RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
2 MB. Its primary purpose was to provide me with ready access to commonly needed
formulas and reference material while performing my work as an RF system and circuit
design engineer. The World Wide Web (Internet) was largely an unknown entity at
the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps
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Mail" when a new message arrived...
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4 of the September 2019 homepage
A Primer on Single Sideband
Single-sideband (SSB) modulation was a big
deal when it was first introduced at a time when the radio spectrum was getting
pretty crowded - particularly in the commercial broadcast bands. It allowed more
channels / stations to be packed into available space, which was obviously a good
thing, but the other main benefit of SSB is the transmission efficiency - especially
when a suppressed carrier format is used. At really high powers, electronic component,
antennas, cabling, and facilities are very expensive, so being able to broadcast
a signal over a given distance at a lower power represents a cost savings. As the
old saying goes, though, "there is no free lunch." Modulators in transmitters ...
Get a Charge out of Device Capacitance-Voltage
Axiom Test Equipment has posted a new blog
entry entitled, "Get a Charge Out of Device Capacitance-Voltage Testing." Read
their latest blog to learn what to look for when selecting test equipment for semiconductor
device capacitance-voltage (C-V) measurements and learn how C-V measurements can
greatly assist the modeling and design of circuits with semiconductor devices. "Transistors
and integrated circuits (ICs) make many of our modern electronic 'toys,' such as
cellular telephones and computers, possible. But before it is possible to reliably
design supporting circuits for new semiconductor devices, they must be accurately
tested to better understand their electrical characteristics. Last month's blog
looked at the ways in which current changed with changing voltage. As a follow-up,
this blog will explore capacitance ...
AC Calculations for Parallel and Series-Parallel Circuits
When you read a lot of tutorials about introductory
electronics on the Internet, most are the same format where stoic, scholarly presentations
of the facts are given. Those of you who don't have enough fingers and toes to count
all of the college textbooks like that which you have read know of what I speak.
When hobby articles are written in a similar fashion, it can quickly discourage
the neophyte tinkerer or maybe even a future Bob Pease. The ARRL's QST
magazine has printed a plethora of articles over the years that are more of a story
than just a presentation of the facts. My guess is the reason is because often the
authors are not university professors who have forgotten how to speak to beginners.
This article on basic calculations for
AC series and parallel circuits is a prime example ...
World's First Wireless Charger
with 16 Charging Coils
"Have you ever accidentally misplaced your
phone on a
wireless charger and consequently woken up with a phone that
has an almost empty battery? ZENS, a wireless charging expert has solved this problem
with the launch of ZENS Liberty - a wireless charger with 16 overlapping charging
coils. The 16 coils will give complete freedom of placement, allowing you to place
two devices anywhere on the charging pad. So far, existing wireless chargers only
have a few charging coils and your device needs to be placed on a specific spot
on the charging pad. ZENS will launch two variations of the 16-coil wireless charger ..."
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.
The Hi-Fi Power Rating Hassle
President Ronald Reagan once stated that
the nine most terrifying words of the English language were, "I'm from the government
and I'm here to help." I share the sentiment generally while acknowledging that
there are some areas where government oversight and regulation is needed. Problems
arise where the opinions and beliefs of a self-appointed group of "experts" are
allowed to impose subjective standards toward the creation of objective standards.
Such was the case in the 1970s when the FTC sought to publish a set of rules by
which high fidelity (hi−fi)
stereo equipment manufacturers must publish performance parameters. The EIA
had their own ideas for how equipment specs should be reported. Popular Electronics
magazine published hundreds of product reviews for receivers, recording and playback
devices, power amplifiers, equalizers, speakers ...
