|
 "Are
we killing the broadcasting goose, layer of many golden eggs?" Dr. Lee de Forest
asked in his inaugural address, upon his election to the presidency of the Institute
of Radio Engineers. So went the opening editorial in a 1930 edition of Radio
News magazine. It was directed at the question of whether excessive, "gratuitous"
advertising was going to be so offensive to listeners that they would turn off the
set and go back to their former silent worlds. Remember that many, if not most,
households, and certainly not automobiles, even had radios at the time. Building
an audience was essential to nurturing the new phenomenon of radio, and to saturate
the listeners with commercials would surely doom...
 Here are three more
technology-themed comics from vintage of Radio & Television
News magazines. Some issued had multiple comics, but these three had just one apiece,
so I combined them onto a single page. There is a huge list of previously posted
comics at the bottom of the page. With many of these comics, you might need to be
familiar with the mindset of the electronics world back in the day. Today it considered
hilarious today to see a video of someone walking into a street lamp pole while
staring obliviously into a smartphone. In the middle of the last century, fun was
made of wives not understanding their hubbies' hobbies, dealings with servicemen,
and and goofy things do-it-yourselfers...
 Amplifier
Solutions Corporation (ASC) is a manufacturer of amplifiers for commercial &
military markets. ASC designs and manufactures hybrid, surface mount flange, open
carrier and connectorized amplifiers for low, medium and high power applications
using Gallium Nitride (GaN), Gallium Arsenide (GaAs) and Silicon (Si) transistor
technologies. ASC's thick film designs operate in the frequency range of 300 kHz
to 6 GHz. ASC offers thin film designs that operate up to 20 GHz. ASC
is located in an 8,000 sq.ft. facility in the town of Telford, PA. We offer excellent
customer support and take pride in the ability to quickly react to evolving system
design requirements.
 In the days before people were so easily
offended by light-hearted poking, it was not uncommon to find magazine articles
written by the wives of hobbyist husbands lamenting the habits and proclivities
of their matrimonial mates. Over the years I have read many such treatises in model
and full-scale airplane, electronics, and Ham radio publications. As with "A
Radioman's Wife Puts in a Good Word" from a 1951 issue of Radio-Electronics
magazine,
they typically start by expressing frustration of having lost their once-doting
husbands to alternative loves in the form of hobbies (I once saw a boat named "The
Other Woman"). Determined to win back the devotion of their sweethearts, they...
 Most people who have been in the electronics
world for a while know that neon light bulbs* used to be commonly employed as a
"pert-near" voltage regulator reference of between 55 and 65 volts, depending on
the type. The familiar NE-2 has a turn-on voltage of 65 Vac (90 Vdc),
for instance, and the voltage across the terminals remains there with little change
regardless of the current through the bulb - a lot like a Zener diode. Neon bulbs
are also used as non-invasive RF power detectors. Most people probably do not know,
however, that incandescent bulbs also have properties that make them useful for
purposes other than just lighting up a dark space.
Incandescent light bulbs have...
 This newest edition to RF Cafe's *FREE*
Espresso Engineering Workbook was a major bit of work. The ABCD-,
s-, h-, T,- Y- Z- Parameter Conversions worksheet will convert a
2-port
matrix of any of those types of matrices into the equivalent of all the others.
Enter the real and imaginary parts and click the appropriate button. I do not
know of any similar FREE conversion facility. True, the vast majority of
visitors will never need to perform such conversions, but for those who do,
well, here you are. My first exploit with them was way back around 1990 when
writing a DOS program to do a cascade calculation of components whose
s-parameters were known, but needed to be converted to an ABCD matrix for
simpler calculation...
 Since 2000 - that's 20 years - I have been
creating custom
technology-themed crossword puzzles for the brain-exercising benefit and pleasure
of RF Cafe visitors who are fellow cruciverbalists. The jury is out on whether or
not this type of mental challenge helps keep your gray matter from atrophying in
old age, but it certainly helps maintain your vocabulary and cognitive skills at
all ages. A database of thousands of words has been built up over the years and
contains only clues and terms associated with engineering, science, physical, astronomy,
mathematics, chemistry, etc. You will never find a word taxing your knowledge of
a numbnut soap opera star or the name of some obscure village in the Andes mountains.
You might, however, encounter the name of a movie star like Hedy Lamarr or a geographical
location like Tunguska...
