a 1966 issue of Popular Electronics magazine.
Most RF Cafe visitors will easily identify eight or nine of the ten diagrams. Relatively
few will be familiar with the Rieke diagram (hint: power amplifier designers will
know about it). The Biasing diagram is a bit misnamed IMHO, and could cause confusion...
 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 ceramic bandpass filters have
been announced for October 2024 - a 2275 MHz center frequency filter with a
bandwidth of 250 MHz, a 2275 MHz center frequency filter with a bandwidth
of 250 MHz, and a 6245 MHz center frequency filter with a bandwidth of
360 MHz. 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.
 When you read this 1963 Electronics
World magazine article's title, I doubt you immediately assumed it would be
about a vacuum tube circuit, or even one that uses discrete transistors to implement
the circuit. Rather you most likely though it would be about an integrated circuit
(IC).
Operational amplifiers (opamp) are building blocks characterized (ideally) by
their infinite input impedance, zero output impedance, infinite open-loop bandwidth
and gain, zero input offset voltage, amongst other defined parameters. The first
commercially produced integrated circuit (IC) opamp came to market in 1964 via Fairchild
Semiconductor (the µA702, brainchild of Bob Widlar)...
 Nickel-cadmium (NiCad) batteries have a
long and significant history in energy storage, with their invention attributed
to Swedish engineer Waldemar Jungner in 1899. Jungner's work laid the foundation
for an electrochemical power source based on nickel oxide hydroxide and cadmium,
leading to the development of the rechargeable NiCad battery. It was a pioneering
breakthrough because it represented one of the earliest forms of rechargeable energy
storage systems. This battery technology found widespread use in various industries
due to its robust performance and ability to be recharged multiple times. At its
core, the chemistry of NiCad batteries involves the reaction between cadmium (the
negative electrode) and nickel oxide hydroxide (the positive electrode), with potassium
hydroxide as the electrolyte. During...
 These two
tech-themed comics from the September 1969 issue of Electronics World
magazine are pretty good. I especially like the one where the guy's wife entered
his printed circuit board layout in an art contest. PCBs were just starting to gain
momentum in production electronics as they replaced the old point-to-point wiring
method. Also popular in that era was high fidelity stereo equipment. Owning a system
with speakers that operated from 1 Hz through 30 to 40 kHz was major evidence
of an audiophile's technical savvy, even though the human ear con only detect frequencies
in the 30 Hz to 20 kHz range. Dogs can hear frequencies up into the 45 kHz
range. Porpoises can hear up to 150 kHz. A ferret can hear from 16 Hz...
 TotalTemp Technologies offers advanced
and innovative methods for meeting and optimizing your thermal testing requirements.
We specialize in benchtop thermal testing because small batches are typically the
most cost-effective approach. We offer heat transfer by conduction with thermal
platforms, forced convection as in traditional temperature chambers, combined systems,
and thermal vacuum for Space Simulation.
Thermal testing of Traveling Wave Tube Amplifiers and other devices with dramatically
uneven power dissipation can easily be achieved with a dual zone thermal platform.
Managing the heat produced by the electron gun side allows for the RF outputs side
to be tested at various required temperatures. The Dual Zone Thermal Platforms allows
the user to maintain safe controlling...
• Ham
Radio Serving Southeast U.S. Recovery Efforts
• Radio
"A Godsend for So Many" in Helene's Aftermath
• Estate
Planning for Hams
• Intel's Woes Damaging
U.S. Chip Indpendence
• Is
Gen-Z Low Car Ownership a Threat to Radio? (they
can't afford cars due to massive inflation - not because they don't want a car)
 Amrad, American Radio & Research Corporation,
was based in Medford Hillside, Massachusetts and was founded in 1915 with funds
from J. Pierpont Morgan. The company's first manager, Harold James Power, was an
amateur radio enthusiast and built a research laboratory. In 1916, Amrad made its
first broadcast to J. Pierpont Morgan Jr., who was aboard the ocean liner "Philadelphia."