Nikola Tesla - Master of Lightning
I ran across this full-length video of the
documentary titled, "Nikola Tesla - Master
of Lightning," which was aired by PBS in 2000. It is the most extensive visual
resource of information on Tesla that I have seen. Most people, if they have ever
even heard of Nikola Tesla, associate him with gigantic high voltage generators
making his hair stand on end, but his contributions to the world of electricity
go far beyond that. Aside from the lightning machines, he also developed almost
single-handedly the basic concept of alternating current (AC) power generation,
distribution, and motors. The battle, both personally and corporately, with Thomas
Edison and his proposed direct current (DC) system is epic and tragic. Documentaries
like this one tend to flourish the tale a bit with exaggerations that build sympathy
for the featured good guy du jour ...
Custom MMIC Intros Low Noise Amplifiers
for 2-16 GHz
Custom MMIC, a leading designer and manufacturer
of high performance monolithic microwave integrated circuits (MMICs), is proud to
introduce three new Low Noise Amplifier (LNA) MMICs to its industry leading portfolio
of high-performance RF and Microwave MMIC products. These three new GaAs devices
offer customers a broad frequency range that addresses many popular wireless applications
in the Aerospace, Defense and Instrumentation markets. The CMD308P4 is a broadband
MMIC low noise amplifier housed in a leadless 4x4 mm plastic surface mount
QFN package. The device operates from 2 to 6 GHz and delivers 31 dB of
gain with a corresponding output 1 dB compression point of +12 dBm and
a noise figure of 1.6 dB. The CMD308P4 includes on chip blocking capacitors
and is internally matched to 50 ohms which eliminates ...
Post Your Engineer & Technician
Job Openings on RF Cafe for Free
Cafe's raison d'être is and always has been to provide useful, quality content for
engineers, technicians, engineering managers, students, and hobbyists. Part of that
mission is offering to post applicable job openings. HR department employees and/or managers of hiring
companies are welcome to submit opportunities for posting at no charge (of course
a gratuity will be graciously accepted). 3rd party recruiters and temp agencies
are not included so as to assure a high quality of listings. Please read through
the easy procedure to benefit from RF Cafe's high quality visitors ...
Electronics and the International Geophysical Year
International Geophysical Year(IGY) was an international
scientific project that lasted from July 1, 1957, to December 31, 1958. It marked
the end, after Joseph Stalin's death, of a long period during the Cold War when
scientific interchange between East and West was seriously interrupted. As many
as 67 countries participated among which were all major ones with the exception
of mainland China. The IGY encompassed eleven Earth sciences: aurora and airglow,
cosmic rays, geomagnetism, gravity, ionospheric physics, longitude and latitude
determinations (precision mapping), meteorology, oceanography,
seismology and solar activity. Both the U.S. and the Soviet Union
(USSR) launched artificial satellites ...
Navy's New Radar For Nimitz Class Carriers
and Amphibious Assault Ships
"A new generation of advanced and highly
capable modular radar systems is going to be deployed across the Navy's fleet in
many configurations. A staple feature on Nimitz class supercarriers and America's
'Gator Navy' of amphibious assault ships may begin to disappear in the not so distant
future and in its place will be a very different looking system. The AN/SPS-48 three-dimensional
air-search radar has been fielded across the Navy for over five decades. Today,
a modernized version - the AN/SPS-48G - of the big, square, billboard-like, spinning
array can still be found on Nimitz class carriers, San Antonio class landing platform
docks, and Wasp and America class amphibious assault ships. But that is slated to
slowly change ..."
Withwave: RF & Microwave Components
Withwave manufactures an extensive line of
metrology quality coaxial test cable assemblies, connectors (wave-, end-, vertical-launch,
board edge, panel mount), calibration kits (SOLT), a fully automated 4-port vector
network analyzer (VNA) calibrator, between- and in-series connector adaptors, attenuators,
terminations, DC blocks, torque wrenches, test probes & probe positioner. Special
test fixtures for calibration and multicoax cable assemblies. Frequency ranges from
DC through 110 GHz. Please contact Withwave today to see how they can help
your project succeed.
