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 As with most things of consumer, commercial,
and industrial nature, the battery - more correctly "cell" - science has come a
long way in a relatively short time. Alessandro Volta invented the eponymous
voltaic pile in 1799; it consisted of zinc and copper electrodes
immersed in a sulfuric acid electrolyte, thereby being a wet cell. The first dry
cell was the zinc-carbon type invented by Guiseppe Zamboni (not the guy who invented
the ice rink resurfacer) in 1812. Rechargeable dry cells of the NiCad variety hit
the scene in 1899. Then, it wasn't until 1991 - a century later - that Sony commercialized
the Li-Ion cell (and varieties thereof) that now dominates...
 Johanson Dielectrics and
Johanson Technology, located in
Camarillo, CA, are now supporting RF Cafe's publication. Johanson Technology designs
and manufactures RF & microwave ceramic chip capacitors, inductors and integrated
passives. These includes chip-format antennas, capacitors, lowpass, highpass, and
bandpass filters, couplers, inductors, baluns, power dividers, substrates, chipsets.
 Johanson Dielectrics has produced ceramic
chip capacitors for over 60 years. They design and manufacture capacitors that include
standard and high-voltage SMT ceramic chip capacitors, as well as a variety of standard
and custom high voltage & high capacitance value ceramic capacitors.
Please return the favor by exploring their offerings when planning your projects!
 Allen Kushner's (Times Wire and Cable) 1968
Electronics World magazine article portrays
coaxial cables as essential microwave components with impedance, power-handling,
attenuation, time-delay, and shielding traits that must hold steady over broad frequency,
temperature, and harsh environmental conditions like moisture, corrosion, and flexing.
Optimal use demands impedance matching for maximum energy transfer, minimizing VSWR,
radiation losses, and delays; dielectric selection -- solid polyolefins/PTFE for
moisture resistance versus low-loss foamed or air-spaced types with aluminum sheaths
reducing attenuation by 20%; and superior shielding, from ~80 dB in single-braid...
 I have to admit to not recalling ever having
heard of Dagmar; have you? Crack electronics technician "Red" mentioned her in this
episode of "Mac's Radio Service Shop" appearing in the March 1952 edition
of Radio & TV News. I thought Prince and Cher were the first man (ostensibly)
and woman, respectively, to use a single-name public moniker, but evidently Dagmar
beat them to the punch ...but I digress. John T. Frye, author of the popular
Carl & Jerry series that appeared later in Popular Electronics magazine,
wrote this series before that time. On this cold and wintry day, Red and Mac are
discussing troubleshooting methods and how looking for and interpreting certain
symptoms...
 "Finding accurate positions in dense urban
areas remains difficult for satellite-based navigation systems, where high-rise
buildings and signal blockages can cause large errors or complete loss of service.
A recent study outlines a deeply integrated positioning method that combines commercial
5G New Radio (NR) signals with Global Navigation Satellite Systems (GNSS) to
address these issues. By reinforcing 5G signal tracking and tightly merging it with
satellite measurements, the approach improves both ranging stability and overall
positioning accuracy in demanding city environments..."
 Even with the ready availability of programmable
calculators and smartphone apps, there are still times when having a handy-dandy
nomograph printed out and hanging on the wall for quick reference can be a great
asset. This nomograph which appeared in a 1965 issue of Electronics World
magazine provided ready conversion between two different (input and output) voltage
and power values to equivalent decibel values. It seems strange that the watts and
voltage scale is on the left and the milliwatts and millivolts scale is on the right.
That might be more intuitive for a nomograph of attenuation, but not - at least
to me - for positive gain as through an amplifier...
 Seamless
integration of wireless communications with wired communications
has not always been a yawn in technical strategy discussions. It has really only
been since the early 1990s with the introduction of ubiquitous cellphone systems
that someone on a wireless device could connect directly with a wired contact and
not need an intermediary operator to facilitate. Some military comms, the Inmarsat
system and a few other proprietary systems were available, but not to the public
at large. This article reports on some of the Army's early attempts at implementing
wireless-to-wired communications, specifically as implemented during the Normandy
Invasion on D-Day (June 6, 1944). Unlike present...
