|
 The
Chronistor, which appeared in a 1958 issue of Popular Electronics, was a compact
elapsed time indicator in the form of a common glass fuse. Powered by electroplating,
it requires roughly 1 mA of DC current to migrate metal ions from anode to
cathode via an electrolyte, resulting in visible cathode deposition along a glass-printed
hour scale. Standard options included 500, 1000, or 2500-hour ranges, with specials
(like a 1-year, 8760-hour version) from Bergen Laboratories. The article outlines
a basic series circuit for AC line operation, comprising a half-wave rectifier,
pilot lamp, and limiting resistor for the Chronostat...
 If
you have kids, you'll probably appreciate these two
comics that appeared in the May 1956 issue of Young Men • Hobbies • Aviation
• Careers magazine. Young Men was a fairly short-lived publication,
having existed for only a couple years around the 1956 timeframe. It was not affiliated
with the Academy of Model Aeronautics (AMA), which had its own series of magazines.
Howard McEntee, famed radio control pioneer, was on the staff, and Albert L.
Lewis was editor. Unlike the other aviation magazines of the day, Young Men covered
a broad range of activities and hobbies including model boating and cars, electronics,
chemistry, physics, school, amateur magic tricks, shooting, and more.
 "Google's parent Alphabet has reached a
definitive agreement to
acquire renewable energy developer Intersect Power for $4.75B, a transaction
that signals a structural transformation in how Silicon Valley intends to power
the AI era. By owning a power utility, Google can secure energy for its data centers
directly. This acquisition marks a departure from the industry's decade-long standard
of signing Power Purchase Agreements, where companies contract for energy from third-party
developers. Instead, Google is taking ownership of a 3.6-GW pipeline of late-stage
solar and wind projects, along with 3.1 GWh of battery storage..."
 Well... it was 50 years ago referenced to
the year this story was published in 1937. That makes it 138 years ago referenced
to 2025. The story's point is that half a century had passed already since the confirmation
of existence of electromagnetic waves as proposed by James Clerk Maxwell.
Heinrich Hertz's "Funken-Induktor" (spark inductor) and his "Knochenhauershen
Scheiben" (Karl-Wilhelm Knochenhauer's disk-type capacitors) were key to his ability
to generate, transmit, and receive EM energy. The work originated from attempts
to prove that light was a form of electromagnetic waves...
 Before the advent of companies like Sam's
Technical Publishing information packets, it was often impossible to obtain schematics
and service information from manufacturers unless you were a certified service shop
and/or dealership. In response to many inquiries from Radio-Craft magazine's
readers, publisher Hugo Gernsback queried the
top manufacturers of the day to determine their policies for distributing such
data. Unlike the last couple decades, procuring service information on commercial
products could be very time consuming, and often resulted in not even obtaining
what you needed. Thanks to the Internet being populated with schematics and mechanical
drawings for seemingly everything ever made, we no longer need to call or mail order
for information needed to repair your radio, television, cellphone, lawn mower,
toaster...
 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
WMC-0.5-20-30dB-S is a wideband 30 dB power coupler is a wideband 4-way
in-line power splitter covering 500 MHz to 18 GHz with very good return
loss, low insertion loss, and high isolation performance. The device covers military
bands C through J (upper UHF band, L, S, C, X, Ku, and K bands), delivering much
value to the program. No Worries with Werbel!...
 A lot of the guys I knew from my time in
the U.S. Air Force as an Air Traffic Control Radar Repairman (AFCS 303x1) went to
work for the government or defense contractors after separation. Many were retirees,
so they were (are) collecting military retirement pay on top of really good pay
doing field service work. At this point, probably most of those guys are now doubly-retired,
and collecting Social Security. They're living pretty well these days, probably
with nice homes paid off long ago. 1957, the year this solicitation for
field engineers appeared in Popular Electronics magazine, was right
at the end of the Korean War, and only a decade after World War II. A lot of
new equipment was designed and delivered...
