|
 The
bridged-T filter is a quick-and-dirty construct used to notch out a specific
frequency that is interfering with a desirable frequency or band of frequencies.
It is a resonant LC (inductor-capacitor) circuit consisting of a single inductor
"bridging" a pair of series capacitors having a resistor to ground between them,
or, if preferred, a capacitor bridging one or two inductors. A convenient
nomogram (aka nomograph) is provided by the author in this 1964
Radio-Electronics magazine article for quickly selecting values, which was
a very popular design aid in the pre-calculator era. A slide rule could be used
to calculate a range of values when only a single variable was in play, but
juggling more than one variable (component value) was greatly aided by a
multivariable nomograph. Truth is nomographs can still...
 Television, in 1955, was still a relatively
new phenomenon to many - maybe even most - people. According to multiple sources,
the portion of American households with a TV set went from under 20% in 1950 to
nearly 90% ten years later in 1960. That was a meteoric rise, particularly considering
the expense of even a minimal TV. The technology was not even available commercially
when most people were born, so the rush to join in on the craze was akin to the
mass adoption of cellphones in the 1990s. "Carl &
Jerry" creator John Frye used his pair of electronics-savvy teenagers to help
make the "magic" behind recreating a moving picture on a CRT miles away from where
it was created. Water flowing through a garden hose has often been employed as an
analogy for current flowing through a wire to explain electricity to laymen and
beginning students of the craft. Here, it is not water flowing through the hose
but water leaving the hose and flowing through the air that serves to represent
an electron stream travelling from the electron gun to the phosphor-coated glass
front of a CRT. Frame rates, scan lines, deflection coils, and other relevant terms
are i
 "The
RF front-end (RFFE) industry, valued at $21 billion, is expanding beyond its
traditional focus on mobile and infrastructure to drive innovation in the automotive
sector. Each segment within the industry presents unique dynamics and growth opportunities.
After a difficult 2022, the smartphone market is showing signs of recovery, with
expected year-over-year growth of 4%, projected to reach 1.2 billion units by 2024.
The mobile RFFE market is predicted to hit US$18 billion by the end of 2024, though
it may face stagnation due to market saturation and pricing pressures. This
market is expected to expand, with the 2027 launch of RedCap..."
 I'm having a hard time writing this with
my eyes rolled back in my head. The last time I experienced this level of overwhelmedness
was probably the third or fourth week of my feedback and control class at UVM. Even
though
electricity and magnetism shares many complimentary and parallel concepts, for
some reason thinking in terms of magnetics when describing amplifiers, mixers, modulators,
etc., has always caused brain freeze. Maybe it has to do with an ingrained bias
due to my earliest dealings with circuits being from a technician background before
earning an engineering degree. The equations of electric fields and magnetic fields
are very similar so that helps lower...
 Temwell is a manufacturer of
5G wireless communications filters for aerospace, satellite communication, AIoT,
5G networking, IoV, drone, mining transmission, IoT, medical, military, laboratory,
transportation, energy, broadcasting (CATV), and etc. An RF helical bandpass specialist
since 1994, we have posted >5,000 completed spec sheets online for all kinds
of RF filters including helical, cavity, LC, and SMD. Standard highpass, lowpass,
bandpass, and bandstop, as well as duplexer/diplexer, multiplexer. Also RF combiners,
splitters, power dividers, attenuators, circulators, couplers, PA, LNA, and obsolete
coil & inductor solutions.
 Here we are with another set of three "What's
Your EQ?" circuit challenges, these from the February 1962 issue of Radio-Electronics
magazine. As usual, those challenges provided by Jack Darr are the purview of television
servicemen of the era. The photo shown of the problematic CRT display looks like
a chest x-ray or maybe hieroglyphics in the dark corner of a cave, but evidently
the artifacts are readily identifiable to an initiated few. The Forbidden Current
Path circuit answer is not what I thought it would be. I maintain that whether my
answer or the designer's answer is correct depends on the physical...
