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4 of the March 2019 homepage archives. Sunday 31
 Since 2000, I have been creating custom
technology-themed crossword puzzles for the brain-exercising benefit and
pleasure of RF Cafe visitors who are fellow cruciverbalists. The jury is out on
whether or not this type of mental challenge helps keep your gray matter from
atrophying in old age, but it certainly helps maintain your vocabulary and
cognitive skills at all ages. A database of thousands of words has been built up
over the years and contains only clues and terms associated with engineering,
science, physical, astronomy, mathematics, chemistry, etc. You will never find a
word taxing your knowledge of a numbnut soap opera star or the name of some
obscure village in the Andes mountains. You might, however, encounter the name
of a movie star like Hedy Lamarr or...
Friday 29
 Here is an instructive look back at the near
post World War II and Korean War timeframe when U.S. bureaucrats and industry
titans were considering the pros and cons of
selling our technology to foreign countries - especially to present and recent
past sworn enemies. 1964, when this article appeared in Electronics
magazine, was the Bay of Pigs era when the threat of nuclear war was on
everybody's mind. In those days there were still company directors who would
rather sacrifice potential profit in order to assure that their country would
retain its technological leadership, its military superiority, and its national
security. Others adopted the attitude that is the overwhelming rationale today -
if we don't sell products and along with it the technological intelligence -
then somebody else will. That philosophy slowly but surely...
 Custom MMIC, a leading independent microwave
and millimeter wave circuit design center, seeks an experienced
Senior MMIC Design Engineer to join their design team. The candidate should
have a strong background in high frequency integrated circuit design (especially
above 5 GHz) using a variety of GaAs and GaN semiconductor processes including,
but not limited to: MESFET, PHEMT, mHEMT, and HBT. The candidate must be able to
handle all aspects of circuit design, from specification review to simulation, layout,
and prototype testing. Experience in amplifiers (low noise, drive, power), mixers,
switches, phase shifters, and/or attenuators is required. This position requires
significant independent work with minimal supervision...
 Beginning in the middle of the 1930s, engineering
labs in the U.S. and Europe were experimenting with radar systems. Early radars
did not have the slick plan position indicator (PPI) displays that modern systems
use for plotting target movement for indication of azimuth (direction) and range
(distance). Instead, oscilloscopes showed radar returns as amplitude blips along
a time base that represented range. Azimuth was determined by where the operator
pointed the antenna (rotating versions came later). Since radar cross section stealth
technology had not been invented yet, the amplitude of the signal was useful a measure
of the size of the target. Prior to the invention of radar (RAdio Detection And
Ranging), other means were needed to detect...
 The history of AI is often told as the story
of machines getting smarter over time. What's lost is the
human element
in the narrative, how intelligent machines are designed, trained, and powered by
human minds and bodies. In this six-part series, we explore that human history
of AI - how innovators, thinkers, workers, and sometimes hucksters have created
algorithms that can replicate human thought and behavior (or at least appear
to). While it can be exciting to be swept up by the idea of super-intelligent
computers that have no need for human input, the true history of smart machines
shows that our AI is only as good as we are. Part 2: The Invisible Woman
Programmers of ENIAC...
 "By completing the anechoic chambers in Europe,
AGC has established a framework for accelerating the research and development of
antennas to meet demand for 'connected' cars in the age of IoT and supporting automobile
development by its customers on a global scale. With the completion of this R&D
facility, AGC has established a tri-polar R&D framework for automotive
on-glass antennas in Japan, the United States
and Europe for the first time in the glass industry. In a future mobility society,
cars will be equipped with devices such as cameras, LiDARs and sensors. Cars
will need to be both connected to each other and have communicative
functionality that delivers V2X..."
At VidaRF, the phrase 'Providing Simple
Solutions for Complex Connections' is more than just a slogan – it's a mindset,
a mission, and a driving force behind everything we do. Their pledge is to design
and distribute high performance, cost effective
RF Microwave products to fit each customer's
unique applications. Please visit VidaRF today to see how their lines of attenuators &
terminations, directional couplers, power dividers, coaxial connectors, and circulator &
isolators can be of use to your project. "When the standard just will not do, VidaRF
has the solution for you!"...
Thursday 28
 Oops, I forgot to post the piece after posting
back in September the "Radar
Adds Beep to Home Sets" article from the February 28, 1964 issue of Electronics
magazine. The April 20th issue published a reader response to the problem of the
U.S. Air Force recently commissioned AN/FPS-24 long range "superpower radar" in
some of the country's major seaboard and northern cities. Designed to watch for
ICBM's and intruding long-range aircraft from the U.S.S.R., it operated in the
214 to 236 MHz band (VHF) at a 7.5 megawatt peak power output. Immediately there
were massive reports from surrounding homeowners and businesses about the
annoying beeps being heard on radio and television every time the rotating
antenna pointed in their direction...