Bell Telephone New Diode Speeds Voices
The first time I saw a microwave diode in
this type of ceramic package was in the detector stages of the S-band airport surveillance
radar (ASR) and the X-band precision approach radar (PAR) that made up the AN/MPN−14
radar system I worked on in the U.S. Air Force back in the late 1970s / early 1980s.
Both radars were primarily vacuum tube systems with a few upgrades to solid state
components in areas where suitable substitutes for the original tubes were available.
By the time this Bell Telephone Laboratories advertisement appeared in a 1958 issue
of Popular Electronics magazine, no transistors had yet been invented for
operation in the microwave realm, at least not other than the "laboratory curiosity"
type. It had only been a decade since Drs. Brattain, Shockley, and Bardeen announced ...
R&S September 2019 Newsletter
In this September 2019 Rohde & Schwarz
newsletter, we provide you the latest information in RF Measurements, Signal and
Power Integrity. We've curated the most recent documents, videos and webinars to
support you in your on going education. Included are Making Effective Use of Doherty
Architecture, Measurement of the Phase Difference Between Several Signals, and our
Mixer & Frequency Converter Fundamentals Seminar on October 16th. If you'd like
to learn more, talk to your dedicated representative, get a product demo or quote,
please click on the button below. We're here to support your projects and business
How Radio Waves Are Propagated
If you or someone you know is just starting
in the realm of radio and want a really nice pictorial presentation of the basics
radio wave propagation, then this one-page article from a 1935 edition of
Short Wave Craft is just what you need. Phormula phobia
(aka formula fobia) will not be an issue for anyone.
The fundamentals have not changed in the intervening 85 years, and this same sort
of analogy is still used in introductory physics classes today.
Electro-Photonics LLC, a market leader in RF and Microwave components has released
a new series of
band pass filters featuring frequencies from 500 MHz –
50 GHz. Our new wide bandwidth filters future high stop band suppression and
compact size. These RF/Microwave and mmWave filters can dissipate up to 20 W
of continues wave power. Electro-Photonics, LLC, is a global supplier of high-frequency
components and services. Our products include, SMT hybrid and directional couplers,
high frequency test fixtures, evaluation test boards, and wire bondable passive
World's First Quantum Radar Demonstrated
"A team of researchers from the Institute
of Science and Technology Austria demonstrated a
quantum radar that relies on using entangled photons and operates
at such low power levels that it can hide behind background noise, making it useful
for biomedical and security applications. One of the advantages of the quantum revolution
is the ability to sense the world in a new way. The general idea is to use the special
properties of quantum mechanics to make measurements or produce images that are
otherwise impossible. Much of this work is done with photons. But as far as the
electromagnetic spectrum is concerned, the quantum revolution has been a little
one-sided. Almost all the advances in quantum computing, cryptography, teleportation ..."
TotalTemp Technologies: Thermal
Platforms for −100°C to +200°C
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. Please contact TotalTemp Technologies today to learn
how they can help your project.
September 11, 2001 - Never Forget
Incredibly, 18 years has passed since the extremist Islamic attack on American soil
on the morning of
September 11, 2001. Nearly 3,000 citizens died that day. World
leaders have embarked on a path of colonizing our homelands with groups of people
that are known to harbor sympathies for the terrorists. They dwell among us now
and mean to do us harm when opportunity presents itself - which it has on numerous
occasions in the past many years. Never forget the people who died in the burning
towers, the Pentagon, and the airplanes, and those left behind to grieve and get
on with life. Never forget the police and military members who fought - and some
died - to keep us safe and free. Never forget the rotten politicians who imperil
our existence with their selfish agendas.
The Electron Microscope
published in a 1955 issue of Popular Electronics magazine is a really good
primer on the history and working principles of the
electron microscope. It also explains why such a device is needed; i.e., why
an optical microscope cannot do the job when really high levels of magnification
are required. As object dimensions are spaced at distances near to or less than
the optical wavelength being observed, it becomes impossible to resolve into separate
features. Accordingly, when observing at the upper end of the visible light spectrum
at around 400 nm, under ideal conditions you would not be able to clearly discern
two feature less than about 800 nm apart. Current (2019) CMOS gate thicknesses
run about 5 μm, so visible light cannot be used to image those structures.