 "A new
world record
in wireless transmission, promising faster and more reliable wireless communications,
has been set by researchers from UCL. The team successfully sent data over the air
at a speed of 938 Gb/s over a record frequency range of 5–150 GHz. This speed
is up to 9,380 times faster than the best average 5G download speed in the UK, which
is currently 100 Mb/s or over. The total bandwidth of 145 GHz is more
than five times higher than the previous wireless transmission world record. Typically,
wireless networks transmit information using radio waves over a narrow range of
frequencies..."
 Sputnik refers to the first series of satellites
launched by the Soviet Union. The word "Sputnik" means "satellite" in Russian. The
launch of Sputnik 1 on October 4, 1957, marked a monumental moment in human history,
heralding the dawn of the Space Age and sparking a fierce technological competition
known as the Space Race between the United States and the Soviet Union. This satellite,
the world's first artificial one, orbited Earth at an altitude of roughly 215 to
939 kilometers and broadcast a radio signal that astonished the world, particularly
in the United States, where it spurred rapid advancements in aerospace and scientific
research. The successful launch of Sputnik was an achievement that was years in
the making, involving a combination of visionary planning, political motives, and
intensive engineering by some of the Soviet Union's top scientists.
Blog: Air Quality
Measurements with Particle Counters
 Transcat | Axiom Test Equipment, an electronic
test equipment rental and sales company has published a new blog post entitled "Provide
Essential Air Quality Measurements with These Particle Counters" that covers
how particle counters can provide essential measurement capabilities that can help
avoid contamination and support high manufacturing yields. These measurement tools
can detect and measure microscopic particles suspended in air that can contaminate
the most carefully planned manufacturing lines. Air particle counters can be designed
for various...
 In 1958, most people were not accustomed
to seeing the now-familiar maps plotting
sinusoidal
courses of satellites across the face of the earth. It had only been in October
of the previous year that any object other than the moon was in orbit around our
home planet - that was U.S.S.R.'s Sputnik. Just as people of all ages and all backgrounds
enthusiastically joined in the newfangled phenomenon of aeroplanes after the Wright
Brothers flew their fragile craft at Kitty Hawk, electronics communications and
scientists worldwide hopped aboard the satellite train. This article from a 1958
issue of Radio & TV News magazine provided insight into the construction
and flight characteristics...
 LadyBug Technologies was founded in 2004
by two microwave engineers with a passion for quality microwave test instrumentation.
Our employees offer many years experience in the design and manufacture of the worlds
best vector network analyzers, spectrum analyzers, power meters and associated components.
The management team has additional experience in optical power testing, military
radar and a variety of programming environments including LabVIEW, VEE and other
languages often used in programmatic systems. Extensive experience in a broad spectrum
of demanding measurement applications. You can be assured that our Power Sensors
are designed, built, tested and calibrated without compromise.
 What were some of the
top issues of the radio and television industry half a century ago? In a lot
of respects, the same things that concern it today. A ready supply of service technicians
was a concern that was taken seriously by the Electronics Industry Association (EIA).
While there are not many local repair shops for electronics products nowadays, there
is still a huge demand to techs who are willing and able to do the hard work of
keeping the world's communication infrastructure operational - climbing towers,
repairing cell equipment. Now, as then, good pay, job security, benefits, and respect
for the job being done were at the top of...
 In a parallel to the traditional test setup
of signal generation and signal acquisition, RIGOL Technologies announced today
the latest additions to its portfolio of
performance measurement equipment with the introduction of the DG5000 Pro Series
Generators and DHO/MHO5000 Series Oscilloscopes. The DHO/MHO5000 Series bring next-level
performance to RIGOL's respected line of high-resolution oscilloscopes, while the
DG5000 Pro generators do the same for the company's capable Pro Series arbitrary
waveform generators...
