Friday the 21st
Website visitor Daniel O. wrote to request
that I post this "Designing
a Low-Distortion 12-Watt Amplifier" article from the August 1958 issue of Radio-Electronics
magazine, which of course I was glad to do. It is nice to know there is still some
interest in building vacuum tube circuits, just to keep the knowledge alive. When
reading through the vintage magazines in search of good articles, I typically do
not include ones like this not because I don't think they are worthy of posting,
but because they are narrowly focused and would not be of interest to a wide number
of people. If you run across an article which appears in the table of contents of
one of the hundreds of old magazines I have posted, let me know and I'll be glad
to do the same for you...
"Researchers from Osaka University, Japan,
and the University of Adelaide, Australia have worked together to produce the new
multiplexer made from pure
silicon for terahertz-range communications in the 300 GHz band. Terahertz
waves are a portion of the electromagnetic spectrum that has a raw spectral bandwidth
that is far broader than that of conventional wireless communications, which are
based upon microwaves. The team has developed ultra-compact and efficient terahertz
multiplexers, thanks to a novel optical tunneling process. 'To control the great
spectral bandwidth of terahertz waves, a multiplexer, which is used to split and
join signals, is critical for dividing the information into manageable chunks that
can be more easily processed and so can be transmitted faster from one device to
another,' said Associate Professor Withawat Withayachumnankul..."
Have you heard of an
Alford Loop antenna? I hadn't until reading this article. It is a four-sided
structure consisting of identical folded ½-wave dipoles on each side, with a common
feed. Opposing sides have their elements 180° out of phase with respect to each
other. The intention is to provide nearly omnidirectional FM radio reception across
the entire 88-108 MHz band. A little research on the Alford Loop reveals that
Mr. Andrew Alford developed this configuration to enable simultaneous, co-located
transmissions of FM radio stations. In that case the four antennas are individually
fed by transmitters on different frequencies. Alford is credited with inventing
antenna systems for the VFH Omnidirectional Range (VOR) and Instrument Landing System
(ILS) navigational aids...
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Somehow I missed this. According to stories
this science and news publications last fall is renewed interest in a mysterious
low-level pulsation recorded on seismographs with a
26 second period (a "microseism"). It was discovered by researcher
John "Jack" Oliver
in the 1960s. Renewed interest occurred in 2005 when graduate student Greg Benson
and advisor Mike Ritzwoller performed a triangulation process to locate the signal's
origin in the Gulf of Guinea.
The effort was published in the 2006 Geophysical Research Letters article,
"Source location of the 26 sec
microseism from cross-correlations of ambient seismic noise."
Lotus Communication Systems began in 2009,
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Thursday the 20th
nuvistor triode amplifier, a component largely unknown to most people, even
during its brief heyday in the late 1950s through the early 1960s, was an attempt
to bridge the technology gap between the sunsetting of vacuum tubes and solid state
transistors. Its relatively low noise figure, small size, ruggedness, metal shield,
and higher operating frequency (near a gigahertz) were the main marketing features
when RCA introduced the nuvistor in 1959. Although adopted enthusiastically by many
aware of its existence, the nuvistor, as pointed out in this 1962 Electronics
World article, tended to oscillate if its metal body was not adequately grounded.
You might expect the schematics included in the article to explicitly show a ground
connection to the can, but that is not the case. Ultimately, a quick adoption of
transistors by industry and hobbyists, with their rapidly improving specifications
and decreasing price, rendered the nuvistor to the dustbin of electronic history...
2D cousin of flash memory is not only roughly 5,000 times faster, but can store
multiple bits of data instead of just zeroes and ones, a new study finds. Flash
drives, hard disks, magnetic tape and other forms of non-volatile memory help store
data even after the power is removed. One key weakness of these devices is how they
are often slow, typically requiring at least hundreds of microseconds to write data,
a few orders of magnitude longer than their volatile counterparts. Now researchers
have developed non-volatile memory that only takes nanoseconds to write data. This
makes it thousands of times faster than commercial flash memory and roughly as speedy
as the dynamic RAM found in most computers..."
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etch and laser trim capability. The company is a leader in development and production
of the films required for these type of RF/microwave components. Please check out
Res-Net Microwave's website to see how they can help with your current project.
American Radio Relay League
(ARRL) has been running an announcement in its QST magazine regarding employment
opportunities. Amongst current openings are Acquisitions Editor, Director of Information
Technology, Director of Operations, Public Relations & Outreach Manager, and
Senior Lab Test Engineer. It says, "Start each day with enthusiasm and purpose,
knowing you're working to advance and grow the hobby you love! ARRL is looking for
energetic and motivated professionals with passion for Ham Radio to join our team.
