A large percentage of people today do not
remember or were not alive during the days of analog over-the-air (OTA) broadcast
television, so the question, "What
Ever Happened to Channel 1?" is moot for them. For that matter, the standard
VHF selector knob beginning with the number 2 and not 1 was probably was never a
matter of concern. I do remember wondering why there was no channel 1, but it wasn't
until a few years ago that I learned why that was. By that time, the Internet is
full of explanations, as is the case for most information you want to know. This
article from a 1982 issue of Radio-Electronics magazine lays out the answer
to the question in great detail, and provides some interesting history on the development
of television broadcast standards...
In our continuing saga Wireless Networking
in the Developing World, we now turn our attention to
transmission lines and coaxial connectors, where we find: The transmitter that
generates the RF power to drive the antenna is usually located at some distance
from the antenna terminals. The connecting link between the two is the RF transmission
line. Its purpose is to carry RF power from one place to another, and to do this
as efficiently as possible. From the receiver side, the antenna is responsible for
picking up any radio signals in the air and passing them to the receiver with the
minimum amount of distortion and maximum efficiency, so that the radio has its best
chance to decode the signal. For these reasons, the RF cable has a very important
role in radio systems: it must maintain the integrity of the signals in both directions...
"A superconductor can switch the magnetic
moment of a
single-molecule magnet placed on top of it. This novel phenomenon, discovered
by researchers in Italy, occurs because of quantum tunneling of magnetic spins,
and might be exploited in future quantum information technologies. Single-molecule
magnets are paramagnetic materials that can switch their magnetization between two
states - 'spin up' and 'spin down,' for example. At low temperatures, these molecular
complexes retain their magnetic state even in the absence of a magnetic field because
reversing the magnetization would require them to overcome an energy barrier. This
magnetic 'memory' effect could be exploited in spintronics and quantum computing
Here is a 1950s
vintage crossword puzzle from Popular Electronics magazine. Unlike
the weekly crosswords from RF Cafe that use only relevant technical words, this
one uses some common words unrelated to electronics and science to fill in where
needed. It's still a good puzzle, though. Print it out for use during your next
boring meeting or 12-hour flight to China. A list of many other puzzle from
Popular Electronics and Electronics World is presented at the bottom
of the page. Have fun.
Fairview Microwave has a new article posted
on the Microwave Product Digest (MPD) website entitled, "The
Role and Trending Requirements of RF Limiters in Multifunctional AESA Radar."
You don't tend to see a lot of pieces on RF limiters. It begins, "In the past few
years, active electronically scanned array (AESA) radar have transitioned from cutting-edge
radar technology designed to be deployed on next-generation multi-role fighters,
to capability and life extension systems for older aircraft and legacy radar designs.
There are an increasing number of radars replaced with AESA systems, with one of
the major demands being multifunctional capability to meet multi-mission and multi-role
expectations for modern radar. These new expectations present substantial design
difficulties, especially for the receive signal chain in a transmit/receive module
driving a high number of AESA antenna elements. The design constraints of high antenna
element AESA radar are further complicated when the AESA is forced into footprints
catering to a previous generation of mechanical radar..."
Windfreak Technologies designs, manufactures,
tests and sells high value USB powered and controlled radio frequency products such
as RF signal generators, RF synthesizers, RF power detectors, mixers, up / downconverters.
Since the conception of WFT, we have introduced products that have been purchased
by a wide range of customers, from hobbyists to education facilities to government
agencies. Worldwide customers include Europe, Australia, and Asia. Please contact
Windfreak today to learn how they might help you with your current project.
Once World War II was over and the
peoples of the world could breathe and start enjoying life again, television, which
had just begun to take off before the war, quickly gained widespread adoption in
homes. As with so many areas of technology and science, advancements in electronics
and wireless communications during the war years redounded very beneficially to
TV industry. Early schemes for television combined both electronics and mechanical
elements using rotating discs, vibrating mirrors, and other far-out schemes to convert
electrical signals to moving pictures. Due to the small size of the first cathode
ray tubes (CRTs), commonly called kinescopes at the time, light beams were launched
toward physically maneuvered mirrors to steer the image onto the back of a larger
glass screen - basically the first projection screen televisions ...but I digress.