Amrad received orders for military radio equipment during World War I, but discontinued
these orders after the war ended. To keep the company afloat, Amrad produced items
such as electric egg beaters and cigar lighters. In 1919, Amrad was awarded a contract
to make 400 SE1420 receivers, and it began advertising components for amateur radio
enthusiasts...
 This "Which
Dry Battery for You" article is a follow-on from the previous month's "Dry Cell
Battery Types" in Radio-Electronics magazine. It was a time long before the dominance
of rechargeable lithium batteries. In 1963, battery-powered devices were nowhere
near as widespread and diverse as they are nowadays. Hand tools like drills, saws,
routers, planers, and screwdrivers got their power either from a wall outlet or
the user's arm and hand muscles. Lawn mowers, grass and hedge trimmers, chain saws,
and snow blowers were powered mostly by gasoline, although some models plugged into
the wall. Those devices which did use batteries most often had no built-in...
 "Researchers have developed a new architecture
for optical computing called
diffraction casting, offering power-efficient processing by using light waves.
This method promises better integration and flexibility for high-performance computing
tasks and could be used in fields like AI and machine learning. As artificial intelligence
and other complex applications demand ever more powerful and energy-intensive computers,
optical computing emerges as a promising solution to enhance speed and power efficiency.
However, its practical application has faced numerous challenges..."
 The Atomic Energy Commission (AEC) was established
in 1946 as a result of the Atomic Energy Act, signed into law by President Harry
S. Truman. This legislative decision marked the United States' formal entry into
managing and controlling atomic energy, a rapidly advancing field that had been
essential in concluding World War II through the development and use of nuclear
weapons. The AEC was conceived to handle not only military applications of atomic
energy but also to develop peaceful uses, such as energy production, medical research,
and industrial applications. The creation of the AEC emerged from the Manhattan
Project, the secret wartime effort to develop atomic bombs. The Manhattan Project
brought together prominent scientists like J. Robert Oppenheimer, Enrico Fermi,
and Niels Bohr. After the war, however, the question arose...
 Empower RF Systems, the technology leading
provider of high-performance RF amplifiers, is proud to announce the launch of the
Model 2221 X-Band Pulsed High Power Amplifier. The Empower RF 2221 amplifier
operates in the 9-10 GHz X-band, delivering an impressive 8000 W peak
output power with long and short pulse widths. Its applications encompass radar
systems, electronic warfare, HPM research, and electromagnetics effects testing.
With a rugged, modular design, the 2221 offers a reliable, high-performance solution
for applications demanding significant X-band power. Key Features and Specifications
The model 2221 amplifier operates in the 9-10 GHz X-band frequency range, delivering
an impressive 8 kW of peak pulsed output power...
 Although not in the title as it used to
be, this 1964 Electronics World magazine piece by John T. Frye is
a "Mac's
Service Shop" story. If Mac and Barney are the stars of the saga, then it can
be none other. The story is about how the misdeeds of a few dishonest operators
can taint the reputation of an entire industry - nothing new there. Barney is telling
Mac about a "sting" ploy pulled by a consumer protection group whereby TV sets with
a specific easy-to-troubleshoot problem introduced to see how repair technicians
from a suspect company would bill the service. I'll not spoil the ending for you;
however, a comment mentioned that $10 would have been a reasonable price for a house
call that included the fix. According to the BLS's inflation calculator, $10 in
1964 was the equivalent of about $102 in 2024...
 Ever the futurist, in 1962 Radio-Electronics
magazine editor Hugo Gernsback was making the case for occupying
millimeter- and submillimeter-wave bands. In fact, he first proposed the concept
back in 1959. He refers to it as "gap between the infrared (IR) and radio regions."
