Today in Science History -
 "Scientists at the University of Rostock,
in close collaboration with partners from the Vienna University of Technology, have
developed a novel process that can
render artificial materials transparent or even entirely invisible, on demand.
Their discovery was recently published in the renowned journal Science Advances.
Turning something invisible is a common trope in science fiction, such as the Cloak
of Invisibility in Harry Potter. Certainly, it sounds cool, but the reason it is
so common in stories is that it would be incredibly useful technology. The uses
for espionage and the military are obvious, but there are far more applications.
Given its immense usefulness, it may not come as a surprise that this is something
scientists and engineers have been actively working on. They've had quite a bit
of progress too, using molybdenum trioxide, metamaterials, metascreens, and
dielectric materials to fashion invisibility cloaks. It all comes down to
manipulating light in the proper way, and what is especially marvelous is that
innovation in this
 Empower
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is superior to anything in the market at similar frequencies and power levels.
 Center of
Telecommunication Technologies (CTT) is proud to announce immediate availability
of version 2.0 of their popular Antenna Pattern Editor.
Antenna Pattern Editor 2.0 is a universal tool to view, create, edit and
convert antenna patterns. See the New Features in Antenna Pattern Editor 2.0
list at the left. The main idea embedded in the program is to provide the user
with the opportunity to quickly create an antenna pattern file using various
methods. Antenna pattern file is a simple text or xml file that describes the
main characteristics of the antennas - radiation patterns, gain, frequency
range, name, manufacturer and other data. These files are used in various radio
planning tools including our RadioPlanner, Indoor Radio Planner, and
MLinkPlanner. There are a large number of antenna pattern file formats, but it
often happens that there is no file in the required format. In this case, using
the Antenna Pattern Editor, you can easily convert the file to the format you
need. Sometimes the antenna information is just a picture of the antenna
pattern...
 This
reactance measuring bridge circuit which appeared in a 1931 issue of Radio−Craft
magazine employs a very unique element for generating an alternating current: an
electromechanical buzzer which doubles as an audio source. Sure, it doesn't produce
a pure sinewave, but for the method used here to determine inductance and capacitance
it does not matter. Rather than attempting to measure an absolute value of inductance
or capacitance, a known reactance is used as part of a balanced bridge. This is
by no means a precision instrument since accuracy depends on the user's interpretation
of the presence or absence of an audible "buzz" in a pair of headphones, but in
an era when "real" test equipment was beyond the budgets of many (maybe most) hobbyists,
the scheme was better than nothing at all...
 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...
Reactel has become one of the industry leaders in the design and manufacture
of RF and microwave
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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.
 In no way do I advocate going back to the
"old ways" for manufacturing electronic components, but I do admire and like to
give credit to the people who used to perform the tedious procedure of
building
vacuum tubes, hand-wire chassis assemblies, circuit boards, etc. This 1932 issue
of Radio−Craft magazine article is good example. The process required being
able to sit or stand at the same work station and perform the same range of operations
day after day, often for years on end. Of course at the time, automation processes
were not what they are today and machinery needed to be driven by mechanical means
using motors, solenoids, and limit switches. That made employing people more financially
rewarding than using a machine. You can find details on the algorithms and methodology
for designing those contraptions in older engineering handbooks. It is an amazing
sight to to tour a WWII vintage battleship and look at the hardware that stabilized
and steered the cannons without an electronic computer in sight...
 "Researchers have discovered a
single-molecule switch that can act like a transistor and store binary information
such as the 1s and 0s used in classical computing. The molecule is around five square
nanometers in size - more than one billion of them would fit onto the cross-section
of a human hair. The researchers believe that molecules like the ones they have
discovered could offer information density of around 250 terabits per square inch,
which is around 100 times the storage density of current hard drives. The smart
molecular switches as seen with a scanning tunneling microscope. In the study, molecules
of an organic salt can be switched using a small electrical input to appear either
bright or dark, providing binary information. This information can be written, read,
and erased at room temperature and in normal air pressures. These are important
characteristics for practical application of the molecules in computing storage
devices..."
 There was a time when having a career in
any field of
electricity or electronics related work was an enviable mark of a person's technical
prowess that conveyed a degree of respect. The whole controlling of electrons thing
boggled the minds of most people, whether it meant wiring homes and buildings for
lights, receptacles, and motors, or designing "all wave" radio sets for listening
to the evening broadcast of "The Lone Ranger." Today, with nearly everyone alive
having grown up with such conveniences, the "wow factor" is pretty much gone, except
maybe with those of us who still chose to engage. If an electronics appliance or
device stops working nowadays, it is discarded rather than repaired. This 2-page
advertisement from a 1946 edition of Radio News magazine inviting men to
become a "bonded electronic technician" is typical of those found in the era, and
even in the 1920s and 1930s...