TV's popularity grew so fast in the late 1940s and early 1950s that the Federal
Communications commission (FCC) issued a moratorium on the building of new broadcast
stations until a scheme could be devised to deal with signal overlap (interference)
from too closely spaced stations...
Here is the electromagnetic wave section
of the "Wireless Networking in the Developing World," book (open source). "Wireless
communications make use of
waves to send signals across long distances. From a user's perspective, wireless
connections are not particularly different from any other network connection: your
web browser, email, and other applications all work as you would expect. But radio
waves have some unexpected properties compared to Ethernet cable. For example, it's
very easy to see the path that an Ethernet cable takes: locate the plug sticking
out of your computer, follow the cable to the other end, and you've found it! You
can also be confident that running many Ethernet cables alongside each other won't
cause problems, since the cables effectively keep their signals contained within
the wire itself. But how do you know where the waves emanating from your wireless
device are going..."
"Dutch shipbuilder Royal Huisman applied
the same concurrent engineering process developed by ESA for space missions to the
superyacht Sea Eagle II, due to become the world's largest aluminium sailing
yacht when delivered to its owner this spring. This uniquely contemporary 81 m-long
three-masted schooner was recently transported by barge from the company's shipyard
in Vollenhove to Royal Huisman Amsterdam, where its carbon composite rig will be
installed, leaving her ready for sea trials and on-board crew training..."
Z-Communications is pleased to announce
a new RoHS compliant
fixed frequency phase locked loop operating in the Ku−band. The RFS12000C−LF
is a plug and play PLO which is designed to produce a fixed signal output at 12 GHz.
Utilizing an internal 10 MHz reference clock, this unmatched PLO makes for
simple integration into any system as no external programming is required. This
simple to use RFS12000C−LF features a typical low noise performance of −72 dBc/Hz,
−86 dBc/Hz, and −116 dBc/Hz at the 1 kHz, 10 kHz and 100 kHz
offsets, respectively. The high performance RFS12000C−LF is designed to deliver
an output power of 0۬±3 dBm while operating off a two input supply voltages...
Naval communications and their communicators
have always been held in high regard. Operating and maintaining sophisticated electronics
equipment is difficult enough on solid ground, but doing it on the ocean with winds
and waves tossing the platform (ship) relentlessly can exacerbate the problem tremendously.
It is a wonder that radar systems can even be useful with the antenna constantly
rotating about pitch, roll, and yaw axes while simultaneously shifting in the x,
y and z axes. Sure, airborne platforms have the same sort of challenge, but their
perturbations are not typically as violent, as great in magnitude, or as prolonged
as a naval vessel in rough seas. For the record, I'm a former USAF radar guy so
I'm not just trying to glorify my own branch of service...
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...
By Lou Frenzel: "How
Much Do You Really Know About Communications Electronics?". "As communications
wends its way into virtually every electronic product, having a solid understanding
of the technology becomes essential. Here are steps you can take to achieve that
goal. If you're an experienced RF communications engineer, you probably don't have
to read this blog. But if you're a beginning engineer, an engineer recently assigned
to a communication project, a tech manager overseeing communications engineers,
or those of you who test or sell comm gear, you may want to take a look. Learning
About Comm The largest sector of electronics is communications. Name an electronic
product today that does NOT have some comm function..."
SF Circuits' specialty is in the complex,
advanced technology of
PCB fabrication and assembly, producing high quality multi-layered PCBs from
elaborate layouts. With them, you receive unparalleled technical expertise at competitive
prices as well as the most progressive solutions available. Their customers request
PCB production that is outside the capabilities of normal circuit board providers.