 While working as an electronics technician
at the Oceanic Division of Westinghouse in Annapolis, MD, in the 1980s, I received
a vintage 1941 Crosley model 03CB console style radio for Christmas from Melanie.
It was in poor condition, having spent the previous few decades sitting in a barn
on the Eastern Shore of Maryland. Due to the era of manufacture, vacuum tubes rather
than transistors provided all the necessary amplification. One of the engineers
I worked for at Westinghouse (Mr. Jim Wilson, engineer extraordinaire)
was a Ham radio operator and had been from boyhood in Pittsburgh, PA. After learning
of my Crosley, he gave me his
B&K Dyna-Quik Model 650 tube tester for use in restoring the
radio. The Model 650 was a rather high-end portable tube...
 "Firefly Aerospace's Blue Ghost Mission
2 with the LuSEE-Night radio
telescope aboard will attempt to become the third successful mission to land
there. The moon's far side is the perfect place for such a telescope. The same RF
waves that carried images of Neil Armstrong setting foot on the lunar surface, Roger
Waters's voice, and hundreds of Ned Potter's space and science segments for the
U.S. broadcast networks CBS and ABC interfere with terrestrial radio telescopes.
If your goal is to detect the extremely faint and heavily redshifted signals of
neutral hydrogen from the cosmic Dark Ages, you just can't do it from Earth..."
 In the early days of television, what we
today refer to as cathode ray tubes were called
kinescopes. The kinescope on the receiving end displayed images generated
by a tube called an iconoscope on the transmission end. Kinescopes had round faces
onto which a rectangular picture was electronically drawn. Once manufacturing technology
evolved sufficiently, it became possible to make them rectangular in order to save
on material and to fit a larger picture in a smaller area. The real story as told
in this 1947 Radio News magazine article from my perspective is appreciating the
ingenuity of the manufacturing engineers for an ability to develop machines that
handle very complex operations. They were wonders of electromechanical manipulation.
Oh, and I learned a new word - "lehr"...
 This Radio Service Data Sheet for the
Sparton Model 40 6-Tube T.R.F. Automotive Receiver is an example
of the dozens of similar schematic and alignment instruction sheets that have been
posted on RF Cafe over the years. Obtaining technical information on most things,
even readily available items, prior to the Internet era was often very difficult
- if not impossible. Service centers had what was need provided by manufacturers
and distributors, but if you wanted to find a part number or service data on a refrigerator,
radio, lawn mower, garage door opener...
 Here is a great primer on the operation
of
traveling wave tubes (TWT). A controversy exists over who first invented the
TWT - Bell Telephone Labs' Dr. Rudolf Kompfner, or Andrei Haeff while at the Kellogg
Radiation Laboratory at Caltech. Regardless of its provenance, the device was a
major advancement in the development of high power microwaves. A TWT amplifies broadband
microwaves continuously: an electron gun emits a high-speed beam through a vacuum
tube, interacting with the weak input signal propagating along a helical slow-wave
structure. The helix slows the signal's phase velocity to sync...
 Take a break from workaday drudgery by trying
your hand at this week's
Amateur Radio crossword puzzle. Every word in the RF Cafe crossword
puzzle contains the usual collection of science, math, and engineering terms, and
also includes special words related to Amateur Radio (clues labeled with asterisk
*). There are no generic backfill words like many other puzzles give you, so you'll
never see a clue asking for the name of a movie star or a mountain on the Russia-China
border. You might, however, find someone or something in the otherwise excluded
list directly related to this puzzle's technology theme, such as Hedy Lamarr or
the Bikini Atoll, respectively. Enjoy.
