See Page 1 |
2 |
3 |
4 |
5 | of the August 2020 homepage archives. Monday 31
 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...
 NorthEast RF's comprehensive
antenna testing
services include linear | circular polarized antenna measurements and OTA cellular
device pre-compliance. Up to 18" diameter and <10 kg weight. Antennas can be
rapidly evaluated and optimized using our fast near field spherical system. Test
results supplied in data file with pattern viewer software. A picture of the test
configuration is included to help aligned axis. Our selection of human head and
hand phantoms are ideal for verification of body worn devices. Turnaround time is
usually 3-days.
 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...
 Darrel Emerson, AA7FV, G3SYS, has
an article in the ARRL's QEX magazine entitled, "Patterns
and Polarizations of Modestly-Sized Loop Antennas," which might be of interest
to you. Inexpensive antenna field pattern software like
EZNEC make experimentation very practical.
"Patterns and polarizations of square loops up to about 0.4 wavelengths in perimeter
are examined." "In 'Small Gap-resonated HF Loop Antenna Fed by a Secondary Loop1,'
K. Siwiak, KE4PT, and R. Quick, W4RQ, provide improved formulas for loop current
and impedance, leading to an accurate determination of far-fields and null depths
for loops up to 0.3 λ (wavelengths) in circumference. See also, KE4PT and W4RQ,
'Small Gap-Resonated HF Loop Antennas.' In 'Effect of Small HF Loop Near Fields
on Direction Finding,' KE4PT shows how the near-field response of a small loop can
provide polarization at right angles to the normal far field..."
 There
 they go again. The same Federal Government
that delivers
billions of dollars in cash in the middle of the night to terrorist nations
and hands out grants to every whacko special interest group now wants to
charge Amateur Radio Operators a $50 licensing fee. What an excellent way to
discourage participation in an educational and public service technical sport whose
members volunteer incredible amounts of talent and equipment at no cost to taxpayers. "The
$50 fee would apply to all Amateur Service applications, including those for vanity
call signs. 'Although there is currently no fee for vanity call signs in the Amateur
Radio Service, we find that such applications impose similar costs in aggregate
on Commission resources as new applications and therefore propose a $50 fee,' the
FCC said." It's time to write to your Senators and Congressmen. BTW, the FAA
has already implemented a similar licensing fee scheme to model airplane sportsmen.
 ConductRF is continually innovating and
developing new and improved solutions for RF Interconnect needs. See the latest
TESTeCON RF Test Cables
for labs. ConductRF makes production and test coax cable assemblies for amplitude
and phased matched VNA applications as well as standard & precision RF connectors.
Over 1,000 solutions for low PIM in-building to choose from in the iBwave component
library. They also provide custom coax solutions for applications where some standard
just won't do. A partnership with Newark assures fast, reliable access. Please visit
ConductRF today to see
how they can help your project!
Sunday 30
 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.
Friday 28
 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.
 "Amazon cleared an important hurdle when
the U.S. FCC announced on 30 July that the company was authorized to deploy and
operate its
Kuiper satellite constellation.. The authorization came with the caveat that
Amazon would still have to demonstrate that Kuiper would not interfere with previously
authorized satellite projects, such as SpaceX's Starlink. Even with the FCC's caveat,
it's tempting to imagine that the idea of putting a mega-constellation of thousands
of satellites in low-Earth orbit to provide uninterrupted broadband access anywhere
on Earth will become a battle between Jeff Bezos' Kuiper and Elon Musk's Starlink.
After all, even in space, how much room can there be for two mega-constellations..."
 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)...
 Scott Roleson, KC7CJ, had an article
printed in the July-August issue of QEX magazine entitled, "Receiver
Step Attenuator." It is the one free to the public article posted each month.
QEX tends to have more construction features and be a bit more theoretical
than QST. He begins, "This step attenuator is an easy way to improve a
receiver's handling of strong signals and to add signal diagnostic capability. Having
been bitten by the software defined receiver (SDR) bug and experimenting with simple
SDR 'dongles' and an HF converter, it didn't take long for me to start thinking
of ways to improve this simple receiver. It was readily apparent that an HF receiver
like this was wide open to strong signal overload from commercial broadcast signals
and even from the ham across town. One way to deal with strong signal overload is
to add a broadband attenuator between the receiver and the antenna..."
