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 According to this full-page advertisement
in the June 1955 issue of Radio & Television News magazine, Bell Telephone
Laboratories was responsible for designing and fielding "waveguide pipe," aka flexible circular waveguides. According to
other historical sources, both George Southworth of Bell Telephone Laboratories
and Wilmer Barrow of the Massachusetts Institute of Technology (M.I.T.) independently
and simultaneously developed circular waveguide, but the early devices were rigid
pipe rather than being fabricated from tightly wrapped, insulated wire that permitted
it to be bent rather than requiring separate corner and offset pieces. Insertion
loss and VSWR is typically not as good as with rigid waveguide, but the ease of
installation in many situations justifies the poorer electrical performance. Bell
Telephone Laboratories was responsible...
 Having recently struggled a little with
re-stringing the dial cord on a vintage Realistic (Radio Shack) Patrolman-50
Radio, it really became apparent why the
Sams Photofact Folders were of such value to electronics servicemen.
Unlike the tangled mess of dial cord shown in the ad, I had the advantage of being
able to carefully open the chassis and photograph the routing and wrapping of the
broken dial cord around pulleys and shafts. Even so, a lack of experience required
some trial and error to get the tensioning correct. No doubt many unqualified radio
owners attempted to fix their own broken dial cords prior to breaking down and committing
to spending a few bucks to have a pro do it correctly. The tight quarters in my
portable radio had me using tweezers to do some of the routing...
 My mother loved
Norman Rockwell paintings for their ability to get to the heart of Americana.
She was an avid collector of books on Rockwell and decorated plates for display
- as avid as one can be on my newspaper classified ad manager father's feeble
salary, anyway. I, too, have a great appreciation for Rockwell's great talent
to choose his subject matter and models and to, when fitting, include a nearly photographic
level of detail within. The Saturday Evening Post magazine featured many of his
works spanning from 1916 until 1971 - from the middle of World War I and on
through World War II, Korea, and Vietnam. Summer, spring, fall, and winter;
Christmas, Easter, Veteran's Day, President's Day, Mother's Day, New
Year's, and other annual events; experiences of love, happiness, joy, surprise,
sadness, and a host of other emotions...
 Time to put on the thinking cap again for
three more "What's
Your EQ?" circuit challenges, compliments of Radio-Electronics magazine
in May 1962. The first is a classic "black box" type problem which, from reading
its description, involves some sort of resonant circuit. that's all I'll say on
that. The next, called "An Easy One?" should, by the way it is drawn, be a clue
that it might be easier to solve if you re-draw it to make a familiar-looking circuit.
Hint: Summons the spirit of Sir Charles Wheatstone. Just the name of the last one,
"Iterative Network," is enough to induce a cold sweat. As with most of these "What's
Your EQ?" problems, successful completion of a first year college circuits course
is plenty to get through them. A few are better attempted by people with hands-on
experience troubleshooting circuits, but don't let that scare you off...
 KR Electronics has been designing and manufacturing custom filters
for military and commercial radio, radar, medical, and communications since 1973.
KR Electronics' line of filters includes lowpass, highpass, bandpass, bandstop,
equalizer, duplexer, diplexer, and individually synthesized filters for special
applications - both commercial and military. State-of-the-art computer synthesis,
analysis, and test methods are used to meet the most challenging specifications.
All common connector types and package form factors are available. Update: KR Electronics
has been acquired by NIC, where KR Electronics'
legacy of quality and innovation will continue to thrive, offering the same trusted
products and services under NIC's leadership. For over three decades, NIC has delivered
high-quality component performance and reliability, ensuring the successful deployment
and operation of our clients' mission-critical solutions. Designed and manufactured
in the USA. Please visit NIC today to see how
we might be of assistance.
 Roger McCraw sent me these photos from his
assignement in U-Tapao, Thailand, cicra 1973. I submitted a couple of the images
to AI for colorization - amazing! Says Roger, "The pictures were taken at U-Tapao,
Thailand and are dated April 1973. I was there from Jan 73 till Jan 74
and was a 30351 in the 1985th Comm Squadron. Since I was the newbie I was selected
to change the light bulbs so I decided to give a Nixon peace sign for the photographer.