 Here is Part 14 of a series entitled
"The Saga of the Vacuum Tube," by Gerlad Tyne, that appeared in
Radio News magazine in 1944. Part 1 was printed in March 1943, and Part 22,
the final chapter, was published in April 1946. It could have been a stand-alone
book. If I manage to be able to buy issues with some of the other parts, those will
be posted as well. You might be aware of the origins of the amplifying vacuum tubes,
beginning with the accomplishments of Dr. de Forest and his Audion. As with
most new technologies, progress moved very rapidly once other researchers glommed
on to the concept. Here, Mr. Tyne discusses the development of the "Kenotron,"
"Pliotron"...
 Electronics wizard, repairman, and experimenter
extraordinaire Mac McGregor, as sort of alter ego of author John T. Frye, provides
a brief lesson on electrostatics for his repair shop apprentice wing man Barney
(I don't think his last name was ever mentioned). In this 1973 Popular Electronics
magazine article, Mac had built two types of
electroscopes - one using a pair of pith balls suspended from
silk strings and another that was a cobbled-together version of a gold leaf electroscope.
His motive was two-fold. First and foremost was to accommodate his own interest
in electrostatics, and second to hopefully engender enough curiosity in Barney to
cause him to do a dive into science books...
 Citizens Band Radio (CB) in the United States
grew out of the post-World War II idea that ordinary citizens, small businesses,
farmers, contractors, hunters, motorists, and families should have access to short-range
two-way radio without the technical qualifications required for amateur radio. The
Federal Communications Commission created the Citizens Radio Service in the 1940s,
initially in the UHF region, but CB became culturally important only after the FCC
opened the 27 MHz "11-meter" band to Class D Citizens Radio in 1958. That band,
26.965 MHz to 27.405 MHz today, is what most Americans mean by "CB radio.” CB was
originally licensed. Users paid for an FCC license...
 Robert Taylor, along with inventing the
concept of "super-modulation," also coined the new communications term "Intelligence Transmission Efficiency." It refers in part to the
ratio of power in the intended sideband relative to power in the at least partially
suppressed other sideband and carrier. Admittedly, I have not read this material
enough to fully comprehend the concept of super-modulation, but at least based on
the Fig. 1 waveform, there seems to be an element that adds a DC bias to the
detected signal due to a nonsymmetrical (about 0 Vdc) transmitter modulation by
pumping more power into the positive peaks. I'm happy to be corrected by any
knowledgeable reader. For that matter...
 Robert Taylor claims - without contention
from what I can find - to have invented the concept of "super-modulation," whereby the normal "splatter" created by greater
than 100% amplitude modulation (AM) can be mitigated through use of specialized
circuits. As with many paradigm-changing discoveries, much was made of super-modulation
in the late 1940s through early 1950s, and then it pretty much dropped off the charts.
The cause might have been that the sophistication of circuitry needed to keep everything
tuned and tracking properly to prevent harmonic and sideband was deemed not worth
the trouble once frequency modulation (FM) came on the scene. FM quickly gained...
 It would be more than a decade after the
publishing of this article before the first
direct-to-home satellite television broadcasts would be a reality,
so it shows how long plans were being made for such systems. Rural landscapes are
still peppered with the large vestigial C-band (~4 GHz) satellite dishes, many
with faded eyeballs and other clever (and ugly) artwork on them. Before coaxial
cable was strung beyond suburbs, country dwellers who either could not pull in over-the-air
broadcasts from downtown locations or just wanted more viewing options paid dearly
for satellite service. Equipment and installation costs on early systems could run
into the $30k realm. Today's satellite TV systems use...
 At least in the U.S., laws regarding the
recording of telephone conversations seem to be constantly changing
and vary from state to state. Violation penalties - including imprisonment - can
be severe in both cases. Some states require that all parties in the conversation
be apprised of the recording, while others only require that at least one party
(obviously the one doing the recording) be aware of it. As mentioned in this 1954
"Macs Radio Service Shop" story, some areas require that an audible "beep" be sounded
at regular intervals while recording is occurring. With the ubiquitous use of smartphones
featuring built-in recording capabilities, opportunities for recording and being
recorded are constant...