 Skyworks is pleased to introduce a high
linearity, low-threshold,
dual PIN limiter diode module that addresses the growing need for receiver protection
in cellular infrastructure (including 5G) and microwave radio communications. The
SKY16603-632LF is a fully integrated module comprised of two PIN limiter diodes
and two DC blocking caps designed for use as a passive receiver protector in wireless
systems up to 6 GHz. Targeted for cellular infrastructure base station, repeater,
and wireless backhaul OEMs, it can also be used in broad market wireless systems
including VSAT, S-band radar, military communications transceivers... Be sure to
also see their
PIN Limiter Diode Design Guide.
 Copper Mountain Technologies develops
innovative and robust RF test and measurement solutions for engineers all over the
world. Copper Mountain's extensive line of unique form factor
Vector Network Analyzers
include an RF measurement module and a software application which runs on any Windows
PC, laptop or tablet, connecting to the measurement hardware via USB interface.
The result is a lower cost, faster, more effective test process that fits into the
modern workspace in lab, production, field and secure testing environments.
Thursday 27
 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...
 "The U.S. Army's tactical network program
office expects to reap the full benefits of low-and medium-Earth
orbit satellite constellations in the 2025-2027 time frame, the head of the
office said August 18. Speaking on a webinar hosted by the Defense Advanced Research
Projects Agency, Brig. Gen. Rob Collins, program executive officer at Program Executive
Office Command, Control, Communications-Tactical, said the two constellations types
offer 'game-changing technologies' that will likely be fully mature and ready for
soldier use in Capability Set '25 or '27, the two-year cycle of new network tools
the service is fielding. One of the connectivity benefits of the LEO and MEO constellations
in the field, Collins said, is that they can allow for..."
 Anatech Electronics offers the industry's
largest portfolio of high-performance standard and customized
RF and microwave filters and filter-related products for military, commercial,
aerospace and defense, and industrial applications up to 40 GHz. The AE15550B10783
5G cavity bandpass filter has a passband range from 15350-15750 MHz, with an insertion
loss of less than 1 dB in the passband. It can handle up to 150 W of power with
a rejection of more than 50 dB at 11000 MHz and more than 40 dB at 20000 MHz. The
AD6981-9800C131 combines the 6875-7087 MHz and 9600-10000 MHz bands. The bandpass
filter exhibits a small package and a steep rejection above and below the passband.
Insertion loss in the passband is less than 3 dB and more than 40 dB at the rejection
frequencies. Custom RF power directional coupler designs can be designed and produced...
 Jason Smith, engineer and owner of
Absolute EMC, requested that his company
be listed on the
Technical
Services page here on RF Cafe, which I was glad to do. Along with an extensive
array of EMC industry products, there is an online calculator page that includes
one for TEM/GTEM
Cell fields and another for
Antennas.
"Absolute EMC is a North American company specializing in EMC testing knowledge
and equipment. We offer consulting services for the use of all EMC & RF test
equipment. This includes standards training, equipment training, and system building.
With extensive background knowledge with all brands and available technologies.
Also offering insight and market knowledge into equipment sales."
 The ARRL's QEX monthly magazine
usually makes one full article available online to all visitors, as opposed to the
full edition only being available to subscribers. This is a good policy since it
protects the investment of paying customers while providing a useful sample of content
to the public. The December 2018 issue featured a piece by Dave Leeson, W6NL, entitled,
"The
Story of the Broadband Dipole." It begins: "A dipole can be broadbanded by a
number of techniques including by matching with resonant sections of transmission
feed lines. The 80-meter amateur band covers a very large fractional bandwidth.
I was looking for a way to avoid retuning my 80-meter inverted V on a 140-foot guyed
tower, since the ends are out of reach even if they are folded straight down. I
found that lumped element matching networks or the often referenced Bazooka dipole
and other forms of thicker conductors were neither practical nor effective for me
at the lower HF bands.1 In a November 1997 posting on the Tower Talk..."