 Alliance Test Equipment sells
used / refurbished test
equipment and offers short- and long-term rentals. They also offer repair, maintenance
and calibration. Prices discounted up to 80% off list price. Agilent/HP, Tektronix,
Anritsu, Fluke, R&S and other major brands. A global organization with ability
to source hard to find equipment through our network of suppliers. Alliance Test
will purchase your excess test equipment in large or small lots. Blog posts offer
advice on application and use of a wide range of test equipment. Please visit Allied
Test Equipment today to see how they can help your project.
 Proper grounding often makes the difference
between success and failure in a circuit - from DC to light. I recently fix an intermittent
hum in a vintage cassette tape deck by discovering and repairing a cold factory
solder joint on the shield connection of an input RCA plug. Improperly grounded
shields in electronic circuits cause coupling and interference issues, addressed
via single-point or multi-point grounding based on interference frequencies, cable
length, and circuit sensitivity to high- or low-impedance fields. Single-point grounding
suits short shields (L/λ < 0.15, where L is length and λ is wavelength of highest
frequency), with each insulated shield grounded individually, effective for low
frequencies like audio but failing against magnetic...
 "Researchers based in France, USA and Italy
claim the first demonstration of avalanche breakdown behavior in
quasi-vertical gallium nitride (GaN) diodes fabricated from selective area growth
(SAG) material on silicon (Si) substrate. The advantage of avalanche breakdown is
that it is non-destructive. The breakdown of the diodes was 720V at room temperature.
The team, from Université Grenoble Alpes in France, Stanford University in the USA,
and University of Padova in Italy, believes that the performance of the devices
can be improved “through the optimization of the design geometry..."
 Narrow-band frequency modulation (NFM) was
a relatively new technology in 1947, having been advanced significantly during World
War II. Amateur radio operators were just getting their gear back on the air
after having been prohibited from transmitting for the duration of the war. Few
were probably thinking about adopting and exploiting new modulation techniques,
but for those who were and recognized FM as the path to the future of radio, QST
published this fairly comprehensive treatment of both frequency modulation (FM)
and phase modulation (PM). Mathematically, FM is the time...
 The advent of
FET-input multimeters greatly reduced reading accuracy errors
due to not taking into account the impedance of devices being measured. A certain
amount of familiarity with how to interpret the indication on a meter movement on
analog meters is still required based on the multiplier switch position and scale
selected, but for most users simply reading the number beneath the pointer - or
interpolating its position between two numbers - is good enough. Mirrored scales
take the some of guesswork out of that by reducing parallax issues. Finally, digital
multimeters (DMMs) hit the scene and made slackers out of just about all of us when
it comes to making voltage, current, and resistance measurements. With few...
 Withwave manufactures an extensive line
of metrology quality coaxial test cable assemblies, connectors (wave-, end-, vertical-launch,
board edge, panel mount), calibration kits (SOLT), a
fully automated 4-port vector
network analyzer (VNA) calibrator,, between- and in-series connector adaptors,
attenuators, terminations, DC blocks, torque wrenches, test probes & probe positioner.
Special test fixtures for calibration and multicoax cable assemblies. Frequency
ranges from DC through 110 GHz. Please contact Withwave today to see how they
can help your project succeed.
 The "Recent
Developments in Electronics" column in a 1968 issue of Electronics World
magazine featured among other topics, a six-foot McDonnell-Douglas DC-10 jet model
tested inside a charged wire enclosure generating controlled electromagnetic fields
to evaluate communications and navigation antennas across flight attitudes on the
179-foot tri-jet led to modern anechoic chambers for 5G and aircraft testing. An
all-solid-state bright radar display provided daylight air traffic control to enhance
monitoring and safety to replace dim scopes. A nuclear reactor attained criticality
with 211 fuel elements for 600 kW thermal power in a 66-lb flight unit convertible
for moon/orbit craft, inspiring RTGs in Voyager and Perseverance rover...
 Not sure what the image has to do with the
subject, but... "Electromagnetic
compatibility (EMC) and compliance engineering are critical fields in ensuring
that electronic devices operate without causing or being affected by electromagnetic
interference (EMI). As technology advances, new challenges and opportunities arise
in EMC and compliance engineering. This article explores emerging technologies,
innovations in EMC testing, and potential future challenges in the field. Emerging
Technologies..."