 Here is an advertisement for Electro-Voice
Manufacturing Company
microphones that I scanned from page 101 of my copy of the February
1943 QST magazine. As with many companies during the World War II
era, this one's theme is the service their products are providing to America's
servicemen. Per the ad: If you were receiving radio messages from men in the midst
of earsplitting battle noises, you'd hear crisp speech undistorted by background
sound effects. Electro-Voice Microphones, in military service, are helping to make
it possible. Similar microphones, designed to achieve such results, will be available
for specific commercial applications ... after our wartime job is done...
 Voltage standing wave ratio (VSWR), often
shortened to SWR in radio work, is a measure of how well a load impedance is matched
to a transmission line. It is defined as the ratio of the maximum RF voltage to
the minimum RF voltage along a transmission line when forward and reflected waves
interfere: VSWR = Vmax / Vmin = (1 + |Γ|) / (1 - |Γ|),
where Γ, the reflection coefficient, is the complex ratio of reflected
voltage wave to incident voltage wave. A perfect match has Γ = 0 and VSWR = 1:1.
An open circuit or short circuit has |Γ| = 1 and VSWR is infinite. In practical
RF systems, VSWR is a convenient scalar indication of mismatch, but it does not
by itself show...
 Who says engineers and scientists have no
sense of humor? This is not an April Fools joke or an attempt to punk you into reading
the story. An Internet browser with strict parental control settings enabled might
even prevent this page from even being displayed. In actuality, the term "G-String Transmission Line" was so dubbed by its inventor, Dr. George
Goubau, as a tribute to his own name - both first and last. Out of an abundance
of caution, I reference the Library of Congress' "G-String" entry for the good
doctor and the device's legitimacy. A drawing similar to Fig. 1 in this
1951 issue of Radio-Electronics magazine can be seen on the chalkboard
behind Dr. Goubau in the LoC...
 Usually, when I read about yet another launching
of rockets from Gaza into Israel, what comes to mind is the barrage of
V1 Buzz Bombs and ultimately the V2 rockets that Germany terrorized
London with during World War II. Although overall not very effective individually,
they did cause brief spells of horror for the localized group of people that were
affected through maiming, killing, or property destruction. The difference between
the Nazi's weapons and Hamas' weapons is that the Germans didn't depend
on other terrorist entities to supply them with their weapons of destruction; they
were brilliant people who had evil intentions of world domination. Hugo Gernsback
writes...
 The 20th Century American electronics industry
produced some of the most influential companies in technological history, from the
laboratories that invented the transistor to the factories that put televisions
in every American home. Yet by the end of the century, many of these
iconic names had passed into foreign ownership through a series of acquisitions
driven by globalization, shifting competitive dynamics, and changing corporate strategies.
Finnish, South Korean, French, Dutch, German, Chinese, Japanese, and other international
buyers acquired what had once been pillars of American innovation. Bell Laboratories,
RCA, Zenith, Magnavox, Sylvania, IBM's PC division...
 Sangamo Electric Company was a "heap" big
name in capacitors in the realm in the middle of the last century. The company always
featured an American Indian in its electronics magazine advertisements, and usually
also included some form of "indian-ese" statements as part of the sales pitch. Of
course such marketing schemes would be vehemently raided and those responsible figuratively
"scalped," if you will pardon the gratuitous expressions. As with using names like
the Washington Redskins, the Atlanta Braves, the Chicago Blackhawks, and the Cleveland
Indians to appropriate and celebrate the bravery and might of the named peoples,
Sangamo implied quality, durability, and reliability...
 Phased
vertical stacks of two or more antennas were fairly common in
the television realm - especially once color broadcasts became more dominant in
the 1950s. Up to 3 dB per additional antenna is possible, but due to various
non-ideal physical parameters (summed phase angle, imperfect antenna geometry, etc.),
realized gain is typically in the 2.5 to 2.8 dB range. Higher signal to noise
ratios were needed to guarantee good color separation with the National Television
System Committee (NTSC) and stereo channel audio separation with the advent of Multichannel
Television Sound (MTS). As you might expect, companies appeared claiming to have
invented physics-defying antennas...
