Today in Science History -
 When this "Clandestine
Broadcasters" article appeared in a 1967 issue of Popular Electronics
magazine, we were at the height of the Cold War era with Communist forces spreading
all over the globe and inching closer to the U.S. mainland with moves in the West,
north of the Equator. The Cuban Missile Crisis occurred just five years earlier,
and the spy game kept all sides busy trying to hide their own secrets and discover
the secrets of others. Mysterious radio broadcasts were routinely picked up and
reported by Amateur Radio operators and Short Wave Listeners. Their elusive broadcast
content and station location enhanced the intrigue for people. Of those, it was
the "numbers stations" that garnered the most attention because they issued a string
of numbers, then ceased transmission. It was believed to be a means of sending encoded
messages to spies. The practice continues to a lesser extent to this day...
 "Keeping IoT applications across the world
connected is a challenge, yet imperative. The term 'ubiquitous
coverage' is often thrown around in the supply chain and logistics industry
- and for a good reason. Breaks in the chain of visibility leave logistics vulnerable,
especially as businesses scramble to keep up with the introduction of new technologies
and services. This is why the challenge lies in finding a universal solution that
connects IoT applications all over the world, providing a continuous view no matter
where assets are. The first step to improving the deployment of IoT applications
is to understand the common obstacles within the industry, like internal operations.
Supply chain and logistics have long struggled to streamline internal processes
to monitor the flow of goods and services from supplier to customer. And supply
chain demands have only exacerbated this challenge..."
 As in the past, I am posting these Radio
Service Data Sheets as a service to someone who might be doing research on vintage
radios and/or restoring one. Roamio is not producing automobile radios anymore,
but they did until recently make TiVo recorders and streaming media players. The
Crosley Roamio Automotive T.R.F. Receiver Models 90, 91 and 92 was made in the
early 1930's at a time when cars and trucks were just starting to experience such
luxury. Crosley did not begin manufacturing its own line of cars until 1939, so
none of these radios made it into Crosley autos...
 Here is Part 2 of the InCompliance
article "Getting
the Best EMC from Shielded Cables up to 2.8 GHz." Every day the electromagnetic
noise in our environment intensifies as the world goes more and more wireless. Just
as PCB layout needed to adopt distributed element methods for successful operation
at higher speeds (digital and analog), interconnect cabling has been forced to accommodate
frequencies with wavelengths near to or less than the cable length. At high frequencies,
cables and shields begin to act like antennas for both emission and absorption.
This installment reviews empirical testing done on cable configurations previously
discussed. Note: Use this
Part 1 link because the one on the page is bad...
 Don't let the title fool you. This "Ultrafax"
system developed by RCA in the late 1940s was essentially the first attempt at video
on demand, or streaming video. Rather than piping the signal over cable or local
broadcast frequency towers, a microwave link was used. While initial system equipment
space and financial requirements meant only corporations, universities, and governments
could procure an Ultrafax, engineers who developed the system envisioned an eventual
culmination of equivalent systems in every home. Even at the end of the last century
it was still not possible for program providers to personalize broadcasts to individuals.
It wasn't until broadband Internet came on the scene in the 2000s that such services
were possible. Now, a decade later, people watch any video they want on cellphones
while riding in a car. We've come a long way, baby...
 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.
 Empower RF Systems is a global leader in
power amplifier solutions. Empower RF Systems is an established and technologically
superior supplier of high power solid state RF & microwave amplifiers. Our offerings
include modules, intelligent rack-mount amplifiers, and multi-function RF Power
Amplifier solutions to 6 GHz in broadband and band specific designs. Output
power combinations range from tens of watts to multi-kilowatts. Unprecedented size,
weight and power reduction of our amplifiers is superior to anything in the market
at similar frequencies and power levels.
 Even those of us old enough to remember
the days when nearly all
electronic components had identification markers on them find it challenging
to correctly interpret color codes on resistors, capacitors, and inductors. The
numbers are easy enough to remember, but getting tolerances and temperature coefficients
correct is not guaranteed. Usually the color bands on a component are biased toward
one end so there is no ambiguity as to where to begin decoding, but I have seen
plenty where getting the right interpretation is a crap shoot unless the last band
happens to be gold or silver. Gold and silver have no numbers associated with them,
but brown and red are also used for tolerance (brown:±1%, red:±1%, respectively).
Reading capacitor dots can also be a little tricky, but after you've read a few,
it's a piece of cake...
 Here is a fairly major treatise on
folded and loaded
antennas that appeared in a 1953 issue of QST magazine, with "Suggestions
for Mobile and Restricted-Space Radiators." It is not for the faint of heart or
anyone with math phobia or math anxiety. Integral calculus is part of the presentation,
although an understanding of calculus is not required to get the gist of the article.
Equations for calculating the antenna configuration radiation resistances are given
for the 3λ/4-wave folded dipole, the λ/8-wave folded monopole, the bottom-, center-
and top-loaded λ/8-wave monopole, the bottom-loaded λ/16-wave monopole, and the
λ/4-wave monopole folded twice, to name a few...
 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.
 This is kind of weird. It's either a phenomenal
discovery or bad news for the Ingenuity coaxial helicopter making airborne rounds
on Mars. The video clip shows the 'copter descending without anything hanging from
its landing gear leg, and then there is a wispy object dangling from it after taking
off again. It looks like a weak water flow from an aerated faucet - which obviously
it cannot be - or maybe a piece of Saran Wrap - which it also cannot be (... or
could it be litter from a Martian's sandwich?). NASA has designated it as
Foreign Object Debris (FOD). It'll be interesting to learn of NASA's conclusion.
 Synzen Precision Technology has unveiled
ALCOR and ATRIA - two new
low-profile antennas which are perfect for the wearable market or any IoT devices
which require an ultra-slim design. Both designs deliver excellent performance at
a limbo-defying height of only 1.6 mm. ALCOR is a 5G low-profile surface mount
antenna that has been developed to be compact but still cover bands from 617-6000 MHz.
It has a small footprint of 40 x 10 x 1.6 (mm) and a fallback to 4G/3G/2G. ATRIA
is even more compact but still covers bands from 698-2690 MHz (also falls back
to 3G/2G). It measures only 30.0 x 7.0 x 1.6 (mm) and requires a small clearance
area (don't be fooled by claims of small antennas which often need a much bigger
clearance area)...
 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!
 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...
 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...
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