 When selecting articles for posting here
on RF Cafe, I like to include ones that are directed toward newcomers to the field
of electronics as well as for seasoned veterans. This piece from a 1958 issue of
Radio & TV News magazine entitled "Basic Electronic Counting," is a
prime example in that it introduces the concept of binary numbers. We've all been
there at some point in our careers. A big difference between now and when this article
appeared is that in 1958, almost nobody was familiar to binary numbers, and fuggetabout
[sic] octal and hexadecimal. Only those relatively few people designing and working
with multimillion dollar, vacuum tube-based digital computers installed in universities,
megacorporations, and government research facilities had ever dealt with digital
numbers. The earliest example of powers of two I remember was back in junior high
school. It had to do with a
 "Every invention begins with a problem -
and the creative act of seeing a problem where others might just see unchangeable
reality. For one 5-year-old, the problem was simple: She liked to have her tummy
rubbed as she fell asleep. But her mom, exhausted from working two jobs, often fell
asleep herself while putting her daughter to bed. 'So [the girl] invented a teddy
bear that would rub her belly for her,' explains Stephanie Couch, executive director
of the Lemelson MIT Program. Its mission is to nurture the
next generation of inventors
and entrepreneurs. Anyone can learn to be an inventor, Couch says, given the right
resources and encouragement. 'Invention doesn't come from some innate genius, it's
not something that only really..."
 Mechanical filters of the type described
in this 1969 Electronics World magazine article are yet another example
of the genius of some people. They are actually a form of electromechanical device
in that the applied electrical signals are first converted into mechanical signals,
followed by resonant mechanical elements that discriminate according to frequency,
and finally a conversion back to an electrical signal is made. It is fundamentally
the same principal as a crystal, SAW, or BAW filter, albeit each with distinctly
different methods and topologies. Mr. Donovan Southworth, of Collins Radio, presents
the basics of mechanical filters in this brief write-up...
LadyBug Technologies was founded in 2004
by two microwave engineers with a passion for quality microwave test instrumentation.
Our employees offer many years experience in the design and manufacture of the worlds
best vector network analyzers, spectrum analyzers, power meters and associated components.
The management team has additional experience in optical power testing, military
radar and a variety of programming environments including LabVIEW, VEE and other
languages often used in programmatic systems. Extensive experience in a broad spectrum
of demanding measurement applications. You can be assured that our Power Sensors
are designed, built, tested and calibrated without compromise.
 Attempts at making an
electronically printed facsimile (fax) of an original document at a location
distant from the source have been around for quite a while. As mentioned by
Radio-Electronics magazine editor Hugo Gernsback in this article, Samuel Morse
had a crude working device for printing messages on paper even before his eponymously
named code of dots and dashes became famous in 1837. A couple decades earlier, a
fellow named John Redman Coxe, of Philadelphia, Pennsylvania, devised a method of
electronically printing images and text on paper using a conductive solution and
a direct current pile (aka battery). Dr. Coxe, a physician, is not a well-known
figure in the electronics world, but in his day...
 "Researchers have discovered how the 'edge
of chaos' can help electronic chips overcome signal losses, making chips simpler
and more efficient. By using a metallic wire on a semi-stable material, this method
allows for long metal lines to act like superconductors and amplify signals, potentially
transforming chip design by eliminating the need for transistor amplifiers and reducing
power usage. A stubbed toe immediately sends pain signals to the brain through several
meters of axons, which are composed of highly resistive fleshy material. These axons
operate using a principle known as the 'edge of chaos,' or semi-stability, enabling
the swift and precise transmission of information..."
 The January 1969 issue of Electronics
World magazine published an extensive list of
Japanese company trade names and their addresses. Many of them went out of business
or were bought by other corporations long ago, as occurs in all countries. "Aiwa"
is listed twice, but that might have been a legitimate duplication due to separate
locations (BTW, I owned an Aiwa stereo at one time). My first "real" cassette tape
deck was made by TEAC (founded in 1953 as the Tokyo Electro Acoustic Company) and
my first "real" stereo receiver was made by Sansui. I remember the line in "Back
to the Future 3" where Doc Brown, having time-travelled from 1955, makes a
disparaging remark about a circuit in the DeLorean failing because of it being labeled
"Made in Japan." Marty counters...
