In 1971 the International Telecommunications
Union (ITU), convened a meeting dubbed the World
Administrative Radio Conference for Space Telecommunications (WARC-ST). The
ITU was a specialized agency of the United Nations for telecommunications, with
a membership of 140 nations. Satellite communications was barely a decade old, but
already the need for international agreements on spectrum usage had become very
apparent. Prior to the 1971 meeting, there was the 1963 Extraordinary Administrative
Radio Conference held in Geneva, Switzerland. Amateur radio had its presence in
the game acknowledged with further allocations for its members' OSCAR birds; six
had been flown already. As of this writing there are about 20 OSCAR satellites still
in operation. Amateur satellites take many forms these days, including the newest
trend in CubeSat platforms with a well-defined set of specifications on dimensions
and mass per cube. Launches are provided on a space available basis at a substantially
To help grow the next generation of RF Engineers,
Copper Mountain Technologies (CMT) has become a corporate partner with the
Purdue University Electrical and Computer Engineering (ECE) Program in West
Lafayette, Indiana. The mission of CMT is to extend the reach of engineers by providing
vector network analyzers that are portable, accessible, and affordable. By partnering
with Purdue, we hope to promote growth in the increasingly important field of RF
engineering. Despite a recent rise in engineering students and degree options, there
is a shortage of RF engineers. With the abundance of wireless and IoT devices being
created around the world, the requirement for engineers researching, designing,
and working with these devices has grown and the demand for these professionals
is not being met. There is a wide range of job opportunities for RF engineers in
QST did a regular series of articles
titled "Hams in
Combat" during World War II. This story is unique in nature in that it tells
of a newspaperman-turned-soldier who, in the story writer's mind, would have been
the most suited for the job of author. It tells a far different story of the South
Pacific than we were treated to in weekly episodes of McHale's Navy! "Had this story
been written by the man who should have written it - Capt. William H. Graham, W9BNC
- it would have been one of the greatest "Hams in Combat" yarns ever told in these
pages. But Bill Graham never got around to writing his story. He was too intensely
occupied with the living of it - too keenly aware of the new paragraph... Note the
letter I received from Capt. Graham's great grandson.
5G mobile wireless networking
technologies are slated to dramatically increase in both scale and speed, enabling
much faster access to data collected from billions of connected devices. This supercharged
information highway is envisioned to play an important role across several industries,
ranging from medicine to manufacturing. Major advances in 5G, including new core
network features will make it easier to customize the network at a wide variety
of locations. This new flexibility offers many benefits, but at the same time introduces
novel security challenges. Today's proprietary 5G technologies make it difficult
to achieve the transparency necessary for security-related risk analysis and mitigation.
This lack of security assurance makes it harder..."
Some of what you and I consider common knowledge
is largely unrealized by most people. Call me a geek, but I take pleasure in pointing
out to people that the
Fahrenheit and Centigrade scales are equal at -40°, and I especially enjoy working
out the simple proof for them. Most people appreciated the effort and are amazed,
claiming to have never seen that before. When I read the following in Smithsonian
magazine, "Winter temperatures here, some 250 miles northeast of St. Petersburg,
sometimes plunge to minus 40 degrees Fahrenheit," I wondered whether the author
knew that -40°F = -40°C. Maybe he just didn't want to confuse his readers by omitting
the redundant superfluous 'F' or 'C,' and it couldn't be 'K' because there are no
negative Kelvin degrees. It could also be that he knew but figured most people do
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
This article describes a method for
tuning beam antennas from the ground rather than needing to experiment with
matching capacitors and/or inductors at the antenna end of the transmission line.
The scheme uses a separate length of transmission line attached to the reflector
element at a length an integer number of half-wavelengths as required to reach the
ground. That way, tuning elements can be installed and adjusted for one or more
bands without needing to climb up to the antenna. The method can be used for any
number of elements, but of course it could get a bit messy with more than a couple.
The author, Major Charles E. Spitz (W7JHS), describes using a field strength meter
to verify tuning correctness. Having read many QST magazine articles on
antennas over the past decade or so...
RF 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...
"Researchers at the National Institute of
Standards and Technology (NIST) have demonstrated a new type of sensor that uses
atoms to receive commonly used communications signals. This
atom-based receiver has the potential to be smaller and work better in noisy
environments than conventional radio receivers, among other possible advantages.
The NIST team used cesium atoms to receive digital bits (1s and 0s) in the most
common communications format, which is used in cell phones, Wi-Fi and satellite
TV, for example. In this format, called phase shifting or phase modulation, radio
signals or other electromagnetic waves are shifted relative to one another over
time. The information (or data) is encoded in this modulation..."
