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4 of the April 2022 homepage archives. Thursday the 14th
 In 1942 and throughout the War Years,
Life magazine (and many others) ran many articles promoting industries,
services, organizations, and individuals who contributed toward our ultimate victory.
Of course no one knew for certain that we would prevail in the end, but if it hadn't
turned out that way, it wouldn't have been for lack of effort and sacrifice. Part
of the objective was to inform the populace about how the country was pooling its
resources - physical, labor, and mental - to defeat the Axis Powers that sought
to takeover the world. This particular issue of Life focused on the
chemical industry, with the raw materials and processes used to produce needed
products both for fuel and for the base components of other finished goods. Sulphur,
potassium, and coal mining and processing, along with petroleum, common table salt,
and air and water were some of the most fundamental ingredients of every other item
needed to aid the effort. Ever hear of Ameriopl rubber?
 "Exotic materials known as
kagome superconductors can play host to a rare state of matter in which electric
currents form 'loops' around unit cells in the material’s crystalline lattice. This
discovery, made by researchers at Switzerland's Paul Scherrer Institute (PSI) together
with international collaborators, could reveal new information about how superconductivity
emerges in materials where complex effects such as frustrated magnetism and intertwined
orders play a major role. Kagome metals are named after a traditional Japanese basket-weaving
technique that produces a lattice of interlaced, corner-sharing symmetrical triangles.
When the atoms of a metal or other conductor are arranged in this so-called kagome
pattern, their electrons behave in unusual ways, giving rise to interaction-driven
electronic phases of matter that can be identified by studying symmetries of the
material. In one such electronic phase, electrons organize themselves into a looped
pattern along the kagome bonds between regions of the lattice with high and low
concentrations of electric charge..."
 Depending on which news story you believe,
both
AM
and FM (and television for that matter) over-the-air broadcasting is dying out
at an increasingly rapid rate. Between recordable podcasts, wired Internet connections,
and the growing ubiquity of Wi-Fi connectivity, a large majority of people in the
civilized world are getting their broadcasts via the Web. If you "follow the money"
in broadcast advertising, the lion's share of dollars have shifted to online venues,
simultaneously draining revenue from local stations. When this story was written
in 1946, OTA radio was king for real-time and free reception of information - particularly
in a mobile environment. A dilemma arose in the form of RF spectrum allocation in
border regions between the U.S. and Canada, both of which were scrambling to stake
a claim on channels. AM was old-hat and sharing issues had largely been worked out,
but the advent of FM (frequency modulation) and an entirely new band of frequencies
opened a real can of worms for national and international regulators...
 With more than 1000
custom-built stencils, this has got to be the most comprehensive set of
Visio Stencils available for RF, analog, and digital system and schematic
drawings! Every stencil symbol has been built to fit proportionally on the included
A-, B-, and C-size drawing page templates (or use your own page if preferred). Components
are provided for system block diagrams, conceptual drawings, schematics, test equipment,
racks (EIA 19", ETSI 21"), and more. Test equipment and racks are built at a 1:1
scale so that measurements can be made directly using Visio built-in dimensioning
objects. Page templates are provided with a preset scale (changeable) for a good
presentation that can incorporate all provided symbols...
 Axiom Test Equipment allows you to
rent or
buy test equipment,
repair
test equipment, or sell or trade test equipment. They are committed to providing
superior customer service and high quality electronic test equipment. Axiom offers
customers several practical, efficient, and cost effective solutions for their projects'
TE needs and is committed to providing superior customer service and high quality
electronic test equipment. For anyone seeking a way to offload surplus or obsolete
equipment, they offer a trade-in program or they will buy the equipment from you.
Some vintage items are available fully calibrated. Please check out Axiom Test Equipment
today!
Wednesday the 13th
 The Varian brothers, Russell and Sigurd,
are widely credited for invention of the klystron around 1937. Credit for further
developments in the
klystron - from its technology to origin of the name - is a bit fuzzy based
on many articles I have seen. According to a 1944 Radio News magazine article,
Sperry Gyroscope Company developed the tube into commercial viability and was assigned
the trademark name "klystron" based on their creation of the field of "klystronics."
However, the Wikipedia entry for Stanford professor Hermann Fränkel claims the name
"klystron" was suggested by him. This full-page Bell Telephone Labs promotion in
a 1956 issue of Radio-Electronics magazine tells of their 60 GHz klystron
design by employee G.K. Farney, but makes no mention of the device's history.