 It is a pretty good bet that most multi-element
TV aerials you find on rooftops and even on ancient towers were decommissioned years
ago. They have been replaced either with cable (whether via CATV or Internet) or
satellite dishes. A few hold-outs still use them for local over-the-air broadcast
stations and/or even FM radio reception. There was a time, though, that photographs
taken looking across a vast expanse of house roofs showing an endless array of antennas
and guy wires was a sign of 'modern' living. Most were erected by Harry Homeowner
types or minimally qualified service technicians, and were well-known for toppling,
twisting, bending or un-aligning when stiff winds were imposed upon them. This story-lesson
from the March 1953 edition "Mac's Radio Service Shop...
 Werbel Microwave began as a consulting firm,
specializing in RF components design, with the ability to rapidly spin low volume
prototypes, and has quickly grown into a major designer and manufacturer with volume
production capacities. Our
WM2PD-0.45-7.5-S is a 2-way in-line power splitter covering the continuous bandwidth
of 450 MHz to 7.5 GHz in an enclosure measuring 5.75 x 2.80 x 0.55 inches
with versatile mounting options. The device is RoHS compliant. This part has versatile
mounting options. Through holes allow for mounting to chassis on the broad side.
Threaded holes on the connector edges allow for through-panel mounting. No worries
with Werbel...
 A mere five years had elapsed from the time
Echo, a gas-filled metallized plastic sphere that passively reflected radio signals
back to Earth, was launched and the time that 35
television cameras had been launched into space. The Space Race
was at a fever pitch. Although the Ruskies beat us in being the first to launch
both an active satellite (Sputnik) and a man (Yuri Gagarin) into space, America's
deep pool of intellectual resources, consisting of both native scientists and many
of the world's top scientists who chose to flourish in freedom here rather than
oppression behind the Iron Curtain, fostered the advantage that in short order established
the United States as the leading super power both in space and on terra firma. TIROS
satellites began providing real-time visual data on the Earth's weather in 1960.
Not only were cameras transmitting images of the Earth...
 In his 1968 Electronics World magazine
article, Amphenol RF Division VP Tore Anderson emphasizes that
selecting coaxial connectors is as crucial as choosing the cable itself for
optimal RF transmission system performance, maintaining constant impedance despite
dielectric transitions and withstanding power without disrupting VSWR. Engineers
often prioritize familiarity over suitability, leading to problematic adapters and
system degradation, while even manufacturers misuse inexpensive types for high-power
applications, risking damage. Connectors are classified by cable size, coupling
methods (bayonet, threaded, push-on)...
 Arthur Steele is probably enjoying retirement
from
Littelfuse by now. In 1965 he had an article published offering
guidelines on how to select the proper type fuse for protecting the circuit at hand.
The correct choice is seldom a simple matter of adding a margin of some amount onto
the known maximum current draw, especially if you are designing for a commercial
or defense electronics project. Applied voltage, expected current surges, operational
temperature and mechanical stress (vibration & shock, etc.), applicable design
regulations (UL, Mil-Spec, etc.), serviceability, and available space are among
the factors that need consideration. Do you need a fast-blow, medium-blow, or slow-blow
fuse for that circuit? You'll have...
 Anatech Microwave Company (AMC) offers the
industry's largest portfolio of high-performance standard and customized
RF and microwave filters and filter-related products for military, commercial,
aerospace and defense, and industrial applications up to 40 GHz. Three new
models have been added to the product line in November, including a 20 dB directional
coupler with an insertion loss of 0.5 dB over a 2-18 GHz range, a 1 dB
attenuator for 1 kW peak pulse at up to 4 GHz, and an 8-way power divider
with 3° phase balance over 0.5-150 MHz. Custom RF power filter and directional couplers
designs can be designed...
 This week's
crossword puzzle has a "directional coupler" theme in that many
of the words are related to the devices. All of the other words are, as usual, pulled
from a custom-built dictionary containing only terms pertaining to engineering,
mechanics, astronomy, mathematics, chemistry, and names of companies that make components
for the aforementioned fields. Even Dilbert characters appear sometimes. You will
not, however, find names of numbnut Hollywierd celebs or TV shows here...
 Longtime RF Cafe visitor Steve M. sent
me a note about his new RFGraph system modeling
software. It is an online cascade calculator with a drag-and-drop user interface.
Standard or custom components can be placed on the drawing grid, and all system
parameters -- gain, NF, IP, P1dB, etc., can be viewed at any point in the chain.