IR is generally understood to include wavelengths from around 750 nm (400 THz)
to 1 mm (300 GHz). Gernsback cites work done by Professor Gwyn O. Jones,
of Queen Mary College of the University of London, with the claim that among other
advantages of millimeter-wave (mm-wave) is an ability to penetrate certain wavelength
"windows" in the atmosphere where lower frequencies do not propagate efficiently,
more "channels" of communications can be accommodated, smaller antennas could be
used, and narrower focused transmission beams possible...
 Werbel Microwave's WMRD10-7.2-S is a
10-way resistive splitter that covers up to 7.2 GHz with ultra-wide bandwidth.
This unique design accomplishes extremely flat frequency response in a small radial
package. Our unique design approach provides higher than expected isolation between
outputs at far ports than would be achieved in a typical star topology. It has applications
in markets such as CATV, test and measurement, and military radio. Its small size
makes it easy to integrate into compact systems. Designed, assembled, and tested
in the USA.
 Hugo Gernsback, often heralded as the "Father
of Science Fiction," was an extraordinary figure whose influence extended beyond
the realm of speculative literature into the world of electronics, radio communication,
and futurism. His life, inventions, and publications shaped not only popular science
but also the practical development of radio and electronics, making him a pivotal
figure in early 20th-century technological advancements. Gernsback was born Hugo
Gernsbacher on August 16, 1884, in Luxembourg City, Luxembourg, to a wealthy family.
His father, Moritz Gernsbacher, was a winemaker and merchant, while his mother,
Bertha, came from a prominent local family. Hugo had several siblings, though details
of his early family life remain somewhat obscure. From a young age, Hugo showed
a strong interest in science and technology, particularly in electricity and wireless
communication. He attended local schools in Luxembourg and later pursued formal
education at the Technikum in Bingen, Germany...
 These government programs take forever to
implement, then a major portion of the money gets wasted in bureaucracies, payoffs,
and misappropriations (e.g.,
8 EV charging stations after spending $7.5B). "If you know CostQuest at all
you probably think of it as the company that the FCC hired to clean up and refine
its national broadband map. But the company is also working with state broadband
offices on their
Broadband Equity, Access and Deployment (BEAD) programs. To give a little background,
CostQuest works with the FCC on its national broadband map. But it was also hired,
separately, by the National Telecommunications and Information Administration (NTIA)
to work with states..."
|
 "Handie-Talkie"
was the name given to early walkie-talkies used in the field by military communications
troops. Having been written during World War II, the author of this QST
article just assumed that any reader would be familiar with the WERS acronym - it
stands for War Emergency Radio Service. Per the Wikipedia entry: "At the start of
the Second World War the United States Congress had suspended all amateur radio
activity throughout the country. WERS was established by the Federal Communications
Commission in June 1942 at the insistence of the American Radio Relay League. WERS
would remain in operation in through the end of the Second World War in 1945. WERS
was to provide communications in connection with air raid protection, and communications
during times of natural disaster. WERS licenses were given to communities and not
individuals...
 This vintage
Heathkit
AR-1250 Stereo Receiver kit is one the latest Heathkit kits which appeared on
eBay, although this one is mostly built. At least you can see the innards in the
photos. There appears to be a lot of parts to assemble, but by 1985 Heathkit was
shipping kits with major RF circuit components already mounted and tuned. Without
photos of the unassembled kit I cannot be sure, but being declared "a four-evening
kit" means it likely did have pre-assembled sections. I have been saving these kinds
of images in order to preserve the history. A constantly growing list is at the
lower right. The first instance of the AR-1250 Stereo Receiver I could find in a
Heathkit catalog is in the 1985 Spring-Summer issue with a price of $349.95, but
by the time the 1985 Christmas issue was mailed, the price had been lowered to $299.95
($745.61 in 2021 money per the BLS Inflation Calculator)...
 This "The National QSO Page" editorial from
the December 1938 issue of Radio News magazine really took me by surprise. Evidently
there was a rift with amateur radio operators over whether Radio News was
attempting to
overthrow the American Radio Relay League's (ARRL) dominance in the Ham realm.
