Today in Science History -
There are not many technical realms where
Google engineers have not either entered or created. Wireless connectivity is key
to their continued dominance in the information domain, so they understandably have
a vested interest in the "white space"
spectrum debate. White space comprises portions of the electromagnetic spectrum
where bands are either unlicensed or where licensed bands are or will be up for
grabs. An example of the former is the 2.4 GHz Wi-Fi band, and an example of
the latter is some parts of the broadcast television band that is being vacated
in areas. Although this information is a few years old, it shows how Google was
working early−on with the Federal Communications Commission (FCC) to build a real-time
database of what they term "dynamic spectrum" in order to provide useful information
about available white space (now directs here) to both users and providers. A separate
database is available for fixed and mobile spectrum. Enter your location of interest
and the map zooms into that region. For instance, in my town (at the time) of Erie,
Pennsylvania (see marker on map below), as of January 2013 when this was first posted
there were 21 channels available...
This assortment of custom-designed themes
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Purses, Sweatshirts, and Baseball Caps. Choose from amazingly clever "We Are the World's Matchmakers"
Smith chart design or the "Engineer's Troubleshooting Flow Chart." My "Matchmaker's"
design has been ripped off by other people and used on their products, so please
be sure to purchase only official RF Cafe gear. My markup is only a paltry 50¢ per
item - Cafe Press gets the rest of your purchase price. These would make excellent
gifts for husbands, wives, kids, significant others, and for handing out at company
events or as rewards for excellent service. It's a great way to help support RF
Reactel has become one of the industry leaders in the design and manufacture
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Most(?) RF Cafe visitors are probably familiar
with British engineer John Logie Baird as being considered "the father of television."
His work in the 1920s produced both live and recorded motion pictures transmitted
and received electronically. What most visitors (including me) probably did not
know is that he also developed television apparatus using infrared imaging; he called
Noctovision (noct or nox meaning night) was a moving image form of the still imaging
"Noctovisor," which was an early night vision system that converted an infrared
image into an optical image. Radar was still in its infancy in 1942 when this article
appeared in Radio News magazine, and had not been implemented widely enough
to provided needed surveillance against nighttime bombing raids from Germany's Luftwaffe
(air force) flying across the English Channel. According to author Rosen, infrared
wavelengths have 16x the fog penetrating power of optical wavelengths...
Anatech Electronics (AEI) manufactures and
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systems, providing standard LP, HP, BP, BS, notch, diplexer, and custom RF filters,
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can help your project succeed.
Together with Amazon's
Kuiper and the EU's
GalaxySpace and SpaceX's Starlink will
forever transform the night sky by launching tens of thousands of small LEO satellites,
each of which will reflect sunlight to observers situated between them and the sun.
Many - if not most - will be visible to the naked eye and will definitely appear
streaks in time exposure astronomical images. These systems will provide global
broadband connectivity at a projected cost of about $100 per month to those of us
who will actually shell out our wampum
for it, which is about the cost of equivalent cable-based Internet connectivity
now. As is the case now, our expensive subscriptions will continue to subsidize
the many who pay reduced rate or nothing for the service - another instance of a
few pulling the metaphoric welfare wagon while rest are in it for the free ride...
My first major high fidelity (Hi−Fi) stereo
system purchase came during my senior year at Southern Senior High School when I
had saved enough money to buy a combination AM/FM receiver, 8-track tape deck, turn
table, and two speakers with separate woofers, midranges, and tweeters. At the time
I thought the setup might impress friends and relatives... until I learned quite
quickly that "serious" stereo sound connoisseurs decidedly did NOT have equipment
with "Reader's Digest" logos on it. Oh well, the price seemed like a really good
bargain to me give the promised tonal superiority. Compared to the clock radio I
used previously for my music listening sessions, the Reader's Digest stereo system
produced music hall quality sound. Ah, the deep bass notes were grand. Spending
most of my earned money on model airplanes, rockets, and my '69 Camaro left little
disposable income for LPs (referred to as "discs" in this article), so the turntable
did not get much use. I did, however, read up on how to balance the tone arm...
"A TU/e research group has developed a new
near-infrared sensor that is easy to make, comparable in size to sensors in smartphones,
and ready for immediate use in industrial process monitoring and agriculture. This
breakthrough has just been published in Nature Communications, with co-first author
Kaylee Hakkel defending her Ph.D. thesis on January 14th. The human eye is a marvelous
sensor. Using three photoreceptor cells that
visible light into signals for different colors, the eye gives essential information
about the world around us. "When our brain puts the signals together, it makes a
prediction of what the signals mean based on our experiences. For example, a red
strawberry is sweet, but a green one is not..."
