|
 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...
 Even with having been granted more than
400 patents in his lifetime, and being a major player in the realms of energy, data
storage, and semiconductor research and manufacturing, you - as well as most people
- have probably never heard the name
Stanford Ovshinsky. He was somewhat of a celebrity in the 1960s and 1970s when
working hard to promote his concept of "glassy semiconductors," - aka Ovonic devices.
Ovonics are amorphous materials that are used for making switches for digital logic
and memory devices. Either the Ovshinsky process did not pan out for high volume
commercial production or some other technology displaced the what it was hoped to
dominate...
 If I told you that Lester William Polsfuss
is widely credited with being a major player in the pioneering of electric guitars
due to his solid-body (no acoustic resonance chamber) designs, you might wonder
where I came up with that claim. However, if you know that Mr. Polsfuss is the surname
of Les Paul, then you would quickly agree. As if being a popular musician and, along
with wife Mary Ford, selling millions of records wasn't enough, Les Paul was also
an experimenter and inventor in the electronic music realm. This article entitled
"Les
Paul: Technician and Musician" appeared in a 1958 article in Radio-Electronics
magazine, and was at the time a contemporary look inside his...
 Sam Benzacar, of Anatech Electronics, an
RF and microwave filter company, has published his August 2026 newsletter that,
along with timely news items, features his short op-ed titled "Filtering
for Quantum: A Problem No One's Talking About." Sam aptly points out that as
quantum computers scale in size, specialized laboratory-built components become
both expensive and a schedule liability for development efforts. When a handful
of qubits was considered breakthrough-amazing, building all the parts in-house made
sense since processes and materials were being invented in the process of doing
so. However, at the point when thousands of filters, amplifiers, and other types
of components routinely manufactured...
 Georg Simon Ohm's discovery of the relationship
between voltage, current, and resistance revolutionized our understanding of electrical
circuits. Ohm's Law provided a simple, yet powerful mathematical tool that has become
essential to both theoretical physics and practical engineering. Although it was
initially met with skepticism, Ohm's perseverance and commitment to his scientific
work ultimately transformed the way we interact with electricity, influencing technologies
that define the modern world. His legacy lives on not only in the equation that
bears his name but also in the unit of electrical resistance - the ohm - that honors
his contributions to science...
 When you think about it, the speed at which
a human being is able to accurately copy
Morse code is limited by the same kinds of processes that limit
the speed at which binary data can be sent between electronic transceivers (modems).
Noise introduced into the signal at both the transmitting and receiving ends or
in the transmission path connecting the two, degrades the ability of the receiver
(electronic and human) to discern between a "1" and a "0." It can take the form
of electrical or audio interference and distortion. Phase noise in the electronic
realm is sort of the equivalent of an irregular sending human hand that cannot maintain
equal dwell times for dits and dahs, thus making the recognition...
 Why Phase Stability Matters During RF/Microwave
Testing. When engineers evaluate RF test cables, specifications such as insertion
loss, VSWR, shielding effectiveness, and connector type typically receive the most
attention. Yet for many Vector Network Analyzer (VNA) applications, one characteristic
can have a greater impact on measurement accuracy than all of these combined: phase
stability. Phase stability refers to a cable assembly's ability to maintain a consistent
electrical phase relationship when subjected to movement, flexing, temperature changes,
or repeated...
 Magnetic amplifiers (aka "mag amps") use
a property of saturated core inductors (saturable reactors) to obtain signal amplification
via a transformer-type plus diode-assisted voltage multiplication.
Magnetic amplifiers were preferred over vacuum tube amplifiers
in some circuits because they do not require a high bias voltage, are generally
smaller in size, are quite robust and are practically immune to microphonics. Their
biggest limitation is bandwidth. The high number of turns in the core provides a
lot of interwinding capacitance so the self-resonant frequency is in the low megahertz
range. Additionally, the need for the magnetic amplifier reactor to operate in a
saturated condition further...
 Anritsu has been a global provider of innovative
communications test and measurement solutions for more than 120 years. Anritsu manufactures
a full line of innovative components and accessories for
RF and Microwave Test and Measurement
Equipment including attenuators & terminations; coaxial cables, connectors &
adapters; o-scopes; power meters & sensors; signal generators; antenna, signal,
spectrum, & vector network analyzers (VNAs); calibration kits; Bluetooth &
WLAN testers; PIM testers; amplifiers; power dividers; antennas. "We've Got You
Covered."