 We take a lot for granted these days with
the seemingly unlimited availability of cheap stuff of all kinds - some of it complete
junk and other of it pretty darn good. That goes for electronics components and
complete products and test equipment, tools, automobiles, appliances, and utensils,
clothing, medical equipment - you name it. Something as simple as a
pistol-type soldering gun can be purchased at just about any hardware
or home store, and at a price that when adjusted back to equivalent money in the
1940s would be amazingly cheap even then. For instance a Weller Soldering Gun kit
from Lowes sells for $39.48 today (less when on sale), which would have been $3.44
in 1947
 In its continuing effort to provide RF engineers
the tools needed to perform their jobs, everything RF website has just added an online
S-Parameters
Viewer. Upload your Touchstone files (.s1p, .s2p, .s3p or .s4p) - or a .zip
containing many of them - to instantly visualize S-parameters on an interactive
Smith chart alongside magnitude, phase,
 VSWR and return/insertion loss plots. Compare
multiple parts, temperatures, or production lots side by side, right in your browser.
No software to install and no account required. To the right is an example of a
.s3p diplexer filter file set uploaded as a .zip file.
 Spurious frequency intermodulation products,
often called mixer spurs, are unwanted output frequencies generated by the nonlinear
action of a frequency mixer. In a diode mixer, the same nonlinear diode behavior
that makes frequency conversion possible also generates many additional frequencies
besides the desired conversion product. Mixer spurs matter because they can fall
inside the desired IF, RF output, receiver passband, adjacent channel, image band,
ADC Nyquist zone, or regulatory measurement bandwidth. The practical industry method
for estimating mixer spurs is to use a manufacturer-supplied m x n spur
suppression table which list the suppression, in dBc, of each mRF ± nLO...
 Syzygy is a great word for a Scrabble game.
If you use it on a Triple Word Score (TWS) space where the "Z" sits on a Double
Letter Score (DLS) space, it will net you 105 points. About the only way to do better
is to use all 7 letters on a TWS play, where you earn 50 bonus points added to your
word score (I've done it twice in the last year).
Syzygy is an astronomical term referring to an alignment of three
or more celestial bodies - not necessarily in exact alignment, but within a few
degrees. Astrologers (not to be confused with astronomers) have since their knuckles
no longer dragged on the ground exploited such scenarios to predict various events
both good and bad. That was even before they...
 As with my hundreds of previous
engineering and science-themed crossword puzzles, this one for
May 3, 2020, contains only clues and terms associated with engineering, science,
physical, astronomy, mathematics, chemistry, etc., which I have built up over nearly
two decades. Many new words and company names have been added that had not even
been created when I started in the year 2002. You will never find a word taxing
your knowledge of a numbnut soap opera star or the name of some obscure village
in the Andes mountains. You might, however, encounter the name of a movie star like
Hedy Lamarr or a geographical location like Tunguska, Russia...
 Hugo Gernsback is not necessarily a household
name in 2020, but in the early to middle 20th century, he was fairly well known
in both the hard science and science fiction realms. He was a prolific author of
books and magazines in both areas, applying his profound knowledge of technology
and his ability to foretell the futures of many aspects of communications, mechanics,
electronics, and marketing and societal behavior to the aforementioned. This particular
work of prognostication appeared in a 1947 issue of his Radio-Craft magazine.
It presciently claimed that a post-war boom in consumer buying would feed a significant
adoption of
FM radio over...
 Exodus Advanced Communications presents
the
AMP20130 high power solid state amplifier , covering the 80 to 1000 MHz
frequency band with 1300 W of power. Our AMP20130 is a rack-mountable High-Power
Solid-State amplifier delivering >1300 W with 61 dB gain across the
80-1000 MHz range with excellent P1dB power. It features Class A/AB linear
design, ultra-wide instantaneous bandwidth, built-in protection circuits, extensive
monitoring, large local LCD display, and remote interfaces. Ideal for EMI/RFI, lab,
CW/Pulse, and communication applications requiring high efficiency...
 As long-time RF Cafe visitors are aware,
my series of RF Cascade Workbook™ spreadsheets, based in Microsoft Excel, has been
around since 2002. The latest and greatest version, packed with features for creating
and analyzing RF transmitter and receiver component chains, is called RF Cascade
Workbook™ (RFCW) ver L. RFCW™ 2008 brought, along with other new capabilities,
a major change where the components are arranged horizontally across the page, rather
than being stacked vertically. Occasionally, I receive a request to make the RFCW™ 2005
vertical layout an alternative to the horizontal layout. I decided instead to release
RFCW™ 2005 under a new name, "Wireless
System Workbook," and make it available at no cost - compliments of RF Cafe
advertisers and me. The only "price" you pay is having a small, persistent floating
window...