Bell Labs is unquestionably responsible for untold numbers of paradigm-changing
inventions, but for some reason the omission of that information - especially so
close in time to the klystron's arrival on the commercial scene - bothers me a bit...
 "The U.S. Naval Research Laboratory (NRL)
Electronics Science and Technology Division (ESTD) actively performs research and
development in a variety of materials science, physics, and engineering fields pursuing
technological advances crucial to the DoD future high-performance electronic systems.
Research topics span all aspects of electronics, such as advanced fabrication methods
for radio frequency (RF) devices, growth and characterization of exotic electronic
materials, quantum information science, neuromorphic computing, power devices and
solar cells, nanofabrication, and solid state and vacuum electronic RF sources.
'NRL's ESTD aims to harness
3D printing for electromagnetics, such as antennas, metamaterials, and millimeter-wave
with RF amplifiers operating in very high frequency bands, such as 5G and beyond,'
said Alan Cook, Ph.D., Head of Vacuum Electronics and Material Section. 'With precision
build capabilities of these machines ranging in resolution from small fractions
of a millimeter down to the 100-nanometer scale, NRL's ESTD aims to foster DoD and
Department of Navy concepts...'"
 It is always nice to read an article that
encompasses more than one of my hobbies, whether it be amateur radio and amateur
astronomy like this one, amateur radio and model rocketry, or amateur radio and
radio controlled airplanes. I don't recall ever seeing an article that combined
astronomy and model airplanes. In this 1943 QST magazine piece, author
Hollis French expounds on the necessity for Hams to understand the effects that
atmospheric phenomena, caused primarily by our sun's periodic and intermittent
activity, have on radio signal propagation. Properties of the ionospheric layers
had by 1943 been pretty well surmised based on cause and effect relationships through
indirect observation since at the time no sounding rockets had been launched into
the upper atmosphere to obtain in situ measurements of ionization, magnetic fields,
and free electron activity. Today's knowledge of course is much more detailed and
formulated thanks in large part...
 ASC designs and manufactures hybrid, surface
mount flange, open carrier and connectorized amplifiers for low, medium and high
power applications using gallium nitride (GaN), gallium arsenide (GaAs) and silicon
(Si) transistor technologies. ASC's thick film designs operate in the frequency
range of 300 kHz to 6 GHz. ASC offers thin film designs that operate up
to 20 GHz.
 April
2022 Update: Back in 2015, I ran across
The Old Radio Builder website,
hosted by Mike Starcher, KB4YJ, of Louisville, Kentucky. He has a nice collection
of vintage radio restorations and building projects, all of which are useful to
hobbyists. Sadly, I received word from a good friend (Gary F.) of Mike's that
he is now a Silent Key, and was asked whether there is a way to get Mike's website
back up since the Old Radio Builder website has been taken down. Fortunately, I
discovered that the Archive.org website has many captures of the website's pages,
so in effect it is still up and available! The last capture of The Old Radio Builder
before it expired appears to be March of 2019. It lives on in perpetuity...
 Here are a few more tech-themed comics from
older editions (1962 and 1970) of Popular Electronics magazine. The first
comic with the transistors and fuse is really clever, IMHO. The other two are directed
toward amateur radio operators, but you don't need to be one to appreciate the humor.
There is a hyperlinked list at the bottom of the page of most of the other comics
I've posted over the years. It's a shame that comics rarely appear in contemporary
technical magazines - probably too afraid of offending someone...
 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...
 Centric RF is a company offering from stock
various RF and
Microwave coaxial components, including attenuators, adapters, cable assemblies,
terminations, power dividers, and more. We believe in offering high performance
parts from stock at a reasonable cost. Frequency ranges of 0-110 GHz at power
levels from 0.5-500 watts are available off the shelf. Order today, ship today!
Centric RF is currently looking for vendors to partner with them. Please visit Centric
RF today.
Tuesday the 12th
 This episode of "Mac's
Radio Service Shop" is a prime example of the difference between a business
owner and an employee when it comes to always thinking about how to make things
more efficient and attractive to customers - and therefore more profitable. To be
fair, there is no reason to expect an employee to have as high a level of devotion
as an owner other than for better job security. The October 1950 story entitled
"Mending Harness," appearing in Radio & Television News magazine, is a prime
example. Mac, the proprietor, had spend many hours in the evenings completing service
jobs and clearing the shop of its sizeable backlog. Barney, the employee, loved
the situation since he thought it would mean some slack time for him. Mac, though,
planned to use that time for repairing, aligning, and improving the test equipment
- something that had gone wanting during the busy times. As always, Mac's Service
Shop docu-dramas are a good mix of useful lessons and good humor...