 The National Company, of Malden, Massachusetts,
which made this
cesium-based Atomichron in the mid-to-late 1950s, began life as
a toy manufacturer. It had an output frequency at the nominal resonance frequency
of cesium - 9192.631830 MHz - and was accurate to better than a second in 600
years. The unit was 7 feet tall and weighed 500 pounds. Modern cesium standards
are more stable and are portable. As of January 2013, the NIST-F1 cesium fountain
primary frequency standard is accurate to within one second every 100 million years!
That's a tad better than the Atomichron, non...
 This Bell Telephone Laboratories (aka Bell
Labs) advertisement appearing on the inside back cover of the 1958 issue of
Radio & TV News magazine celebrated the 10th anniversary of their
announcement of the world's first
point contact transfer resistance (transresistance) semiconductor
device - aka the transistor. John Bardeen, William Shockley and Walter Brattain
recorded the monumental event in a lab notebook on December 23, 1947 - a nice Christmas
present for the world! The trio's invention was not like the robust bipolar
transistors used today, or even ten years later in 1958. Rather than employing point-contact
"cat's whisker" metallic probes for making the emitter and collector...
 For many years, I have been scanning and
posting schematics & parts lists like this one that appeared in radio and electronics
magazines in the middle of the last century. Most use vacuum tubes. This
General Electric Model 280 Farm Radio "Radio Data Sheet" was in
the May 1947 issue of Radio-Craft magazine. The Radio Museum website has
more information on the GE Model 280 Farm Radio. Farm radios were designed to work
on storage batteries since until the Rural Electrification Act of 1936 was put into
effect, most rural properties had no commercial AC electric power service. 11 years
later, work was in progress to light up the entire country, but many locations had
to wait while resources...
 Here are a couple new-old
tech-themed comics from vintage Popular Electronics magazines.
Both have a Ham radio theme, so maybe you need to have been there to appreciate
the scenario... or maybe not. It is possible that the presence of clothes pins on
twin lead or ladder line could de-tune the line, and could crush the internal dielectric
of a coaxial line. There is no metal on boxer shorts, but maybe the clothes pins
are the type with a metal spring. For the other comic, you just need to know what
••• --- ••• is to get it. Enjoy...
 Question: If a fuse is rated at 3 amps,
at what value of current should it "blow?" Answer: Not at 3 amps. As this
Littelfuse company advertisement from a 1954 issue of Radio & Television
News magazine informs us, fuse ratings do not indicate the current value at
which a fuse opens to protect a circuits, but rather the maximum current level at
which it will NOT blow (open circuit). The same goes for circuit breakers. Various
types of fuses are available to handle certain types of applications. For instance,
a highly capacitive load will according to the well-known equation iC(t) = C * dv/dt
could draw a very large amount of initial (inrush) current if there is not enough
series resistance to limit it to prevent...
 Ohm's Law is the bedrock of electrical engineering.
Formulated by Georg Simon Ohm in 1827, it establishes the fundamental linear relationship
between voltage (V), current (I), and resistance (R) in an ideal conductor. This
simple yet profound equation -- V = IR -- allows engineers to predict circuit behavior,
design voltage dividers, calculate power dissipation, and troubleshoot complex systems
with ease. While it holds true for most metallic conductors under constant temperature,
real-world circuits often involve non-linear components and temperature-dependent
materials where the law must be applied with nuance. This
Ohm's Law Quiz covers
the core mathematical relationships, units of...
 "Our first complete column devoted to the
subject [of v.h.f. and u.h.f. signal variation], presenting material similar
to that which follows, was withheld from publication at that time in compliance
with censorship." That is an amazing statement from a time when almost any form
of technical information that was not already public knowledge was withheld for
the sake of the war effort. Nothing that might even remotely give the enemy an edge,
and consequently possibly harm our troops, got past the government censors at the
War Department. Most citizens and even media editors willingly complied. Compare
that with today's 5th column traitors at most of the media outlets that not
only can't wait...
 Waaaay back in the mid-1980s when I first
became aware of
Digi-Key, it was one of the relatively few electronics component
suppliers that had a large on-hand stock of commonly used parts and provided fast
shipping. Places like Newark Electronics and Allied Electronics also provided good
service, but Digi-Key usually offered lower prices than the others. By the 1990s,
I was placing orders at least weekly during circuit design projects. Digi-Key was
founded in 1972 in Thief River Falls, Minnesota - the town that for many years often
had the country's lowest recorded daily temperature. This 1/4-page advertisement
appeared near the back of a 1974 issue of Popular Electronics magazine...
