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At least 10 clues with an asterisk (*)
in this
technology-themed crossword puzzle are pulled from this past week's
(7/16 - 7/20) "Tech Industry Headlines" column on the RF Cafe homepage. For the
sake of all the avid cruciverbalists amongst us, each week I create a new technology-themed
crossword puzzle using only words from my custom-created list related to engineering,
science, mathematics, chemistry, physics, astronomy, etc. You will never find among
the words names of politicians, mountain ranges, exotic foods or plants, movie stars,
or anything of the sort. You might, however, see someone or something in the exclusion
list who or that is directly related to this puzzle's theme, such as Hedy Lamar
or the Bikini Atoll...
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Any time I see an article that references
causing limb movements by poking the brain with electrical signals, I think of the
old The Far Side comic. Artist Gary Larson drew quite a few hilarious operating
room scenarios.
Electrocution is of course not a laughing matter - unless it happens
to someone else and it is not serious and no harm is done. Then - and only then
- can it be funny. I've laughed at myself many times after receiving a good
jolt due to stupidity. Sometimes after such an experience I wonder how I never killed
myself from getting zapped as the result of being too lazy to turn off a circuit
breaker before servicing a light switch or receptacle. The sad thing is that I'll
probably do it again some day...
Empower RF Systems is the technological
leader in RF & microwave power amplifier solutions for EW, Radar, Satcom, Threat
Simulation, Communications, and Product Testing. Our air and liquid cooled amplifiers
incorporate the latest semiconductor and power combining technologies and with a
patented architecture we build the most sophisticated and flexible COTS system amplifiers
in the world. Solutions range from tens of watts to hundreds of kilowatts and includes
basic PA modules to scalable rack systems.
Popular Electronics magazine printed
in April 1966 its first notice of
new frequency units to be used beginning with the June edition.
The May issue included this piece titled, "Comes the Revolution - or - '40 Million
Frenchmen Can't Be Wrong'." Predictably, not everyone liked it. With the
June issue came the promised change and along with it the first in a series of reader
responses. I also found a reader's opinion from the August issue as well. Evidently,
not everyone wanted to honor Heinrich Hertz by naming the base unit of frequency
in his honor...
"Eventually," Dr. Herwald said, "we believe
it will even be possible to automatically and continuously produce actual electronic
equipment, such as radio receivers and amplifiers, starting from a pool of molten
semiconductor materials." That was in early 1960 in an Electronics World
article titled, "Molecular Electronics." The term "molecular" references what eventually
became integrated circuits (IC), the first of which was realized in 1958 by Texas
Instruments engineer Jack Kilby. Kilby's IC incorporated one transistor, one
capacitor, and three resistors on a germanium substrate. Building on that success,
researchers envisioned single-chip semiconductors which contained hundreds, thousands,
and even millions of transistors, diodes...
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 models have been added to the product line in June, including
a 9660 MHz (COM1 - COM3) cavity bandpass filter, a 2442 MHz waveguide
band stop filter, and a 2072.5 MHz / 2250 MHz / 1800 MHz triplexer
filter. Custom RF power filter and directional couplers designs can be designed
and produced with required connector...
I suppose a more appropriate title for this
chart would be "Foreign Valve Substitution Data," considering that most (if not
all) of Europeans refer(red) to vacuum tubes as "valves." As with having posted
scores of Radio Service Data Sheet pages for the benefit of hobbyists who restore
and service vintage radio equipment, I also post other hard-to-find reference resources
when I find them. Sure, the number of people looking for this information is extremely
small, but they are extremely grateful for this when in the throes of finding replacement
tubes (valves). Posting a hyperlink to this page on the RF Cafe homepage will assure
that...
My father used to refer to the "sweet-voiced
lady predicting the weather over and over again" as my girlfriend because I would
call the "WEather 6-1212" phone number (936-1212) so often. It really wasn't
because I was infatuated with her voice, it's that I was obsessed with weather forecasting.
Most of my free time as a kid and teenager was spent building and flying model airplanes
and rockets, and at eighteen years of age I began taking full-size aeroplane flying
lessons, so my world revolved around a zone extending from terra firma up to about
5,000 feet AGL. This collection of communications news...
Innovative Power Products has been designing
and manufacturing RF and Microwave passive components since 2005. We use the latest
design tools available to build our baluns, 90-degree couplers, directional couplers,
combiners/dividers, single-ended transformers, resistors, terminations, and custom
products. Applications in military, medical, industrial, and commercial markets
are serviced around the world. Products listed on the website link to detailed mechanical
drawings, electrical specifications, and performance data. If you cannot find a
product that meets your requirements on our website, contact us to speak with one
of our experienced design engineers about your project.
