 Friday the 21st
 Despite having heard of and used the "voltage-regulating
transformer" (aka "constant voltage transformer," CVT), I never knew exactly
how they work. This installment of Mac's Service Shop in the July 1965 issue of
Electronics World magazine happens to address the device, so now I at least
have some idea what's going on to magically hold the secondary voltage at an amazingly
constant value regardless (within reason) of the primary voltage. It is a purely
passive device that uses ferroresonance for feedback. The price to be paid for such
a convenience is explained to Barney by Mac after Barney gets befuddling readings
on his voltmeters. Mac invokes the name of the inventor, Joseph Sola, who manufactured
CVT's in the Sola Electrics Company premises. According to the SolaHD (merger of
Sola and Hevi-Duty) About Us webpage, "Sola Electric opened in 1930 as an emerging
laboratory in two modest size rooms in a Chicago bank building. It was a small beginning,
but Joseph G. Sola had big ideas. Beginning in the 1930's, he practically invented
the field of transformer magnetics...
 "Lynk Global, the world's leading
satellite-direct-to-standard-phone telecoms company, will launch the world's
first 5G cellular base station in space in a first-of-its-kind demonstration. This
test will demonstrate the ability to send a 5G signal from space to standard mobile
devices on Earth. The test has been funded by an undisclosed partner. Lynk is the
only company in the world to demonstrate satellite-direct-to-standard-mobile-phone
technology. Earlier this September, Lynk received the world's first satellite-direct-to-phone
commercial license from the Federal Communications Commission (FCC). Lynk has also
patented the ability to connect to existing standard 5G devices on Earth w/no change
to existing..."
 Magnetic tape was the recording medium de
rigueur for more than half a century, after the era of wax and wire and before the
era of magnetic and optical disks. In fact, magnetic tape is still the storage medium
of choice when analog signals must be stored without first being digitized. Magnetic
data storage media each has its own characteristic lifetime because of factors like
the initial quality of the magnetic domains, the dimensional stability of the substrate,
and susceptibility to outside influences. Just as vinyl records and other vintage
technologies have been experiencing a comeback with both young and old alike, Kodak
recently announced it is ramping up in Rochester, NY, for higher production volumes
of its 35 mm film due to increasing demand. I wonder if home film processing
equipment is resurging, too...
 Lotus Communication Systems, a manufacturer
of connectorized, cascadable RF and microwave components, has developed a new
high performance, ultra-flat gain low noise amplifier (LNA), PN#: LADC8GFR.
This LNA have low noise figure 1.8 dB and ultra-flat gain ±0.5 dB over
wide frequency range from DC to 8 GHz. EMI Shielding (includes weatherproof)
option is available for all our LNAs. Lotus' LNA can be customized to add integrated
Bias Tee, wide voltage operation (+6 ~ +34 V), integrated RF limiter,
multi-stage high gain, and meet customer's mechanical requirement. Lotus Communication
Systems, Inc. has CNC machine shop in house with 4th axis Robodrill for RF enclosure
manufacturing. Lotus also has state-of-art SMT line in house that use automatic
stencil printer, automatic pick and place and reflow oven...
 I have to admit to not remembering (or ever
knowing) that Radio Corporation of America (RCA) manufactured
electrical test equipment, so seeing this full-page advertisement in a 1963
edition of Popular Electronics magazine was a surprise. RCA made a few types of
analog multimeter kits, some project and experimenter kits, and even an oscilloscope
kit. A little more thumbing through other Popular Electronics magazine editions
revealed the RCA Institutes, which was a mail order electronics training program
similar to the ITT Institute and National Radio Institute (NRI, from whom I took
a course many moons ago). Knowing that if you wait long enough, just about everything
shows up on eBay, I did a quick check and found a few vintage RCA Institutes items,
including an RCA Institutes Ham Radio Signal Generator Kit...
 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!
 TotalTemp Technologies has more than 40 years
of combined experience providing thermal platforms.
Thermal Platforms
are available to provide temperatures between −100°C and +200°C for cryogenic cooling,
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.
Thursday the 20th
 Learn-at-Home correspondence courses for
a career in electronics maintenance and repair was a big deal throughout most of
the last century. Similar training was offered by many other trades, such as automobile
/ aircraft engine repair, plumbing, HVAC, electrical wiring / control / motors,
small appliance repair, watch / clock repair, etc. Many moons ago (c.1985) I took
an electronics course from
National Radio Institute. It included a few pieces of test equipment which required
building and aligning, including a digital multimeter, signal generator, and a 10 MHz
bandwidth oscilloscope. I still have many of the electronic components - lights,
inductors, switches, transistors, ICs, diodes, capacitors, solderless breadboard,
terminal strips - that came with it for experimentation. This particular course
in the December 1954 issue of Radio News magazine offered instruction in
television repair...