 The Radio Service Data Sheets that were
published in Radio−Craft magazine usually seem to have more information
included than those published in other magazines, at least in the same era (1940-ish).
It might have to do with how much material is provided by the manufacturer rather
than a decision by the magazine editors. Either way, here are the schematics, chassis
layout, and service info for the
Lafayette Model B−100 through B−103. As with most radios built in the era, the
woodwork and artistic design of the cabinet are exquisite. There are still people
searching for such data, but fortunately the Internet is making it much easier to
locate. None of the three models show up on eBay as of this writing...
 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.
 Aegis Power Systems is a leading supplier
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 This advertisement for a
Zig−Zag Antenna, offered by Trio Manufacturing, appearing in a 1952 issue of
Radio−Electronics magazine, states "patent pending." When I looked up "zig−zag
antenna" at the U.S. Patent and Trademark Office (USPTO), the earliest assignment
I could find for that configuration was US3213457A, "Zig−zag antenna," designed
by John W. Carr and assigned to Lockheed Corporation, in 1961. Maybe Trio never
received a patent, or my search wasn't thorough enough. The claim to fame from Trio's
design is that the zig−zag pattern consisted of various element lengths that resonated
on specific channels while all others acted as parasitic elements. I don't know
if it is coincidence or intention (probably the latter), but there are twelve sections
that might correspond to channels 2 through 13. There are not many (if any) zig−zag
antennas being sold by companies today for amateur or other uses. It evidently was
just another fad to have something different from all the rest - and there were
lots of unique TV antenna configurations back in the day which promised to pull
in far-away stations, reduce ghosts, noise, etc...
 "The Hybrid Channel Emulator is one of the
projects that is currently being developed as a part of ESA's ongoing ARTES (Advanced
Research in Telecommunication Systems) program. The HCE is developed under a
strategic goal namely 'Space for 5G' and the aim of the project is to design an
emulator which can emulate radio propagation conditions of two bi-directional 5G
carriers with accurate emulation of satellite-satellite and satellite-terrestrial
link characteristics. The objective of the Hybrid Channel Emulator project is the
development and validation of a single solution capable of emulating the radio propagation
conditions of two bi-directional 5G carriers (satellite-satellite or satellite-terrestrial).
This has the twin challenges of providing an emulator that accurately models the
dynamics, and tightly controls the channel impairments, of a wide variety of scenarios,
and one that covers frequency bands spanning nearly 30 GHz..."
 Quantic PMI, a leading supplier of custom,
high-reliability
MIC/MMIC components and subsystems for applications in space, military, communications,
commercial and consumer electronics systems for more than three decades, recently
introduced five new products in their extensive line of RF and microwave components.
Included are an 8-12 GHz digitally tuned phase attenuator, a 333 to 368 MHz
variable frequency comb generator, a 0.5 to 18 GHz 4−way power divider, an
8 to 12 GHz digitally tuned phase shifter, and a 0.1 to 40 GHz SP2T absorptive
switch. Contact Quantic PMI today for more information...
 This item from Tarek Mealy showed up on
my LinkedIn feed. He created a nifty software app called "SymMos"
that allows you to use a drag-and-drop interface to create a schematic using MOSFETs,
resistors, inductors, capacitors, bias voltages, and signal sources. Then, click
on the appropriate button to get the transfer function equation for input impedance,
gain, transconductance, or noise figure. SymMos is a work in progress and is available
as a free download. After unzipping the file, you need to change the SymMos.txt
file extension to .exe. Launch the executable and then you'll need to wait many
seconds while the program loads (a black screen is displayed while waiting). BTW,
Norton flagged the file as dangerous since it is new and hasn't seen it before,
but I allowed it to run anyway with no problems. I recreated the example shown in
the YouTube video and it works as advertised...
 "If you have dark eyes and blonde hair and
are under 30, you're due for some easy squeezing. Milligan's Appliance Center, 84
Main Street, is giving every girl between 16 and 30 who has these striking features
a newly patented orange squeezer, to introduce the new item ... Note: Any traces
of recent peroxide rinse will disqualify applicants." That is advertising copy offered
as an example of effective promotional material in a 1947 edition of Radio News
magazine. My first reaction was to think how something like that would never fly
today, but then I wasn't so sure. It seems there must be anti-discrimination laws
in this "offend nobody" climate today that prohibits singling out a certain demographic
for inclusion or exclusion; however, there are many such promotions run today such
as members only, active military and student discounts, senior citizens, etc. It
is clear that these days
only certain privileged sectors of society are still allowed to discriminate...