Please take a moment to visit San Francisco Circuits today. "Printed Circuit Fabrication &
Assembly with No Limit on Technology or Quantity."
Punch cards have been used in computer systems
since the very early days of digital programming. They were probably the first form
of read-only memory (ROM), come to think of it. I hate to have to admit it, but
the meager computer used in my high school computer lab (circa early-mid 1970s)
punched cards. I never took the class, but stories abounded of how pranksters
would shuffle a stack of punch cards while the student programmer wasn't watching
and then get a good laugh when nothing worked. There are also plenty of cases where
a stack was inadvertently knocked onto the floor and had to be laboriously re-ordered.
IBM is the brand that comes to most people's minds when thinking about the old punched
card computer systems, but other companies like NCR (National Cash Register), HP
(Hewlett-Packard), DEC (Digital Equipment Corporation), and plenty of others others...
Doug Grant (K1DG) and the ARRL just published
a book entitled "Amateur Radio Contesting for Beginners." While the title and
cover photo suggest it is directed toward teenagers, "Beginners" encompasses people
of all ages, whether veteran operators who had not competed before or relatively
newly licensed guys like me who finally earned my first Ham license (Technician)
in 2010 at age 51 (now Amateur Extra, BTW). "Contesting is one of the most exciting
aspects of amateur radio. It's called 'radiosport' because it really is a sport
– a competition to see who can contact the most stations in an allotted amount of
time. Regardless of the size of your station, you can compete, too!" The book is
available in softcover and Kindle formats.
Contributors to the Wikipedia article on
Yagi-Uda antenna credit Japanese professor Shintaro Uda primarily for the antenna's
development, with Hidetsugu Yagi having played a 'lesser role." Other sources assign
the primary role to Yagi. Regardless, history - and this article's author, rightly
or wrongly, has decreed that this highly popular design be referred to commonly
as the Yagi antenna and not the Uda antenna. I don't recall seeing advertisements
for 'Uda' television or amateur radio antennas. Harold Harris, of Channel Master
Corporation, does a nice job explaining the fundamentals of the Yagi antenna...
experiment is famous for demonstrating the principle of interference. Andrew
Murray explains why it's now possible to carry out an equivalent experiment using
lasers that have excited individual rubidium atoms Over the last 20 years I must
have spoken to more than 400 school pupils who want to study physics here at the
University of Manchester. One subject that regularly comes up at interview is Young's
double-slit experiments, which clearly interest my prospective students. But when
I ask them what the experiments are all about, I'm invariably told they involve
using electrons to demonstrate wave-particle duality - one of the cornerstones of
quantum physics. That's curious because Thomas Young performed his experiments in
1804 - long before we knew anything about electrons or the subatomic world..."
I ran across a really nice e-book entitled
"Wireless Networking in the Developing World," which is a collaborative work by
many authors, and it is published under the Creative Commons licensing scheme (a
la Wikipedia). That permits reprinting with attribution. Some of the more pertinent
sections will be posted here on RF Cafe. "The exact theory of Fresnel zones is quite
complicated. However, the concept is quite easy to understand: we know from the
Huygens principle that at each point of a wavefront new circular waves start, we
know that microwave beams widen as they leave the antenna, we know that waves of
one frequency can interfere with each other. Fresnel zone theory simply looks at
a line from A to B, and then at the space around that line that contributes to what
is arriving at point B. Some waves travel directly..."
Anatech Microwave Company is a privately-held
company founded in 2003 that focuses on supplying quality RF and microwave products
for military, commercial, aerospace and defense, and industrial applications up
to 40 GHz. In their March Product Update, Anatech has introduced
three connectorized power dividers: a DC to 4.0 GHz 8-way resistive
power divider, a 1000 to 4000 MHz 2-way reactive power divider, and a 2000
to 18000 MHz 4-way reactive power divider. Custom RF power directional coupler
designs can be designed and produced when a standard cannot be found, or the requirements
are such that a custom approach is necessary...
