Today in Science History -
 I believe this is the very first episode
of the highly popular "Mac's
Radio Service Shop." This series of instructive stories was the brainchild of
none other than John T. Frye, creator of the Carl and Jerry series that ran
in Popular Electronics for many years. "Mac's Radio Service Shop" began life in
April 1948 in Radio News magazine (which later became Radio & Television News,
then Electronics World), and changed its name to simply "Mac's Service Shop" until
the final episode was published in a 1977 Popular Electronics magazine. "Mac" is
electronics repair shop owner Mac McGregor, and Barney Jameson his his eager, if
not somewhat naive, technician assistant. "Lessons" are taught in story format with
dialogs between Mac and Barney. Interestingly, here we have Barney on his first
day on the job, and Mac is just now asking him whether he has any experience servicing
electronics gear. Wouldn't you think he would have asked that question prior to
hiring him?
 "Machine learning models
are growing exponentially larger. At the same time, they require exponentially more
energy to train, so that they can accurately process images or text or video. As
the AI community grapples with its environmental impact, some conferences now ask
paper submitters to include information on CO2 emissions. New research offers a
more accurate method for calculating those emissions. It also compares factors that
affect them, and tests two methods for reducing them. Several software packages
estimate the carbon emissions of AI workloads. Recently a team at Université Paris-Saclay
tested a group of these tools to see if they were reliable. 'And they're not reliable
in all contexts,' says Anne-Laure Ligozat, a co-author of that study who was not
involved in the new work. The new approach differs in two respects, says Jesse Dodge,
a research scientist at the Allen Institute for AI and the lead author of the new
paper, which he presented last week at the ACM Conference on Fairness, Accountability,
and Transparency (FAccT)..."
 ConductRF is continually innovating and
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 Electronic warfare (EW) is a familiar term
today, but in 1947 its use was a relatively new concept. As you know, great advancements
in electronics occurred during the War years - from all the major Allied and Axis
countries involved. Transmitters and receivers, modulation techniques, antenna designs,
transmission lines, component introductions and improvements, ruggedness and portability
features (packaging), reliability, serviceability, operational techniques, and other
aspects of electronics benefitted from that oft-credited "mother of invention" named
"necessity." Along with electronic communication improvements came the need to thwart
the enemy's efforts to exploit those new methods; hence, the term "electronic warfare"
(aka electronic counter-measures, ECM). Now we also have electronic counter-counter-measures
(ECCM) to thwart the thwarting of the enemy. Can ECCCM be far behind?...
 According to this promotion in a 1948 issue
of Radio News magazine, the Howard W. Sams company had published more
than 5,500
Photofact service data packs since beginning in 1938 - that's averaging 550
per year. There would have been many more if not for the cessation of domestic radio
production during the war years from 1942 through the middle of 1945. Once televisions
were being cranked out in huge numbers in the early 1950's, the number of data packets
quickly grew into the tens of thousands (including also phonographs, tape recorders,
and other electronics wonders for the home. In fact, by September of 1949 the magazine's
title was changed to Radio & Television News in order to reflect the
importance of servicing the burgeoning TV industry...
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...
 Windfreak Technologies designs, manufactures,
tests and sells high value USB powered and controlled radio frequency products
such as RF signal generators, RF synthesizers, RF power detectors, mixers, up /
downconverters. Since the conception of WFT, we have introduced products that have
been purchased by a wide range of customers, from hobbyists to education facilities
to government agencies. Worldwide customers include Europe, Australia, and Asia.
Please contact Windfreak today to learn how they might help you with your current
project.
 Hams like members of the Mogollon Rim Collins
Collectors Club (K0CXX)*, play an important role in the preservation of vintage
radio equipment. They own a nice example of a
Collins model 30K-5 medium power (250 W) AM transmitter that is the subject
of this 1946 article in Radio News. At 5½ feet tall and weighing 350 pounds, the
30K is many times the volume and weight of a modern solid state transmitter (transceiver
+ PA) having the same capability. Its advertised price in 1946 was $1,450, which
is equivalent to $19.9k in 2022 money - obviously not in the affordability range
of your typical amateur radio enthusiast...
 Author Joel Kellogg* published Part 1
of his "SCIF
and Radio Frequency Secured Facility Design" article a bit over a year ago in
the InCompliance website. Now,
Part 2 is available. He states, "In recent years, we've noticed a growing
confusion in the industry over design and performance requirements for sensitive
compartmented information facilities (SCIF). Part 2 of this article is intended
to highlight the significant difference in the performance of radiofrequency (RF)
shielding between facilities designed per ICS/ICD‑705[1] and those intended to meet
NSA 94-106[2] performance requirements. We will also highlight some of the design
and construction methodologies that lead to significant differences in performance.
