Today in Science History -
 This schematic and parts lists for the
Arvin
model 444 and 444A tabletop radio were scanned and OCR'ed from the November
1946 issue of Radio News magazine. It was a compact, stylish, and affordable radio
for the early post-World War II era. From what I can find, it was built in
the 1945-1946 timeframe, so it was one of the first having been newly made radios
after the three to four year suspension of domestic electronics production while
the War Powers Act allowed the government to mandate companies dedicate capacity
to wartime products. There are still many people who restore and service these vintage
radios, and often it can be difficult or impossible to find schematics and/or tuning
information. This is an abbreviated version of the very informational Radio Service
Data Sheets usually printed...
 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...
 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.
 Here is your custom made
RF-themed
crossword puzzle for October 2nd, 2022. There are at least 16 instances of this
puzzle's theme included. 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!
 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...
 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!
 This "Introduction
to Radar" material is from the U.S. Air Force's "Air University" collection
of tutorials. I found it in a bin at Goodwill, bound along with a few other sections
by the Extension Course Institute including Electronics Fundamentals and Television
Principles. This treatise on radar is the first of those sections which will be
posted here on RF Cafe. No date is included in the document, but my guess based
on the content and drawings is sometime in the late 1950's. No mention is made of
Doppler (a 1940's development), although it was used to some degree toward the end
of World War II. The existence of over-the-horizon radar (a 1960's development)
is alluded to, but not expounded upon. The "A" in the "A-scan" radar display stands
for "amplitude;" it is an oscilloscope time-based sweep. An "A-scan" display is
what the mountaintop UHF radar operators in Hawaii were monitoring when Japanese
aircraft attacked Pearl Harbor on December 7, 1941...
 "The Department of Defense (DOD) seeks innovative
and creative solutions to complex, classified challenges, but the DOD is currently
only able to access a limited pool of companies cleared to work on them. Companies
must have a facility clearance and their employees must hold security clearances
to do classified work. But for a company to have a facility clearance, it must have
a contract requiring classified work to justify the clearance. This current model
results in a cyclical pattern that precludes the injection of new companies and
ideas into the classified DOD research and development ecosystem. DARPA announced
the Bringing Classified Innovation
to Defense and Government Systems (BRIDGES) program, which aims to tap into
innovation from companies that traditionally do not work with the DOD on classified
research and development efforts. BRIDGES will connect innovators directly to the
challenging problems that exist in the classified realm so they can help develop
solutions. 'There's a large U.S. innovation talent base at small companies across
our country that we currently aren't able to tap into for solutions to classified
technology challenges..."
 Here's a little more
electronics humor from the November 1961 issue of Popular Electronics
magazine. This time the topic is stereo equipment, which was a big deal in the era.
Most equipment was still of the vacuum tube variety, and the country was still enjoying
the post-Korean war and low inflation economy, so there was disposable income to
be spent on creature comforts. Hobby and home improvement magazines od the day were
filled with reviews and recommendations on receivers, speakers, phonographs, tape
players, tone arms, stylus types, cables, antennas, and all the support equipment.
Articles on room design for optimized acoustic properties included sound absorbing
ceilings, walls, and floors, speaker placement, furniture location for the best
stereo (and quadrophonic) experience, etc...
 Signal Hound's
SM435C 43.5 GHz, high-performance spectrum analyzer and monitoring receiver
is now available to order. The SM435C includes a 10 Gigabit Ethernet SFP+ port,
enabling the SM435C to communicate with a PC over long distances using a fiber optic
cable. Designed for remotely-located accurate RF data analysis at the lowest cost
possible, the SM435C also includes a signed calibration certificate and a printed
packet of calibration data. The Option-80 variant of the device provides downconverter
functionality, allowing engineers working with 5G to utilize 800 MHz of continuous
real-time data for in-depth analysis. The SM435C Option-80 is also a perfect fit
for applications requiring extremely clean phase noise. The affordability of the
SM435C opens the door to industry professionals who were previously unable to attain
this power in a compact and economic package. It is available now, with a U.S. retail
price of $25,380...
 "QRT" is the Q-code used in amateur radio
to tell someone to stop transmitting. Hams very much anticipated the day when Germany
and Japan would be defeated, the war would end, and they could go home to resume
their beloved radio hobby. You might know - or not - that during
World War II ham radio transmissions were prohibited in the U.S. for a
mix of reasons. Foremost was to inhibit the broadcasting of information, intentionally
or unintentionally, that might give away strategic military strategy. Innocent chatter
about whose son left for boot camp, where he was going afterwards, what his ambitions
and fortes were, which factory Mom and Aunt Rosie worked for and what they did (Auntie
was riveter, maybe), who died in service to his country, blackout hours, scrap material
recycling collections, all was potential fodder for enemy tacticians. Another reason
for the prohibition was to free up production materials and labor for the making
of military equipment. The fate of the free world depended on it - literally...
 It was a lot of work, but I finally finished
a version of the "RF & Electronics Schematic & Block Diagram Symbols" that
works well with Microsoft Office™ programs Word™, Excel™, and Power Point™.
This is an equivalent of the extensive set of amplifier, mixer, filter, switch,
connector, waveguide, digital, analog, antenna, and other commonly used symbols
for system block diagrams and schematics created for Visio™. Each of the 1,000 or
so symbols was exported individually from Visio in the EMF file format, then imported
into Word on a Drawing Canvas. The EMF format allows an image to be scaled up or
down without becoming pixelated, so all the shapes can be resized in a document
and still look good. The imported symbols can also be UnGrouped into their original
constituent parts for editing. Check them out!