 Modelithics, the industry leader in providing
innovative and high-quality custom modeling and measurement services for RF, microwave
and millimeter-wave electronic devices provides this update on the latest happenings
with their products and industry partners. Modelithics® Releases the COMPLETE+3D
Library™ v22.4 for Ansys® HFSS™ Included in this library are over 370 highly scalable
Microwave Global Models™ for capacitor, inductor, and resistor families from many
popular vendors. Also included is Modelithics' collection of over 500 3D electromagnetic
(EM) geometry models for inductors, capacitors, filters, packages, and connectors.
With both circuit and 3D EM models, the Modelithics COMPLETE+3D Library now includes
over 30 vendors for more than 850 models representing over 25,000 individual components.
Modelithics Offers New Attenuator and Resistor Models from Smiths Interconnect...
 There are still many old-timers and beginning
nostalgic collectors out there who nurse heirloom and otherwise procured vacuum
tube radios - like this
Arvin Models 150TC, 151TC combination radio / phonograph - back to health (operating
condition) and/or keep them in good health. While it is possible to purchase schematics,
parts lists, and service instructions from many different models, there are still
some that have escaped the scanners of those publishers. For those kindred spirits
in search of such reference materials, I happily scan, clean up as necessary, and
post this collection (see complete list at bottom of page). I have dozens more that
will eventually be added over time, so check back later or send me an e-mail if
I have an issue (check the lists first, please) of Radio News, Radio-Craft, etc.
known to contain the information you need...
 It's time! The 2022
ARRL Online Auction begins
Friday, October 21st and runs through the 27th. A preview is available right now.
As of this post, there are 123 items to bid on including Ham Radio transceivers,
books, apparel, vintage QST magazines, test equipment, and accessories. "Proceeds
from our yearly Online Auction go directly to ARRL's education programs, including
promoting activities to license new hams, strengthening Amateur Radio's emergency
service training, offering continuing technical and operating education, and creating
instructional materials." Please contact immediately the ARRL if you have items
for donation...
 I
have never been a fan of "free verse" poetry,
be it in the form of a sonnet or otherwise.
In my humble opinion,
poems that do not both rhyme
and have some measure of meter
represent laziness on the part of the "poet."
Without requiring poetry to rhyme,
all that is required to declare anything a poem
is to break the writing into poem-like lines,
et voilà - you have a poem.
It is like slinging a brush-load of paint
onto a canvas and calling it art.
Example -- I hereby proclaim the above to be a poem because I broke it into separate
lines - see what I mean? That ain't no poem; we both know it.
I will excuse the following example since it was written by a Ham about
Amateur Radio
- although most of its lines do actually rhyme...
 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...
 Innovative Power Products (IPP) has over
35 years of experience designing & manufacturing RF & microwave passive
components. Their high power, broadband
couplers, combiners, resistors, baluns, terminations
and attenuators are fabricated using the latest materials and design tools available,
resulting in unrivaled product performance. Applications in military, medical, industrial
and commercial markets are serviced around the world. Products listed on website
link to detailed mechanical drawings that contain electrical specifications as well
as performance data. Please take a couple minutes to visit their website and see
how IPP can help you today.
Wednesday the 19th
 Here is a great collection of
electronics-themed comics from the October 1952 issue of Radio−Electronics
magazine. My favorite is the one on page 100 where the radio repair shop mocks the
next-door pharmacy's promotion of a self-repair manual. The page 144 comic is another
play on the theme that casts aspersions on the do-it-yourself electronics repairmen
of the day. Many self-help books were written purporting to make repairing a radio
or television a simple task, while convincing people that repair shops were just
out to cheat them. I have posted many comics illustrating the folly of such endeavors.
Two of the comics are ham radio related, and the other (a total of seven!) is a
self-deprecating shot at a hobbyist building a circuit of some sort...
 "Semiconductors - the digital machinery
that runs smartphones and computers, and helps run everything from cars and doorbells
to water and power supplies and military systems - are ubiquitous. Also called chips
or integrated circuits, they are usually pieces of silicon with transistors etched
in them - transistors keep track of the 1s and 0s that run all digital systems.
Back in the late 1950s, getting four transistors to work on a small piece of silicon
was a big accomplishment. The latest iPhone14's processor has 16 billion transistors.
While the U.S. has led the development of chips,
most are now fabricated outside the country. Taiwan and South Korea have cornered
the market on building the most advanced chips - though the U.S. and China are trying
to change that. Having the world's leading makers in political hotspots is a concern,
too..."
 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.