At the time, the ARRL had only been in existence for 24 years. There had been some
previous criticism of the ARRL for not sufficiently (in Radio News' opinion)
defending access to dedicated Ham spectrum and legal transmit power levels, and
also for the ARRL counting among its membership anyone who subscribed to the organization's
QST magazine. The former point is arguable, but the latter seems rather
petty since likely the percentage of subscribers who were not ARRL members, too,
is probably very small. Interestingly, Radio News accused the ARRL of being weak
lobbyists in Washington...
 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...
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...
 "There's a WAR to be won." So goes the headline
in an advertisement in the April 1942 edition of QST magazine. Like many
American companies during World War II,
Cardwell Manufacturing Corporation gave its highest priority to
serving the needs of our nation's military. Patriotism was actually taught in schools
back in the day, and the majority of citizens understood the need to devote their
efforts to achieving victory, even if it meant putting personal interests on hold.
The ad content typifies that attitude: "Though all our facilities of men and machines
have long been pledged to the fulfillment of our assigned tasks, and though hundreds
of thousands of Cardwell components are in active service on the far flung battlefronts
of the United Nations, many times this effort is needed. And so, to our loyal personnel,
we are saying, 'Let's redouble production again..."
 A column entitled "Radio-Electronics
Monthly Review" appeared in each issue of Radio-Craft magazine. As now, things
were moving quickly at the time. With WWWII recently ended, a lot of the new technology
developed to help beat back Nazism and Communism was being transferred to peacetime
uses. The May 1947 issue contained, amongst other items, info regarding how radio
servicemen were organizing efforts to get its ranks educated on FM sets as AM was
being replaced and/or supplemented with the new miracle noise-free broadcast systems.
It also reported that the IRS decided not to go forward with earlier plans to tax
television shows being displayed in public places. Attempts to tax the air that
you breathe are to this day still being worked on, though. The U.S. Bureau of Standards
(now NIST) announced adoption of international standards of measure for certain
electrical units...
 Computer analysis in 1976 was a job performed
on a corporate, university, or government mainframe. Radio Shack's TRS-80 came out
in 1977, but it did not have the capacity to calculate and plot antenna gain charts
like the one in this QST article. Yes, an ambitious programmer could write
the code necessary to perform the double integrals presented in the article, but
to do all the figuring needed to create all the graphs in Figure 4, the job would
just about be finishing up today - and that's not too much of an exaggeration. For
some reason the authors never mention what computer was used or where it was based.
When I saw the title of "Loops vs. Dipole,"
I expected the loop to be round or square, but for analysis purposes it was modeled
as a pair of parallel elements representing the horizontal components of a square
loop antenna. Justification for omission of the vertical sides...
 The newest release of RF Cafe's spreadsheet
(Excel) based engineering and science calculator is now available -
Espresso Engineering Workbook™. Among other additions, it now has a Butterworth
Bandpass Calculator, and a Highpass Filter Calculator that does not just gain, but
also phase and group delay! Since 2002,
the original Calculator Workbook has been available as a free download.
Continuing the tradition, RF Cafe Espresso Engineering Workbook™ is
also provided at no cost,
compliments of my generous sponsors. The original calculators are included, but
with a vastly expanded and improved user interface. Error-trapped user input cells
help prevent entry of invalid values. An extensive use of Visual Basic for Applications
(VBA) functions now do most of the heavy lifting with calculations, and facilitates
a wide user-selectable choice of units for voltage, frequency, speed, temperature,
power, wavelength, weight, etc. In fact, a full page of units conversion calculators
is included. A particularly handy feature is the ability to specify the the number
of significant digits to display. Drop-down menus are provided for convenience...