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...
 Atenlab has been operating in Taiwan for
more than a decade, and has sold and installed hundreds chambers around the world.
Holistic, affordable Over-the-Air (OTA) measurement
systems perform comprehensive measurement and test in a controlled environment.
Compact Antenna Test Range (CATR) with one-touch operation supports multiple systems
- 2G, 3G, 4G, 5G - and major instrument brands. [M]ulti-probe OTA measurement systems
offer reduced time measurements over single-probe systems.
Wednesday 26
 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...
 Guerrilla RF introduces the
GRF5507, one of ten new ¼ W linear power amplifiers being released over
the next two quarters as part of the company's expansion into the cellular market.
These new InGaP HBT amplifiers were designed specifically for 5G/4G wireless infrastructure
applications requiring exceptional native linearity over temperature extremes of
-40°C to 85°C. Spanning a frequency range of 700-800 MHz, the GRF5507 variant
is tuned to operate within the n12, n14, n28 and n29 5G new radio (NR) bands. The
device can deliver over 24 dBm of linear power over the entire -40°C to 85°C
temperature range...
 If this device used chromium oxide, would
that make it a "Cro-Magnon" switch? "Researchers have demonstrated a potentially
new way to make switches inside a computer's processing chips, enabling them to
use less energy and radiate less heat. The practical technique controls magnons,
which are essentially waves that travel through magnetic materials and can carry
information. To use magnons for information processing requires a switching mechanism
that can control the transmission of a
magnon signal through the device. While other work created techniques that carry
and control magnons, the new approach brings two important firsts: Its elements
can be built on silicon rather than exotic and expensive substrates..."
 PCB Directory is the largest directory of
Printed Circuit Board (PCB) Manufacturers,
Assembly houses, and Design Services on the Internet. We have listed the leading
printed circuit board manufacturers around the world and made them searchable by
their capabilities - Number of laminates used, Board thicknesses supported, Number
of layers supported, Types of substrates (FR-4, Rogers, flexible, rigid), Geographical
location (U.S., China), kinds of services (manufacturing, fabrication, assembly,
prototype), and more. Fast turn-around on quotations for PCB fabrication and assembly.
 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...
 Russia recently declassified and released
to the public information and a video of testing of what was (and still is) the
largest nuclear bomb ever detonated -
Tsar Bomba (aka "Ivan").
The graph shows the comparative sizes of
 nuclear
bombs detonated by the USA and Russia during testing. That little circled area in
the lower left represents the Hiroshima and Trinity bombs. On the right is the massive
Tsar Bomba hydrogen bomb. At 50 megatons, it was 3300x the power of the 15 kiloton
Hiroshima (Little Boy) explosion
on the left. Ivan's length of 26' and 7' diameter dwarfed Little Boy's 10' length
and 28" diameter. Ivan created a mushroom 7x the height of Mount Everest. Tsar Bomba
represents 1961 technology. Nowadays, explosions are done by supercomputer simulations.
Imagine what 2020 science can produce - scary.
 Triad RF Systems designs and manufactures
RF power amplifiers and systems.
Triad RF Systems comprises three partners (hence 'Triad')
with over 40 years of accumulated knowledge of what is required to design, manufacture,
market, sell and service RF/Microwave amplifiers and amplifier systems. PA, LNA,
bi-directional, and frequency translating amplifiers are available, in formats including
tower mount, benchtop, rack mount, and chassis mount. "We view Triad more as a technology
partner than a vendor for our line-of-sight communications product line." Please
check to see how they can help your project.
Tuesday 25
 The famous words of Jorge Agustín Nicolás
Ruiz de Santayana y Borrás (aka George Santayana) immediately came to mind when
I saw this Bell Telephone Laboratories advertisement in a 1955 issue of Radio &
Television News magazine: "Those who cannot remember the past are condemned
to repeat it." Anyone involved in the electronics field at the beginning of the
lead-free (Pb-Free) craze in the early 2000's probably remembers the purportedly
unexpected phenomenon of
tin whiskers growing out of lead-free solder joints and wreaking havoc with
the short circuits caused when whiskers between adjacent elements made contact.