 This "Hetrofil,"
(sometimes errantly referred to as a "Heterofil") shorthand for "heterodyne filter,"
was conceived of, designed, and built by author Raymond Woodard. A Wien bridge is
used to selectively null out interference caused by leakage of the heterodyne beat
frequency into the audio (phone) circuit. The beauty of the Hetrofil is only a few
inexpensive passive components are needed. It is inserted between the receiver headset
jack and the headset. A couple years later, Wade Caywood applied the Hetrofil concept
to an oscillator tuning and stabilization circuit (see "An Amateur Application of
the Wien Bridge," January 1941 QST. Also, a form of the Hetrofil was used
in Hewlett-Packard's Model 200A audio generator...
 ConductRF's latest innovation is
Hi−Frequency RF Jumper Cables with 2.92 mm, 2.4 mm or 1.85 mm
connectors as standard. This assemblies use our optimized direct solder attached
connectors and our superior double shielded hi-frequency A61SW flexible cable with
shielding effectiveness greater than -100 dB. These cables are design to support
the latest requirements for 5G applications for cross connecting modules, but can
equally be used in any field where hi-frequency jumper cables are required. Beyond
our standard interconnect, we can also offer solutions with SMP, SMPM, SMA and many
other common connector interfaces. Hi-Performance right angled options are available
utilizing hard setting shrink tube to form the cable bend...
 RF Cafe visitor David M. wrote to ask that
I scan and post this article from the January 1963 edition of Popular Electronics
magazine. It is written by Philip Hatfield, of the Receiving Tube Department of
General Electric, describing a very simple design that uses a
"Compactron" vacuum tube, which consist of two triodes and a pentode. The Compactron
was a vacuum tube version of the multi-amplifier integrated circuit of today, only
without the peripheral passive biasing and coupling components. Plug-in coils (inductors)
for quick and easy frequency band changes are the key feature here. RCA 6AF11 Compactron
vacuum tubes are still sometimes available for purchase on eBay for $10-$40 bucks
each...
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...
 Since 2003, Bittele Electronics has consistently
provided low-volume, electronic contract manufacturing (ECM) and turnkey PCB assembly
services. It specializes in board level turnkey
PCB assembly
for design engineers needing low volume or prototype multi-layer printed circuit
boards. Free Passive Components: Bittele
Electronics is taking one further step in its commitment of offering the best service
to clients of its PCB assembly business. Bittele is now offering common passive
components to its clients FREE of Charge.
Tuesday the 18th
 It was 1958, over the Taiwan Strait, when
the first Sidewinder air-to-air missile flew up the tailpipe of a MIG−17 Fresco
after being launched by an F−104 Starfighter. The age of
offensive infrared (IR) warfare had begun. It is amazing that the detection
and guidance system for the Sidewinder was built largely from discrete components,
without the advantage of large scale integration. IR night vision devices were actually
used by the military as early as WWII with the renowned Snooperscope (handheld)
and the Sniperscope (mounted to a carbine rifle). Both required an infrared light
source to illuminate the target. Today's night vision goggles and scopes are sensitive
enough to be totally passive. This "Infrared" article from the February 1961 issue
of Popular Electronics magazine talks about early developments in infrared
technology. Corny-looking prototypes of IR wireless phones are shown, but obviously...
 This "Electronics
Fundamentals" material is from the U.S. Air Force's Air University collection
of tutorials (Course 3050, dated 1960). It was found in a bin at Goodwill, bound
along with a few other sections by the Extension Course Institute including Introduction
to Radar and Television Principles. A few days ago I posted the Introduction to
Radar section. A very thorough introduction to electric principle is presented,
and is as useful as any modern text on the subject. Note in figure 21 that current
flow (electron flow, or EF) is depicted as going from negative to positive, which
is the correct physical model. Prior to World War II, current flow was considered
to be from positive to negative; that scheme is now called conventional current
flow (CCF). At semiconductor boundaries there is a sort of flow from positive to
negative called "hole" current. A "hole" is the absence of an electron in an atom's
valence bands...
 At Euronaval 2022, taking place from October
18 to 21 in Paris, France, Rohde & Schwarz is proud to announce the launch of
its new liquid-cooled R&S SK4105/4110 HF high-power transmitters. With this,
the company is offering next generation technologies in
beyond-line-of-sight (BLOS) communications. Over the past decades, Rohde &
Schwarz has been a reliable innovator in HF technology. This new transmitter offers
extreme reliability, best-in-class availability and low total cost of ownership.
The company's high vertical integration ensures service and maintenance for the
entire lifecycle. Unsurpassed performance through HF wideband capability as well
as 5 kW or 10 kW output power make the R&S SK4105/4110 unique on the market...