 Anatech Electronics 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. Three new
filter models have been introduced - a 0-450 MHz / 900-2100 MHz L-C diplexer
with SMA connectors, a 824-891.5 MHz cavity bandpass filter with N-type connectors,
and a 3.2 MHz L-C lowpass filter with SMA connectors. 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...
 "Energy harvesting, with its many manifestations,
is often an attractive and viable solution to providing long-term low levels of
operating dc power.
RF-energy harvesting is especially attractive since that energy is pervasive,
while capturing it incurs no discernable negative impact on intended users - it's
truly 'going to waste.' Further, unlike many (but not all) fixed-in-place solar,
vibration, or thermal-harvesting installations, most RF-harvesting arrangements
can be mobile to go with system they're powering. Key to use of ambient RF energy
as a harvestable source is the energy collector. It acts as a transducer to capture
electromagnetic energy and transform it into useful electrical energy and power
in the form of voltage and current. While a regular antenna can be used for this
function - after all, that's what an antenna does - the capture efficiency is quite
low and generally insufficient unless a fairly large and resonant antenna is used.
Addressing this challenge, a team at the University of South Florida has developed
a metasurface-based antenna..."
 Radio astronomy has been the motivation for
much research work in the design of low noise, high sensitivity receivers, but also
in determining the characteristics of the Earth's upper atmosphere. Before sounding
rockets could be launched to verify theoretical proposals, observed versus predicted
behavior in radio signals being reflected off the moon and planets needed to be
explained and, if necessary, corrected. One notable example of atmospheric perturbation
is the rotation of polarization caused by electrons in the ionosphere (the Faraday
effect). Parametric and cryogenically cooled receiver front end technology has been
primarily driven by the needs of radio astronomy. The International Geophysical
Year (IGY), launching (literally) a coordinated multinational effort to more fully
understand the upper atmosphere's effects on communications, began the same year
this story appeared in Radio-Electronics magazine. While it is true that radio astronomy
has the advantage of not needing to wait for clear, dark skies to be useful the
way observation in visible wavelengths...
 "ARRL
is seeking candidates for job opportunities at its headquarters in Newington, Connecticut.
Available positions include Director of Information Technology, Public Relations &
Outreach Manager, Social Media Strategist, and others. ARRL Human Resources Manager
Luci Goodwin explained that some of the jobs are brand-new positions, established
to help advance the association's ongoing digital transformation across membership
programs, services, and publishing. 'Some of the positions are responsible for increasing
awareness and growth of amateur radio,' said Goodwin. 'A new program area will expand
ARRL's visibility in promoting ham radio to the public and through our outreach
to like-minded communities.' A list of open positions, including the responsibilities
and qualifications for each job, is posted on the
ARRL Careers webpage.
Employment opportunities are available for candidates with or without an amateur
radio license..."
With more than 1000
custom-built stencils, this has got to be the most comprehensive set of
Visio Stencils available for RF, analog, and digital system and schematic
drawings! Every stencil symbol has been built to fit proportionally on the included
A-, B-, and C-size drawing page templates (or use your own page if preferred). Components
are provided for system block diagrams, conceptual drawings, schematics, test equipment,
racks (EIA 19", ETSI 21"), and more. Test equipment and racks are built at a 1:1
scale so that measurements can be made directly using Visio built-in dimensioning
objects. Page templates are provided with a preset scale (changeable) for a good
presentation that can incorporate all provided symbols...
 ConductRF is continually innovating and
developing new and improved solutions for RF Interconnect needs. See the latest
TESTeCON RF Test
Cables for labs. ConductRF makes production and test coax cable assemblies for
amplitude and phased matched VNA applications as well as standard & precision
RF connectors. Over 1,000 solutions for low PIM in-building to choose from in the
iBwave component library. They also provide custom coax solutions for applications
where some standard just won't do. A partnership with Newark assures fast, reliable
access. Please visit ConductRF today to see how they can help your project!