Welcome to the
RF Cafe
Isolators & Circulators Quiz, an essential assessment for engineers focused
on the reliable sampling and monitoring of signal flow. Directional couplers are
the cornerstone of power metering, reflected power detection, and signal injection
in high-frequency transmission systems. Whether you are calibrating a forward-power
monitor, auditing VSWR in a feedline, or balancing a complex signal distribution
network, a rigorous understanding of coupling factor, directivity, and insertion
loss is vital. This quiz challenges your knowledge of these passive structures,
covering the mechanics of coupled transmission lines, the significance of isolation
and directivity, and the critical trade-offs in power splitters and tap networks.
By evaluating your grasp of these core principles
Werbel Microwave's
WMADC-0.38-3-40DB-SERIES is a high-power 40 dB directional coupler covering
380 to 3000 MHz, supporting a wide range of VHF, UHF, cellular, LTE, and wireless
infrastructure bands. Built on an air dielectric coaxial structure, this design
delivers low insertion loss, excellent power handling, and exceptional directivity
for accurate forward and reverse power discrimination. Unlike many broadband couplers
that prioritize ultra-flat coupling, this model is engineered to maximize directivity
across the band, ensuring cleaner separation between forward and reflected signals.
In most real-world systems, coupling variation is easily calibrated out...
The
medical x-ray machine shown here reminds me of the "Illudium Q-36 Explosive
Space Modulator" contraption Marvin the Martian wanted to use in "Hare-Way to the
Stars" to disintegrate the Earth (because it blocks his view of Venus). Of course
our hero Bugs Bunny thwarts his plan, whereupon Marvin asks, "Where's the kaboom?"
Can you imagine being fraught with cancer and getting strapped into a chair with
that huge hypodermic-needle-looking thingy pointed at you, as shown in this 1959
issue of Popular Electronics magazine? The Caduceus sword in the pic doesn't
help matters, either. The trauma of such an experience might have been worse than
the treatment for some people. As usual the pioneers took the arrows so that we
can benefit from the treatments enjoyed today, and the equipment does not look nearly
as intimidating. See also "After Class: X-Rays" for more info...
A wee bit of levity in the form of comics
is good for the soul on a busy workday.
Good humor, it is said, contains a degree of truth in it, and this group from
vintage editions of Radio-Craft magazine is no exception. One of the comics
in particular struck a chord with me - the one with the table model radio where
the serviceman is speaking on the phone with his customer. The first familiar feature
is the shape of the radio and the removed rear cover; it reminds me of my Tesslor
R-601S. The second thing is the dead bugs. Just like a stray cat will climb into
your car's engine compartment on a bitter cold day in search of heat, so will
bugs be drawn to a heat source such as that provided by an electronic appliance
filled with warm, glowing vacuum tubes...
Innovative Power Products has been designing
and manufacturing RF and Microwave passive components since 2005. We use the latest
design tools available to build our baluns, 90-degree couplers, directional couplers,
combiners/dividers, single-ended transformers, resistors, terminations, and custom
products. Applications in military, medical, industrial, and commercial markets
are serviced around the world. Products listed on the website link to detailed mechanical
drawings, electrical specifications, and performance data. If you cannot find a
product that meets your requirements on our website, contact us to speak with one
of our experienced design engineers about your project.
The concept of
exploding wire propulsion is a fascinating relic of the early Space Age concepts,
reflecting an era of high-energy-density experimentation that prioritized power
density over long-term system efficiency. While this 1962 Electronics Illustrated
magazine report captured a valid physical phenomenon - the rapid plasma expansion
of a metallic conductor - the practical implementation for spacecraft encountered
insurmountable engineering hurdles relative to the chemical and electrical propulsion
benchmarks that followed. When you dump several thousand amperes into a 1-mil wire
in nanosecond timescales, you bypass traditional heating...
Here is another article about a
"prodigal" Ham who returned to amateur radio after about a 30-something year
respite, per this 1955 Popular Electronics magazine. Author Charles Meistroff's
previous experience had been with surplus World War I - yes that's WWI! He must
have been in Heaven to be able to now get his hands on all the new-fangled equipment
now (then) available on the World War II surplus equipment market! I don't know
if the military is still making surplus equipment available like they did even up
through Korea and Vietnam. There must be some great stuff from the Middle East wars
if it is circulating within the surplus market. Then again, other than ruggedness
factors, most commercial equipment is as good or better than MIL-SPEC stuff...
"If the car is parked in a dark remote spot
it is better to do the job where the car is. This is because auto burglary is a
lesser crime than stealing the whole damn car." That remark was made by a 'former'
thief who ostensibly gave up a life of crime after spending nearly two decades in
the slammer for various infractions of the law. One of his specialties was breaking
into cars to steal radios - AM, FM, CB, Ham, or whatever was available. Mr. X
volunteered his insight for the benefit of QST readers who might want to take proactive
steps to help minimize the chance of being a victim. The year was 1967, but you
can bet the same mindset pervades the thinking of modern day break and grab thieves
today. Even though most modern portable electronics equipment is protected from
access by passwords, that wouldn't stop a thief from stealing...