The problem appeared with closely spaced connector pins, fine pitch integrated circuit
packages, high density surface mount circuit board layouts, etc. Military and aerospace
engineers and scientists had fits initially trying to figure out what was going
on...
 Part 3 of a 6-part series of articles on
phased arrays by Peter Delos, Jon Kraft, Bob Broughton
is about Linear-Array Beam Characteristics and Array Factor, and is available
on the Microwaves & RF website. "In Part 1, we covered beam
direction and working with a uniformly spaced linear array of antennas. Part 2 focused
on antenna gain, directivity, and aperture, as well as array factors. In Part 3,
we'll dive into beamwidth, combining element and array factors, and antenna plots.
Beamwidth Beamwidth provides a metric of angular resolution for antennas. Most commonly,
beamwidth is defined by either the half-power beamwidth (HPBW) or the null-to-null
spacing of the main lobe (FNBW). To find the HPBW, we move 3 dB down from the peak
and measure the angular distance..."
 "Aalto University researchers have developed
a
black silicon photodetector that has reached above 130% efficiency. Thus, for
the first time, a photovoltaic device has exceeded the 100% limit, which has earlier
been considered as the theoretical maximum for external quantum efficiency. 'When
we saw the results, we could hardly believe our eyes. Straight away we wanted to
verify the results by independent measurements,' says Professor Hele Savin, head
of the Electron Physics research group at Aalto University. The independent measurements
were carried out by the German National Metrology Institute, Physikalisch-Technische
Bundesanstalt (PTB), which is known to provide the most accurate and reliable measurement
services in Europe. Head of the PTB Laboratory of Detector Radiometry, Dr. Lutz
Werner comments, 'After seeing the results, I instantly realized that this is a
significant breakthrough..."
 Once mobile and other high-vibration and
impact operational environments became the norm for communications, it became necessary
to design hardware so that electronic components would not work themselves loose
and cause intermittent or total failure. With vacuum tubes, placing locking shields
over them did the job, but that caused other issues such as increased cost, poor
cooling, and increased chassis size and weight. Some circuits with high power and/or
frequency benefited from shields, but most did not need them. Sylvania introduced
a scheme called "Lock-In" (trademark name of "Loktal")where
the center pin incorporated a circumferential groove that latched into a capturing
mechanism...
 Editor emeritus of Microwaves &
RF magazine Barry Manz has an interesting article on the Microwave Product
Digest (MPD) website entitled, "NIST's
Key Role in 5G Development." NIST is the new name (as of 1988) for the National
Bureau of Standards, which was first instituted in 1901. He begins, "The National
Institute of Science and Technology (NIST) may be the most underappreciated player
in the development and advancement of systems that rely on electromagnetic energy.
Its role today is arguably as important as at any time in its 119-year history,
as the wireless industry moves into uncharted territory. For example, researchers
at NIST recently used state-of-the-art atomic clocks, light detectors, and a measurement
tool called a frequency comb to increase the stability of microwave signals by 100
times. This should enable much more accurate dissemination of time, improved navigation,
more reliable communications, and higher-resolution imaging for radar and astronomy.
The approach transfers the stability of a laboratory ytterbium lattice atomic clock
operating..."
 RF Cascade Workbook 2018 is the next phase in the evolution
of RF Cafe's long-running series, RF Cascade Workbook. Chances are you
have never used a spreadsheet quite like this. It is a full-featured RF system cascade
parameter and frequency planner that includes filters and mixers for a mere $45.
Built in MS Excel, using RF Cascade Workbook 2018 is a cinch and
the format is entirely customizable. It is significantly easier and faster than
using a multi-thousand dollar simulator when a high level system analysis is all
that is needed. An intro video takes you through the main features...
 Please take a few moments to visit the
everythingRF website to see how they can assist you with your
project. everythingRF is a product discovery platform for RF and microwave products
and services. They currently have 267,269 products from more than 1397 companies
across 314 categories in their database and enable engineers to search for them
using their customized parametric search tool. Amplifiers, test equipment, power
couplers and dividers, coaxial connectors, waveguide, antennas, filters, mixers,
power supplies, and everything else. Please visit everythingRF today to see how
they can help you.