Alliance Test Equipment sells
used / refurbished test
equipment and offers short- and long-term rentals. They also offer repair, maintenance
and calibration. Prices discounted up to 80% off list price. Agilent/HP, Tektronix,
Anritsu, Fluke, R&S and other major brands. A global organization with ability
to source hard to find equipment through our network of suppliers. Alliance Test
will purchase your excess test equipment in large or small lots. Please visit Allied
Test Equipment today to see how they can help your project.
A few days ago I mentioned that a popular
early form of radio detector circuit involved the used of a flame - yes, the flame
of a fire, not a romantic significant other. The subject arose in a couple articles
in the January 1947 issue of Radio-Craft magazine that celebrated the 40th
Lee de Forest's Audion vacuum tube invention. This particular piece was
authored by de Forest himself, who was a personal friend of Radio-Craft
editor Hugo Gernsback. It is a very interesting autobiographical account of the
early days of experimentation and the evolution of what eventually became the world's
first mass producible signal amplifying device. You will also read that de Forest
created the designation of the "B" battery for a reason he makes obvious. Also,
although you have probably seen pictures of the old household type gas light fixture...
"The UK government has announced a
raft of measures to boost science in the country as it gets ready to leave the European
Union on 31 January. They include investing £300M over five years to fund mathematical
sciences, the lifting of visa restrictions on scientists coming to the UK, as well
as removing the need for researchers to make 'impact' statements when submitting
grant applications to UK funding councils. The boost for mathematics comes via the
Engineering and Physical Sciences Research Council (EPSRC), which will invest
£60m per year in the field - double what it currently spends. EPSRC says it will
provide £19m towards funding PhD students for four years 'as standard' and offer
five-year funding for research associates to 'compete with the U.S. and Europe'..."
Cadence / AWR just published volume 19.4
of their monthly "AWR Design
Magazine." This issue includes updates on the latest AWR software design applications,
success stories, software updates, and e-learning and training tools. The feature
story is entitled "AWR is Now Cadence Customer." Content also includes power amplifier
design tackling high peak-to-average power ratio with digital predistortion, best
practices for efficient and effective planar EM simulation, and a piece on Richardson
RFPD and INAF SDARS and radio astronomy...
After previously presenting the permanent
magnet, chapter 12 of the NAVPERS series of courses takes a look at the
electromagnet. It is like a natural or artificial magnet in its attraction but
unlike in its control. Its attraction is tremendous-it can hold tons of iron. But
because this magnet is powered by an electric current, the magnetism can be turned
on and off with the flick of a switch. Electrically-powered magnets are called electromagnets.
Electromagnets come in all sizes and shapes - and do all kinds of jobs. All electromagnets
use a coil of wire and a core of iron to produce their magnetism. The coil furnishes
the magnetic flux and the iron concentrates it. To understand how it works, you
should start with the magnetic field around a conductor. All conductors carrying
current are surrounded by a field-of flux. As in the case of artificial magnets,
iron filings will make this field visible. Connect a wire to a battery and dip the
wire in iron filings...
RF Cafe typically receives 8,000-15,000
website visits each weekday and about half that on weekends.
RF Cafe is a favorite of engineers, technicians, hobbyists, and students all
over the world. With more than 10,000 pages in the Google search index,
RF Cafe returns in favorable
positions on many types of key searches, both for text and images. New content
is added on a daily basis, which keeps the major search engines interested enough
to spider it multiple times each day. Items added on the homepage often can be found
in a Google search within a few hours of being posted. I also re-broadcast homepage
items on LinkedIn. If you need your company news to be seen, RF Cafe is the
place to be. Advertising begins at $45/month.