 Randy Rogers, AD7ZU, mentioned in the May 2020
issue of QST magazine the Smith Chart software called "SimSmith,"
by Ward Harriman, AE6TY. SimSmith first appeared around 2011. Being written in Java,
it will run on any operating system that supports Java. Recent versions incorporate
Numerical Electromagnetics Code (NEC) code and bear the name "SimNEC."
At present, several versions of SimSmith/SimNEC are available. If you are following
a video and want to use the SimSmith release closest to that used in the video,
look at the top of the screen to see the version of SimSmith being used and then
choose between older versions. If you new to the software, he strongly...
 When really good researchers set out to
write books on history, they do not simply cull information from the publications
of fellow contemporary authors; instead, they look for sources that were published
during or around the time of the subject being covered. Doing so helps minimize
the possibility that inaccuracies have crept into the knowledge pool and that information
other authors might have either deemed insignificant or have missed can be recovered.
That is part of my motivation for going to the trouble of buying these vintage magazines
and posting articles like this one which reports on early
maser developments. It delves fairly deeply into the solid state physics of
rare earth...
|
Loading history...
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.
 Are you between 16 and 17½ or between
26 and 35 and not in uniform? Are you 1-C or mildly 4-F or otherwise ineligible
for military service? Are you interested in a radio operating job in direct support
of the war effort? Then there's a place for you in the
U. S. Maritime Service. If you hold a commercial radio-telegraph
second or higher-grade license, so much the better. But you don't need a ticket
to start with; in fact, you don't need any previous radio training whatsoever.
The Maritime Service will train you. It will make a proficient merchant marine radio
operator out of you at one of the nation's finest operator schools - with pay!
This is an opportunity described several times before in QST...
 This
Engineering Theme Crossword Puzzle for February 28th contains
only words and clues related to engineering, mathematics, chemistry, physics, and
other technical words. 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., Hedy Lamarr or
the Bikini Atoll). The technically inclined cruciverbalists amongst us will appreciate
the effort. Enjoy!
 "My husband wants a selenimum rectalfire,
a silicode capasitator, and a 16 bome appleflyer." That is the caption of one of
the "Hobnobbing with Harbaugh," comics that appeared in the June 1962
edition of Popular Electronics magazine. Dave Harbaugh's "Hobnobbing
with Harbaugh" was a monthly feature for a couple years that dealt with stereotypical
(pun intended) behavior of technophiles and their often unwilling, often unwitting
wives, girlfriends, kids, parents, workmates, and neighbors...
 This
Electronic Puzzle Square, compliments of Lt. C.K. Johnson, appeared
in the January 1945 issue of Radio-Craft magazine. It consists of electronics-related
numerical questions whose answers, if correct, create a 4x4 matrix whose columns,
rows, and long diagonals all add up to 45. Non-integer answers need to be rounded
according to standard rules (do not just truncate). In case you left your slide
rule at the office, a link is provided to assist with Q2. The biggest head scratcher
question is Q4, since it requires the conversion from polar to rectangular coordinates,
but hey, you're an engineer (or a crack technician). Having Euclid on-hand for Q5
might be helpful. A link is provided to a copper ...
 When doing some research for creating a new
quiz on inventors and their inventions, I decided to look for people according
to their countries. I almost always do image searches since doing so does a good
job of filtering out pages that merely mention the topic of interest. My first Google
search was "american inventors." I expected to see the familiar faces of Thomas
Edison, Henry Ford, George Westinghouse, Marie Curie, Alexander Graham Bell, George
Washington Carver, Edwin Armstrong, Hedy Lamarr, Benjamin Franklin, Robert Goddard,
Albert Einstein, the Wright Brothers, Samuel Morse, William Shockley, etc. Those
are the names that first come to my mind, and admittedly the list is dominated...
 Audio crossover networks have the same fundamental
mission as RF multiplexer filters in radio systems, which is to separate and steer
specific bands of frequencies into two or more signal paths. While simple in concept,
implementation in hardware can be a major challenge depending on requirements for
channel separation, feedthrough, phase and group delay, amplitude equalization,
distortion, and other factors. This article discusses some of the decisions used
by crossover network designers when considering where to make band breaks, while
leaving actual circuit design rules to other authors. I built a set of custom speakers
many moons ago and went through the frustrating process...