 $5,000 in 1956 currency is equivalent to
about $46,000 in 2020, per the U.S. Bureau of Labor Statistics' "Inflation Calculator."
That is the value of the amateur radio equipment used by
Mrs. Mary Burke in her work handling "an average of 3000 messages
per month, principally for service personnel overseas." For her tireless wireless
efforts, she was the first woman to win the coveted Edison Award Cup (sponsored
by General Electric). Most of Mrs. Burke's communications was via Morse code, where
she restrained herself to "about 30 words a minute to maintain accuracy". Way to
go, Mary...
 Herein lies the tale of my
LP Gas Tank and Supply Line Installation adventure: In mid-June (2026), I detected
a rather strong odor of LP gas in the vicinity of an 300-gallon underground storage
tank in my daughter's yard. I had detected it a few times before, usually after
a strong rain. My guess is that the gas permeated the soil during a dry spell, then
was forced out as water saturated the ground. LP gas if heavier than air, so it
would tend to prefer residence in the ground if its source was there. The tank,
of late 1980s vintage, is buried about 30 feet from the house, which in and of itself
is OK per code, but the disturbing part is that my grandson's play yard is right
over top of it. Previous attempts to "scare" the adults into relocating...
 Around the time this article was written,
the first wave of the solar and wind (which essentially is also solar) power generation
craze was settling in. A few small windmill generators popped up around where I
lived in the Annapolis, Maryland area, but they were mostly owned by hippie Earth
worshipers who eschewed modern conveniences and didn't need hot water for bathing
anyway. Most of that generation (pun intended) of windmills put out direct current
(DC - typically 12 or 24 volts). We knew a very nice older man and his wife who
lived "off the grid" and grew most of their produce and even kept a goat for milk
(they were clean people). They had some
photovoltaic (PV) solar cells...
 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.
 The
1-dB compression point, usually written P1dB, is a practical large-signal linearity
limit for RF and microwave components such as low-noise amplifiers, power amplifiers,
mixers, active frequency multipliers, driver stages, variable-gain amplifiers, attenuators,
limiters, isolators, filters, switches, and receiver front-end modules. It is the
input or output power level at which the measured gain has fallen 1 dB below the
gain predicted by the small-signal linear gain line. In symbols, if the small-signal
gain is GSS in dB, then at the 1-dB compression point: Pout(measured,
dBm) = Pin(dBm) + GSS(dB) - 1 dB When the input power at that condition
is quoted, it is called input...
 Anytime I see an airplane in a photograph,
my interest is immediately piqued to learn the story behind it - sort of like with
the "MPATI - Its Problems & Solutions" feature in the May 1963 edition of
Electronics World magazine. This "Aerial 'Private Eye' Traces TV Signals" story also involves
airplanes and television broadcasting, albeit in a completely different way. A couple
enterprising broadcast engineers created a company called Tele-Beam Industries,
in Napa, California, that measured and mapped TV signal strength in the region surrounding
transmission towers to provide the stations with information useful in marketing
and radiation characteristic planning. Signal strength...
 Two major radio events were covered in this
1954 issue of Radio & TV News magazine's monthly "Spot Radio News"
column - the rapid advance of microwave technology for building out
high capacity voice and television transmission systems, and the
ever-increasing number of new TV station operation license grants since the ending
of the Federal Communications Commission (FCC) moratorium in 1952. In 1944, the
FCC stopped issuing broadcast permits due to serious unforeseen interference from
co-location interference issues as post-war households enthusiastically adopted
TV. Unlike today's microwave relay networks, in the 1950s most systems were
still analog in nature. Coaxial...
 The first video below is my favorite. It
is a one-minute clip from a 1960s episode of "The Twilight
Zone" television show. It is an outrageous slam on amateur radio operators by
a family whose radio and TV shows are being interrupted by interference. Dad looks
out the window and sees what are actually television antennas on the guy's roof
and when Mom asks if there is anything they can do about the neighbor, he walks
toward the telephone saying he can at least check to find out whether neighbor man
has a license to operate. Mom then says, "Do you think you should, Stu? Those men
seem kind of...threatening somehow." Those d**n evil Hams! As you might expect if
your are familiar with the series...