Another resolution limiting factor is aperture size, which, depending on the wavelength
causes diffraction patterns of two objects to overlap ...
The Current War Movie -October 2019
A few decades ago I might have begun
this sentence with, "Most of us know about 'The War
of the Currents' that pitted Tesla's AC power distribution scheme against Edison's
DC scheme." However, I'm not so sure the epic techno-battle has ever been heard
of by those among us who entered the electrical / electronics world within that
timespan - that is unless he or she is a frequent visitor to RF Cafe, where I make
a point of reminding devotees of the places from whence we came. Fortunately, some
movie producers appreciate science history and share the desire to present it to
their audiences. Some include a political agenda while others stick to the facts
(with a little artistic license thrown in, including modifying the most commonly
used title). "The
Current War" movie is coming to theaters in October. Hopefully, we'll get just
Radio Astronomy - Low Noise Front-Ends
receivers are absolutely essential in radio astronomy work. The need has driven
major advances in the state of the art of
cryogenically cooled front ends with noise temperatures near absolute zero.
Antenna technology has also benefitted from radio astronomy due to the need for
precision steering and narrow beam widths. Phased arrays (aka interferometers) for
interstellar targets requires that element spacing be large enough to require separate
antennas as the elements, which creates a very large effective aperture, hence greater
angular resolution. Networks located continents apart are synchronized with the
use of atomic ...
Homebrew 17-Element Stacked Yagi Antenna Array
builder extraordinaire Dave Jones (N1UAV) outdid himself by replacing his 9-element
dual stacked Yagi antenna array with a 17-element version. He provides some
written instructions and, most helpfully, a YouTube video showing how he did it.
There is also a parts list that, where possible, has Lowe's item numbers for easy
procurement. Dave originally sent me a note back in July about the stacked television
antenna project he undertook after finding the "How
to Stack TV Antennas to Increase Signal Strength and to Reduce Ghosts" article
from the November 1965 issue of Popular Electronics magazine here on RF
Cafe. He lives in an area prone to multipath effects when receiving signals from
a rather distant television station, so he decided to muster his considerable antenna
building skills to see whether a stacked array would work for him ...
Metal Corrosion Sensor Mounts on
to help prevent equipment failure, Mitsubishi Electric's
metal corrosion sensor is small enough to mount on a PCB and
detect the progressive metal corrosion caused by exposure to aggressive atmospheres,
such as those containing sulphur compounds. Each sensor consists of a thin metal
film with resistors. The progress of any corrosion can be gauged by measuring the
increase in electrical resistance of the corrosion sensors, which can be adjusted
by changing the composition and thickness of their metal content. The 1.6x0.8 mm
device can be deployed as multiple sensors with different levels of corrosion resistance
in order to detect various degrees of corrosion in stages, helping industrial OEMs
to prevent ...
Custom MMIC: Off-the-Shelf and Custom
Custom MMIC is a
fabless RF and microwave MMIC
designer entrusted by government and defense industry OEMs. Custom and off-the-shelf
products include switches, phase shifters, attenuators, mixers and multipliers,
and low noise, low phase noise, and distributed amplifiers. From next-generation
long range military radar systems, to advanced aerospace and space-qualified satellite
communications, microwave signal chains are being pushed to new limits - and no
one understands this more than Custom MMIC. Please contact Custom MMIC today to
see how they use their modern engineering, testing and packaging facility to help
Cleveland Institute of Electronics "Troubleshooters"
Cleveland Institute was one of many electronics training organizations that
exploited the rapidly growing electronics service industry in the last century.