Your design is stored in the cloud and can be easily shared with other users or
exported to PDF for inclusion in presentations and white papers. A Basic account
with limited capability is free, and a full-featured Pro account is a mere $9.99/month
or $99/year.
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 • U.S. Congress
Intros
"No Robot Bosses" Bill
• December
Manufacturing Contracts in U.S.
• FCC
Moves to Expel Hong Kong Telecom
• India's
Mobile Fraud Crackdown Takes Sinister Turn
• Technologies Shaping
Modern Supply Chain
 The
RF Cafe Homepage Archive
is a comprehensive collection of every item appearing daily on this website since
2008 - and many from earlier years. Many thousands of pages of unique content have
been added since then.
 "After Class" is a long-running feature of Popular Electronics
magazine that covered a very wide range of topics. In most instances a single major
theme is presented, but in this May 1955 issue there are five separate areas: the
Faraday shield, binary notation, using a tuning fork to resonate a tank circuit,
and two quizzes (one on resistance and capacitance and another on power supplies).
On the topic of Faraday shields, I have to tell you about an e-mail I recently received
from an RF Cafe visitor. He wrote asking whether there was any atmospheric pressure
at which satellite radar could not penetrate to the Earth's surface. I could be
wrong, but usually questions like that are asked by people who believe in a government
conspiracy to surviel (and ultimately control) the populace. I used to dismiss such
notes as being from lunatics, but with all the cameras everywhere and the ability
to track movement via cell towers and Wi-Fi hot spots...
 Allegory is not an often seen style of prose in
the electronics writing world, and typically is not meant to be humorous; however, there
have been a few instances of it in the vintage electronics magazines I read. One of the
most famous examples of allegory is a story by Paul Bunyan titled "Pilgrim's Progress."
"She
Wore a Red Germanium," by Leta Foster Ide, is a more contemporary form of allegory
that RF Cafe visitors will appreciate. Mike R. Fonic (microphonic) is the lead character
in the story who complains to his doctor, "I'm off my feed. Got no capacity. Fact is,
I'm in a breakdown." Mike's wife's Aunt Enna (antenna) is no help, evidently. Come to
think of it, the author's name, Leta Foster Ide...
 This
crossword puzzle from a 1958 issue of Popular Electronics magazine
is a little trickier than some because it uses abbreviations rather than full words.
Not everyone uses the same abbreviation, so some answers are a bit more subjective.
For instance, many people abbreviate the word 'transformer' as 'xfmr,' while others
use 'trans' or 'trr' (I use xfmr). Where you really have to be careful, though,
is with evolutional changes in terminology as is the case for frequency units, where
'cps' was most often used in 1958 rather than today's 'Hz." Enjoy. Switzerland Electronics Market
 This is the electronics market prediction for
Switzerland, circa 1966. It was part of a comprehensive assessment by the editors
of Electronics magazine of the state of commercial, military, and
consumer electronics at the end of 1965. This statement was a bit unexpected:
"Although the Swiss are renowned for their precision work in watchmaking,
machine tools and instruments, their country is regarded as 'a bit backward' in
electronics." Not many major national production companies resided in
Switzerland; IBM and RCA had a large presence, though. Unless you can find a
news story on the state of the industry, detailed reports must be purchased from
research companies...
 Remember the Sunday comics feature for kids
where there was a picture drawn with things wrong in it, and you had to find them
all? This 1950 advertisement for the Sangamo Electric Company's line of capacitors,
which appeared in Radio & Television News magazine, could server as a modern-day
version for the Cancel Culture "woke" crowd that believes it has a duty to criticize
and impugn everything it happens to fear, not like, or not understand. My list is
at the bottom of the page if you want to compare it to yours. On other Sangamo ad
post pages I have provided a bit of research on the background of "Samgamo" to try
to determine whether the use of Native Americans (aka "indians" at the time) was
based on a local tribe. No link has ever been found. Below the ad are a few of the
items discovered...