An app note entitled "90°
Hybrid Coupled Power Amplifier Pros and Cons," by NuWaves Engineering's Justin
Wells, appeared in the latest edition of
Aerospace & Defense Technology magazine. Mr. Wells has authored other
app notes that, like this one, does a good job of distilling complex topics into
articles understandable by newcomers to the RF trade. It begins, "Power Amplifiers
(PAs) are commonplace in radio frequency (RF) systems extensively used in applications
consisting of over-the-air wireless communications. Wireless communications is a
broad market and PAs fill a wide array of those applications. Due to the broad range
of applications, PA design techniques must be chosen carefully for each application-specific
scenario. Single-ended PAs have limitations that restrict their practicality in
many applications, especially where higher output power..."
Teledyne Paradise Datacom, part of the Teledyne
Defense Electronics Group, today announced the wide availability of a new, leading
L- and S-Dual Band solid state power amplifier (SSPA) for today's evolving satellite
command systems. Both S- and L-band frequencies have been the industry's bands of
choice for positioning and tracking applications like global positioning systems
(GPS) and Tracking, Telemetry, and Control (TTC) ground stations. This new dual
band product offers customers a virtual "two for the price of one" SSPA solution
that dramatically lowers the costs of command and control, leaves a much smaller
footprint, but also delivers higher reliability compared to traditional klystron
Nova Microwave is a leader in technically differentiated
electronic and radio frequency Ferrite Circulators and Isolators that connect, protect and control
critical commercial and military wireless telecommunications systems. Our staff
is dedicated to research and development of standard and custom design quality Ferrite
Circulators and Isolators from 380 MHz to 26.5 GHz. Available in single
or multi-junction topographies, the Nova Microwave product line of is specifically
designed for use in varied environmental and temperature extremes.
Motivated by the series of articles about
Lee de Forest in the January 1947 issue of Radio-Craft magazine, I did a search
of U.S. newspapers from 1905 through 1947 looking for news items on him. In particular,
I was hoping to find something about the
lawsuit levied by the Marconi Company against Lee de Forest wherein the
judge was reported to have told him, "...to forever desist from the manufacture,
sale or operation of any system of wireless telegraph." Alas no such information
was discovered, but the search will continue. I did find this piece and many other
interesting items that will be posted as time permits. Here, Mr. de Forest
sued, with the assistance of the U.S. Government, an investment company for defrauding
investors in regard to company stock sales, using a charge of mail fraud to assist
in prosecution. Mail fraud, tax evasion, interstate commerce and other such non-state
related charges were (and still are) routinely used by the Feds...
Try as I did, I could not find any instance
of the Ness Clocks all-digital liquid crystal display (LCD) desktop clock which
appeared in this 1973 Popular Electronics article. There must not have
been many produced. LCDs had only been commercially available for a year or so when
this went on sale. Of the relatively few digital display clocks and watches available
in the 1970s, the vast majority used light-emitting diodes (LEDs), and most sold
for north of $100 (~$600 in today's money). Portable devices with digital displays
really began to flourish with the advent of both
CMOS circuitry and LCD displays; i.e., low current devices that extended battery
life. Wrist watches, which could only accommodate very small batteries with limited
energy storage capacity, were amongst the greatest beneficiary...
"A computer chip can
process and store information using two different devices. If these devices
could be combined into one or put next to each other, there would be more space
on a chip, making it faster and more powerful. Engineers have developed a way that
the millions of tiny switches used to process information (transistors) could also
store that information as one device. The method accomplishes this by solving another
problem: combining a transistor with higher-performing memory technology than is
used in most computers, called ferroelectric RAM. Researchers have been trying for
decades to integrate the two..."
ConductRF's close partnership with TE in
its development of its new Nano-miniature RF Solutions for
VITA67.3 has put us in a great position to support your VPX RF cable assembly
needs. Modular solution supports 8 to 18 positions, flexible 0.047" diameter cable,
supports frequency up to 70 GHz, use with standard solutions (SMA, SMPM, etc.),
2x density of Vita67.1. ConductRF's PFT33 Series of Micro Flexible Cable Assemblies
has been designed directly with TE Connectivity involvement and in partnership to
maximize the capabilities of TE's new Vita67.3 NanoRF VPX modular connector system.
ConductRF offers its soft FEP jacketed ø0.047" cable to facilitate maximum flexibility
and provides solutions for jumper cables ...