Here a new twist in product promotion: Finland's
specialty plywood manufacturer WISA is launching a CubeSat - codenamed "Woodsat"
- with its sides covered in the company's birch plywood. Check out their project
slogan: "WISA Woodsat
will go where no wood has gone before." That will endear them to Trekkies. "The
WISA Woodsat project, being sponsored by plywood supplier WISA in an unconventional
PR initiative, is poised to place a wooden satellite into orbit by the end of the
year. The idea is to test the suitability of treated wood as a low-cost and widely
available material for space applications. The IARU posting for Woodsat indicates
that several amateur radio experiments will be on board as well as photo downlinking,
It is common in electronics courses for an
analogy to be drawn between electrical and mechanical phenomena. In fact, a lot
of circuit analysis methods and equations apply directly to mechanics, and vice
versa. An LC (inductor-capacitor) oscillating tank circuit is akin to a spring and
dashpot. Resistance of a wire is likened to skin friction of water flowing through
a hose. Who among us can forget those lessons? This
Electronic Analogy Quiz from the November 1961 edition of Popular Electronics
presents a challenge both because some not-so-familiar examples of analogies are
offered, and because some are a real stretch. Therefore, don't feel too bad if you
don't get a few. That's my way of saying that I didn't get all of them right ;-)...
Since 2003, Bittele Electronics has consistently
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for design engineers needing low volume or prototype multi-layer printed circuit
boards. Free Passive Components: Bittele
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components to its clients FREE of Charge.
Wednesday the 19th
Betatron particle accelerators date back
to 1935 with the one built by Max Steenbeck in Germany. The name is a portmanteau
of "beta" + "electron," which is sort of a superfluous redundancy. This news piece
is about the world's biggest betatron having been built, with dimensions of 9 feet
high, 6 feet wide and 15 feet long, and 24,000 volt energizing coils. Strangely
(it seems to me), the article interchanges the terms "xxx-volt electrons" and "xxx
electron-volts. I suppose its fundamentally the same thing, but just unusual to
see it that way. Note the robustness of the machine as required to rigidly contain
such powerful magnetic forces...
Announcing new 750 MHz and 1 GHz
PicoScope 6000E Series PC-based oscilloscopes from Pico Technology. These top
end devices also offer 4 analog channels, 16 available digital channels, FlexRes
capabilities, up to 4 GS of capture memory and 21 built-in serial protocol
decoder/analyzers plus much more. They are ideal for design engineers working with
high-performance embedded systems, signal processing, power electronics, mechatronics
and automotive designs, as well as scientific research. These oscilloscopes, with
PicoScope 6 application software, are ideal for design engineers working with
high-performance embedded systems, signal processing, power electronics, mechatronics
and automotive designs...
Unfortunately the James Webb Space Telescope
(JWST) is now 20x over budget and 14 years behind schedule. "'It's like building
a Swiss watch at 40-feet-tall... and getting it ready for this journey that we take
into the vacuum at minus 400 degrees Fahrenheit (−240 °C), four times further
than the Moon,' said
Scott Willoughby of lead contractor Northrop Grumman. He was speaking at the
company's spaceport in Redondo Beach, California, from where the telescope will
be shipped to French Guiana to be launched on an Ariane 5 rocket, with NASA
targeting October 31 for liftoff."
RF Cascade Workbook 2018 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...
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...
The homepage of Oculii's website has a video
showing a real-time comparison of standard radar vs. its new "virtual aperture imaging radar" (left, right,
respectively, in thumbnail). "For decades, commercial radars have suffered from
poor angular resolution and limited FOVs because traditional designs require more
antennas for higher resolution. Additional antennas increase cost, size, and power
exponentially, limiting what is commercially feasible. Oculii's Virtual Aperture
Imaging technology fundamentally breaks this tradeoff by using AI software that
dynamically learns from and adapts to the environment. This software can increase
the resolution of any radar hardware by up to 100x..."
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Tuesday the 18th
The August 1962 issue of Electronics
World magazine featured what could be considered as an early
"infographic" on the topic of sound, music, and audio. Frequency and volume,
perceived equal loudness levels, the audible frequency spectrum, musical frequency
ranges, typical age-related hearing loss, relative sound levels in decibels, and
the musical scale are included. The sound power level chart ranges from the threshold
of hearing value of 10-16 watts/cm2 (0 dBA) to standing
80 feet from the tail of a North American F-86 Sabre Jet taking off, which is a
couple dB above the threshold of pain at 10-3 watts/cm2 (130 dBA).
The charts were useful (and still are for that matter) to the audiophiles who looked
to electronics magazines of the era for technical information...
I have to admit to not being aware of these
- "Based on over 11,500 hours of computer simulation, the research from Oxford Brookes
University found that
Vertical Axis Wind Turbines (VAWTs) boost each other's performance when clustered
together, with grouped pairs seeing a 15 per cent rise in output. This is in contrast
to the more traditional Horizontal Axis Wind Turbines (HAWTs), which produce turbulence
that affects the performance of other HAWTs downwind. 'Modern wind farms are one
of the most efficient ways to generate green energy, however, they have one major
flaw: as the wind approaches the front row of turbines, turbulence will be generated
downstream,' said lead author of the study, Joachim Toftegaard Hansen, and engineering
graduate at Oxford Brookes..."