 Here are a four more
technology-related comics from magazines of the days of yore, this time from
a 1948 edition of Radio-Craft magazine. Readers would submit ideas for
funnies and then artist Frank Beaven would draw the comics. The page 37 comic is
an example. Evidently E.R. Donohue, of Walla Walla, Washington, had issues
with his phonograph featuring a record changer mechanism. My interest in rockets
makes me really appreciate the page 82 comic with the missile's flight being affected
by the musical "interference." In the early days of remote control, audio tones
modulated onto a carrier commanded tuning-fork-like (tuned) "reeds," which acted
as channel filters for separating and directing signals, in the airborne receiver
section to control surface actuators (see video). It is rare to find a comic in
a technical or hobby magazine these days. I don't know why that is...
 Whether or not this kind of stuff goes on
over the Ham bands these days, I couldn't tell you. It is easy to believe the level
of obnoxiousness of some people back in the 1940's when this "'Phone-Band
Phunnies" article appeared in QST magazine, featuring "Little Stinky."
Of course if you assume the way kids are portrayed in contemporary movies and TV
shows is typical of the real world, even the behavior described herein would seem
mild in comparison. Fortunately, kids today have a plethora of social media venues
for treating others to their brands of personalities, so maybe the Ham bands are
spared the abuse...
 During the
Golden Age
of Radio (admittedly a subjective term), electronics innovators were generally
as likely to be hobbyists (amateurs) as they were to be professionals with college
degrees. In fact, according to this open letter from Eugene F. McDonald, president
of Zenith Radio Corporation, in 1939, his company recognized the fact that most
of their best ideas came from amateur radio operators, and that their engineering
staff was populated overwhelmingly with Hams. Accordingly, the letter was a solicitation
to amateurs to submit their ideas to the company to give designers not just valuable
technical information gleaned from real-world experimentation (aka the School of
Hard Knocks) but also insight into what type of equipment the Ham world would like
to have made available for sale...
 No, the
electrolysis and corrosion of boat propellers is not really in line with the
theme of RF Cafe; however, it presents the same sort of problems that grounding
and anchoring systems for radio antennas and equipment shacks have. If you bury
a piece of metal in the Earth, it will, over time, magically disappear. Much effort
has been expended on the part of both amateurs and professionals to mitigate the
anodic action that occurs when dissimilar conductors come into intimate contact
because each metal - be it a base or an alloy - has an electric potential relative
to other metals. What happens when there is a difference of potentials and a conduction
path is present? Yep, current flows. Through that action, material is physically
transferred from the more positive metal to the less positive metal...
 Space Shuttle Endeavour (named after the
ship of British Lt. James Cook) lifts off for the last time tomorrow (April 29).
Atlantis flies next month, marking the end of the USA's manned space flight vehicle
program for the foreseeable future. Henceforth, we will be hitching rides on Chinese
and Russian craft that still land in the desert using parachutes. Here are some
stats on the Shuttle program. Number of shuttles: 5 - Challenger, Discovery, Atlantis,
Endeavour, Columbia; expected launches: 500; actual: 135; total flight time (as
of Jan 2011): 1289 days; shuttles lost: 2 (Challenger, Columbia); total passengers:
836; failure rate: 1:67.5; fuel consumption rate: 660,000 lbs./min. solid, 45,000
gpm liquid hydrogen; 17,000 gpm LOX; time to orbit: 8.5 min.; orbital speed: 17,
500 mph; touchdown speed: 220 mph. As with our oil drilling industry, politicians
have chosen to trash our domestic space transportation industry and send that money
to countries that yearn for our demise...
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 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...
 I found this
Bridge Circuit Quiz in my stack of vintage Popular Electronics magazines.
Your challenge here is to decide what the main function of each type of bridge circuit
is. Most bridge circuits are designed such that a component of unknown value is inserted
into one of its four branches, and then one or more variable components of known values
are adjusted to balance the bridge and thereby create a minimum (null) between opposite
(circuit-wise) nodes. Admittedly, I did not fare well, but it is because I do not recall
having the names associated with many of these bridge circuits. Of course nearly everyone
is familiar with the Wheatstone, Kelvin, and Wien bridges. Hyperlinks are
provided...
 The newest release of RF Cafe's
spreadsheet (Excel) based engineering and science calculator is now available -
Espresso Engineering Workbook™. Since 2002, the original Calculator Workbook
has been available as a free download. Continuing the tradition, RF Cafe Espresso
Engineering Workbook™ is also provided at
no cost, compliments of my generous sponsors. The original
calculators are included, but with a vastly expanded and improved user interface.
