See Page 1 |
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5 of the January 2020 homepage
archives.
 A momentous development that changed the
field of radio communications warranted merely a half-page announcement in 1935
when
frequency modulation inventor Edwin Armstrong had his article
published in Radio-Craft magazine. It indisputably changed the world while causing
poor Mr. Armstrong much grief while defending his right to the invention. Spread
spectrum modulation / demodulation would be the next big communications advance
that began with the frequency hopping (FHSS) scheme dreamed up by Hollywood actress
Hedy Lamarr and pianist Antheil George during World War II. Direct sequence
spread spectrum (DSSS) followed in the digital age, and since then I do not know
of any fundamentally new communications technology in that time...
 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...
"ConductRF-Rugged-Replacement-VNA-Cables-1-21-2020.htm" target="_top">
 Precision ruggedized VNA cables from ConductRF
offer RF engineers great alternatives to costly OEM cables that are now past their
best days, and now you can reach out to Digi-Key for a quick and easy replacement.
We have standards for applications at 18 GHz, 27 GHz, 40 GHz, 50 GHz &
70 GHz. Our torque resistant connector heads and phase stable constructions
ensure great performance for many tests to come. ConductRF VNA series provides customers
with reliable ruggedized solutions for lab and production vector network analyzer
testing. We Know, Results Count...
 "Engineers from the ESA and Sweden's Royal
Institute of Technology (KTH), have designed a novel
'water drop' antenna lens for directing radio
wave signals. In the same way that optical lenses focus light, waveguide lenses
serve to direct electromagnetic radio wave energy in a given direction. This can
be used to minimize energy loss when sending out a radar or a communication signal.
Traditional waveguide lenses have complex electrically-sensitive dielectric material
to restrict electromagnetic signals as desired. But once the top plate of this water
drop waveguide lens has been added on, it comes down purely to its curved shape
for directing signals through it. The inventors of this new lens design, which received
an ESA Technical Improvement award in February 2017, likes to call it..."
 Keysight Technologies' Matt Ozalas and Thomas
Winslow will present a free webinar entitled, "Designing for Stability in High Frequency Circuits," on January
29th at 1:00 pm ET. "High-frequency circuit designers often struggle with stability.
Learn techniques to identify and solve stability problems in the design phase before
they become headaches in the lab. Classical techniques will be discussed, and a
new technique will be introduced using a bidirectional impedance probe in PathWave
Advanced Design System (ADS) called the 'Winslow Probe.' Techniques to identify
and solve stability problems in the design phase Basic design examples to compare
various stability techniques Realistic examples of a successful high frequency power
amplifier design..."
 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."
 One of the photos in this 1958 Radio &
TV News magazine article on the
Jodrell Bank radio telescope shows what appears to be the largest
multi-conductor cable connector I have ever seen. It looks like a early Photoshopping
of a DB-9 connector with a heavy metal back shell. The cable bundle is three to
four inches in diameter. Rather than use slip rings to transfer the control, data,
and power signals from the base to the steerable 250-foot diameter parabolic dish
of the Jodrell Bank radio telescope (now called the Lovell telescope), a single
massive cable does the job. The science of radio astronomy was barely three decades
old at the time it was built. It was in 1931 that Karl Jansky first determined that
radio signals were coming from our Milky Way galaxy. He eventually ended up working
for Bell Labs in Homdel, New Jersey, where he built a radio telescope to investigate
background noise in the 10-20 meter wavelength band, where Bell planned to use its
microwave relay system...
 This assortment of custom-designed themes
by RF Cafe includes T-Shirts, Mouse Pads, Clocks, Tote Bags, Coffee Mugs and Steins,
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 Cafe. Thanks...
 Mr. Mark
Misfud, chairman of the Asia Pacific
Electromagnetic Compatibility Symposium 2020 (APEMC 2020) wrote asking to have
the event announced. It will be held May 19-22 at the Hilton Hotel, in Sydney, Australia.
Per the website, "Modern Society is increasingly becoming more connected and the
technology that is enabling this to happen is operating in a complex and hostile
electromagnetic environment. As such knowledge and practical experience in EMC design,
mitigation and testing is increasingly in demand. Developing technology such as
5G and autonomous vehicles present exciting possibilities but also provide challenges
to those in the field due to the dynamic nature of the electromagnetic environment
that the technology operates in. For the uninitiated EMC is black magic but those
in the industry know it is application of common sense principles based on established
electromagnetic theory and implementation of good design..."
 "2-D semiconductors could have very useful
applications, particularly as channel materials for low-power transistors. These
materials display very high mobility at extreme thicknesses, which makes them particularly
promising alternatives to silicon in the fabrication of electronics. Despite their
advantages, implementing these materials in transistors has so far proved to be
challenging. In fact,
2-D semiconductors are of a dangling-bond-free nature; thus, it
is notoriously difficult to deposit ultrathin high-κ gate dielectrics (i.e., substances
with dielectric properties or insulators) on the materials via atomic layer deposition
(ALD), often resulting in discontinuous films..."