A mere five years 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 U.S. 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, but a month before
this issue of Electronics World went to press the Mariner spacecraft sent
close-up images of the planet Mercury's surface...
Lots of news
headlines are appearing nowadays touting the imminent reality of
6G, at a time when 5G is just getting
a solid base. Most people don't even know what 5G is - or 4G for that matter. Based
on my interpretation, 5G - which is not only about cellphones - is basically the
ability to shed wired connections for just about everything. It encompasses all
formats of wireless connectivity - Wi-Fi, cellular, Bluetooth, ZigBee, etc. Moving
to 5G brought us Gbps over-the-air data rates, previously the domain of wired systems.
6G takes major leap forward with Tbps data, thereby freeing local device of the
need for powerful local processing. It can be done remotely with only user I/O necessary
at the phone, appliance, or machine end - a la a mainframe system vs. PCs. That's
a significant paradigm shift. The downside is THz radio waves
attenuate very quickly
over a distance, so massive cellular networks are needed for a broad coverage. Otherwise,
it's a local technology. - Kirt B.
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!
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Monday the 17th
Crystal diodes have been used as detectors
in radio circuits since the 1910s. Originally, the rectification process was effected
via a point contact "whisker" (aka "cats whisker") pressed against the crystal's
face. It was not mechanically rugged (vibration could cause erratic operation),
was sensitive to heat and humidity (if not contained in a hermetic case), and operated
at fairly low frequencies. Vacuum tube diodes provided some improvement, but were
still limited to operation in the lower hundreds of MHz. Once germanium and silicon
crystals became available, operational frequencies climbed into the upper MHz to
lower GHz realm, even though, as shown in this 1946 Radio-Craft article, the diodes
were of the point contact type. PN junctions at those frequencies were still a few
years off. Their smaller size and construction largely mitigated the environmental
issues of the early types. The 1950s- vintage S-band radar...
have discovered how to make materials that
snap and reset themselves, relying only upon energy flow from their environment.
The discovery may prove useful for various industries that want to source movement
sustainably. The team uncovered the physics during a mundane experiment that involved
watching a gel strip dry. The researchers observed that when the long, elastic gel
strip lost internal liquid due to evaporation, the strip moved. Most movements were
slow but every so often, they sped up. These faster movements were snap instabilities
that continued to occur as the liquid evaporated further. Additional studies revealed
that the shape of the material mattered..."
Let me begin by stating that in general,
I am not an "anti-vaxxer." Since my days in the USAF, I have chosen to get an annual
flu shot, and my kids received all the required / recommended vaccinations during
their school years. I've even had the second-generation shingles shots. No problemo.
All those vaccines were subject to the full scientific regimen of development and
testing prior to being administered to the general public. The current crop of
COVID−19 vaccines, however, are a major exception - especially the mRNA varieties.
None have been thoroughly vetted with the traditional multi-year studies which include
a very wide cross-section of voluntary participants. Furthermore, none have been
approved by normal guidelines - these are emergency approvals. Statistical studies
were performed which attempted to correlate cause and effect. If necessary, necessary
modifications to the formulation were made and then trials began anew. Once the
medical and science community had enough data...
Pliers of the amateur radio hobby have since
the beginning put forth a lot of effort training fledgling entrants in the realm
of electronics and communications. Up until the latter part of the last century,
there were a number of magazines - Popular Electronics among them - that
would regularly print articles covering the basics of electronics. Other than the
ARRL's QST magazine, it seems maybe Nuts and Volts is the only
monthly still in print that you can go to for such information. I suppose it was
inevitable with the emergence and now domination of the Internet as a source for
most knowledge. The "Among
the Novice Hams" column in Popular Electronics often included short
primers on subjects like the basics of capacitors and inductors. Here is one on
inductors from March 1958...
IEEE's Spectrum magazine has a story
about a new type of 95% efficient brushless motor that promises to be a game-changer
in the e-vehicle realm. If successful, it will significantly weaken China's dominating
rare earth magnet resources. "Automakers outside China are scrambling to develop
electric motor designs that use no permanent magnets, partly because the magnets
require rare earths, and mining rare earths causes pollution. It's also partly because
the mining is done in China, a formidable automotive competitor. These alternative
motors turn the rotor using electromagnetic force alone; we've covered more than
one such motor recently. One problem: Designs that put copper windings in the rotor
have to transmit electricity to a moving target, and the point of contact - the
slip ring - is subject to wear and tear..."
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Sunday the 16th
Electronics Theme Crossword Puzzle for May 16th has many words and clues related
to RF, microwave, and mm-wave engineering, optics, mathematics, chemistry, physics,
and other technical subjects. As always, this crossword contains no names of politicians,
mountain ranges, exotic foods or plants, movie stars, or anything of the sort unless
it/he/she is related to this puzzle's technology theme (e.g., Reginald Denny or
the Tunguska event in Siberia). The technically inclined cruciverbalists amongst
us will appreciate the effort. Enjoy!
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