 The good folks at Custom MMIC just posted
a new application note titled, "Theory and Method to Characterize the IP2 of Wideband
Amplifiers." It begins, "We are excited to release our new Application Note
that describes the theory and method used by Custom MMIC to characterize the second
order intercept point (IP2) of its wideband amplifiers. We offer a large selection
of wideband amplifiers as standard products with superior IP2 levels. Distortion
in amplifiers can take many different forms. One type of distortion occurs when
the output signal level gets large and approaches the 1 dB compression point of
the amplifier. In this case, the output waveform is compressed or even clipped,
and this action generates unwanted harmonics..."
 Here is a nice quiz on calculating total
equivalent capacitance for circuits containing various combination of series,
parallel, and series-parallel connections. To help in calculation, all of the individual
capacitor values are the same. Many of them you can probably solve in your head,
especially if you mentally rearrange the circuit into a more readily recognizable
configuration. For instance, circuit #1 can be redrawn having two parallel branches
across the source. One branch has just a single capacitor while the other has two
parallel capacitors in series with one capacitor. The equation is then C + (2C2/3C) = C + 2/3C = 5/3C. For C =
6 pF, Ctotal =
5/3*6 pF = 10 pF...
 Smiths Interconnect currently has a job opportunity
for a
Senior RF Engineer. Smiths is always looking for curious minds. For new colleagues
who want responsibility and relish a challenge. Responsible for all phases of product
development from conception through production of RF / microwave / mm-wave components
(e.g. couplers, power dividers, LNAs, mixers, PAs, switches, phase shifters, attenuators,
oscillators, antennas, ferrite devices, etc.) and subsystems (e.g. transceivers,
frequency converters, RADAR front-ends, radiometer front-ends, LO sources, frequency
synthesizers, switch matrices, arrays) built up from these components. Other possible
duties include bid & proposal...
 "The Army's Engineer Research and Development
Center wants to put
radar systems
that identify environmental phenomena on unmanned aerial and ground vehicles so
they can be used to survey previously inaccessible locations and cover more
territory from the air. Currently, ground-penetrating radar systems are large
arrays mounted on the front of military vehicles to detect improvised explosive
devices. Smaller commercial versions exist as well. Ground penetrating radar has
non-military uses as well; it is currently being used to find cracks and
corrosion in pavement. The Robotics Assisted Bridge Inspection Tool..."
 RF Superstore launched in 2017, marking
the return of Murray Pasternack, founder of Pasternack Enterprises, to the RF and
microwave Industry. Pasternack fundamentally changed the way RF components were
sold. Partner Jason Wright manages day-to-day operations, while working closely
with Mr. Pasternack to develop RF Superstore into a world class RF and
microwave component supplier. RF coaxial connectors & adapters,
coaxial cable & cable assemblies, surge protectors, attenuators. Items added
daily. Free shipping on orders over $99. We're leading the way again!
Wednesday 27
 Here is a great treatise on
waveguide theory put in layman's language. Although published in a 1948 issue
of Radio & Television News at a time when microwave frequencies were
just coming into common use, the language and descriptive drawings are similar to
what you will find in modern textbooks. Waveguide is not practical for use at lower
frequencies because the physical dimensions are prohibitively large. For instance,
for the FM radio band (88-108 MHz), waveguide width for a TE10
cutoff frequency at 88 MHz is around 67.5 inches. According to Wikipedia, the
first waveguide was proposed by J. J. Thomson in 1893 and experimentally
verified by Oliver Lodge in 1894...
 This could easily by a publicity scheme by
PCB maker Trackwise Designs, of Tewkesbury, UK, but it is not. "Trackwise has shipped
a
26-metre long multilayer flexible printed circuit
(FPC), believed to be the longest ever produced, for distributing power and control
signals across the wings of a solar-powered, unmanned aerial vehicle (UAV). The
circuit is one of over fifty supplied by Trackwise into this vehicle. The entire
interconnect system (power and signal) of the vehicle is made of FPCs
representing an estimated total systems weight saving of 60% over traditional
wire harness. This will enable the UAV, which is being manufactured in the U.S.,
to achieve higher payload and/or improved speed and range..."