The MPN was on a turntable so it could service both approaches to the runway. The
ATC displays were in a trailer that was attached to a building, it was just to right
of truck in picture. I only remember the name of one person because his name is
listed on TWS website. He bought a four function calculator...
 This installment of the After Class series
in the December 1957 edition of Popular Electronics deals with inductors.
It is a beginner-level introduction to how
reactive components behave in circuits. For some reason the concept
of magnetism's influence on electrical current (present with inductors but not
capacitors) seems to be more difficult to comprehend than that of electrons, even
though James Clerk Maxwell shows in the mid 1800s that the two phenomena are interrelated.
I am tempted to say that back in the 1950s when this article appeared, people were
less familiar with the relatively new concept of electronics, but in thinking about
it, your typical 2019 reader is probably even less likely to know anything at all
about electronics or the way basic components work. I would bet that maybe 1% could
even tell you the difference between AC and DC current...
 Not very long ago I mentioned
Jean Shepherd (original assignee of W9QWN and later K2ORS call
signs) as being one of my favorite old-time radio broadcasters (1960s-1970s). Jean
was famous for recounting stories of his own life and for reporting news of the
time in a way that could hold you in rapt attention from beginning to end. His humor,
wit, and command of the English language was acknowledged by his contemporaries.
If you listen to enough of his broadcasts you will notice the frequent mention of
electronics and his experiences as a licensed amateur radio operator beginning at
a tender young age. Just recently I listened to him recount his first day in high
school when a SNAFU in the computer-generated (must have been a UNIVAC) class schedule
mistakenly had him reporting to the girls' swimming pool...
 I was born in the era of screw-in glass
fuses in household electric service panels. There was always a supply of replacements
in the cabinet above the stove. Sometime around 1978, prior to enlisting in the
USAF, I replaced the fuse panel with a Square D circuit breaker panel - a skill
learned through four years of electrical work. In the Air Force, I worked on a 1950s
era air traffic control radar system which consisted of many chassis assemblies
having fuse holders on their front panels. The racks themselves had a circuit breaker
panel, but it was a retrofit from sometime in the early 1970s. That was my introduction
into the wide variety of cylindrical glass fuses - high and low voltage, normal-,
slow- and fast-blow, time delay, etc. I learned of the reason why circuit designers
employed each type, and always used exact replacements when possible. Later, as
a circuit and systems design engineer myself, I always was careful to specify the
most
appropriate fuse type. This 1960 article in Radio-Electronics magazine
is a good primer on fuse handling...
 Being that this
Circuit Quiz appeared in a 1966 issue of Radio-Electronics magazine,
the amplifier components shown are transistors, rather than vacuum tubes. I have
to admit to not doing very well on it. One of the challenges is first determining
what the intended function of the circuit is supposed to be, then you figure out
what is wrong with it. Spoiler alert: I'm going to use circuit A as an example.
It is declared to be a voltage regulator circuit, and the deficiency is the lack
of a stable voltage reference. The architecture is typical of a voltage regulator
with the common base setup used to increase the current supply. However, there is
no reason to necessarily assume the DC IN is not itself already regulated, and the
function if merely to increase the current supply capacity. If that is the case,
then the circuit seems sufficient as shown. Maybe the fact that there is no problem
otherwise should tell you make an assumption about the designer's intention and
look for something that would be suspect under that condition. Anyway, that's my
excuse and I'm sticking with it ;-)
 This rather extensive article from a 1947
issue of QST magazine describes the method used by author Philip Erhorn
to experimentally determine optimum
spacing for the parasitic elements of his antenna. Unless you
have electromagnetic field simulation software available for designing antennas,
the procedure typically involves beginning with published formulas for element length
and spacing, then resorting to a cut-and-test method of finding a combination that
works best for your installation and goals. Almost certainly no two Hams end up
with identical configurations because differences in terrain...
 Since this is a presidential election year,
I figured it would be a good time to post a tongue-in-cheek- story that appeared
in the November 1952 issue of QST magazine about a fictional American president
J. Willoughby Winkelspoof. The American Radio Relay League
(ARRL) always has been and still is apolitical, so don't take seriously anything
you read here. If you are an astute follower of politics, you might pick up on the
nuances woven into the story, and might even marvel on how much the political landscape
has changed in the half century since Pres. Winkelspoof graced the Oval Office...