Monday the 11th
 Many moons ago while in the USAF, I designed
and built a pair of speaker enclosures out of pine wood in the base woodshop. Each
had a separate bass, midrange, and tweeter speaker - all bought at the downtown
Radio Shack (and the acoustically transparent cloth for the front). An issue of
Popular Mechanics magazine had guidelines for the cabinet layout and made
passing mention of the need to install an adequate
frequency crossover unit in order to obtain the best performance. That article
did not contain any information for designing your own crossover network, so I went
about trying to figure out my own, based on a fairly limited knowledge of circuit
theory and how to match impedances. There was no Internet back then for conveniently
looking up that sort of stuff. I came up with a circuit that managed to work, but
I honestly have no idea whether the frequency division was anywhere near what I
thought it should be. I probably would have done just as well (or better) to have
bought a high quality 3-speaker unit sold for car hi-fi stereos, and mounted them
in the cabinets...
 It was with sadness that I read on the IEEE
Spectrum website of Robert
"Bob" Lucky's passing March 10th this year. Born on January 9th, 1936, Mr. Lucky
built an amazing legacy for himself through a combination of smarts, ambition, personality,
and intuitiveness. He had a PhD from Purdue (aka "Parvoo"
by Carl and Jerry), and spent many years at
Bell Labs as a communications engineer. Back when I could afford an IEEE membership,
I looked forward to reading his "Reflections" column, which
always mixed serious analysis with a great sense humor and irony. His c1993 book,
"Lucky Strikes ... again," is still a good
read. Peruse through the sample pages on Amazon at the link above to get a flavor
of Lucky's charm. Say, I just made a funny (the
cereal, get it?), but that
is easy to do with his name. Consider the book title, which has to be a play on
the popular (at the time) cigarette brand "Lucky Strike."
RIP, Bob Lucky, and thanks for the laughs.
 Thanks to Ken H. for sending photos
of his
Nuclear Bomb Effects Computer (likely the original 1957 version). Both the computer
and sleeve have EG&G's name printed on it. "This Nuclear Bomb Effects Computer
has been compiled in cooperation with the Atomic Energy Commission, Division of
Biology and Medicine, and Lovelace Foundation for Civil Effects Test Operations
AEC-Biology And Medicine Contract AT(29-1)1242." Quickly and handily calculates
Max. Fireball Radius, Height for Minimal Fallout, Apparent Crater Radius and Depth,
and even Radiation Levels with 1st, 2nd, and 3rd degree burns! Who wouldn't have
wanted one of these back in the 1960s while hunkering down in an underground bunker
or beneath your school desk while thermonuclear ordinance was exploding overhead?
 Most digital and
analog multimeters rely on precision resistors for scaling the input voltage
or current to keep it within the safe operational range of the meter movement or
analog-to-digital converter circuit. Resistance value selection is a relatively
simple matter of series and/or parallel combinations and their resulting divisions
of voltages and/or currents. When this article appeared in a 1931 issue of Radio-Craft
magazine, the whole concept of electrical circuit design was entirely new to most
people, including shunts and multipliers for meter scales. The International Rectifier
Company (IRC) article gives a handy rule of thumb for setting resistor values when
considering the resistance of the meter movement coil. There is a nice table of
resistor values provided, but I was a little disappointed to find that not a single
equation is given for calculating custom values...
RF Cascade Workbook is the next phase in the evolution of
RF Cafe's long-running series, RF Cascade Workbook. Chances are you have
never used a spreadsheet quite like this (click here for screen capture). 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...
 Copper Mountain Technologies develops innovative
and robust RF test and measurement solutions for engineers all over the world. Copper
Mountain's extensive line of unique form factor
Vector
Network Analyzers include an RF measurement module and a software application
which runs on any Windows PC, laptop or tablet, connecting to the measurement hardware
via USB interface. The result is a lower cost, faster, more effective test process
that fits into the modern workspace in lab, production, field and secure testing
environments.
Sunday the 10th
 Here is your custom made
Microwaves-themed crossword puzzle for April 10th, 2022. All RF Cafe crossword
puzzles are custom made by me, Kirt Blattenberger, and have only words and clues
related to RF, microwave, and mm-wave engineering, optics, mathematics, chemistry,
physics, and other technical subjects. As always, this crossword contains no names
of politicians, mountain ranges, exotic foods or plants, movie stars, or anything
of the sort unless it/he/she is related to this puzzle's technology theme (e.g.,
Reginald Denny or the Tunguska event in Siberia). The technically inclined cruciverbalists
amongst us will appreciate the effort. Enjoy!
 New Scheme rotates
all Banners in all locations on the page! RF Cafe typically receives 8,000-15,000
website visits each weekday.