 Empower RF Systems announces the release
of its new
Model 1240, a compact, high-performance RF amplifier module delivering a guaranteed
minimum of 200 watts across the 900-1700 MHz frequency range. Designed to address
the evolving demands of modern electronic warfare (EW) and counter-unmanned aerial
systems (C-UAS), the Model 1240 expands Empower RF's portfolio of tactically deployable,
high-reliability solutions. The Model 1240 is a full gain "smart module" built on
advanced GaN transistor technology, integrating comprehensive control and monitoring
features to ensure consistent RF performance under all environmental conditions.
What sets the Model 1240 apart is its strategically targeted frequency coverage.
The 900-1700 MHz range aligns...
 Pulse compression (aka "chirp") radar was invented in the 1950s by Sperry and a couple
other defense contractors. It was new enough by the time the radar I worked on as
a technician in the USAF that it was not incorporated. Our MPN-13 and MPN-14 radar
systems used simple single-frequency pulses. Pulse compression employs a swept frequency
within a fairly narrow bandwidth to exploit the benefits outlined in this 1965
Electronics World magazine article. If you were to listen to the signal
used to sweep the RF pulse in frequency, it would sound a lot like a bird's chirp,
hence the name. Treatment by author Donald Lancaster is fairly heavy in that it
fearlessly presents the mathematical...
 Raise your hand if you have ever owned a
CB (Citizens Band) radio. Waaaaay back before everyone carried a cellphone (pre-late-1990s),
the most common form of
unlicensed communication was CB radio. Actually, up through the
mid 1970s you were supposed to purchase a license from the FCC, although no test
was required as it was for amateur radio. My first CB was a 23 channel job that
I installed in my 1969 Chevy Camaro SS, during my senior year in Southern Senior
High School. It was right in the middle of big CB radio craze with CW McCall's
"Convoy" song topping the U.S. Billboard charts. My self-appointed 'handle'
was "RC Flyer." Most people had no idea what it referred...
 Admittedly, with all the reading I have
done of vintage electronics magazines, news of this
Crystron (crystal-electron) vacuum tube device invented by Mr. Mohammed
Ulysses Fips, as reported in the April 1947 issue of Radio Craft magazine,
evaded my attention. The article came only a couple months after publication of
the 40th anniversary edition that celebrated Dr. Lee de Forest's invention
of the Audion tube. According to Mr. Fips, his Crystron one-upped the Audion
by virtue of its containing a small amount of radio isotope which obviated the need
for the traditional "B-battery" concept also developed by de Forest to supply
a high voltage for driving the output stage circuit...
 On July 14, 2026, the U.S. Congress voted
to
make Daylight Saving Time (DST) permanent, thereby eliminating the biannual
clock change routine. Daylight Saving Time (DST) is the practice of advancing civil
clocks by one hour during part of the year so that more daylight falls in the evening.
In the U.S., DST has been used intermittently since WWI, standardized nationally
in 1966, and briefly tried as a near-permanent winter policy during the 1974 Oil
Embargo / Energy Crisis (which was such a disaster it was repealed in less than
a year). The Emergency Daylight Saving Time Energy Conservation Act of 1973 put
most of the country on year-round DST beginning January 6, 1974. The idea sounded
attractive: an extra hour of daylight after work and school, but the public quickly
discovered...
 Sam Benzacar, of Anatech Electronics, an
RF and microwave filter company, has published his June 2026 Newsletter that, along
with timely news items, features his short op-ed titled "Overlooked, Not Obsolete:
CB Radio at 27 MHz." Being "old" myself, the bit of nostalgic nearly brought
a tear to my eye. Having "come of age" myself in the 1970s, I was quick to jump
onto the CB radio craze, installing my first 23-channel rig under the dash of my
1969 Camaro SS hot rod. Every guy I hung out with knew all the words to C.W.
McCall's "Convoy" hit song. ...but I digress. Sam points out that while CB radio
is not the hot item is was decades ago, niche groups still occupy the band in number
large enough for the FCC to not reallocate the frequencies to paying clients...
|
 The most effective method for
iisolating DC power traces, low-frequency analog signal traces, high-frequency analog
signal traces, and digital signal traces on a multi-layer printed circuit board
is not simply to "separate everything with gaps." The best-practice method is functional
partitioning combined with continuous, carefully assigned reference planes, controlled
return-current paths, localized power distribution, and layer stackup planning.