On Friday, January 28th and Monday, the 31st,
Rohde & Schwarz (R&S) will be conducting a webinar entitled "HF in a Nutshell."
You would be excused to thinking that this an amateur radio event because many of
the company's employees are Hams, but in fact it is billed as "An overview of current
beyond-line-of-sight communications solutions." Further, "HF communications technology
is reliable, proven and has been in service for decades. This webinar is the first
in a series covering HF topics and will illustrate that HF communications is in
no way your grandparents' technology, but rather THE communications solution for
the future. You will receive an overview of currently available Beyond Line of Sight
(BLOS) communications solutions and the latest developments in this field, i.e.
HF versus satellite communications (SATCOM)..."
Author Howard Wright takes the opportunity
here in a 1936 issue of QST magazine to distill the
of modulation down to its basic operation while dispensing with the garbled
mix of "graphs, formulas, charts, vectors, diagrams, and Greek letters which often
enter into various discussions of modulation." Mr. Wright describes how to
the uninitiated radio dial spinner, the culmination of events occurring behind the
scenes in an AM reception process is akin to this: "...it might be compared to the
reproduction of a color photograph in a magazine. How would we ever know that, to
be reproduced, the picture was broken down into its primary colors, if all we had
to go by was the original print and the magazine?" That is a very apt comparison...
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. 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...
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The era of nuclear weapons of course began
in August of 1945 when they effectively ended World War II, but it wasn't until
around 1955 that another country - the U.S.S.R. - developed a deployable
thermonuclear bomb. Even before that happened, the U.S. Department of Defense
began planning for systems to detect and ultimately disable enemy ICBMs and aircraft-delivered
nuclear bombs. The nuclear arms race had begun, and continues to this day. Now,
there are five countries recognized as possessing thermonuclear weapons, three countries
declaring possession, and one country implying possession. A somewhat insane concept
dubbed MAD asserts that if everyone can strike and counterstrike with equal capability,
that will prevent nuclear warfare because the aggressor will suffer as significantly
as the victim. This 1961 Bell Telephone Labs promotion in Radio−Electronics
magazine introduced one of the early concepts for intercepting inbound ICBMs. The
most familiar and successful system...
Modelithics is excited to launch a new monthly
blog series -
Model Rap! These blog posts will provide helpful tips for RF & Microwave
design success using high-accuracy simulation models in the industry's leading simulation
software. EM/circuit co−simulations are both accurate and painless when using Keysight
Technologies' RFPro EM environment in conjunction with Modelithics models. In this
blog post, learn why this approach for EM/circuit co-simulations offers tremendous
advantages in comparison to traditional methods. The premier edition is entitled,
"EM/Circuit Co-Simulation Made Easy and Accurate with Keysight RFPro and Modelithics
Unlike the Roll Your Own Foil Capacitors
article in the same issue of Popular Electronics magazine, this one advising
how to reactivate leaky capacitors might be of use to a lot more people. The process
is called "reforming," and consists of applying a DC voltage to the faulty capacitor,
beginning at a very low voltage, and then slowly raising the voltage until the rated
working voltage (WVDC) is reached. Doing so, if the capacitor is not beyond rehabilitation,
will reconstitute the oxide layer that serves as the dielectric. This particular
item was presented as the answer to a question posed by a reader. A Google search
capacitor" will turn up more detail about the procedure. Most people recommend
against reforming unless you have no other option, as this writer from India might
have faced at the time...
By late 1962, the United States was launching
new satellites at a very rapid pace. Many were destroyed on the launch pad, others
never turned on once in orbit, still more turned on and operated in a crippled form
and/or only for a small portion of their intended lifespans. It was a learning period
for the entire satellite, rocket, mission control, Earth-based tracking stations,
and the communications equipment that dialoged with the satellites. The "race" part
of the Space Race moniker was literal. Popular Electronics, QST,
Electronics World, and other electronics communications publications regularly
printed a list of
newly commissioned satellites. The lists presented here came from five different
1962-1963 editions of Popular Electronics. The feature was repeated for many years.
Incidentally, the "mc" frequency unit used at the time was the common abbreviation
for "million cycles per second." In 1960, the Hertz was adopted by the General Conference
on Weights and Measures...