 "Advanced threats lead to open architecture
approaches and new
analysis of electronic countermeasures. Over the past decade, preeminent countries
involved in major military conflicts mainly focused on asymmetrical warfare - surprise
attacks by small groups armed with modern, high-tech weaponry. During that same
period, however, near-peer adversaries began attaining impressive electronic warfare
(EW) capabilities. As a result, a plethora of new, dynamic threats flooded the EW
spectrum, pushing threat detection and analysis to keep pace. Large military forces
must now engage in ongoing..."
 Here are a couple more electronics-themed
comics from Electronics World magazine, good for winding down the week.
They appeared in the January 1963 issue. The page 86 comic reminds me of the professor
I had for solid state circuit design. He was supposedly the first person to successfully
use gallium arsenide (GaAs) as a semiconductor, although he also did pioneering
work with silicon. Anyway, Prof. Anderson would say he takes at least one "business"
trip each year to Portugal in order to search for higher quality raw semiconductor
material in sand on the beaches. He spoke Portuguese, BTW. The page 89 comic is
reminiscent of the pre-GPS days of navigation. Raise you hand if you ever drove
around utterly lost while looking for an off-the-beaten-path location...
 In the mid 1930s, hand-assembled products
were by far the rule rather than the exception for most products be they electronics,
furniture, appliances, automobiles, or toys. Many people lament - even curse - the
advent of machine automation in production, but the fact is for the vast majority
of things the consistency and quality of the finished component is typically much
greater. Toiling at the same task, in the same location, day after day, gets unbearable
very quickly for someone like me who likes to accomplish a particular job and then
move on to something new - even if "new" is defined as the same type of endeavor
but with different materials. There are many people, thankfully...
 At Parvoo University, amid relentless November
rain, H-3 dormmates Carl and Jerry pursue H-2's prank: a stolen bronze trophy plaque
hurled into a half-mile muddy stretch of river. Cold, turbid waters bar preclude
dives for a search; non-magnetic bronze defies current-day metal detectors. Jerry
repurposes his cousin's boat depth-finder as an
enhanced sonar, exploiting echo signatures. A motor rotates a neon tube across
a depth-calibrated dial; at zero, contacts trigger a 200-kc ultrasonic pulse from
the transducer in transmit (speaker) mode, flashing initial glow. Bottom echo reflects
to transducer in receive (microphone) mode, amplifying...
 The announcement and public demonstration
of Senatore Guglielmo Marconi's "death ray" device was the coming true of some of the worst fears
of science fiction aficionados. Application of these newly created centimeter wave
"beams" could roast the flesh of man or beast when generated with great enough power.
The diminutive wavelength not only would heat liquids, but also provided a means
of detecting and measuring energy reflected off of "targets" such as aircraft and
boats. It applications were endless. Although not called so, one of the article's
diagrams looks to be an example of a bistatic radar system. The early magnetron
implementation is quite different...
 The Federal Communications Commission (FCC)
is looking for qualified applicants for
Field Agents in seven Enforcement
Bureau (EB) offices across the United States: Atlanta, GA; Boston, MA; Chicago,
IL; Dallas, TX; New Orleans, LA; New York, NY, and Portland, OR. Incumbents will
resolve Radio Frequency (RF) interference, educate users, and enforce regulations.
The GS levels for this position have been expanded to GS 7, opening the opportunity
for new college graduates. One year of work experience is not required for this
position. Closing date is March 2, 2026...
 If you are from a family of electronics
hobbyists and/or professionals, then there is a good chance your grandfather and
possibly even your father kept a handy-dandy list of common
circuit design formulas handy. Part 2 of the list appeared here in a 1930 issue
of Radio-Craft magazine. All the formulas on this page dealt primarily
with vacuum tubes, the schematics for which were presented in Part 1 of the series.
There are still lots of hobbyists who restore and/or modify vintage sets, so the
equations are still worth publishing. There was not an "app for that" back in those
days. Prior to a smartphone in every pocket, notes were pinned to a lab wall or
kept in a hand-written notebook...