Prior to the emergence of
silicon-based semiconductors, selenium and copper(cuprous)-oxide
rectifiers were the alternatives to vacuum tubes. Copper-oxide (Cu2O)
was popular as a small signal detector since its forward voltage drop was similar
to a Schottky type diode - typically around 0.2 V. Copper-oxide diodes were
used in radios and test equipment meters. Selenium (Se) has a forward voltage drop
of around 1 V, but its high reverse voltage withstanding of 20 V or more
made it popular for voltage rectification, with as many layers as necessary being
stacked serially as required. Selenium rectifier stacks...
Centric RF is a company offering from stock
various RF and Microwave coaxial
components, including attenuators, adapters, cable assemblies, terminations,
power dividers, and more. We believe in offering high performance parts from stock
at a reasonable cost. Frequency ranges of 0-110 GHz at power levels from 0.5-500
watts are available off the shelf. We have >500,000 RF and Microwave passive
components we can ship you today! We offer Quality Precision Parts, Competitive
Pricing, Easy Shopping, Fast Delivery. We're happy to provide custom parts, such
as custom cables and adapters, to fit your needs. Centric RF is currently seeking
distributors, so please contact us if interested. Visit Centric RF today.
Welcome to the
RF Cafe Coaxial Cable
Quiz, a technical assessment designed to sharpen your proficiency in the fundamental
transmission media that underpin all radio frequency communications. Whether you
are scaling a tower for antenna installation, troubleshooting impedance mismatches
in a feedline system, or calculating loss budgets for a long-run cable deployment,
a firm command of coaxial theory is vital for maintaining signal integrity and power
efficiency. This quiz challenges your understanding of critical transmission line
metrics, including characteristic impedance calculations, the impact of dielectric
constants on velocity factor, the physics of the skin effect, and the thermal limitations
of power handling. By testing your knowledge...
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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.
Passive repeater antennas have been used
for a long time to overcome line-of-sight-limitations of many - if not most - of
the radio communications universe. Properly designed and implemented
passive repeaters can exhibit very high levels of efficiency,
and in some cases can actually provide gain by focusing signals impinging on a large
panel of multiple wavelength dimensions onto a smaller transmitter or receiver antenna.
That is known as aperture gain. Optical telescopes are a good analogy where for
the same level of magnification at a given wavelength, a larger aperture (refractive
lens or reflector mirror) results in a brighter image at your retina or CCD...
Sprague Electric engineer Benedict Rosen,
discusses how the characteristics of a circuit in need of protection against RF
interference needs to be considered when selecting filter components. He points
out that attempting to hang a shunt
feedthrough capacitor on the input and/or output of a low impedance
(e.g., 50 Ω) RF circuit could make the situation worse, depending on whether
the circuit is strongly capacitive or inductive in its out-of-band region. Sprague
was a major manufacturer of all sorts of capacitors qualified for use in military
and aerospace systems, so they put a lot of effort into characterizing device parameters
over a wide range of voltage, current, power, temperature, mechanical, and frequency
environments...
Monostable multivibrator, one-shot multivibrator,
monocycle multivibrator - it's a matter of semantics, although
the circuit designer doesn't necessarily think so. The distinction, evidently, is
that this monocycle multivibrator uses a positive-going pulse as a trigger and the
output in its rest (stable) state is a digital "0" (low). A mere 2 mA of current
flows since all the unijunction transistors (UJTs) are turned off. A UJT, to refresh
your memory, is not used as a linear amplifier because of its regenerative, negative
resistance operating region that causes it to effectively lock into a fully on or
fully off conduction state until an external stimulus causes...
Simmonds Precision Products, a company in
Vergennes, Vermont, which I worked for for a couple years prior to quitting to attend
the University of Vermont full-time to finish my electrical engineering degree,
had as one of their main products
capacitance-based fuel measurement systems for military and commercial
aircraft. As was common in the era, they made not only the capacitance probes and
associated electronics, but also the cockpit displays and power supplies. Being
a test technician at the time, I got a pretty good exposure to the complexities
of such a fundamentally simple principle as using the...
EIRP - effective isotropic radiated power - is
an important parameter when calculating both intentional and unintentional electromagnetic
emissions. EIRP is a vector quantity that accounts for both power (magnitude) and 3-dimensional
coordinates (direction). It includes antenna directivity that concentrates power in a
particular direction rather than distributing it equally in all directions (e.g., isotropically).
Effective radiated power factors in modulation type and power envelope shape as well.
Knowing how to measure that quantities can make the difference between...