 This is Part II of a 3-part series of articles
on
magnetostriction devices. At audio and low IF frequencies, the
use of ferrite elements to construct relatively high-Q resonant circuits for filtering
was a big deal in the middle of the last century. Although not presented in this
article, design formulas and tables were published to implement the familiar Butterworth,
constant-k, Chebyshev, Gaussian, and other types. Tuning, particularly for higher
order filters, could be a chore since it involved a cut--and-try method on the ferrite
rods. However, that is what was available in the day, and it evidently worked well
enough to be worth the trouble for desired...
 Electronics World magazine often published
electronics-themed crossword puzzles. Unlike RF Cafe engineering crosswords
I created for two decades that use only technical words and clues, this one does
include some unrelated words. A couple clues I was surprised to see pertain to radar;
e.g., 32A: Small visible mark on a radar or scope screen, and 44A: Identification
Friend or Foe. Some words require a familiarity with technology of the era, but
you shouldn't have much trouble. You'll need to print this out on paper to work
it..
 Advances in
transformer technology are driven by the need for miniaturization and efficiency,
particularly in airborne and high-frequency military equipment. By optimizing core
materials and fabrication, engineers can significantly reduce the weight and physical
dimensions of transformers. A major technical milestone highlighted in this 1964
Electronics World magazine article, was the development of grain-oriented
silicon steel, which, through precise crystal alignment, offers superior magnetic
properties and reduced energy losses compared to traditional soft iron. Modern design
further mitigates power loss from hysteresis and eddy currents by employing thin,
insulated laminations...
 It didn't take much in the early days of
radio to capture the curiosity of consumers with buzz phrases like a "Mystic Hand"
to keep the radio tuned properly - really just AFC control, and a "Phantom Conductor"
circuit that boosted the volume of high level audio (a nonlinear amplifier). Here
are 4 more Radio Service Data Sheets from Radio-Craft magazine.
Crosley Model 1316 Radio Service Data Sheet,
Westinghouse Model WR 207 & WR 208 5-Tube Dual-Band Superheterodyne
Radio Service Data Sheet,
RCA Victor "High-Fidelity Electrola," Model R-99 Radio Service
Data Sheet...
 Back in the days when I built a lot of prototype
electronic gear, project enclosures were generically referred as a "Bud
Box." Lab stock rooms always had a good variety of sizes and configurations
of the soft aluminum and sometimes plastic boxes that were easily drilled, punched,
filed, and painted to make professional looking equipment. Not all the project boxes
were made by Bud Industries, but just as everyone knows you're talking about
a cola when you say "Coke," it was understood that a "Bud Box" was a chassis for
a home-brewed circuit. They are still seen in construction articles of electronics
hobby magazines today. I have even seen test equipment and utility items for sale
that are obviously in a Bud Box type of chassis. This full-page advertisement for
Bud Radio appeared in a 1930 issue of Radio Craft magazine - a mere two years after
opening their doors...
 This week's crossword puzzle sports a radar
and radio theme. All RF Cafe crossword puzzles are custom made by me, Kirt Blattenberger,
and have only 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...
 The
traveling-wave tube (TWT), invented by Dr. Rudolph Kompfner during World War
II, revolutionized microwave amplification by providing exceptional bandwidth without
the limitations of traditional resonant cavities. By utilizing an electron gun,
a precision-wound helix, and a magnetic focusing circuit, the TWT transfers energy
from an electron beam to a propagating signal wave. This design enables high-gain,
low-noise performance essential for radar, missile guidance, and high-capacity telecommunications
systems like the TH radio-relay. Although early production faced challenges regarding
reliability and manufacturing complexity, ongoing engineering refinements achieved
the stability necessary for critical applications, including the Telstar communications
satellite...
 Authors Cohen and Hessinger warn about the
need to consider the capacitive loading effects of shielded and closely-space test
leads when measuring other than direct current or very low audio or line frequencies.