 The name
Frank Conrad probably does not sound familiar to most people in
the electronics communications field today, but at one time he was the assistant
chief engineer to the Westinghouse Company. Back when voice radio (as opposed to
Morse code, aka CW) was being pioneered, Mr. Conrad was widely known for his efforts
in commissioning the country's first commercial broadcast installation - KDKA in
Pittsburgh, Pennsylvania. His arranging for live coverage of election night results
in 1920 is credited for launching a huge interest by consumers in purchasing radio
sets for their homes (Warren Harding beat James Cox that night, BTW). Toward the
end of his career, Conrad was active in helping develop...
 Copper Mountain Technologies develops innovative
and robust RF test and measurement solutions for engineers all over the world. Copper
Mountain's extensive line of unique form factor
Vector Network Analyzers
include an RF measurement module and a software application which runs on any Windows
PC, laptop or tablet, connecting to the measurement hardware via USB interface.
The result is a lower cost, faster, more effective test process that fits into the
modern workspace in lab, production, field and secure testing environments. 50 Ω
and 75 Ω models are available, along with a full line of precision calibration
and connector adaptors.
 Details of ancient Parthian
electrochemical batteries unearthed near Baghdad by archaeologist Wilhelm Konig,
dating over 2,000 years, was reported in this 1964 Popular Electronics
magazine article. Housed in earthenware jars sealed with asphaltum (bitumen), they
featured a copper cylinder soldered with 60/40 tin-lead alloy - identical to modern
electronics, prior to PB-free mandates - encasing a corroded iron rod for electrodes,
enabling electroplating of gold, silver, and antimony via electrolytes like copper
sulphate, ferrocyanides, or lye. GE engineer Willard F.M. Gray replicated them successfully
for Pittsfield's Berkshire Museum, using iron rods for series connections. More
cells surfaced in a Seleucia magician's hut and Berlin Museum...
 It seems most of the articles we see on
the subject of attenuator pads are based on signal reduction in terms of decibels
for units of power. Although it is a simple matter to convert power decibels to
voltage decibels, it would be more convenient if you are working with voltage to
have formulas and tables of values based on voltage ratios. This article does just
that. As a reminder, the decibel representation of a ratio is always 10 * log10 (x).
If you have a voltage ratio of V1/V2 = 0.5, then
10 * log10 (0.5) = -3.01 dB. If you have
a power ratio of P1/P2 = 0.5, then 10 * log10 (0.5) = -3.01 dB.
Does that mean that -3.01 dB of voltage attenuation is the same as 3.01 dB
of power attenuation...
 This might be a perfect application for
QuentComm. "Researchers led at the University
of Science and Technology of China (USTC), have achieved a major milestone in quantum
communication. For the first time, they demonstrated a key component required for
scalable quantum repeaters, which later allowed them to carry out device-independent
quantum key distribution (DI-QKD) across 100 kilometers. The results, published
in Nature and in Science, represent important progress toward building a functional
quantum internet. The work also reinforces China's position at the forefront of
quantum research and technology..."
 This Radio Service Data Sheet for the Clarion
"Replacement" Chassis, Model AC-160 A.V.C. Superhet is an example of the dozens
of similar schematic and alignment instruction sheets that have been posted on RF
Cafe over the years. Obtaining technical information on most things, even readily
available items, prior to the Internet era was often very difficult - if not impossible.
Service centers had what was need provided by manufacturers and distributors, but
if you wanted to find a part number or service data on a refrigerator, radio, lawn
mower, garage door opener...
|
 • China
Memory Producers Race to Exploit Shortage
• U.S.
Manufacturing Sector Returns to Growth
• ARRL
Student Coding Contest $25k Award
• Shielding
Electronics Supply Chain from Cyberthreats
• Fund Opens
Defence Contracts to UK Startups
• Global
Trade Holds Its Ground
 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.