As with most technologies that have been around
for decades, the fundamentals of
crystal filters have not changed with time. Materials and methods have changed, of
course, but the equivalent lumped element model (using resistors, capacitors and inductors)
of a crystal filter is essentially the same today as it was in 1969 when this article
appeared in Electronics World magazine. Open a first semester electronics circuits
textbook and the chapter on crystals will look much like this piece by Mr. Robert Kent,
of Damon Engineering. The use of crystal had a profound impact on filter design because
their extremely high "Q" factors...
Did you know that Mallory, the well-known capacitor
maker, at one time was at the forefront of solid state rectifier diodes? Not me, at least
before seeing this infomercial from a 1969 Electronics World magazine. I
know that they made selenium rectifiers that replaced many application which formerly
required vacuum tubes. This installation of Mallory's "Tips
for Technicians" is one of many run for the benefit of service shop guys who needed
to keep abreast of changes in technology. Note the admonition at the end: "Don't forget
to ask 'em - 'What else needs fixing?'"...
Prior to the big push for leadless solder in the
1990s, probably 99% or more of the solder used by industry, tradesmen, and hobbyists
contained lead. The
60/40 Sn-Pb (and 63/47) alloy, both with and without a rosin or acid core, was used
for electrical work, electronics, plumbing, copper guttering, radiators, and many mechanical
assemblies made of steel, brass, copper, tin, etc. Between World War I, "The War
to [Not] End All Wars," and World War II, the electronics industry exploded in growth.
All realms of society and government became utterly dependent on products assembled using
solder. Both tin and lead were abundantly available...
According to author R.R. Freeland, manufacturing
processes for radio-quality manmade crystals saw major improvements toward the end of
World War II. At the time, the process was highly manual-intensive, as can be seen
in this really nicely done 1940s video titled "Crystals Go to War." Prior to the use
of crystals as frequency-determining devices, inductor-capacitor (LC) tank circuits were
the dominant configuration. There were actually other frequency-determining schemes like
spark gaps and even vibrating mechanical reeds. As you might guess, anything less than...
At least 10 clues with an asterisk (*)
in this technology-themed crossword puzzle are pulled from this past week's (1/8 - 1/14)
"Tech Industry Headlines" column on the RF Cafe homepage (see
the Headline Archives page for help). For the sake of all the avid cruciverbalists
amongst us, each week I create a new technology-themed crossword puzzle using only words
from my custom-created related to engineering, science, mathematics, chemistry, physics,
astronomy...
For the benefit of RF Cafe visitors, I have posted
at no charge to companies many employment announcements for engineers, technicians, managers,
and other technical positions. This electronics technician job was located at COMSAT
Laboratories' (Communications Satellite Corporation) Washington,
D.C., facilities since 1969 was prior to when the then-futuristic-looking Clarksburg,
Maryland, campus was established. In the early 1990s, I worked as an RF design engineer
for a few years at COMSAT Laboratories in Clarksburg. About a decade earlier, before
earning my BSEE degree, I was working as an electronics technician at ...
TGIF. If this past week has had you on edge, cheer
up -the weekend's almost here. Once the final fire has been put out - or is at least
contained - give yourself a break and enjoy these
tech-themed comics from a vintage issue of Electronics World magazine. My
favorite is the one on page 83 which is a takeoff on the well-worn comedy meme of the
husband trying to sneak back into the house after a night out with the boys. This poor
guy has been outwitted by his wife, who evidently has a bit of tech savvy working for
her...
Nuclear energy was a big topic in the 1960s and
1970s as it was believed to be the future of electrical power generation for the world
(at least up until the 3 Mile Island and Chernobyl incidents occurred). Ships and submarines
were being powered by reactors that allowed them to run for months at a time without
refueling, atmospheric emissions were practically zero, and the fuel source was abundant
(albeit not simple to obtain). Medical and space applications were increasingly dependent
on a greater knowledge of radiation and its effects on humans, plants, animals, and electronics.
Many people by that...
As mentioned often here on RF Cafe,
especially with an ever-increasing amount of devices and appliances with "no user
serviceable parts inside," the demand for electronics technicians is as great today
as it was decades ago. Associated equipment is significantly different now and a
lot more of it consists of swap-out modules and assemblies rather than performing
repairs in the field. However, there still exists a significant amount of
legacy electronics everywhere, and it all needs to be maintained
until upgrades are installed. There...
Engineering and science magazines, websites,
and discussion panels frequently report on and lament the lack of
women and minorities in both realms. You might think this is a
relatively new concern since, but as evidenced by this 1972 Popular Electronics
tidbit the effort to attract women and minorities into the fields has been going
on for half a century. At the time, women and minorities made up about 2% of undergraduates
in engineering curricula. The proportion was 20% as of 2015 according to a recent
report by the ASEE. During that same time period (1970), according to the National
Center for Education... |