Lead capacitance is especially likely to affect measured values
when the frequency is high and/or the source and load impedances are high. As was
common in the day, capacitance units of μμfd (micro-micro
farads = 10-6 x 10-6 = 10-12 F) are cited,
which is equivalent to units of pF (10-12 F)...
 An old electrician's saying goes "Ground is ground the world around," implying that every point
on Earth's surface is at the same potential - specifically 0 volts. We know, of
course, that it is not so. Maybe on average such a claim could be made, but just
as "sea level" is not the same at all points on the ocean's surface (hence we speak
of "mean sea level"), neither is the voltage potential the same everywhere. Further,
just as the salinity of all points on the ocean surface do not have the same salinity
(and thereby conductivity), the conductivity of various places on dry land vary
- often significantly. Electric power systems are very concerned with soil electrical
conductivity in the vicinity of power generation installations...
 Byron Goodman published a very thorough
diode
modulator article in a 1953 issue of QST magazine. It was one of the
first of such articles that used the very recently available semiconductor diodes
rather than the previously used vacuum tubes. Single-balanced bridge and ring modulator
circuits are presented, along with the theory behind their operation. It would be
a few years more before double balanced mixers with their abilities to reject even
intermodulation products, and triple balanced mixers with very high overall spurious
product rejection, would become commonplace...
 Back in the 1960s, Electronics Illustrated
magazine ran a series of monthly Q&A columns titled "Electronic
Brain," where readers wrote in to query the staff on particular quandaries.
Even if you have been in the electronics game for decades, there were plenty of
questions that probably invoked the "I'm sure I could have answered that at some
point, but it's been so long that I couldn't say for sure," thought. The magnetomotive
force topic in this set of three items did it for me. I knew there was a magnetic
flux equivalent of electric current flow, but I probably would not have been able
to write the equation using the precise...
 We are accustomed these days with stores
having "no questions asked" return policies for just about anything. I once watched
a guy successfully return a 4" PVC plumbing fitting that had clearly been smeared
with glue in the coupling areas. Another time a guy returned a painting drop cloth
that was full of paint, declaring that it wasn't what he wanted. The return counter
bins of Walmart and other stores are always chock full of stuff. Such was not always
the case, though. This episode of
Mac's Radio Service Shop, mentions, among other thing, how busy
he and sidekick Barney had been right after Christmas doing troubleshooting and
repair on various electronic equipment that had been received as gifts. Imagine
receiving...
 San Francisco Circuits, a leading printed
circuit board fabrication and assembly supplier serving commercial and defense markets,
today announced that it has achieved Final
Cybersecurity Maturity Model Certification (CMMC) Level 2 Certification
status following a successful independent assessment by an accredited Certified
Third-Party Assessment Organization (C3PAO). San Francisco Circuits Achieves CMMC
Level 2 Certification The certification confirms that San Francisco Circuits'
enterprise information systems meet the cybersecurity requirements outlined in NIST
SP 800-171 Revision 2, as codified in 32 CFR Part 170, for the protection
of Controlled Unclassified Information (CUI)...
|
 • Skyworks
Reports Nearly $1B in Q2 Revenue
• Price
Rises for Analog, Discrete and Passive Devices
• Apple-Intel Foundry Could
Reshape U.S. Chip Manufacturing
• China Loses Monopoly over
Rarest of Rare Earths
• Samsung
Memory Chip Worker Union Strike Averted
 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.
 Here is Part 1 of a three-part article on
attenuator pad and impedance matching articles that appeared in Radio-Craft
magazine. Although the focus is on audio frequencies, the principles apply in general.
It is interesting to read about wavelengths expressed in units of miles versus feet
and meters like we are used to seeing for radio frequencies. Keep in mind that most
of the decibel formulas used here are for voltage and not for power. 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? Confusingly, no...