• ARRL Defends
902-928 MHz Amateur Radio Band
• FCC's
Auto Safety Spectrum Rules
• $5M in U.S.
Chips Act Money to Metrology Projects
• U.S. State Department Approves
Surveillance Radar System Sale to Romania
•
5G Americas ITU IMT-2030 Vision for 6G White Paper
 John Redman Coxe was a prominent American
physician, scientist, and innovator born on September 20, 1773, in Philadelphia.
Coxe's intellect and curiosity drove him toward an illustrious career in both medicine
and early scientific exploration, which included experimentation in electrochemistry.
He graduated with a degree in medicine in 1794, setting the course for his lifelong
journey into medicine and early scientific innovation. Coxe broadened his approach
to medicine and science, inspiring him to explore the convergence of scientific
methods and practical applications. John Redman Coxe is most remembered not only
for his contributions to medicine but also for his interest in experimental physics,
particularly in the field of electrochemistry...
 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.
 When I saw this 1966 Radio-Electronics
magazine article entitled, "Vibration
and Shock - Nature's Wrecking Crew," for some reason the first thing I thought
of was "The Wrecking Crew," that anonymously played the music for a huge number
of popular singers - mostly those without prominent bands of their own during the
1960s and 1970s rock-and-roll era. ...but I digress. My introduction to the potential
deleterious effects of vibration on electronics was in the 1970s, with airborne
receivers and servos in my radio controlled model airplanes. Even though they were
transistorized, vibration from glow fuel engines could wreak havoc with potentiometers
in servos and solder joints everywhere, including battery packs. I remember seeing
the control surfaces jitter...
 You don't see jobs advertisements like this
anymore. Here is an ad that appeared in the the July 1944 edition of QST
(the American Radio Relay League's, ARRL's, monthly magazine), placed by Raytheon
Manufacturing Company (now just Raytheon Company), looking for
vacuum tube design, test, and processing engineers. Licensed amateur radio operators
were in high demand during the war years because of their knowledge and enthusiasm
for electronics and wireless communications. I hope you didn't come to this page
hoping to really find a tube designer job available. Of course, there are still
vacuum tubes being designed for TWTs and magnetrons, but those are few and far between...
 The "carborundum"
signal detector, an innovative device developed by engineer General H. H. C. Dunwoody
in the early 20th century, represents a significant advancement in radio technology,
particularly in the context of crystal detectors used for receiving radio signals.
This device utilized the unique properties of silicon carbide, also known as carborundum,
which was synthesized in the late 19th century by Edward Goodrich Acheson. The connection
between Dunwoody and the material lies in the application of carborundum as a semiconductor
in radio signal detection. The operational theory of the carborundum signal detector
is rooted in its ability to rectify alternating current (AC) signals. When radio
waves, which are essentially electromagnetic waves...
 "Researchers have created a cutting-edge
structure by placing a very thin layer of a special insulating material between
two magnetic layers. This new combination acts as a quantum anomalous Hall insulator,
significantly broadening its potential use in developing ultra-efficient electronics
and innovative solar technology. A Monash University-led research team has found
that a structure featuring an ultra-thin topological insulator, sandwiched between
two 2D ferromagnetic insulators, transforms into a large-bandgap quantum anomalous
Hall insulator. This heterostructure opens the door to ultra-low energy electronics
and even topological photovoltaics..."
|
 Banner Ads are rotated in all locations
on the page! RF Cafe typically receives 8,000-15,000 visits each
weekday. RF Cafe
is a favorite of engineers, technicians, hobbyists, and students all over the world.