 In the days before just about every multimeter
had a built-in
diode and transistor tester, there was not much - if anything - available for
the hobbyist. Some of the vacuum tube test sets, like my 1961 vintage B&K Dyna-Quik
Model 650, surprisingly included diode and transistor test sockets. This article
for a "non-destructive" type - as opposed to the popular "destructive" type -
homebuilt transistor tester appeared in a 1971 issue of Popular Electronics
magazine. It can identify PNP vs. NPN, measure DC gain, and measure leakage
current. The tester will verify diode integrity as well. There's also a bonus
"Parts Talk" comic on the page at no extra cost...
 "The University of Luxembourg and the Goodyear
Innovation Center in Luxembourg have launched a new research project to study the
use of
Near-Field Communication
(NFC) in automotive safety systems. The 4-year research project has the
potential to initiate major innovations in the automotive sector. It is funded
by the Luxembourg National Research Fund (FNR) and Goodyear. Near-field
communication is poised to fundamentally change the automotive sector. It is a
form of short-range wireless communication that relies on electric and magnetic
fields generated around a transmitting antenna. This communication technology is
now being explored for automotive applications..."
 Reactel
has become one of the industry leaders in the design and manufacture of
RF and microwave
filters, diplexers, and sub-assemblies. Through a continuous process of
research and development, they have established a full line of filters of all
types - lowpass, highpass, bandpass, bandstop, diplexer, and more. They offer
the generally known tubular, LC, cavity, and waveguide designs, as well as state
of the art high performance suspended substrate models. Established in 1979.
Please contact Reactel today to see how they might help your project...
Tuesday 26
 This issue of Electronics magazine's
Newsletter page contained, as usual, a number of topics, but the two that caught
my eye were on the BBC (British Broadcasting Corporation) lobbying their International
Radio Consultative Committee (CCIR) to consider adopting America's NTSC standard
for color television. The two competing standards were France's SECAM (Sequential
Color with Memory) and Germany's PAL (Phase Alternating Line). The main difference
between NTSC and the other two standards is NTSC used 525 scan lines whereas the
other two used 625 scan lines (different frame rates, too). All three were designed
to be backward-compatible with the existing black & white (B&W, or "monocolor"
in Europe) television broadcast scheme...
 Copper Mountain Technologies
develops innovative and robust RF test and measurement solutions for engineers all
over the world. Copper Mountain's extensive line of unique form factor
Vector
Network Analyzers include an RF measurement module and a software
application which runs on any Windows PC, laptop or tablet, connecting to the
measurement hardware via USB interface. The result is a lower cost, faster, more
effective test process that fits into the modern workspace in lab, production,
field and secure testing environments...
 The good folks at TotalTemp Technologies,
experts in the realm of thermal testing methods and equipment, has published a new
Blog topic titled, "Temperature Chamber Choices." Per TotalTemp's
post: "Thermal testing testing of products can't be ignored. Knowing your product
stands up to the harshest environments it will be exposed to over the life of the
product provides proof of the design and verified quality. With TotalTemp
Temperature Chambers and Thermal Platforms you can most effectively run thermal
tests for burn-in or design/production verification. Products meant for
consumers have to be tested, but it's safe to say, products going into space
need far more rigorous verification. Life tests or inappropriate tests can go
too far, thus shortening the life so it is important..."
 Here are a few more
electronics-themed comics from magazines of the days of yore - in this case
Radio-Craft. The country's fascination with all things electronic is
apparent - including robots, which should have taken over the world by now. It
is rare to find a comic in a technical or hobby magazine these days. I don't
know why that is. Enjoy...
 "Intel Corporation and the U.S. Department
of Energy (DOE) will build the first supercomputer with a performance of one
exaFLOP in the U.S. The system being developed
at DOE's Argonne National Laboratory in Chicago, named 'Aurora,' will be used to
dramatically advance scientific research and discovery. The contract is valued at
over $500M and will be delivered to Argonne National Laboratory by Intel and sub-contractor
Cray Computing in 2021. The Aurora systems' exaFLOP of performance - equal to a
'quintillion' floating point computations per second - combined with an ability
to handle both traditional high performance computing (HPC) and artificial
intelligence..."
Electro-Photonics is a global supplier of
RF &
Microwave components. Their products include SMT hybrid and directional couplers,
wire bondable passive components, mounting tabs, filters, transmission lines, and
very useful test boards for evaluating components (spiral inductors, single-layer
capacitors). The Electro-Photonics team can support your small R&D design requirements
with RF & Microwave test fixtures and save you valuable design and characterization
time. Please take a moment to visit Electro-Photonics' website and see how your
project might benefit... Monday 25
 An RF Cafe visitor wrote to ask that I scan
and post this article on the
Leslie Effect Simulator, which appeared in a 1965 issue of Popular Electronics.