Monday 24
 The January 1947 issue of Radio-Craft
magazine was dedicated to editor Hugo Gernsback to articles celebrating the 40th
anniversary of his personal friend Lee de Forest's invention of the Audion
amplifying vacuum tube. Click on the Table of Contents link to access many of the
other articles - all of which are very insightful into the many amazing activities
of Mr. de Forest. Many of the articles were written by friends and business
associates of him. The "radiophone"
addresses here is actually one of the earliest mobile phone, being interconnected
by radio signals rather than a twisted pair of wires. Take note of the "flame audion"
mention, which believe it or not describes de Forest's earliest experiments
which used a pair of salted platinum plates embedded in an actual flame. Yes, that
actually constituted an amplifying element...
 "Electronic filters are essential to the
inner workings of our phones and other wireless devices. They eliminate or enhance
specific input signals to achieve the desired output signals. They are essential,
but take up space on the chips that researchers are on a constant quest to make
smaller. A new study demonstrates the successful integration of the individual elements
that make up
electronic filters onto a single component, significantly reducing the amount
of space taken up by the device. Researchers at the University of Illinois, Urbana-Champaign
have ditched the conventional 2-D on-chip lumped or distributed filter network design
- composed of separate inductors and capacitors - for a single, space-saving 3-D
rolled membrane that contains both independently designed elements. The results
of the study, led by electrical and computer engineering professor Xiuling Li..."
 Source Today has published the
2020 Top 50 Electronics Distributors list. This linked PDF file gives a rundown
on a few of the companies, with a complete tally on the last page. Ranking is evidently
according to total revenue. Arrow Electronics takes top prize with nearly $29B in
sales, and Avnet comes in second at $18B - that's a huge gap. Digi-Key takes 5th
place with $2.8B, and Mouser takes #7 at $1.9B. Richardson Electronics gets 21st
place with $167M, and March Electronics hits 41st at $30M. Bringing up the rear
is Marine Air Supply at a paltry $18M. So goes the 2020 rankings.
 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.
 Here is a short tutorial on how to construct
a
¼-wave stub "trap," or filter to attenuate even-order harmonics from transmission
lines. It applies whether the transmission line is feeding an antenna or is a section
of copper foil running on a microwave substrate. Author Kent Mitchell (W3WTO) discusses
both an open stub and a shorted stub. In case you are not familiar with how quarter-wave
transmission lines stub work, a short at the far end appears as an open circuit
where the stub connects to the main transmission line, and an open stub line appears
as a short circuit. That is because there is a 180° phase shift at the end of the
shorted stub and a 0° phase shift at the end of the open stub. Therefore, there
is a total of 360° (i.e., 90°+180°+90°=360°, equivalent to 0°) with the shorted
¼-wave stub so it has no effect where it attaches to the main transmission line.
The open stub experiences no phase shift...
 Peter McNeil has an article on the
High Frequency Electronics website entitled, "Considerations
for Very-High-Frequency Connectors in Defense Systems." He begins, "Of the hundreds
of different environments in which microwave coaxial cables and connectors are used,
defense systems are probably the most demanding. They're handled by people who don't
realize they're not just 'wires,' but technically sophisticated, precision components.
After all, they're warfighters, not microwave engineers. So, they're run over by
heavy vehicles, used as a handy way to pull equipment carts, and exposed to chemicals,
fuels, saltwater, and many other hazards. Aging and various environmental factors
are major contributors to the failure of cables and connectors, but it is arguable
that most of the damage is done by the people who use them. That's why, according
to one assessment, about 75% of microwave cable assemblies are replaced frequently..."
 KR Electronics designs and manufactures
high quality filters for both the commercial and military markets. KR Electronics'
line of filters includes lowpass,
highpass, bandpass, bandstop 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. Please visit their website today to
see how they might be of assistance. Products are designed and manufactured in the
USA.
Sunday 23
 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.
These archive pages are provided in order to make it easier for you to find items
that you remember seeing on the RF Cafe homepage. Of course probably the easiest
way to find anything on the website is to use the "Search
RF Cafe" box at the top of every page.
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