With more than 17,000 pages in the Google search index, RF Cafe returns in
favorable positions on many types of key searches, both for text and images.
Your Banner Ads are displayed on average 225,000 times per year! 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. If you need your company
news to be seen, RF Cafe is the place to be...
 No matter how proud I was of my family name,
I do believe I would refrain from using "Kluge" as a company moniker. Maybe the
word did no connate the same meaning in 1946 when this advertisement for the
Kluge Electronics "California Kilowatt" Amateur Radio Station appeared in Radio-Craft
magazine. An extensive WWW search turned up no examples of any surviving Kluge "California
Kilowatt" Amateur Radio Stations. One QRZ website discussion supposed that none
were ever manufactured. Per Wikipedia: "A kludge or kluge (klooj) is a workaround
or quick-and-dirty solution that is clumsy, inelegant, inefficient, difficult to
extend and hard to maintain." It has an interesting etymology. I found references
to the term "California Kilowatt" meaning a transmitter putting out more than the
legal power limit. California Kilowatt is also nowadays the name of a Canadian rock
band...
 Since I am currently planning a loudspeaker configuration
to replace the original speaker in my 1941 Crosley 03CB floor model AM / shortwave radio
set, this article made for a good refresh on
audio frequency crossover networks. A very nice set of design charts is provided.
Of course today there is no need to design and build your own since commercial units
are very good and cost less than what I could build myself. Many moons ago while serving
in the USAF at Robins AFB, Georgia, I did actually build my own crossover circuit for
use in custom speaker cabinets I built in the base woodshop. The speaker that came in
the Crosley has a 12" cone, which is still in good condition, but it uses an electromagnetic
voice coil rather than a permanent magnet like modern speakers use...
 According to this 1972 article in Popular
Electronics, there were as many as 50,000 computers in the world at the time using
magnetic core memories. Among them was the Apollo Guidance Computer that was onboard
the Apollo 11 Lunar Module that Neil Armstrong used in July 1969 to land on the
moon*. Semiconductor memories were being manufactured in 1972, but believe it or not
they were not as fast as the magnetic core memories. Machinery was not available with
enough precision and repeatability to thread the read, write, sense, and inhibit wires...
 According to the article in a 1944 issue
of Radio News magazine,
phosphors were discovered in the 17th century by an Italian physicist. However,
they remained primarily a scientific curiosity until a practical use for them was
found in cathode ray tubes. Phosphors efficiently convert energy of various forms
(beta rays, ultraviolet rays, and others) into visible light. They are available
in a wide variety of colors and exhibit a "memory" which allows them to be used
for storing an image (or other information) for seconds, minutes, hours, or even
days. Anyone old enough to remember the old analog storage oscilloscopes is familiar
with phosphorescent memory. As with many other technologies, phosphor knowledge
gained significant advances during World War II, and the public was promised
virtually limitless new conveniences based on those technologies once the nasty
war was out of the way...
 For some reason, a lot of people seem to have
a harder time grasping the
concepts of magnetism than the concepts of electricity. Maybe it is because
most of the machines and appliances we are familiar with run off of electricity
supplied by the electric utility distribution system - not the magnetism distribution
system. The fact that motors, transformers, and relays, which are present in one
form or another in every household, office, and factory, are as reliant upon magnetic
effects as they are electrical effects is lost on the multitudes. Maybe if we received
monthly magnet bills to pay instead of electric bills, there might be more interest
in understanding the phenomenon. At the most fundamental level, electric and magnetic
circuit equations exist that are nearly the same, but with magnetism terms used
rather than electricity terms; i.e., duality ...
 J-pole antennas (aka "J" antennas) are so
named due to their physical shape. The basic "J" antenna is a half-wave
vertically polarized antenna that has an integrated parallel feed quarter-wave
tuning stub. It is very popular with amateur radio operators and is still used
with some commercial radio installations. The azimuth radiation pattern and gain
are very similar to the half-wave dipole antenna, as shown in the Wikipedia plot
below. The J-pole was invented in 1909 for use on the German Zeppelin airships
as a trailing wire antenna. Variations of the J-pole have evolved over the years
that in some cases significantly change the radiation pattern, but the
characteristic quarter-wave stub match is retained in all of them...