As noted in Part 1 of this article, there is a common misconception that a SCIF
design utilizing ICS/ICD‑705 construction recommendations will achieve the performance
requirement set forth in NSA 94-106, the NSA standard for RF shielding performance
and testing. Part 1 reviewed the typical construction recommendations identified
in ICS/ICD‑705, recommended materials, and typical installation methodologies used..."
* Anyone else remember "K, E, double-L, O, dougle-GGood,
Kellogg's best to you!"
 Exodus Advanced Communications, is a multinational
RF communication equipment and engineering service company serving both commercial
and government entities and their affiliates worldwide. We are pleased to present
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designed for EMI/RFI, lab, and general communication applications, suitable for
linear CW and composite signal channel modulation standards & applications...
 In CONGRESS, July 4, 1776.
The unanimous Declaration
of the thirteen united States of America, When in the Course of human events,
it becomes necessary for one people to dissolve the political bands which have connected
them with another, and to assume among the powers of the earth, the separate and
equal station to which the Laws of Nature and of Nature's God entitle them, a decent
respect to the opinions of mankind requires that they should declare the causes
which impel them to the separation. We hold
these truths to be self-evident, that all men are created equal, that they are endowed
by their Creator with certain unalienable Rights, that among these are Life, Liberty
and the pursuit of Happiness. -- That to secure these rights, Governments are instituted
among Men, deriving their just powers from the consent of the governed, --That whenever
any Form of Government becomes destructive of these ends, it is the Right of the
People to alter or to abolish it, and to institute new Government, laying its foundation
on such principles and organizing its powers in such form, as to them shall seem
most likely to effect their Safety and Happiness. Prudence, indeed, will
dictate that Governments long established should not be changed for light and transient
causes; and accordingly all experience hath shewn, that mankind are more disposed
to suffer, while evils are sufferable, than to right themselves by abolishing the
forms to which they are accustomed. But when a long train of abuses and usurpations,
pursuing invariably the same Object evinces a design to reduce them under absolute
Despotism, it is their right, it is their duty, to throw off such Government, and
to provide new Guards for their future security.--Such has been the patient sufferance
of these Colonies; and such is now the necessity which constrains them to alter
their former Systems of Government. The history of the present King of Great Britain
is a history of repeated injuries and usurpations, all having in direct object the
establishment of an absolute Tyranny over these States. To prove this, let Facts
be submitted to a candid world...
 You are taught early in your electronics
career to be mindful of the tendency for
measurement
equipment to affect the circuit it is measuring, and therefore the indicated
results. In the case of high frequency circuits, even minute amounts of capacitance
and/or inductance can render results utterly unusable, but even in circuits operating
down to D.C. the simple internal resistance of a meter can profoundly affect measurement
accuracy. High impedance circuits are particularly vulnerable to such "loading"
effects by test equipment. For example, consider a circuit being measured (device
under test, aka DUT) that has an impedance of 10 kΩ and the internal resistance
of the VOM is 100 kΩ (see diagram to left). If the open circuit "true" voltage
level is 11 V, then voltage division effected by the 100 kΩ meter in series
with the DUT's 10 kΩ internal resistance would produce a VOM reading of 10 V
(ten elevenths of 11 volts) - clearly incorrect. In the days before FET (field effect
transistor) input multimeters, when most volt-ohm-milliammeters (VOMs) consisted...
 New Scheme rotates
all Banners in all locations on the page! RF Cafe typically receives 8,000-15,000
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RF Cafe is a favorite of engineers,
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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.
 Anritsu has been a global provider of innovative
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 In these times of communists and Marxists
(and other "-ists") infiltrating high positions of American government and destroying
our hard-won legacy of freedom, compassion, traditional family values, hard work,
and patriotism, this
Independence Day theme crossword puzzle is created to celebrate our heritage
and resist the corrupters. The Cancel Culture mobs will never dissuade our staff
(Melanie and me) here at RF Cafe! Clues with an asterisk (*) are related to the
puzzle's theme. 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...
 SF Circuits' specialty is in the complex,
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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."
 Life is a constant battle on all fronts,
be it in health, personal relationships, business, medicine, careers, education,
technology, or any other realm. Scientists, engineers, and technicians at the former
Bell Telephone Laboratories are affected by that maxim as well as any group
of people. The company, known to many as Bell Labs, invested a huge amount of funds
and personnel effort into fighting the problems which constantly cropped up both
during research and development and while servicing their massive installed base
of equipment and transmission lines. Bell Labs regularly ran full-page
ads in magazines (including technical and others like Life, The Saturday Evening
Post, Woman's Day, etc.) informing the paying public of the extents they went to
in order to bring new products to market and to keep existing systems providing
excellent quality communications (the best in the world). This example for a 1948
issue of Radio News magazine tells of the unexpected chemistry issues solved by
their crack teams of employees...