In practical PCB design, signals do not travel only in copper traces. Every signal
current has a corresponding return current, and at higher frequencies that return
current follows the path of lowest impedance, usually directly under...
 In this episode of John T. Frye's "Carl &
Jerry" series, the intrepid pair of teenage electronics hobbyists and Ham radio
operators are experimenting with an audio amplifier rig that uses a parabolic dish
for concentrating sound waves at a focal point where they have a microphone mounted.
Aside from picking up bird noises and a neighbor lady scolding her husband for not
properly washing the windows during a round of Spring cleaning, Carl imposes upon
Jerry for a lesson in
feedback techniques - both positive and negative - and the reasons one is
preferred over the other. The story winds up with a clever double entendre
comment referring to osculation...
 We all know that for the most part television
stinks. Back in 1951 when this article appeared in Radio-Electronics magazine,
the technology was very new and it was considered a miracle not to be wasted on
inane programming. Newscasts actually presented news and not opinion, movies and
sitcoms cast the nuclear family, law enforcement, the military, religion, and patriotism
in a positive light rather than as the purveyors of evil in the world. By the end
of the 1960s to early 1970s a lot of that had changed. Political and social agendas
weaseled their way into nearly all programming to the extent that terms like "boob
tube" and even, yes, "smellivision," became common monikers for television...
 I'm not sure how much
mechanical filters are used in circuit design these days due to their somewhat
large size and complexity. They typically exhibit a high "Q" with a relatively flat
passband (with some ripple) and very sharp cutoff in the skirts, and the insertion
loss is low compared to lumped element equivalents (for comparative out-of-band
cutoff). Operational frequencies were limited to a few hundred kilohertz, so they
are useful only at intermediate and baseband frequencies. This article, appeared
in a 1953 issue of Radio-Electronics magazine, describes the basics of mechanical
filter design and construction. Mechanical filters from aircraft radio manufacturer
Collins and other can be...
 X-parameters are a frequency-domain
behavioral modeling framework for nonlinear RF and microwave components. They
were introduced commercially by Agilent Technologies, now Keysight Technologies,
as an extension of the earlier Polyharmonic Distortion, or PHD, modeling theory
developed by Jan Verspecht, David Root, and collaborators. X-parameters are
often described as the nonlinear equivalent of S-parameters, but that phrase
must be understood carefully: X-parameters generalize the wave-based,
port-oriented language of S-parameters to large-signal, harmonic-rich, nonlinear
operating conditions, but they are not a universal, exact, global description of
every possible...
 This article explains the six most
common
two-port network matrix descriptions used in circuit theory, RF/microwave
engineering, filter design, amplifier design, and transmission-line analysis:
Z-parameters, Y-parameters, h-parameters, ABCD-parameters, S-parameters, and
scattering-transfer T-parameters. Each representation describes the same linear
two-port network, but each chooses a different set of independent and dependent
variables. Because of that choice, some matrix types are natural for
low-frequency circuit analysis, some for cascade calculations, and some for
high-frequency measurement where direct open- and short-circuit tests become
impractical. The most important...
 RF Cafe visitor Brad B. just provided
the following
Watkins-Johnson Tech Notes for the collection: v5-3, v5-4, v5-5, v5-6, v6-2,
v6-3, v6-4, v6-5, v6-6, v8-1, v8-4, v9-1, v9-2, v9-3, v9-4, v9-5, v10-2, v10-5,
v10-6. They run the gamut from Solid State Limiting Amplifiers and Antenna Polarizations
to Digital Signal Processing for Multichannel Receiving Systems. Many old-timers
consider the W-J Tech Notes to be some of the best sources of circuit and systems
design guides ever written, especially for military, defense, and aerospace applications. Waaaaay
back in the 1970s and 1980s when I was new to the electronics design world,
offices, cubicles, laboratories, company...
 Prior to the advent of
FET-input multimeters, obtaining a very high input impedance meter required
the use of a vacuum tube circuit that used a buffer stage to isolate the measured
signal from the loading effects of the meter movement. As most people reading this
article already know, the voltage value indicated by a non-buffered meter can be
greatly affected by the meter's loading of the device under test (DUT) if the meter's
impedance is not many times greater than the DUT's impedance. The voltmeter is used
in parallel with the circuit under test, so for example if the impedance of the
DUT is 100 kΩ and the meter's impedance is also 100 kΩ, the meter will
display a value as if the DUT...
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