"What the heck is the Leslie effect?" you are probably asking, as did I. Basically,
it is a mechanism for artificially creating the "wobbulating" effect of a pipe organ
in a large echoing environment. Inventor Donald Leslie worked for the Hammond organ
company and developed an electromechanical contraption that rotated a baffle in
front of speakers to create the effect. Commercial electronic Leslie Effect products
were sold back in the 1960s and 1970s when high fidelity (hifi) stereo equipment
was the "in" thing, like computers were in the 1990s and cellphones are now.
There were a lot of electronics hobbyists that loved to build projects printed
in magazines...
 Rohde & Schwarz has published an application
note titled, "Comparison of Time Domain Scans and Stepped Frequency
Scans in EMI Test Receivers." For EMI testing, the use of Time Domain Scan
greatly reduces measurement time without compromising accuracy. The paper takes
a critical look at the technology and its advantages. It compares measurement
speed and level measurement accuracy of a conventional stepped frequency scan
versus an advanced FFT-based time domain scan, learn the principles of
overlapping in the time and frequency domain, and discuss how to choose the
right measurement tool for CISPR and MIL-STD testing. During product
development, the frequency spectra of disturbances need to be measured
frequently and compared...
Find a Signal's Bandwidth from
Its Harmonics
 Bob Witte has an interesting article on the
website titled, "Find a Signal's Bandwidth from Its Harmonics."
It begins, "There are several ways to evaluate the bandwidth of a signal in the
time domain and frequency domain. Previously we looked at the classic relationship
of rise time (tr) and bandwidth (f3db), captured by this equation: Eric Bogatin
also provided Rule of Thumb #2 for estimating the signal bandwidth from the
clock frequency. Eric emphasizes that you really should use the rise time to
calculate signal bandwidth, but you can get a reasonable answer quickly using
this Rule of Thumb: In Eric's article, he makes a key..."
 This story reads like an infomercial for
IBM, which it probably is. Of course infomercials had not been invented by 1957,
so IBM was ahead of its time. The answer to the article's title, "How
Far Can You Go in Electronics Without a Degree?" was the same 55 years ago
as it is today: As far as your intellect and ambition will take you. Back then,
as with today, few people could rise to the level of design engineer without a
college degree. However, there are many aspects of electronics that requires no
formal education at all if you possess the requisite skills. I never have bought
into the feel-good lie about anyone being able to be whatever he or she wants to
be. Some people simply cannot achieve the mastery necessary to do a particular
job...
 "A new 'quantum radio'
has been demonstrated that can detect the weakest signals allowable under
quantum mechanics. Researchers have demonstrated how to detect the weakest radio
signals allowed under quantum mechanics, opening the door to advances in radio
astronomy and medicine, and physics. The Quanta in the Noise Researchers at
Delft University of Technology (DUT) in the Netherlands have built a quantum
circuit that allows them to listen to the faintest signal allowable under
quantum mechanics, leading to possible advances in radio astronomy, medicine,
and attempts to reconcile quantum mechanics and relativity..."
 TotalTemp Technologies has more than 40 years
of combined experience providing thermal platforms.
Thermal Platforms are
available to provide temperatures between -100°C and +200°C for cryogenic
cooling, recirculating circulating coolers, temperature chambers and temperature
controllers, thermal range safety controllers, space simulation chambers, hybrid
benchtop chambers, custom systems and platforms. Manual and automated
configurations for laboratory and production environments...
Sunday 24
 Since 2000, I have been creating custom
technology-themed crossword puzzles for the brain-exercising benefit and pleasure
of RF Cafe visitors who are fellow cruciverbalists. The jury is out on whether or
not this type of mental challenge helps keep your gray matter from atrophying in
old age, but it certainly helps maintain your vocabulary and cognitive skills at
all ages. A database of thousands of words has been built up over the years and
contains only clues and terms associated with engineering, science, physical, astronomy,
mathematics, chemistry, etc. You will never find a word taxing your knowledge of
a numbnut soap opera star or the name of some obscure village in the Andes mountains.
You might, however, encounter the name of a movie star like Hedy Lamarr or a
geographical location like Tunguska, Russia, for reasons which, if you don't
already know, might surprise you...
These archive pages are provided in order to make it easier for you to find items
that you remember seeing on the RF Cafe homepage. Of course probably the easiest
way to find anything on the website is to use the "Search
RF Cafe" box at the top of every page.
About RF Cafe.
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