 Center of Telecommunication Technologies
(CTT) is proud to announce immediate availability of its
Indoor RadioPlanner v1.0 software. Indoor RadioPlanner is a planning tool for
Wi-Fi and other indoor wireless networks. Release 1.0 is mainly intended for planning
Wi-Fi networks in the 2.4 GHz, 5 GHz, and 6 GHz bands, but it can
be used for planning indoor GSM/ 3G / LTE / 5G networks in the frequency range 300 MHz
– 7.5 GHz. With Indoor RadioPlanner, you can design Wi-Fi networks of any scale
- from a small office to a large multi-story building...
 Berkeley Nucleonics recently added a couple
of courses on
Quantum Computing in the Berkeley Nucleonics Academy. Because you have taken
previous RF courses with 100% completion, you are entitled to those QC courses at
no charge. Would you like a passcode? You may also share this code with any colleagues
or students who may have an interest. Completion of the course takes approximately
4 hours and includes CEU units, a Completion Certificate and a BNC "60 Years" Commemorative
Tee-Shirt. The Nuts and Bolts (and Qubits) of Quantum Computing: This exclusive
course will dive into the immersive world of quantum computing. Take quizzes, watch
videos and get current knowledge of quantum computing from experts in the industry.
QC 02 - Quantum Computing Instrumentation in Use Today" A cursory look at some of
the research and development tools...
 Selenium rectifiers were the first widely
used replacements for vacuum tubes in commercial electronic equipment. Since amplification
was not possible - that came in late 1948 with the invention of the transistor,
compliments of Shockley, Brattain and Bardeen - diode action in AC-DC power supplies
was its primary application. Typical reverse breakdown voltage is in the neighborhood
of 20 volts and current handling capability depends on the interface surface area.
Cost kept the selenium rectifiers from being widely adapted early in their history
(1933), but by 1946 when this article was published in Radio-News magazine
it had dropped enough to make their use economical. Eliminating one or two vacuum
tubes in a radio or television power supply made the sets more efficient and increased
reliability since the selenium rectifiers rarely suffered failures if designed into
the circuit correctly...
 Amentum is seeking a motivated
Junior RF Engineer
in Hanover, MD, willing to dive into the world of satellite communication coordination.
Job Summary: We are looking for an engineer with the curiosity to work problems
until truly understood and then the drive to identify and implement efficiencies
in the problem-solving process. You have a foundation in radio frequency (RF) engineer
principles to apply that knowledge in the RF analysis of new and existing satellite
systems being proposed. Responsibilities will include analysis and certification
for emerging spectrum dependent technologies, review of new satellite network submissions,
and evaluation of RF related interactions between satellites. Beyond the analytical,
you'll also need to communicate highly technical findings to a large international
stake holder community. You will be part of a team evaluating the risk to Department
of Defense (DoD) assets...
 Well I'll be darned, old Mac the master
radio repairman taught me something else new in this October 1949 issue of Radio &
Television News magazine. Along with giving sidekick and trusted technician
Barney a lesson on business ethics and how honest dealing can pay dividends as societal
conditions change, he also put on his Sherlock Holmes cap and deduced a
surprising cause for circuit failure based on the physical location of a lady's
radio; read on to learn the details. As usual, the exact scenarios of the stories
do not apply to today's environment and/or equipment, but the troubleshooting logic
certainly does. And, as usual, the time of year wherein the technodrama takes place
aligns with the edition's month of publication...
 I have to admit to not being real certain
why I selected this article on
feedback tone control for posting. It appeared in the December 1958 issue of
Hugo Gernsback's Radio−Electronics magazine. Although it is a good write-up
on some simple audio frequency filtering circuits, and the principles can be applied
to any frequency, it is most likely this page was marked because it contained an
electronic-themed comic on it. Oh well, Melanie already scanned and OCRed it for
me, so you might as well go ahead and read it...
 "The quest to transmit electric power wirelessly
and over distance has been a goal of electrical engineers since the end of the 19th
century, when Nikola Tesla tried his hand at it, to no avail. In the 1970s, NASA
and the U.S. Department of Energy engineers achieved some notable successes in
wireless power transfer
(WPT) in the kilowatt-kilometer range, their efforts spurred on by the energy crises
of the time. Interest waned, however, as energy became plentiful again. Now, with
the advent of 5G and its ability to transmit at high frequencies in the millimeter-wave-band
range, new opportunities and approaches are opening up for WPT. Researchers at the
Tokyo Institute of Technology have developed a prototype 64-element millimeter-wave-band
phased-array transceiver that can send and receive data while simultaneously receiving
power. The aim is to employ the transceiver initially as a 5G relay, and later to
integrate into Internet of Things (IoT) devices..."
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