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...
 Berkeley Nucleonics Corporation (BNC) is
a leading manufacturer of precision electronic instrumentation for test, measurement,
and nuclear research. Founded in 1963, BNC initially developed custom pulse generators.
We became known for meeting the most stringent requirements for high precision and
stability, and for producing instruments of unsurpassed reliability and performance.
We continue to maintain a leadership position as a developer of custom pulse, signal,
light, and function generators. Our designs incorporate the latest innovations in
software and hardware engineering, surface mount production, and automated testing
procedures.
 With few exceptions, I, RF Cafe webmaster
Kirt Blattenberger, have for more than two decades designed a custom crossword puzzle
every week for the benefit of website visitors. This
Science Theme Crossword Puzzle for was created for June 26th, 2022. All crossword
puzzles use a personally built dictionary of thousands of words and clues related
to RF, microwave, and mm-wave engineering, optics, mathematics, chemistry, physics,
and other technical subjects. As always, this crossword puzzle 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!
 TotalTemp Technologies has more than 40 years
of combined experience providing thermal platforms.
Thermal Platforms
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recirculating circulating coolers, temperature chambers and temperature controllers,
thermal range safety controllers, space simulation chambers, hybrid benchtop chambers,
custom systems and platforms. Manual and automated configurations for laboratory
and production environments. Please contact TotalTemp Technologies today to learn
how they can help your project.
 Supreme Publications was another of the
more prominent publishers of electronic equipment service manuals back in the middle
of the last century. Howard W. Sams Photofact was of course the most well-known,
but there were others including this one and Rider Service Manuals. Supreme Publications
claims their content is provided by the manufacturers; to wit, " factory instructions
for troubleshooting, repairing, and alignment." For a mere $2.00, a service shop
could have the required data to service every AM and FM radio and television receiver
produced for model year 1948, when this issue of Radio News magazine was published.
According to the BLS Inflation Calculator, that's the equivalent of $24.56 in 2022
- a pretty good deal. A version of the manual with extra diagrams could be had for
an additional 50¢...
 As the opening sentence indicates, National
Company ran a very long series of advertisements in QST magazine that were
in a format more reminiscent of a short essay than a company promotion. This installment
for the December 1952 edition was number 224. Subjects ran the gamut from technical
innovations from the company's research and development laboratory to social and
political issues relevant to electronics technicians, hobbyists, students, and engineers.
Being that it was a presidential election year in the U.S.,
National
Company felt compelled to remind readers of their patriotic duty to vote. Although
this was the December issue, it would reach readers' mailboxes prior to the election.
Dwight D. Eisenhower ran against Adlai Stevenson. The latter won the South and the
former won everything else. Note the thinly veiled criticism at the bottom about
why amateur radio participation rate was down at the time...
 RF Cafe visitor
Jonathan Zane (KC2SHO) recently sent me a hyperlink to his collection of photos
taken when he visited a
broadcast facility in Balkhash, Kazakhstan. A sample of his extensive image
cache is shown here. You can view the entire set that includes vintage electronic
equipment, facilities, and city streets on his kc2sho.com website. You will see
a huge stash of vacuum tube assemblies, large coaxial cables, operation and maintenance
manuals, and spare parts. These kinds of treasure troves exist all over the world;
it's a matter of finding them. Imagine what all that abandoned equipment and components
would sell for on eBay! Along with requesting permission to post a few of his photos,
I invited him to provide some text to accompany them. Here is what he wrote - you
will definitely like the anecdote at the end. Many thanks to Jonathan for this!
 Simpson Electric is a name most RF Cafe
visitors are probably familiar with as being the maker of high quality analog multimeters,
with the Simpson 260 line being the most famous (it is still manufactured today).
Not as many people, however, know that Simpson also used to make oscilloscopes.
This article from a 1957 issue of Radio & TV News magazine was written
by a Simpson Electric engineer whose job was, in part, to respond to questions asked
by users. It covers basic operations like how to calibrate the display, adjust the
horizontal time base and vertical amplitude scales, and how to synchronize the display
with the input signal. Some explanation of
how to interpret periodic and pulse type waveforms is provided as well as tips
on how to avoid overloading and possibly damaging the instrument...
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