 Mya
Rae Nelson has an excellent article in the current issue of Fine Woodworking
magazine entitled, "The Science Behind Epoxies." I was surprised to read that epoxy
has only been around since the
1940s, so
when I first used it in the early 1970s, it was only a three decade old technology.
As with cellphones, now that we have epoxy, how did we ever get along without it?
Ms. Nelson uses layman terms to describe the molecular makeup of both the epoxy
resin and the hardener, and describes how the bonds between the resin atoms are
broken then reestablished with the insertion of hardener atoms into the matrix.
If you attended classes for and understood the basics of chemistry, that will help
with understanding the technical side of epoxy curing and strength, but even without
the nerd knowledge you will still gain a better understanding of how this indispensible
modeler's brew works.
 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.
 Before there was the annual
International Microwave Symposium (IMS) trade show, the Institute
of Electrical and Electronics Engineers' (IEEE) Microwave Theory and Techniques
Society (MTT-S) hosted the show, which was widely known as the MTT-S show. Before
that, the event went by a variety of names, including "Intercon," (International
Convention and Exposition) as reported in this 1972 issue of Popular Electronics
magazine. For the first few decades since its inception in the 1950s, New York City
was the venue, often in a hotel. As with tides and solar cycles, enthusiasm and
attendance waned and ebbed over the years. 1972 was one of the low years. Per the
story, about half the number of people were there compared to two years prior. I
could not locate a chart of attendance numbers over the years, nor the numbers to
generate my own chart...
 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.
 One day in late spring of 1973 I found myself
walking around the gymnasium of Annapolis Junior High School (AJHS) trying to decide
which courses I would prefer upon beginning tenth grade the following fall. It was
one of the final days of ninth grade, which had been by far my least happy year
in school. Living in Mayo, Maryland, I and my fellow neighborhood ninth graders
should have attended Southern Senior High School (SSHS) in Harwood, Maryland, where
our predecessors had gone for ninth grade, but overcrowding caused the Anne Arundel
School Board wizards to decide that for at least that year, we would remain at AJHS
for another term. Historically, kids from my area went to AJHS only for seventh
and eighth grades and then switched to SSHS. Annapolis, being the capital city of
Maryland, was significantly more urban than the rural areas to which SSHS type people
were accustomed. The clientele was much more aggressive in the big city. Sure, we
had our "red neck greaser" rowdies in the southern part of the county, but at least
their parents would whip them if they got caught getting into trouble...
 "Researchers at Imec have demonstrated what
they believe to be the first functional GaAs-based heterojunction bipolar transistor
(HBT) devices on 300 mm Si, and CMOS-compatible GaN-based devices on 200 mm
Si for mm-wave applications, showing cut off frequencies in the 40/50 GHz region. In wireless
communication, with 5G as the next generation, there is a push towards higher operating
frequencies, moving from the congested sub-6GHz bands towards mm-wave bands (and
beyond). The introduction of these mm-wave bands has a significant impact on the
overall 5G network infrastructure and the mobile devices. For mobile services and
Fixed Wireless Access (FWA), this translates into increasingly complex front-end
modules..."
 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. This video entitled, "Automatic Calibration Module Confidence Check," is one of a series
of videos that can be found on the Copper Mountain Technologies website. "How many
times have you completed a series of measurements to find them tainted by a bad
cable...
 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...
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!"
 Imagine reading an article from a 1958 magazine
that references the schematic for a specific radio manufactured in Germany, and
then being able to download a copy of it for free on the Internet. Such is the case
with this Mac's Radio Service Shop story entitled, "Was Ist Los?" Mac is describing
to his sidekick Barney the difficulty in troubleshooting and repairing a
Metz Transformatoren: Babyphon 56 that a serviceman had purchased
while stationed overseas. The diagram is of course in German, which requires Mac
to pull out a language translation dictionary. The problem was that many words unique
to technical jargon were not in it. Additionally, units of measure for the capacitors
and inductors were not like U.S. units. Mac noted that many capacitor values were
labeled with units of "u," "n," and "p," for "micro," nano," and "pico." He mentions
the "micro" prefix for the letter "u," but never calls the "n" and "p" by the now-standard
terms...
 QST reader George P. Orphan, KG4DXJ,
wrote in the February 2020 issue's "Letters from Our Members" column about an episode
of the old "Hazel" television show entitled, "Stop Rockin' Our Reception," where interference on the Baxters'
TV set was blamed on the "shortwave set" operated by a teenager, Bruce, who had
recently moved in down the street. George Baxter, the household's impulsive lawyer
father, was convinced enough that Bruce, a friend of his son, Harold, was responsible
that he paid a visit to the boy's house and spoke to his father about it. Bruce
politely informs Mr. B that unless his television was was manufactured before
1950, it was unlikely that his operations on the 10-meter band would be causing
the interference, but it fell on deaf ears. Shortly thereafter, a power company
investigator was seen walking around the front yard with a box bearing a loop antenna
on the top of it. At the request of Bruce's father...
 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 7,000 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, Facebook, and Twitter. If you need your company news
to be seen, RF Cafe is the place to be. Banner advertising begins at $175/month...