RF Cascade Workbook 2018 is the next phase in the evolution
of RF Cafe's long-running series, RF Cascade Workbook. It is a full-featured
RF system cascade parameter and frequency planner that includes filters and mixers
for a mere $45. Built in MS Excel, using RF Cascade Workbook 2018
is a cinch and the format is entirely customizable. It is significantly easier and
faster than using a multi-thousand dollar simulator when a high level system analysis
is all that is needed. An intro video takes you through the main features...
PCB Directory is the largest directory of
Printed Circuit Board (PCB) Manufacturers,
Assembly houses, and Design Services on the Internet. We have listed the leading
printed circuit board manufacturers around the world and made them searchable by
their capabilities - Number of laminates used, Board thicknesses supported, Number
of layers supported, Types of substrates (FR-4, Rogers, flexible, rigid), Geographical
location (U.S., China), kinds of services (manufacturing, fabrication, assembly,
prototype), and more. Fast turn-around on quotations for PCB fabrication and assembly.
Lee de Forest, upon whom was conferred
the honorary title "Father
of Radio" by Radio-Craft editor Hugo Gernsback (and others), exemplifies
personal traits of most great inventors: high intelligence, stick-to-itiveness,
courage, passion for his subject, determination, and a willingness to endure a lot
of personal and financial abuse. The January 1947 issue of Radio-Craft
magazine celebrated the 40-year anniversary of Mr. de Forest's invention
of the Audion vacuum tube by including a large number of articles by various authors
who knew him personally and attest to his greatness. I will be posting a few of
those pieces, and you will probably be shocked at some of the shenanigans that went
on by conniving people and naysayers who tried to deny de Forest due credit.
For example, based on his work to make more sensitive receivers a judge in a lawsuit
brought by Marconi strictly enjoined him "to forever desist from the manufacture,
sale or operation of any system of wireless telegraph...
This article entitled "Rad-Hard
Microelectronics for Space Applications," from the February issue of Aerospace &
Defense Technology magazine, does a nice job of boiling down the most significant
problems and solutions faced by engineers and scientists. Due to the high weight
and volume required to sufficiently shield electronics from the effects of damaging
space-borne particles and rays, methods have been devised to live with some of the
damage while still being able to function - even if in a crippled mode. Redundancy
is a big part of the strategy, as is actively monitoring and avoid ejecta from the
sun, known debris from asteroids, comet tails, asteroids, and man-made space junk.
Here is another exciting episode of the sleuthing
adventures starring Popular Electronics' tech savvy teenagers,
Carl and Jerry. The Hardy Boys of electronics are the creation of author John
T. Frye, who created short story adventures for many years - long enough to at one
point require a major modification in the boys' appearances to reflect more modern
attire and eyewear (Carl's "The Far Side"-style glasses had to go). This particular
adventure begins with Carl considering whether his ham radio hobby is more useful
from the standpoint of its technical aspects or of its social aspects.
"U.S. Marines with Information Group II Marine
Expeditionary Force (II MIG) participated in an
amateur radio general licensing course January 27 – 31 on base as part of the
group's High Frequency Auxiliary Initiative. Members of the Brightleaf Amateur Radio
Club of Greenville, North Carolina, helped the Marines in the class learn the principles
of HF radio operations as a contingency against a peer-to-peer adversary in real-world
operations. During the course, Marines learned ham radio theory, band allocations,
conventional and field-expedient antenna theory, and general ham radio operation
and control. II MIG Commanding Officer Colonel Jordan Walzer created the High Frequency
Auxiliary Initiative after recognizing the need for additional options in combat
Copper Mountain Technologies (CMT) has produced
a series of videos to help users of its diverse line of vector network analyzers
(VNAs) get the most out of their extensive capabilities. Proprietary features in
both hardware and software supplies VNAs designed by CMT with capabilities far beyond
similar equipment by other companies. In this video entitled, "In-Circuit
Antenna Verification," CMT's Brian Walker, Senior RF Design Engineer, shows
how there can be significant variation of performance of a PCB mounted antenna when
it is close enough to other objects to disturb the near field response. It is best
to measure the return loss of an embedded antenna in its final configuration and
be prepared to add matching elements to improve radiation efficiency...
Empower RF Systems
is a global leader in power amplifier solutions. Empower RF Systems is an established
and technologically superior supplier of high power solid state RF & microwave
amplifiers. Our offerings include modules, intelligent rack-mount amplifiers, and
multi-function RF Power Amplifier solutions to 6 GHz in broadband and band
specific designs. Output power combinations range from tens of watts to multi-kilowatts.