 Phased
vertical stacks of two or more antennas were fairly common in the television
realm - especially once color broadcasts became more dominant in the 1950s. Up to
3 dB per additional antenna is possible, but due to various non-ideal physical
parameters (summed phase angle, imperfect antenna geometry, etc.), realized gain
is typically in the 2.5 to 2.8 dB range. Higher signal to noise ratios were
needed to guarantee good color separation with the National Television System Committee
(NTSC) and stereo channel audio separation with the advent of Multichannel Television
Sound (MTS). As you might expect, companies appeared claiming to have invented physics-defying
antennas that "outperform all present antennas." This particular "Super 60"
model from All Channel Antenna Corporation further claims to outperform antennas
that use a mechanical rotator (see my Alliance U-100 Tenna-Rotor) by virtue of its
9-position electronic phase switching...
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...
 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...
 This
Radio
Theme Crossword Puzzle for July 25th has many words and clues related to RF,
microwave, and mm-wave engineering, optics, mathematics, chemistry, physics, and
other technical subjects. As always, this crossword 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 (e.g., Reginald Denny or
the Tunguska event in Siberia). The technically inclined cruciverbalists amongst
us will appreciate the effort. Enjoy --- This one is going to take a while!
 Notice that the output (collector) of Q1
is connected directly to the input (base) of Q2. The network of R4, R5, and R6 is
a voltage divider used to provide the bias and operating voltages for Q1 and Q2.
The entire circuit provides two stages of amplification.
Direct coupling has several disadvantages, however. The major problem is the
power supply requirements for direct-coupled amplifiers. Each succeeding stage requires
a higher voltage. The load and voltage divider resistors use a large amount of power
and the biasing can become very complicated. In addition, it is difficult to match
the impedance from stage to stage with direct coupling. The direct-coupled amplifier
is not very efficient and the losses increase as the number of stages increase...
 With more than 1000
custom-built symbols, this has got to be the most comprehensive set of
Visio Symbols
available for RF, analog, and digital system and schematic drawings! Every object
has been built to fit proportionally on the provided A-, B- and C-size drawing page
templates (or can use your own). Symbols are provided for equipment racks and test
equipment, system block diagrams, conceptual drawings, and schematics. Unlike previous
versions, these are NOT Stencils, but instead are all contained on tabbed pages
within a single Visio document. That puts everything in front of you in its full
glory. Just copy and paste what you need on your drawing...
 By 1950, say the author of this story, "No
longer are 'aerials' merely required to transfer electromagnetic energy into
space," in reference to airborne platforms. Following great advancements in radio
and radar technology during World War II, great interest lay in what would
later become referred to as 'stealth' technology and in secure communications. The
transition of aircraft speeds into the realm of supersonic also mandated that projections
beyond the main airframe outline be either eliminated or very much minimized. The
long cable aerials that stretched from the cockpit area to the tip of the vertical
fin, and the round direction finding antennas hanging from below could not be accommodated
at airspeeds above about 300 knots. The aerodynamic drag would be excessive
and the forces would tear the antennas apart. Douglas Aircraft set up one of the
first antenna measurement laboratories...
 RF Cafe visitor Mike M. sent this very
interesting note after reading this "Frequency
Modulation Fundamentals" article: Again, you hit it out of the ballpark, Kirt!
Great article out of QST. Absolutely accurate to credit "The Old Man" Edwin Armstrong
for the invention/development of FM and much more, plus the work of Dan Noble, who
worked with the Connecticut State Police and Motorola as Director of Research. Also
many, many others. Some that have never been properly credited. Guys like Bob Morris,
W2LV and Frank Gunther, W2ALS. They were both interviewed by Ken Burns for "Empire
of the Air". I was fortunate enough to talk to both of these guys after I got my
Tech license in 1970. My immediate supervisor/mentor from 1972 until he retired
in ~1990, was George. He was a superb mentor, who espoused the best engineering
methods and as he would say " the price of success is constant vigilance." George
had worked for Armstrong at the pioneering FM station, W2XMN in the late 40's and
early 50's. George had several stories about working for "The Old Man..."