Skyworks Solutions' Wes Boyd just posted
a white paper entitled, "Next
Generation Wi-Fi: 6 GHz Is on the Horizon," which, as the title implies,
discusses the wireless industry's motivation to more aggressively occupy the less-used
6 GHz unlicensed band. He begins, "The push to open the 6 GHz band (5.925-7.125 GHz)
to unlicensed use is being driven by explosive growth in consumers' data needs,
particularly from applications such as video streaming and video on-demand. The
demand for data is being further bolstered by social media applications, audio platforms,
and smart home devices. In addition, new and burgeoning applications such as virtual
reality (VR) and augmented reality (AR) will continue to drive significant data
demand into the future..."
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
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!
"Qualcomm Technologies, Inc. today announced
ultraSAW filter technology, another groundbreaking innovation in the company's
industry-leading wireless technology portfolio that builds on the company's legacy
of developing breakthrough technologies and enabling new experiences and expanding
the mobile ecosystem. Radio frequency (RF) filters isolate radio signals from the
different spectrum bands that phones use to receive and transmit information. By
achieving as much as 1 decibel (dB) improvement in insertion loss, Qualcomm ultraSAW
filters offer a higher performance solution compared to competing bulk-acoustic
(BAW) filters in the sub-2.7 GHz frequency range..."
Despite all the prefabricated, relatively
inexpensive products available these days, there are still many people who like
to build their own projects. Whether electrical or mechanical - or both - some sort
enclosure is usually involved. Often, you can cannibalize an existing, retired
project to use its chassis or find a product at Walmart or a home improvement store
that does not cost too much that you can buy just to get its enclosure. Buying a
pre-formed chassis for your project can get expensive, so there are times when the
best option is to obtain a piece of sheet metal (which can also be expensive) and
bend it yourself. If you have never attempted such an endeavor, believe me it can
be pretty challenging, especially with heavier gauge metal. It is usually best to
lay out and drill / cut / punch / file as many holes as possible prior...
Following the developments of the coronavirus
(COVID-19) outbreak closely and its impact on colleagues and customers in China,
Horizon House announced today that
CHINA, May 12-13, 2020 in Beijing, China has been rescheduled for September
27 and 28, 2020 at the Chinese National Convention Center (CNCC), Beijing, China.
"We express our sincere thanks to our exhibitors, sponsors, and media partners for
their ongoing support of EDI CON CHINA, and we send our very best wishes to our
colleagues, friends, and customers who are directly affected by the COVID-19 virus,"
said Ivar Bazzy, President of Horizon House, "We thank everyone for their patience
as we shift to a new date for our 2020 event in the fall in Beijing...
Transient Specialists specializes in
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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.
L-Com product manager Mark Miller
has an article on the High Frequency Electronics website entitled "Antennas
Evolve to Meet 5G Requirements." He discusses the need for active antenna systems
to service the high bandwidth and high reliability mandated by 5G communications
requirements. Included is a veritable
cornucopia of associated
abbreviations and acronyms. To wit: "It is largely believed by market research groups,
industry consortiums / standards bodies, original equipment manufacturers (OEMs),
academic researchers, and even consumers, that 5G technologies will offer seamless
voice, data, and control services magnitudes beyond the services commonly experienced
in today's metropolitan and suburban regions. It is only a common opinion that advanced
antenna systems (AAS) or smart antennas (SAs), will be necessary in delivering enhanced
mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and
massive machine-type communications (mMTC), which are considered three pillars of
early 5G use cases. Upgraded antenna technologies, such as massive multi-input multi-output
Reactel has become one of the industry leaders in the design and manufacture
of RF and microwave filters,
diplexers, and sub-assemblies. They offer the generally known tubular, LC, cavity,
and waveguide designs, as well as state of the art high performance suspended substrate
models. Through a continuous process of research and development, they have established
a full line of filters of filters of all types - lowpass, highpass, bandpass, bandstop,
diplexer, and more. Established in 1979. Please contact Reactel today to see how
they might help your project.
As with my hundreds of previous
science and engineering-themed crossword puzzles, this one for March 1, 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