 Earth-Moon-Earth (EME) communications have
been used by amateur radio operators for a few decades now, made possible by more
capable transmitters and receivers as well as digital encoding which facilitates
operation closer to the noise floor. EME is regarded largely as a novelty branch
of Ham radio since relatively few people are set up to exploit it. In 1946, the
U.S. Army Signal Corps created "Project Diana," named for the Roman moon goddess
Diana, as an experimental exercise to bounce radar signals off the Moon and receive
the reflected signals. It was the first attempt at radar astronomy and was the first
time a terrestrial radio signal was bounced off another celestial body. Once artificial
satellites were orbiting in the late 1950's, Hams and other entities were encouraged
to detect and track orbits and signal transmission properties - including frequency
and power - to aid government engineers and scientists in determining stability
(electrical and mechanical), speed, rotation, altitude, path, atmospheric and cosmological
noise sources, and other parameters...
 For some reason the "too clever by half"
saying (but not in an insulting way) comes to mind when reading this article about
color TV from a 1951 issue of Radio & Television News magazine. The
color television industry was still searching for an acceptable standard broadcast
format when this was written, and the electromechanical contraption was not considered
too elaborate considering the original color TV schemes were all a conglomeration
of whirling colored wheels, light sources, and photodetectors coupled with accommodating
timing and intensity signals. Because there was not agreement on what the final
commercial broadcast signal format would look like, there was not a lot of motivation
for test equipment makers to invest time and money into providing gear for research
and development laboratories. Do you remember the ads for the screen that installed
on the front of a TV set to convert black and white (B&W) to color...
 Early investigations into
RF signal atmospheric "ducting" was reported in this 1956-era article in Popular
Electronics. Ducting effects were first noticed during World War II when Nazi
broadcasts from occupied Paris were received occasionally in London. Scientists
discovered that a small change in the humidity of the air near the surface has the
effect of trapping radio waves, a trapping process dubbed "ducting." These waves
are conducted as if they were inside of a metallic waveguide. Research by the U.S.
Army Signal Corps determined a sudden temperature rise at around 50 to 200 feet
above the surface appears to have the strongest effect...
 August 16th's custom
Electrical 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.
 Barney, Mac McGregor's trusted technician
sidekick, would be in a heap of trouble in today's workplace. His complimentary
and sincere remarks to office secretary Matilda are considered as harassment and
even misogynistic by current standards. The unintended consequences - or maybe they
are intended - has been to cause tense and guarded environments where traditional
interpersonal behaviors and attitudes are avoided rather than risk offending someone
and paying a steep price for it. Mentioned in this "Tape
Recorder Tips" from a 1958 issue of Radio & TV News magazine
is the chemical compound carbon tetrachloride, aka carbon tet. At one time is was
commonly used as a cleaning agent because of its ability to efficiently clean oily
and fatty residues. Tape recorder heads, rubber drive wheels, and metal guide posts
get gunked up fairly quickly...
 As radio equipment builders and operators,
we still battle two fundamental issues that have been around since the beginning
of time (well, from Marconi's time, anyway) -
grounding and power supply fluxuations. Both topics are addressed briefly here
in this editorial column from a 1932 The Wireless World magazine. Back
in the day, grounding was referred to as "earthing," and was/is essential to optimal
wireless and wired performance. Line voltage fluxuations are generally much less
severe today than in the 1930s thanks to better transformers, automated monitoring
and adjusting of line voltages, and better distribution designs. The worst type
of power line fluxuation - a lightning-induced surge - has been greatly reduced
thanks to superior engineering, primarily by the simple running of a grounded neutral
"static" wire running at the top of all the lines below it on utility poles and
transmission towers...
 August 30th's custom
Radio & Radar themed crossword puzzle contains only only words from my custom-created
lexicon related to engineering, science, mathematics, chemistry, physics, astronomy,
etc (1,000s of them). 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.
 Here's one last thing to do before you
leave work for the weekend. This "Polarity
Quiz" by Robert Balin appeared in a 1968 issue of Popular Electronics.
If you know your left- and right-hand rules for magnetism and induction, then a
100% score is practically guaranteed... provided you also are a whiz at diode and
meter connections. Since the author did not do so, I provided brief explanations
for the answers at the bottom of the page. When applying the hand-rules, assume
conventional current (flow from more positive to more negative), not electron current.