 A nice article by Donald Lancaster appeared
in an issue of Radio-Electronics magazine that introduces and puts into
layman's terms the relatively new (at the time) world of
digital logic circuits. Rapidly falling prices and equally
rapidly rising performance fuelled the craze. By 1969, most of the barriers
preventing former never-tubers from adopting the fledgling semiconductor
paradigm and there was by then a new generation of electronics hobbyists,
technicians, and engineers who had "grown up" on transistors and integrated
circuits. I like the author's analogies for AND gates and OR gates that involve
the familiar objects that include a garden hose with the house tap and nozzle,
and the kitchen sink faucet with the hot and cold handles. It's interesting how
often water, a substance generally to be avoided around electricity...
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...
 In 1945 when this series was published in
Radio-Craft magazine,
microwaves were pretty much the realm of corporate and university
research laboratories and - often coincidentally - secret Department of War projects.
Radar was the primary application, although some work was being done on high bandwidth
communications by the aforementioned entities, in some cases following in the footsteps
of amateur radio operator's discoveries about how the higher frequencies were affected
by the ionized layers of the Earth's atmosphere. Immediately following the end of
World War II, the government began declassifying a lot of information learned
about microwave, and magazines were fast to pick up on it. In fact, there were instances
where editors saw fit to write columns asserting their right to do so when criticisms
were heaped upon them by readers accusing them of divulging critical security-related...
 This assortment of custom-designed themes
by RF Cafe includes T-Shirts, Mouse Pads, Clocks, Tote Bags, Coffee Mugs and Steins,
Purses, Sweatshirts, Baseball Caps, and more, all sporting my amazingly clever "RF Engineers - We Are the World's Matchmakers"
Smith chart design. These would make excellent gifts for husbands, wives, kids,
significant others, and for handing out at company events or as rewards for excellent
service. My graphic has been ripped off by other people and used on their products,
so please be sure to purchase only official RF Cafe gear. I only make a couple bucks
on each sale - the rest goes to Cafe Press. It's a great way to help support RF
Cafe. Thanks...
 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...
 According to the Wikipedia entry, "the
Institute of Radio Engineers (IRE) was a professional organization which existed
from 1912 until December 31, 1962. On January 1, 1963 it merged with the American
Institute of Electrical Engineers (AIEE) to form the Institute of Electrical and
Electronics Engineers (IEEE)." The IRE's annual convention, quite often held in
New York City at the Waldorf-Astoria Hotel, was the equivalent to what is (was)
today (except 2020 and likely 2021, 2022, ...) the IEEE MTT-S International Microwave
Symposium (IMS). Product vendors hacked their wares, technical presentations were
made, and professional liaisons were made. A visit to the IMS 2021 website shows
they are pretending as if there really will be a physical show in Atlanta, Georgia.
Georgia is one of the 14 states which as of December do not require face masks...
 One of the Notable Tech Quotes which has
appeared on RF Cafe is, "The nice thing about standards is that you have so many
to choose from," by computer scientist Andrew Tanenbaum. In the middle of the last
century, a change in the fundamental understanding of current flow precipitated
what has become a very large opportunity for people to misunderstand descriptions
of
current direction caused by a difference in voltage potential (voltage) - depending
on the era a particular description was written. Beginning with Benjamin Franklin,
electron current flow was assumed to be from positive to negative, ostensibly but
incorrectly, because a positive thing must contain an excess of something (charge
carriers - electrons) and a negative thing must have a deficiency. Hence, current
flowed from an excess source to a deficient sink. We now know that negative things
contain more electrons (relatively) than a positive...
 Decisions, decisions, decisions. As the title
states,
color television manufacturers were, in 1965, finding themselves
between a rock and a hard place, as the saying goes, regarding a change from vacuum
tubes to transistors. The buying public (aka consumers) had mixed emotions about
the newfangled semiconductors based at least partly on bad information about transistors.
Transistors had been designed in various circuits for a decade and a half and were
gaining rapidly in performance and reliability. The price was coming down, but as
reported here, still cost $5 to $10 apiece compared to a $1 vacuum tube. Company
management needed to decide whether to delay implementing the new engineering and
production methods required to deal with transistors for a couple more years until
the market had more time to make up its mind whether to begin. A couple firms enthusiastically...