RF Cafe is a favorite
of engineers, technicians, hobbyists, and students all over the world. With more
than 12,000 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.
 Please take a few moments to visit the
everythingRF website to see how they can assist
you with your project. everythingRF is a product discovery platform for RF and microwave
products and services. They currently have 267,269 products from more than 1397
companies across 314 categories in their database and enable engineers to search
for them using their customized parametric search tool. Amplifiers, test equipment,
power couplers and dividers, coaxial connectors, waveguide, antennas, filters, mixers,
power supplies, and everything else. Please visit everythingRF today to see how
they can help you.
Friday the 8th
 In most instances the method and materials
have changed over the years, but fundamental principles of writing and reading data
to and from
magnetic media are the same today as when this article was written in 1947.
If you find that your lexicon of technical jargon lacks terms such as coercivity
and remanence, then you might want to invest a few moments reading this short article
that appeared in Radio-Craft magazine. I realize most regular RF Cafe visitors won't
be interested, but hopefully someone, somewhere, searching for this information
will now be able to find it. Thanks for your indulgence. Part I, "A Modern
View of Permanent Magnet Theory," appeared in the October 1947 issue and Part II,
"Benefits of Tape Recording," appeared in the November 1947 issue...
 Kite- and
balloon-lifted antennas are very popular in the amateur radio realm. They are
primarily used for short-term activity such as during a contest or during an emergency;
however, some operators use them on a more extended basis. A really good series
of articles on the use of balloons and kites for suspending antennas can be found
at qsl.net/g4vgo/antenna1.htm. Equations for calculating necessary balloon and kite
sizes and predicting wind effects are included along with lists of 'Dos' and 'Don'ts.'
This is not a new phenomenon. A 1940 edition of QST magazine described
how to employ weather and sounding balloons to provide needed antenna configurations
in places where suitable permanent structures were not available. Those balloons
were intended to support antennas for extended periods of time - measured in weeks
rather than hours. Here is a Short-Wave Craft article titled "Balloons
Raise Shortwave Antenna..."
 "The
embrace of millimetre wave by the 5G era was celebrated as opening up vast new swathes
of spectrum real estate that would enable hitherto unimaginable wireless data rates.
There was just one problem, however - the
propagation characteristics. While traditional low-frequency radio waves penetrate
walls and windows as if they weren't there, the higher you go, the less effective
spectrum is at this. That's one of the reasons the main use-case for mmWave so far
has been fixed wireless access, because you can just create a point to point, line
of sight, fixed setup, much like the microwave communications between cellular base
stations. But in this scenario the customer premises equipment (CPE) still needs
to be on the outside of the building, for the aforementioned propagation reasons.
Glass, as you would expect, is easier for electromagnetic radiation to penetrate
than brick, but how much easier depends on the glass, it seems. In these eco-conscious
times the trend is towards low-emissivity (low-E) glass, which has superior insulating
properties. The problem is that works both ways and double-glazing..."
 Long before there were smartphones and software
"apps," engineers and scientists carried around portable "apps" of another kind.
These apps were made from printed heavy cardboard stock and typically had either
a sliding section sandwiched between two outer layers, or a rotating layer on a
fixed base layer. They even sported rivets to hold them together - like the original
Levis dungarees. I and guys much older than me [ ;-) ] routinely carried them in
our shirt pockets, securely snugged behind our plastic pocket protectors. You definitely
always wrote your name on them in indelible ink since there was a tendency for those
cardboard slide rules to sprout legs and walk away while you were at lunch or in
the can. These
cardboard slide rule calculators used to be included on the Traditional Slide
Rules page, but thanks to generous RF Cafe visitors who either sent me hard copies
or high-res photos, the number has grown so large that they required their own page.
You are invited to submit examples of your own collection for inclusion in the informal
Cardboard Calculator Museum...
 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 can 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...
 Triad RF Systems designs and manufactures
RF power amplifiers
and systems. Triad RF Systems comprises three partners
(hence 'Triad') with over 40 years of accumulated
knowledge of what is required to design, manufacture, market, sell and service RF/Microwave
amplifiers and amplifier systems. PA, LNA, bi-directional, and frequency translating
amplifiers are available, in formats including tower mount, benchtop, rack mount,
and chassis mount. "We view Triad more as a technology partner than a vendor for
our line-of-sight communications product line." Please check to see how they can
help your project.
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.
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