 Here is a unique type of article from a 1974
issue of Popular Electronics. Author Ralph Tenny presents a
poor-man's environmental test chamber constructed with a Styrofoam
picnic cooler, a dry ice sump, a heater, a thermocouple, and a bunch of input/output
ports for making electrical measurements. While working on my senior project at
college - an electronic remote weather station - I needed to verify functionality
up to 150°F and down to 0°F. Having the Torture Box would have been handy, but instead
I used the kitchen oven and freezer with the interconnect cable mashed between the
door gasket and frame. Unfortunately I don't have any...
 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+ 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...
 Walter
Sneijers, an RF Applications Engineer at Ampleon, offers this paper titled "Doherty
Amplifiers in UHF." It is an abbreviated version of his more extensive white paper
titled "Doherty Architecture in UHF," both of which feature Ampelon's BLF8xx transistor
family. An introduction to the Doherty amplifier is given along with basic design and
test configurations. Both the classical 2-way and the ultra wide-band (UWB) architectures
are discussed...
 Being the birthday of Dr. Robert W.
Wilson, there is no better occasion to post this article about the "sugar-scoop" antenna used by the two Bell Telephone Labs engineers
(the other being Dr. Arno A. Penzias) who serendipitously discovered the cosmic
microwave background radiation (CMBR) believed to be a signature of "The Big Bang."
The pair were investigating an unexplained hiss in the background of the very low
noise receiver attached to the antenna. That microwave energy was constant and came
from all areas of the sky, regardless of where the antenna was pointed. They eventually
deduced that the signature was consistent with...
 In all-too-typical style, the Federal Communications
Commission (FCC) decided to look for a scapegoat it could not just blame for but strong-arm
a solution for claimed problems plaguing
Citizen Band (CB) radio as it was rapidly becoming a popular hobby in the
1960s. In the same manner in which bureaucrats blame gun and steak knife
manufacturers for the abusive actions of a minority of their products' users,
the FCC sought to curtail improper (maybe even illegal) operation of CB radios
by imposing type certification and feature restrictions on equipment
manufacturers. To demonstrate its magnanimity , though, the FCC offered to give
companies half a year to deplete their existing inventories. At the time and
through 1977, CBs had 23 channels, after which time 40 channels became the new
mandate...
 We really have it good today compared to the
early days of the semiconductor revolution. Most of the most difficult problems
were solved long ago. Point contact devices were still fairly commonplace even in
1964. Recall that the very first manufactured solid state diodes and transistors
were the point contact type that were
encapsulated in glass with a space gap where the contact was made. That left
the device vulnerable to vibration and impact damage and to contamination if the
hermetic seal failed between the metal lead and the junction(s). Unitrode claims
to have been the first to eliminate that issue with essentially a fully bonded package.
Keep in mind, however, that even the early semiconductor device packaging was no
worse that the vacuum tubes that they replaced, since the tubes also suffered from
the same vulnerabilities due to their construction. In fact, the process used with
the early solid state device packaging descended directly from vacuum tube construction ...
 Dr. Linder's patented AC and DC generators
exploited alpha (proton) and beta (electron) particle emissions from radioisotopes contained
within. The device is basically a metallic sphere concentric to an enclosed mounting
platform for polonium (α particle emitter), phosphorous
(β particle emitter),
or similar elements. With just a gram of radioactive material, the charge which accumulates
on the outer sphere generates a very high voltage (~1 MV) driving a low current
(~1 mA). Georg Ohm's work tells us that is equivalent to 1 kW of power - quite
a lot for a fairly compact device. Dr. Linder envisioned multiple
atomic generators combined in series and/or parallel to obtain the required power.