The newest release of RF Cafe's spreadsheet
(Excel) based engineering and science calculator is now available -
Espresso Engineering Workbook™. Among other additions, it now has a Butterworth
Bandpass Calculator, and a Highpass Filter Calculator that does not just gain, but
also phase and group delay! Since 2002,
the original Calculator Workbook has been available as a free download.
Continuing the tradition, RF Cafe Espresso Engineering Workbook™ is
also provided at no cost,
compliments of my generous sponsors. The original calculators are included, but
with a vastly expanded and improved user interface. Error-trapped user input cells
help prevent entry of invalid values. An extensive use of Visual Basic for Applications
(VBA) functions now do most of the heavy lifting with calculations, and facilitates
a wide user-selectable choice of units for voltage, frequency, speed, temperature,
power, wavelength, weight, etc. In fact, a full page of units conversion calculators
is included. A particularly handy feature is the ability to specify the the number
of significant digits to display. Drop-down menus are provided for convenience...
 Here are three more
technology-themed comics from vintage of Radio & Television New magazines.
Some issued had multiple comics, but these three had just one apiece, so I combined
them onto a single page. There is a huge list of previously posted comics at the
bottom of the page. With many of these comics, you might need to be familiar with
the mindset of the electronics world back in the day. Today it considered hilarious
today to see a video of someone walking into a street lamp pole while staring obliviously
into a smartphone. In the middle of the last century, fun was made of wives not
understanding their hubbies' hobbies, dealings with servicemen, and and goofy things
do-it-yourselfers of the era were doing.
 This
vector circuit matching quiz will hurt the brain a little more
than most of the ones that were printed in Popular Electronics. In order to
score well, it helps to visualize the circuits relative to where they would
appear on a Smith Chart. Capacitive impedances lie in the bottom half and have
negative phases (-s, -jω). Inductance lie in the upper half and have positive
phases (s, jω). The familiar 'ELI the ICE man' mnemonic helps, too. Be sure to
pay attention to the color of the vector arrow heads. Example: In a purely
inductive circuit like #4, voltage leads current by 90°. Since phase rotation is
CCW, you need to look for lettered phase diagram where the white arrowhead
(voltage) is 90° ahead of the black arrow head...
 Summer begins this week in the northern hemisphere,
and winter begins south of the equator. Counterintuitive to northerners not familiar
with the geometric cause of seasons (axis tilt) is that the Earth is actually closest
to the sun in January than it is in July. Our orbital path is nearly circular, with
an eccentricity of just 0.0167. Anyway, I thought the onset of summer would be a
good time to post this installment of
Mac's Radio Service Shop entitled, "Summer Seminar." Typical of author John
Frye's techno-sagas, more than one theme runs through the story. It begins with
shop owner Mac admonishing technician Barney for throwing away a faulty selenium
rectifier when he knows there is an industry-wide shortage on supplies of the element
and the bad components should be submitted for recycling. Fretting over as common
an element ...
 Here is a humorous "Kool-Keeping
Kwiz" that appeared in the June 1970 issue of Popular Electronics magazine.
Your answers to questions will determine whether you are a truly cool technophile,
or you are just a maniacal misanthrope who happens to know something about radios
and regulations. This would probably have been more aptly printed two issues earlier
as an April Fools' joke...
 In times of peace and times of war,
Amateur radio operators are the first in line to serve their countrymen and
citizens all over the world. As documented in the pages of the American Radio Relay
League's QST magazines throughout the years of World War II, Hams proved
to be invaluable to the effort. Even though probably none had previous radar system
experience, their practiced aptitude for electronics made them perfect candidates
for the task. In appreciation for their heroic efforts to help ultimately win the
war on all fronts, the U.S. military put a lot of effort into preparing radiomen
and radarmen for life in the civilian world. This article from April 1945, nearing
the end of the war, discusses the value of military experience ... |