Although this particular two-page spread appeared in a 1968 issue of Popular
Electronics magazine, the trend began back in the 1930s. Earlier electronics
hobby and professional electronics publications like Short Wave Craft and
Radio News were pitching the unlimited opportunities for anyone with the
smarts and motivation for technical subjects as employees and/or owning a business.
Even in the days when there were user-serviceable parts (primarily vacuum tubes
and fuses) inside many electronic products, few people were willing to risk causing
harm to themselves or their hard-earned radio and television sets. Even by 1968
when most of the electronics industry had shifted to solid state circuitry, the
vast majority of existing equipment still had tubes in them. The television set
my parents owned ...
Anatech Electronics September
2019 Product Update
Inc. 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. Anatech has introduced
three new filter designs for the
5G NR (New Radio) bands: an n257 Band / 26.1 GHz cavity bandpass filter
with N-type connectors, an n258 Band / 28 GHz cavity bandpass filter with 2.92 mm
(SMA) connectors, and an n260 Band / 39 GHz cavity bandpass filter with 2.92 mm
(SMA) connectors. Custom RF filters designs are used when a standard cannot be found,
or the requirements are such that a custom approach is necessary.
"All-American" TV Technicians Win General Electric Awards
for Public Service
the middle of the last century,
television technicians were considered nearly as god-like as doctors, especially
those who made house calls to cure an ailing entity - be it a TV with its vertical
synch circuit running amok or a child running a fever. OK, I exaggerate a bit, but
General Electric mounted a media campaign to build a favorable image of TV repairmen
in the public eye. People from every walk of life and of every type employment (ok,
maybe not mafia hit men and politicians), gave of their free time to help community
efforts in charitable ways without any expectation of returned favors (which is
why I included politicians along with mafia hit men). This 2-page advertisement
which appeared in a 1958 edition of Radio-Electronics depicted TV technicians
who were bestowed the "All American Award" for public service ...
World's Most Powerful RF Emulator
a National Wireless Research Asset
The Colosseum - a
channel emulator used to run DARPA's Spectrum Collaboration Challenge - transitions
to National Science Foundation's PAWR Program after October finale. Over the past
three years, DARPA's Spectrum Collaboration Challenge (SC2) has relied on a custom-built
virtual testbed called the Colosseum to host thousands of competitive matches and
scrimmages, which will include the final match to determine the winner of the $2M
grand prize. Supporting SC2's mission to reimagine new spectrum access strategies
in which radio networks autonomously collaborate to determine how the RF spectrum
should be used moment-to-moment required the development of a research environment
capable of emulating communication signals at real-world scope and scale. Working
with engineers ...
Transient Specialists: EMC,
EMI, RFI Test Equipment Rentals
Specialists specializes in EMC test equipment rentals and carries a complete line of ESD
guns, surge immunity test equipment, and EFT generators. Rentals available for military
(Mil-Std 461), automotive (ISO 7637), and commercial (IEC 61000-4) EMC testing.
Flexible terms, accredited calibrations and technical support on EMC testing equipment
offered. Equipment consists of top EMC Test System manufacturers, including Teseq,
Thermo Keytek, EM Test and EMC Partner. Contact Transient Specialists today for
your ESD / EMC / RFI testing needs.
Engineering & Technical Headlines Crossword Puzzle
for September 8
RF Cafe Engineering & Technical Headlines Crossword Puzzle contains at least
10 words from headlines posted on the homepage during the week of September 2 through
September 6, 2019 (marked with an asterisk*). These custom-made engineering and
science-themed crossword puzzles are done weekly for the brain-exercising benefit
and pleasure of RF Cafe visitors who are fellow cruciverbalists. Every word and
clue - without exception - in these RF Cafe puzzles has been personally entered
into a very large database that encompasses engineering, science, physical, astronomy,
mathematics, chemistry, etc. Let me know if you would like a custom crossword puzzle
built for your company, school, club, etc. (no charge).
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