 Prior to the availability of affordable
synthesized transceivers under microprocessor control, Ham radio operators needed
to tune a continuously variable local oscillator (internal or external) or have
a selection of crystals for specific frequencies. Even by 1982 microprocessors were
relatively expensive, so equipment incorporating them was also pricey. Heathkit's
model
SS-9000 transceiver claimed to be designed by amateurs for amateurs, and was
"so feature-conscious, it has no options." That's right, anything and everything
that could be imagined was included in the base model; there we no upgrades. It
used a high accuracy and stability internal 10 MHz reference oscillator for
the PLL synthesizer. Also incorporated was an RS-232 serial port for control via
computer (up to 9600 baud!), such as the Heathkit/Zenith personal computer (the
IBM PC had hit the market in the prior year, and the the Radio Shack TRS-80
and Apple II had been around since 1977). The SS-9000 was solid state throughout
(likely where the "SS" prefix originated)...
 Author Lawrence Sharpe pointed in 1955
in this Radio & Television News article the potential for confusion
when reading columns and advertisements written by our brothers from Across the
Pond when they appeared in American electronics magazines. Most of us are familiar
with valve vs vacuum tube, bonnet vs. hood (car), football vs. soccer, fag vs. cigarette,
holiday vs. vacation, nappy vs. diaper, petrol vs. gasoline, torch vs. flashlight,
flat vs. apartment. There are many more, but those come to mind. Read through this
short list of purely electronics terms and learn that
"earthed" is the same as our "grounded." One thing that surprised me was how
the Brits had already adopted pico (e.g. pF) for the numerical unit of 10-12
while we were still using micromicro (10-6 x 10-6 = 10-12,
e.g., μμF). Note how I omitted a comma... After Class: Explaining Tuned Circuits
 Fundamentals of
resonant tank circuits has not changed since they were first investigated more
than a century ago. This "After Class" tutorial that ran in the May 1961 edition
of Popular Electronics is typical of the series where the author speaks
as though he was giving an impromptu lesson to a gathering of students after the
scheduled classroom period was over or, in this instance as though he was having
a casual discussion with a friend who was perplexed by a particular electronics
phenomenon. Figures and equations are often drawn by hand to augment the informal
setting rather than being typeset. Here, "Larry" is amazed by the great performance
of his Ham radio with its ability to filter out adjacent channel interference. Mentor
"Ken" takes the opportunity to explain the mathematics and physics of resonant circuits
both to tuning antennas...
 What better subject is there to post on
the birthday of Dr. Lee de Forest than an article entitled, "Three
Anecdotes of the Audion's Early Days," which appeared in the January 1947 issue
of Radio-Craft magazine whose theme was the 40th anniversary of the Audio's invention?
That was a rhetorical question, of course, sort-of, because any of the multiple
Audion article from that issue would be a great subject. Find out from the man who
coined the term how the vacuum tube's grid was named. Did you know that thanks to
lawsuits and unscrupulous actions by competitors, that de Forest went through
multiple cycles of plenty and near poverty? In a related note, as chronicled in
"Lee de Forest and the Navy," faced powerful skeptics when attempting to facilitate
adoption of wireless communications aboard U.S. Navy ships - not unlike the Wright
Brothers' struggles with convincing the U.S. Army of their aeroplane's usefulness
in armed conflict...
 Here is a very basic
introduction to schematic reading from the August 1955 edition of Popular
Electronics.. To someone who has been exposed to schematics and mechanical
drawings for five decades, reading them is second nature. However, to the newcomer
to electronics, it can be a bit cryptic. It is the equivalent of handing someone
who has never read sheet music from Beethoven's 5th and asking him to make sense
of it. Of course there is a lot more to schematics than presented here, but you
have to begin somewhere...
 While company branding and the user interface
have changed over the years since
AppCAD first appeared on the Hewlett Packard (HP) website, it is still as handy
a desktop tool as ever. The most recent incarnation was provided by Avago Technologies,
which bought Broadcom in 2015 and then adopted its name. You can now download a
free copy of AppCAD from the Broadcom website. Rather than do an extensive write-up
about all the calculation screens in AppCAD, I've posted a sampling of screen shots.
Amongst them are a Smith chart s-parameter plotter, a lumped element balun designer,
a microstrip calculator, a mixer spurious product calculator, and thermal dissipation
calculator... |