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.
 "In sailing, rock climbing, construction,
and any activity requiring the securing of ropes, certain knots are known to be
stronger than others. Any seasoned sailor knows, for instance, that one type of
knot will secure a sheet to a headsail, while another is better for hitching a boat
to a piling. But what exactly makes
one knot more stable than another has not been well-understood,
until now. MIT mathematicians and engineers have developed a mathematical model
that predicts how stable a knot is, based on several key properties, including the
number of crossings involved and the direction in which the rope segments twist
as the knot is pulled tight. 'These subtle differences between knots critically
determine whether a knot is strong or not,' says Jörn Dunkel, associate professor
of mathematics at MIT..."
 Sam wrote from his One SDR website to request
I post a note about the resources he is providing on
Software Defined Radios. It
is in its start-up phase and already has many articles introducing the concepts
of SDR. Topics include low noise amplifiers, filters, bias tees, and how to shop
for equipment. Says Sam, "I hope to demystify RF technology and make it more accessible
to the growing community of SDR enthusiasts." The amateur radio community is adopting
SDR in a major way in order to make existence in the crowded electromagnetic environment
more successful.
RF Superstore launchedin 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!
 If you are a radio guy (or gal) who likes
international sleuthing, mystery, and intrigue, then you will probably want to read
an article entitled, "Decoding Numbers Stations," from the November 2019 issue of the
ARRL's QST magazine. Author
Allison
McLellan, who is interested in communications history but apparently not a Ham
herself, writes, "Scanning through the bands on AM, you stumble upon something odd.
It might be the last few notes of a folk song, a sound clip from an old cartoon,
or phrases in a different language. A voice cuts through the static, methodically
calling out, 'Mike, India, Whiskey, One, Four...' But this isn't a fellow ham announcing
their call sign. These are numbers stations, an eerie subset of radio stations that
has intrigued hams and non-hams alike for decades. Numbers stations are shortwave
AM radio stations that transmit messages via voice or Morse code, believed to be
coded in one-time pad (OTP) cryptography. In OTPs, the message is comprised of strings
of numbers..."
 I'm guessing most RF Cafe visitors who are
more than 50 years old are familiar with, and even have seen, the
Sams Photofacts packages of documentation for consumer electronics
appliances that include televisions, radios, phonographs, clock-radios, tape recorders/player,
amplifiers, etc. Most electronics service shops couldn't have existed with them
since many manufacturers did not distribute technical and service data to anyone
who was not a certified, sanctioned dealer. Howard Sams, the company's founder,
did the equivalent for electronics of what Chilton did for cars and trucks. They
basically reverse engineered models bought off a showroom floor. This advertisement
from a 1958 issue of Radio & TV News magazine features the man
himself, Howard Sams, so now you'll recognize him if you pass him on the street...
 This excerpt from SpaceWeather.com reads
like the plot from an episode of Star Trek: "Earth may have crossed through a fold
in the heliospheric current sheet, described as 'a giant, wavy membrane of electrical
current rippling through the solar system'." It comes from a story on the ARRL news
webpage entitled, "Norway Experiences Unexpected Ground Current 'Shockwave'." On
January 6, "unexpected electrical currents were detected in the soil of northern
Norway starting at around 1930 UTC. 'It seemed to be some kind of shockwave,' said
Rob Stammes, who monitors ground currents at the Polarlightcenter geophysical observatory
in Lofoten. 'My instruments detected a sudden, strong variation in both ground currents
and our local magnetic field. It really was a surprise'..."
 The American Radio Relay League (ARRL) includes
a free online sample article from their monthly QST magazine - definitely
a good policy to help sell the publication (and membership in the ARRL). The February
2020 edition offers "An SWR-Shifting 'T'," written by Mr. Bill Conwell, K2PO.
It includes some useful Smith chart techniques. "Any feed-line mismatch can be brought
to a 1:1 SWR with a single shunt capacitor, provided its value and the location
where it bridges the coaxial center and shield conductors is chosen correctly. This
is because there are two locations at every half-wave along a mismatched feed line
where the impedance is exactly 50 Ω in parallel with a reactive component.
By extending or shortening the coax so that one of these locations is at the transmitter-end
of the coax, a counter-reactive shunt component can be applied using a coaxial T
connector..."
Particle Accelerator in a Silicon
Chip
 "Researchers in the U.S. are designing a
silicon chip that can accelerate electrons to over 94% of the
speed of light. The team at Stanford University and the SLAC particle accelerator,
backed by the Gordon and Betty Moore Foundation set up by one of the founders of
Intel, and the European Union's Horizon 2020 Research and Innovation Programme,
used infrared lasers and a nanoscale silicon channel to build the accelerator. The
infrared pulses are synchrnised to boost the energy of the electrons. Details of
the prototype accelerator-on-a-chip were published in today's issue of Science.
The key is the design and fabrication techniques can be scaled up to deliver particle
beams..."
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
engineering and science-themed crossword puzzles, this one for
January 19, 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 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. Some quoted items have been shortened
to save space. About RF Cafe.
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