No mention was made of the effective internal resistance, which would ultimately determine
the terminal voltage when connected to a load...
 A
"V" Antenna is a bi-directional antenna used widely in military and commercial
communications. It consists of two conductors arranged to form a V. Each conductor
is fed with currents of opposite polarity. The "V" is formed at such an angle that
the main lobes reinforce along the line bisecting the "V" and make a very effective
directional antenna (see figure 4-35). Connecting the two-wire feed line to the
apex of the "V" and exciting the two sides of the "V" 180 degrees out of phase cause
the lobes to add along the line of the bisector and to cancel in other directions,
as shown in figure 4-36. The lobes are designated 1, 2, 3, and 4 on leg AA', and
5, 6, 7, and 8 on leg BB'. When the proper angle between AA' and BB' is chosen,
lobes 1 and 4 have the same direction and combine with lobes 7 and 6, respectively.
This combination of two major lobes from each leg results in the formation of two
stronger lobes, which lie along an imaginary line bisecting the enclosed angle...
 Each autumn I used to anxiously await the
appearance of the newest edition of
The Old Farmer's Almanac on the store shelf, and such was the case with this
1981 issue. It is not that I was/am an avid farmer, just that I enjoy reading the
anecdotes, tales, and interesting historical tidbits included amongst the pages
along with tables of high and low tides, moon and sun rising and setting times,
astronomical events, and weather patterns expected for the year that lay ahead.
Most of all, I liked working the puzzles and riddles. Over the years the difficulty
levels gradually got lower and lower (aka dumbed down), to the point where for the
last decade or so I have not even bothered buying the OFA. Now it is full of numbnut
stuff...
 August 23rd's custom
Science & Engineering themed crossword puzzle contains only only words (1,000s
of them) from my custom-created lexicon related to engineering, science, mathematics,
chemistry, physics, astronomy, etc. You will never find among the words names of
politicians, mountain ranges, exotic foods or plants, movie stars, or anything of
the sort. 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. The technically inclined cruciverbalists amongst
us will appreciate the effort.
 This is pretty cool. If I owned a good receiver
(which I don't), I would definitely give it a try. In 1970 when this Popular
Electronics article was written, a lot of Hams were still using tube receivers
so the recommendation to let the equipment warm up for several hours prior to making
the fine frequency adjustments was good advice. Nowadays the warm-up time and stability
of receivers should permit 30 minutes or so to suffice (even ovenized frequency
references need time to stabilize when first powered up). Unless I missed it, the
author does not explicitly state that the
frequency change measured over time is due to gravity acting on the mass of
the crystal reference, but I suspect that is his intention since part of the experiment
involves disconnecting the antenna and shielding the receiver from outside interferers.
Over a lunar month period (29.5 days) we experience a leap tide and a neap tide...
 Here for your enjoyment during another workweek
are three more vintage
electronics-themed comics - this time from a 1966 issue of Popular Electronics
magazine. The "quarter-inch Mylar" referenced in the title is recorder tape used
in the very popular machines of the day. Not only were serious" music aficionados
huge proponents of the medium, but so were the many recreational users. There was
a sort of mystique involved with being able to record and instantly play back even
normal conversations - sort of like with videos these days, except there is no mystique
anymore because most users couldn't care less about the technology which enables
their proclivities. The magazines of the era were full of stories on tape recorders
and advertisements for buying them ...
 Super-low-noise-figure
receivers are absolutely essential in radio astronomy work. The need has driven
major advances in the state of the art of
cryogenically cooled front ends with noise temperatures near absolute zero.
Antenna technology has also benefitted from radio astronomy due to the need for
precision steering and narrow beam widths. Phased arrays (aka interferometers) for
interstellar targets requires that element spacing be large enough to require separate
antennas as the elements, which creates a very large effective aperture, hence greater
angular resolution. Networks located continents apart are synchronized with the
use of atomic ... |