 This is one of a multi-part series of articles
that appeared in Popular Electronics magazine on using an oscilloscope
(o-scope) to
analyze signal waveforms. An introduction to square waves and how to accurately
measure them is covered here. Frequency-compensating the o-scope probe is always
an important step prior to sampling just about any waveform other than a pure sinewave,
because per Fourier series analysis, every periodic waveform can be defined by a
series of sinewave and various frequencies, phases, and amplitudes. The author demonstrates
with a square wave being composed of the fundamental frequency and its odd harmonics.
I remember being amazed to learn whilst in engineering school that mathematically
it takes a summation of an infinite number of odd harmonics (appropriately amplitude-adjusted)
to define a pure square wave (the Gibbs phenomenon)...
 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.
 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.
Monday the 17th
 If you look up "bit" on Wikipedia, is claims
the word is a portmanteau of binary + digit, but according to the "Electronic
Counter Tube" article in the March 1956 issue of Radio−Electronics
magazine, it comes from binary + unit. The cited reference is a 1980 book. That's
a minor point, but I wonder if the belief has changed over time. Going further down
the metaphorical rabbit hole, per the same source, "The term byte was coined by
Werner Buchholz in June 1956, during the early design phase for the IBM Stretch
computer." Now, back to the topic at hand. The E1T "Decade Counter Tube" was produced
by Mullard, located in the UK. It had an ingenious design which directed an internal
electron beam onto fluorescent numerical segments according to the number of pulses
supplied to the increment grid (D1 in Fig. 1). A holding voltage...
 Prior to the advent of FET-input digital
multimeters (DMMs), the
vacuum tube voltmeter (VTVM) was the primary instrument for use when high input
impedance was required. For the newcomer to electrical measurements, high input
impedance for the measuring instrument is needed when measuring high impedance circuits
so as not to load down the circuit under test and cause an erroneous result. For
instance, suppose you are trying to measure the voltage across a 100 kΩ resistor
that is in series with a 50 kΩ and your voltmeter has a 100 kΩ input impedance.
The parallel combination of the two 100 kΩ resistances (resistor and voltmeter)
is 50 kΩ. If the supply voltage is 3 volts, the voltage across the 100 kΩ
resistor would actually be 2 volts, but with the voltmeter across it, the reading
would be 1.5 volts. If the input impedance of the voltmeter was 10 MΩ instead,
the parallel resistance across the 100 kΩ resistor would be about 99 kΩ,
which would only introduce a very small error...
 "Discarded electronic devices, such as cell
phones, are a fast-growing source of waste. One way to mitigate the problem could
be to use components that are made with renewable resources and that are easy to
dispose of responsibly. Now, researchers reporting in ACS Applied Materials &
Interfaces have created a
prototype circuit board that is made of a sheet paper with fully integrated
electrical components, and that can be burned or left to degrade. Most small electronic
devices contain circuit boards that are made from glass fibers, resins and metal
wiring. These boards are not easy to recycle and are relatively bulky, making them
undesirable for use in point-of-care medical devices, environmental monitors or
personal wearable devices. One alternative is to use paper-based circuit boards,
which should be easier to dispose of, less expensive and more flexible..."
 The
General Electric (GE) Model 250 portable radio was considered a "suitcase" style
because it looked kind of like - guess what? - a suitcase. It ran on either 120
volts AC or an internal 2.1 volt battery. A charging circuit was provided for the
battery, which was a nice feature so the owner didn't have to keep buying new batteries.
Fortunately, there seems to be many of these GE 250 radios available in various
states of reconditioning. eBay* currently has four listed ranging in price from
$40 to $150. One listing has very nice photos of the internal workings and of the
Willard model RADIO−25−2 wet storage cell battery (see below, right). Click on the
thumbnails for larger images. The nomenclature label for the radio is fully legible.
This Radio Service Data Sheet for the GE 250 radio appeared in the August 1946 issue
of Radio−Craft magazine...
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.
 Anritsu has been a global provider of innovative
communications test and measurement solutions for more than 120 years. Anritsu manufactures
a full line of innovative components and accessories for
RF and Microwave Test and Measurement
Equipment including attenuators & terminations; coaxial cables, connectors &
adapters; o-scopes; power meters & sensors; signal generators; antenna, signal,
spectrum, & vector network analyzers (VNAs); calibration kits; Bluetooth &
WLAN testers; PIM testers; amplifiers; power dividers; antennas.
Sunday the 16th
 This custom-made
Electrical Engineering-themed crossword puzzle for October 16th, 2022, is brought
to you by RF Cafe. 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 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!
 SF Circuits' specialty is in the complex,
advanced technology of PCB fabrication and assembly, producing high quality multi-layered
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."
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