 What's the big deal about
multicolor radar, you might ask? Not much today, but in 1955 color displays
were in their infancy. The earliest color cathode ray tubes (CRTs), developed by
John Logie Baird in the early 1940s, used just two phosphor colors (magenta and
cyan), illuminated by two separate electron guns, to produce a limited color display.
Ernest Lawrence came along later in the decade with his tri-color Chromatron CRT,
which had separate red, blue and green phosphor dots deposited in a triangular pattern
across the inner face of the tube. That is the scheme employed in this first multicolor
radar system. It was a major improvement for air traffic controllers since it facilitated...
 Lee de Forest, inventor of the Audion vacuum
tube, created a business called
De Forest Radio Company. This advertisement for his company's electron tubes
appeared in the December 1931 edition of the ARRL's QST magazine. If you
research Lee de Forest, you will find his name spelled in many different forms:
de Forest, De Forest, deForest, DeForest, Deforest, to give a few. When in doubt,
go straight to the source, which in this case is the signature that de Forest
placed on his patent applications - he used "de Forest." Note that the official
company name, according to the advertisement address at the bottom, is "De Forest
Radio Company," (space used) yet the text of the copy uses the form "deForest" (no
space), and the marking on the base of the tube says, "de Forest." Sometimes marketing
companies screw up, so I went searching for a more reliable source - the name given
on the company's stock certificate. Sure enough, "de Forest" was the official
name...
 Other than for DC power supply applications
where you might need to implement current steering and/or redundancy schemes, there
are not too many times when a combination of transistors and/or diodes would be
used for logic circuitry in place of integrated circuits. That has not always been
the case. Early packaged IC blocks were expensive compared to discrete components,
so both hobbyists and professional designers often used a combination of technologies.
Resistor-transistor logic (RTL) and diode-transistor logic (DTL), emitter-coupled,
logic (ECL), and other variations were covered in a 1969 Radio-Electronics
article by titled "How IC's Work: Integrated Circuit Logic Families." This piece
provides a little more insight into the construction of those families and shows
how to construct logical combinations using diodes and NOR gates...
 A few times in the past I have mentioned
the U.S. Army's long-running comic-book-style of training material for vehicle maintenance.
It began in 1940 under the title of The Army Motors and ran through the
end of World War II. In June 1951, at the beginning of the Korean War, the
publication was re-introduced as
PS Magazine - The Preventative Maintenance Monthly, where the "PS" part
stands for "Post Script," a la the "p.s." you might put at the end of a written
letter. In this case the "p.s." is a post script to the regular Army vehicle maintenance
manuals. I recently happened to run across the RadioNerds.com's extensive section
on PS Magazine, and it is a treasure trove of downloadable PDF versions of the magazines.
As you can see from the cover illustrations and the contents, its appeal was primarily
to the predominantly male vehicle maintenance force...
 It has been three or four decades since I
have seen anything about a
Lecher Line, the last time in memory being in a college lab. It might have been
a physics lab, but most probably an EE lab. We used one to measure wavelengths of
signals from an RF generator. The apparatus looked sort of like the one in the Wikipedia
link, only just a little more modern (but not much more, being typical school equipment).
This new patents report from a 1947 issue of Radio-Craft magazine has a
waveguide version of a Lecher Line that supposedly was able to do more precise measurements
of very short wavelengths by providing for detecting the internal wave over multiple
wavelengths instead of just a single half wavelength. It was developed at Bell Telephone
Laboratories...
 Following on the heels of the record-setting
demand for the January 1975 issue of Popular Electronics magazine (Part 1),
this February edition contains the second part of the
Altair 8800 Minicomputer article. The first article covered theory of operation
and constructions of the Altair 8800 Minicomputer, then the one introduces
the concept of computer programming. BASIC (Beginners' All-purpose Symbolic Instruction
Code) came about in the 1960's, but it was not until Altair BASIC (created by Microsoft)
hit the community in 1975 that it really started being used by a larger cadre of
programmers. It was for the Intel 8080 microprocessor, which the Altair 8800
used. Interestingly, BASIC is not referred to in this article; rather, machine language
code is demonstrated. The authors probably did so in order to emphasize the relationship
between the instructions being given and the actual machinations of the microprocessor
and logic circuitry...