 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!
 A few interesting historical statistics were
presented in this "Electronics
and Car Thievery" episode of "Mac's Service Shop," which appeared in a 1972
issue of Popular Electronics magazine. One is that steering column locks first came
out on 1970 auto and truck models. My 1969 Chevy Camaro did not have a steering
column lock, come to think of it. Also, a year earlier (1971), one in a hundred
cars in the U.S. were stolen. The aforementioned steering column lock dramatically
reduced the number of stolen vehicles. Car jacking was a thing in the early 1970's,
so that's not a relatively new crime - it's just that now we have video surveillance
everywhere so we get to see it. This story was particularly pertinent to a couple
recent experiences (not the same day) where visitors to our daughter's house locked
keys in their cars...
 "For more than a decade, [Museum
of Consumer Electronics] in Solothurn, Switzerland, has been a place where history
buffs can explore and learn about the development and growth of computer and consumer
electronics in Switzerland and the rest of the world. On display are computers,
calculators, floppy disks, phonographs, radios, video game consoles, and related
objects. Thanks to a new four-year partnership between the museum and the IEEE Switzerland
Section, IEEE members may visit the facility for free. They also can donate their
time to help create exhibits; translate pamphlets, display cards, and other written
media; and present science, technology, engineering, and math workshops..."
 As a life-long aircraft enthusiast, my attention
is always drawn to photos, drawings, and titles in articles dealing with any aspect
- but particularly a historical aspect - of aviation. This 1937 edition of Radio-Craft
magazine reported on the fledgling field of aircraft radio maintenance, and in particular
the opportunities presented to radio repairmen.
Aircraft electronics (aka avionics) have of course changed significantly over
the last 80 years. Accordingly, maintenance has become such a highly specialized
skill that other than swapping out entire pieces of equipment, relatively few facilities
exist that are qualified for the task. According to the article, at the time there
were a mere 5k privately owned airplanes. As of 2019, the AOPA estimated a total
of around 224k private aircraft (down from 220k in 2011), with 720k currently licensed
pilots (all categories) per the FAA...
 ConductRF supports customers with all standard
RG cables, however, a very common standard is
M17/60-RG142. This cable has a solid PTFE Dielectric core over a Solid Silver
Covered Copper Clad Steel Conductor. It is double braided and has an outer jacket
of Tan colored FEP. ConductRF offers a wide selection of standard connectors including
out Type-N males which offer a coupling nut that allows both finger tightening and
torque wrench tightening. ConductRF 100% validates RF performance of these assemblies
through factory network analyzer testing prior to shipping...
 In the 1930s, electricity and electronics
were mysteries to most of the population. The concepts were relatively new and few
had a firm grasp on the technology. That reality was exploited by Hugo Gernsback
during the 1934 Electrical Exposition to challenge attendees to discover how "the Mystery
Set" radio receiver sitting on the top of an empty, clear glass case was being
powered. It was a clever ruse that reportedly stumped most people. The secret is
revealed here in this 1934 issue of his Radio−Craft magazine. BTW, my guess
is that an even smaller proportion of our current citizens would be able to figure
it out, or for that matter even realize that maybe there should be a power source
of some sort...
 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...
 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.
 The term "metallized
dielectric" at first might seem like an oxymoron. After all, if you add a conductive
substance to the dielectric of a capacitor, then you have compromised the integrity
of the dielectric as a non-conducting substance. Here's the deal: The dielectric
material between the conductive plates does not receive the metallization; a non-conductive
(dielectric) material like paper is impregnated with metal and that is used for
the plate material. The advantage of this scheme is that the plate material can
be thinner, thereby reducing the size of the capacitor package for a given capacitance
value. It comes with a price, of course, and that is a lower operational and maximum
applied voltage rating. With proper design in circuits like power supplies, metallized-dielectric
capacitors can facilitate great space savings. A major benefit of metallized-dielectric
capacitors is an ability to self-heal when the plate material develops a short circuit
through the dielectric...
 3D printing of antenna and waveguide components
has been advancing rapidly in the past few years. Early research used plastic that
was then coated with a conductive substance. Once 3D printing using a metallic filament
was developed to the point that the structure could withstand heat cycling, vibration,
and shock associated with aerospace environments, the creation of complex, compound
shapes never deemed possible with traditional machining became reality. Using proprietary
additive manufacturing techniques developed in-house, virtually any form of waveguide
and/or antenna can now be fabricated by companies like
Swissto12,
based in Switzerland. As can be seen in the included images from the
Swissto12 website, the surfaces are not perfectly
smooth...
 Designing, building, and tuning low frequency
filters is much easier for the person without a professional grade suite of
software, fabrication, and test equipment than is RF / microwave frequency filters.
Most of my design and integration work has been with system level transmit and receive
racks for radar and satellite earth station installations, and typically for prototyping
and/or very low quantity production. Accordingly, I often used connectorized components
cascaded together where each functional block was predefined and tested. I would
be handed a system input/output document that specified parameters for gain, phase
noise, intercept points, noise figure, group delay, bandwidth(s), power levels,
switching and settling times, current consumption, volume, weight, cost constraints,
etc. That explains why my software offerings like RF & Electronics Symbols for
Visio and RF Cascade Workbook all deal with system level design...
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