Error-trapped user input cells help prevent entry of invalid values. An extensive
use of Visual Basic for Applications (VBA) functions now do most of the heavy lifting
with calculations, and facilitates a wide user-selectable choice of units for voltage,
frequency, speed, temperature, power, wavelength, weight, etc. In fact, a full page
of units conversion calculators is included. A particularly handy feature is the
ability to specify the the number of significant digits to display. Drop-down menus
are provided for convenience. Now that a more expandable basis has been created,
I plan to add new calculators on a regular basis...
 Electronics repair shops - what's left of them
- probably don't experience the sort of problem illustrated in this story composed after
the manner of John Frye's "Mac's Service Shop" dramas. However, similar situations can
and almost certainly do crop up in many other customer service venues. The point of the
article is how easily, especially in the span of an entire year, seemingly minor oversights
repeated with regularity, can add up to
alarmingly large numbers. Actually, the phenomenon occurs for you with many things
when you bother to tally them up. Example: According to the U.S. census Bureau's 2017
report, the average one-way commute time is about 26 minutes both to and from work, or
about 52 minutes per day. Allowing for two weeks of vacation, two weeks...
 Long before there were computer programs
to instantly plot antenna radiation patterns, there were engineers who used slide
rules to generate tables of values for power levels based on fundamental equations,
and then plotted those points by hand on graph paper. Any copies were either hand
generated like the original, or were run off on a mimeograph machine with its characteristic
purple ink. Such was the case for the antenna radiation patterns published in the
November 1942 edition of QST that describes the virtues of a
circular
antenna in the UHF band. It is too bad that the author did not include the equations
for the antennas presented; that would really give you an appreciation for computers...
 At my request, Dmitriy provided a few additional
screen shots of RF / microwave type functions for his
Circuit Calculator
app for Android phones. There are 170+ circuits for design, 50+ electronics
calculators, 20+ application notes, and a logic solver. The Power Stage Design Tool
is for switch mode power supplies. Filter Designer handles multi-stage analog active
filters, and there is a stand-alone Resistors app. He even has a Cost, Please! app
for tracking travel-related costs. I could be wrong, but it appears most of the
capability of the other two design apps is included in Circuit Calculator. All apps
work offline without an Internet connection. Files sizes are significantly smaller
than similar apps. Does the world need yet another circuit design app when so many
already exist, you might ask? According to Dmitriy: "There is a list of well-known
electronics design tools for Android which can be found in every review for the
last 10 years: 'Electrodoc,' 'Every Circuit,' 'Droid Tesla,' 'Electronics Toolbox,'
'RF & Microwave Toolbox,' and so on. Also, there is a lot of trash on the market
that turns finding a good tool into a quest..."
 Many thanks to website visitor Mr. Ferrous S.
for providing an OCR version of this
Carl & Jerry story, and for writing the following: "The earliest optoelectronic
devices are photodetectors, and the basis of photodetectors is the discovery and
research of photoelectric effects. In 1873, Willoughby Smith discovered the photoconductivity
of selenium. In 1888, German Heinrich Hertz observed that when ultraviolet light
irradiated the metal, it could make the metal emit charged particles. In 1890, Philipp
Lenard determined the charge-mass ratio of charged particles and proved them to
be electrons, thus clarifying the essence of photoelectric effect. In 1900, German
physicist Planck introduced energy quantum into the study of blackbody radiation,
and proposed the famous Max Planck formula to describe the phenomenon of blackbody
radiation, which laid the foundation for quantum theory. In 1929, Kohler made a
silver-oxygen-cesium photocathode and a photocell resulted. In 1939, Vladimir Zvorakin
of the Soviet Union made a practical photomultiplier tube...
 There are still a lot of people who wind
their own coils, whether it be for an amateur radio rig or for work in the lab.
I know I've wound many a coil around a drill bit or wooden dowel - a somewhat
awkward task. This simple
coil winding machine that appeared in a 1931 edition of the ARRL's
QST magazine would be a handy addition to anyone's bag of tricks, especially
if you find yourself winding single-layer coils that have a precise, fixed space
between the windings. The home stores like Lowes and Home Depot sell small pieces
of oak and maple that would be perfect for this kind of project. Soft woods like
pine and poplar would not hold up as well under the strain of winding wire. Use
your soldering iron to burn your name onto the base. A little stain and a coat of
varnish would give it a real vintage look...
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