 This might be my oldest copy of
QST, being Vol. XIII, Number 6. Up until a few decades ago, authors
commonly appropriated themes and characters from familiar fairy tales and
fables for use in articles of instructional nature. Some publications even
used comic book style formats for teaching to beginners. The term 'wabbulation'
(aka "wobbulation" and "wobulation") is spoken to Uncle Jimmy by the fabled
Piper, and I have to admit not being familiar with the term. According to
W2PA's story, 1920s era QST technical editor Robert Kruse coined the word
to describe inadvertent modulation of the carrier frequency during CW or phone
operation. Per the Wikipedia entry, "wobulation is Hewlett-Packard's term
for a form of interlacing designed for use with fixed pixel displays...
 How often have we all mistaken "spooks"
for
Barkhausen oscillations? Yeah, it's embarrassing, but we've all done it. I can't
tell you how many times as a kid I saw the tell-tale effects on our old black and
white TV and said, "Mom, can you remind Dad to do something about those dang Barkhausen
oscillations when he gets home from the newspaper office?" If you believe that line
of bull hockey, I've got some waterfront property in the Sahara Desert to sell you.
The only thing close to "Barkhausen" I might have known back then was the name of
a German beer house on Hogan's Heroes (for which I own the entire DVD set). Anyway,
this article, written in the days of over-the-air television broadcasts, presents
a solution to the annoying "spook" effect caused by poor oscillator circuit shielding...
 Thyratrons, klystrons, and magnetrons I've
heard of, but
trochotrons, charactrons, tonotrons I ain't heard of. That made this quiz more
of a learning exercise for me than a test of any sort of knowledge possessed. Heck,
I thought an 'ignitron' was a pejorative term for a really dumb techie wannabe.
In all there are 17 types of '-tron' devices given for which to match from a list
of descriptions. You'll probably do better than I did on this quiz that appeared
in the October 1963 issue of Electronics World magazine.
 The first installment of this two-part "Computer
Memory Devices" series discussed the use of magnetic data storage in the form
of drums and tapes. Both types provide long-term, non-volatile storage, but both
suffer from a relatively slow execution of writing and reading to and from, respectively,
the media. In 1960 when Electronics World magazine printed the articles, drums and
tape were used during execution of programs because electronic storage in the form
of vacuum tube circuits was extremely costly in terms of power, cost, and physical
space. As recently as the early 1980's, magnetic tape storage still dominated the
data storage field, especially where huge amounts on information needed to be stored
and retrieved. Semiconductor memory, while less voluminous and less power hungry,
still added a lot to the cost of computers. If you were around at the time and used
a PC, you remember that 64 kilobytes or RAM...
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...
 News was a bit slow to spread prior to the
Internet. Unless you worked in a newsroom with a ticker machine clacking away all
day heralding breaking headlines from around the world, your access was relegated
to the discretion of media editors and producers. Items like the
passage of radio pioneer Guglielmo Marconi on July 20, 1937, due to a heart
attack would surely have been broadcast on radio shows and printed in major newspapers,
but long lead times for magazines meant a three or four month delay for publications
as in this October 1937 issue of Radio-Craft. This story appeared along
with a separate editorial by Hugo Gernsback. Not to tarnish the man's name, but
you might be interested in this article which included mention of Marconi's fascist
political bent, even embracing Mussolini's faction in the 1920s. There is a link
to a New York Times quote where he claimed to be the "first fascist in
the field of radiotelegraphy." Should the world therefore, as is the trendy Cancel
Culture practice, reject and abandon any invention associated...
 One aspect of advertising on the RF Cafe
website I have not covered is using
Google AdSense.