 Constant K filters are not seen much in modern
designs, but were some of the earliest types of controlled impedance frequency selective
networks. George Campbell is credited with inventing constant K filters in the early
days of the last century. He referred to the circuits as "electric wave filters."
Campbell's filters consisted of identical cascaded sections of "T" and "pi"
inductor and capacitor combinations, yielding arbitrarily high (theoretically) out-of-band
cutoff and band edge steepness. Less than ideal quality factor of the components
causes realizable filters to exhibit increasing insertion loss and reduction in
band edge corner sharpness as sections are added. Within a couple decades as improved
filters...
 Even though my fingers stop working when
exposed to temperatures below freezing, I love the northern climate - four full
seasons, snow, iced-over lakes, migrating birds, fiery autumns, cool summers, the
whole experience. Having the option of not participating in the cold outdoor environs
is what makes it good. However, the
U.S. Army Signal Corps guys pulling duty in Alaska during World
War II did not have that luxury. As told by radio engineer Major Colvin in
this story from a 1945 edition of ARRL's QST magazine, winter life in Alaska
at -40° was a real challenge. It was a world where Prestone antifreeze froze, the
sun shone only a few hours a day, vehicles had to be left running...
 For the past few months, this full-page BridgeCom
advertisement has been running in the American Radio Relay League (ARRL) magazine
QST. When I first saw it I though it might be one of those research laboratory
hydraulic apparatuses for generating the kind of pressure found at the center of
the Earth. Scientists use such devices to synthesize diamonds by compacting coal.
In actuality, the four cylinders are part of the
BridgeCom BCD-144250 Rack Mount VHF Duplexer. Per their website:
BridgeCom Systems' BCD-144250 Duplexer for amateur and commercial applications.
The BCD-144250 utilizes four high-quality cavities that results in uncompromising
duplex isolation. It will handle up to 250 W...
 Yes, this is another article that will probably
appeal to a small percentage of RF Cafe visitors, but please countenance my indulgence
in things aeronautical as well as things electrical. The early 1930s was a time
when both airplanes and electronics were a wonder and a mystery to most of the public
worldwide. Of course today both are still a mystery to the public but the wonder
is gone - it's merely taken for granted. Many idiosyncrasies of
airborne electronic communications were encountered for the first
time, like the need for proper grounding and static electricity dissipation. Ruggedization
of chassis assemblies in terms of mechanical vibration and shock as well as for
temperature extremes was...
 Since there does not seem to be service-related
trade magazines - at least for electronics - anymore, most people have never gotten
first-hand experiences of the kinds of travails endured by servicemen as imposed
by customers. Radio News, Radio-Electronics, Popular Electronics,
Radio-Craft, and other such magazines regularly carried articles and sometimes
regular monthly columns with content contributed by guys in the repair shop and
in homes. Some were actual scenarios and others were fictional based on typical
experiences. The most entertaining were told in story form, and were undoubtedly
embellished a bit in order to increase the drama factor. This Serviceman's Experiences...
 When civil engineers and mechanical engineers
take their introductory classes in hydraulics, are they taught that the
functional equivalent of water pressure in a pipe is equivalent
to voltage in a battery, and that the rate of water flow is equivalent to current
in a circuit, and that the diameter and surface finish of pipes are equivalent to
resistance in electricity... in the same manner that electronics students are taught
from the opposite point of view? The answer is 'yes,' they are. It's
kind of funny how for some reason using an analogy from another familiar physical
process always seems to help make more sense of the subject at hand. In fact, for
macro level problems, the mathematical equations that govern...
 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...
 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...
 The August 1958 issue of Radio News
marked the merging of All-Wave Radio with Radio News, both founded
by Hugo Gernsback. Radio News began publication in July 1919 (actually titled
Radio Amateur News for the first year) and All-Wave Radio debuted
in September 1936. "All-wave" radio referred to a class of radios popular at the
time which could tune in most of the worldwide commercial broadcast stations, spurring
the accompanying "short wave listening" craze. This instance of the monthly "Within
Earshot of the Editor" column received a lot of attention because it fired a shot
across the bow of the ARRL for not sufficiently lobbying the FCC for the
electromagnetic spectrum access rights...
|