Unprecedented size, weight and power reduction of our amplifiers is superior to
anything in the market at similar frequencies and power levels.
Whereas this "Choosing
the Right Antenna" from a 1958 issue of Radio & TV News magazine
article concerns television antennas, the information applies generally for any
application. Folded dipoles, conicals, Yagis, log periodic, and other types were
used by homeowners sometimes desperate to receive a good signal from a far away
broadcast station or from a location buried in obstacles (terrain, buildings, water
bodies, automobiles, towers, etc.) blocking and reflecting otherwise strong signals,
thus causing fading and multipath degradation. You might think the advent of cable
and satellite TV, along with Internet access, might have removed the need for rooftop
type over-the-air antennas, but it is not so. There are still plenty of people located
in rural areas that struggle to get a good signal, as evidenced by RF Cafe
visitor Dave Jones, (N1UAV) stacked 9- & 17-element yagi TV antenna project...
"A team of physicists from the University
of Würzburg is hard at work developing technology that could one day allow for the
nanoscale antennas with remarkable data transfer properties. Theoretically,
these nanoscale-sized directional antennas would have the power to share data between
different core processors at the speed of light. In a paper published in the journal
Nature Communications, physicists explained how they were able to generate directed
infrared light with the help of an antenna that is both electrically driven and
made out of gold. But this was no typical antenna; known as a Yagi-Uda antenna after
the researchers who invented it back in the 1920s, this device has a few special
features that set it apart..."
Unless you live with or interact regularly
with someone who is blind, it is easy to forget the difficulty everyday life poses
for him or her. I do not know any blind people. A lot of effort has been put forth
to help facilitate those who are severely sight impaired or totally blind. Helen
Keller is probably the most well-known blind person (she turned out to be an outspoken
Socialist Party member - ugh), but I think of Ray Charles when the subject arises.
Melanie and I visited the Florida School for the Deaf and Blind while in St. Augustine
a few years ago, where we learned Mr. Charles was fortunate to have attended
as a child. His rendition of "America the Beautiful" is by far my favorite. This
article from a 1935 edition of Short-Wave Craft reports on efforts to make
the electronics trade accessible to blind people via, in this case,
pseudo-Braille versions of schematics. Although theoretical design and analysis
activities were possible, the potentially lethal...
the late 1950's, Custom Control Sensors (CCS) has been a leader in providing
pressure, temperature and flow sensing
products that include sensors and switches for the Aerospace, Defense, Industrial
and Energy industries. Headquartered north of LA in Chatsworth, CA, CCS is a full
service company offering complete build to specification design, research and development,
3−D modeling, prototyping, manufacturing, testing, quality control and aftersales
support capabilities. CCS has pioneered many programs from the original NASA spacecraft
to leading commercial aircraft, to USAF fighter jets and bombers, and International
Space Station (ISS). Custom Control Sensors is now listed on RF Cafe's "Sensors"
vendor page. Please visit them to see if they can help with your project needs.
With more than 1000
custom-built symbols, this has got to be the most comprehensive set of
Visio Symbols available for RF, analog, and digital system and
schematic drawings! Every object has been built to fit proportionally on the provided
A-, B- and C-size drawing page templates (or use your own). Symbols are provided
for equipment racks and test equipment, system block diagrams, conceptual drawings,
and schematics. Unlike previous versions, these are NOT Stencils, but instead are
all contained on tabbed pages within a single Visio document. That puts everything
in front of you in its full glory. Just copy and paste what you need on your drawing.
The file format is XML so everything plays nicely with Visio 2013 and later.
Anatech Electronics (AEI) manufactures and supplies
RF and microwave filters
for military and commercial communication systems, providing standard LP, HP, BP,
BS, notch, diplexer, and custom RF filters, and RF products. Standard RF filter
and cable assembly products are published in our website database for ease of procurement.
Custom RF filters designs are used when a standard cannot be found, or the requirements
dictate a custom approach for your military and commercial communications needs.
Sam Benzacar's monthly newsletters address contemporary wireless subjects. Please
visit Anatech today to see how they can help your project succeed.
Here is a science and engineering-themed
crossword puzzle for your next long flight or boring meeting. This one for February
16, 2020, contains only clues and terms associated with engineering, science, physical,
astronomy, mathematics, chemistry, etc., which I have built up over nearly two decades.
Many new words and company names have been added that had not even been created
when I started in the year 2002. 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