The reason is that I never took the time to explore how - or even whether it is
possible - to target a specific website for displaying your banner ads. A couple
display opportunities have always been provided for Google Ads to display, but the
vast majority of advertising on RF Cafe is done via private advertisers. That is,
companies deal with me directly and I handle inserting their banner ads into the
html page code that randomly selects and displays them. My advertising scheme is
what the industry refers to as a "Tenancy Campaign," whereby a flat price per month
is paid regardless of number of impressions or clicks. It is the simplest format
and has seemed to work well for many companies. With nearly 4 million pageviews
per year for RFCafe.com, the average impression rate per banner ad is about 225,000k per
year (in eight locations on each page, with >17k pages)...
 This custom RF Cafe
electronics-themed crossword puzzle for June 18th contains words and clues
which pertain exclusively to the subjects of electronics, science, physics, mechanics,
engineering, power distribution, astronomy, chemistry, etc. If you do see names
of people or places, they are intimately related to the aforementioned areas of
study. Being that "R" is the 18th letter of the alphabet, it is used as the first
and/or last letter of many words in today's crossword puzzle - as well as in-between.
Those clues are marked with an asterisk (*). As always, you will find no references
to numbnut movie stars or fashion designers. Need more crossword RF Cafe puzzles?
A list at the bottom of the page links to hundreds of them dating back to the year
2000. Enjoy.
 RF Cafe visitor Jim L. requested that I
post this Build Your Own Vibrato article from the December 1957 edition of Popular
Electronics magazine. "Make like Elvis with an 'electronic' throbbing guitar,"
is the pitch line. Vibrato, for the non-musically inclined, is the "wa-wa" sound
of an instrument as it smoothly wavers in pitch about a central note. This circuit
is for use with an electric guitar, but acoustical stringed instruments like the
violin and cello are routinely played with vibrato effect by rocking the finger
up and down the length of the string. In typical 1950s style, the project is built
with point-to-point wiring rather than using a printed circuit board...
 Transistors were still relatively new when
these cartoons were published in the September 1959 issue of Popular Electronics
magazine. Most people had never seen a transistor, much less handled one. Soldering
irons used for working on the point-to-point wiring used on vacuum tube gear could
also be used for soldering the old copper guttering and downspouts - at least the
ones that got hot enough and had enough thermal inertia to melt solder on sheet
steel chassis'. Does the guy in this General Transistor infomercial look a bit like
Dilbert - or maybe I should ask does Dilbert look a bit like this guy? BTW, are
you thinking what I'm thinking about the picture on the bottom left?
 A few weeks ago I posted a two-part article
on the Taylor
super-modulation principle published in Radio & Television News
magazine in 1948. It was a newly announced technology at the time and was written
by its inventor, Robert Taylor. This piece entitled "Understanding Super-Modulation"
appeared a couple years later by another author, John McCord, where he describes
how it works , how to tune super-modulation circuits, and how it compares to other
modulation methods - all conveniently in "Ham language." Super-modulation is a form
of amplitude modulation (AM) that makes use of carrier and/or sideband suppression
to achieve greater efficiency. A panadaptor - aka pan-adapter, aka panadapter, aka
radio spectrum scope, aka panoramic adapter - is used to view the RF spectrum across
a wide band. Essentially it is a low budget spectrum analyzer...
 If you have been searching for a do-it-yourself
VLF loop antenna that can be resonated from approximately 14 to
25 kHz, then look no more. This article from a 1963 edition of Electronics
World presents a relatively simple to build job that reportedly provides excellent
reception. At these frequencies a wavelength is measured in miles, which makes even
a simple dipole antenna impractical, so the multi-turn loop is the only alternative.
It is the same principle that allows the little ferrite-core antenna inside your
AM radio to work so well when the shortest wavelength in the commercial AM broadcast
band is nearly 600 feet... |
