See Page 1 |
2 |
3 |
4 | of the April 2023 homepage archives. Sunday the 30th
 This custom RF Cafe
electronics-themed crossword puzzle for April 30th contains words and clues
which pertain exclusively to the subjects of electronics, science, physics, mechanics,
engineering, power distribution, astronomy, chemistry, etc. Every other row has
words beginning with "R" and "F." If you do see names of people or places, they
are intimately related to the aforementioned areas of study. As always, you will
find no references to numbnut movie stars or fashion designers. Need more crossword
RF Cafe puzzles? A list at the bottom of the page links to hundreds of them dating
back to the year 2000. Enjoy.
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 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.
Friday the 28th
 Here is an excellent example of how scientific
evaluations performed by two independent subject experts can result in significantly
different conclusions. James Gupton, Jr., reports on what previously had been considered
secret military technology - an
active, electrically small receiving antenna. This particular example, dubbed
the Mini−Tenna, is designed for use on the FM radio band. After building and testing
his antenna, Mr. Gupton offered it to two Radio-Electronics magazine
editors for investigation. Each used a carefully considered method in what are generally
similar environments - urban dwelling with strong signals and opportunity for multi-path,
connected to a commercial FM radio receiver. The divergent results were not commented
upon by the author. As a side note, I still have a 1980s vintage active FM radio
antenna from Radio Shack...
 Apparently SDR now also stands for
Software-Defined Radar, not jut Software-Defined Radio. "Radar systems are increasingly
important in many industries. However, as they carry out complex techniques, they
need transceivers that can meet their needs. Software-defined radio provides a versatile
and effective solution. Radar (or radio detection and ranging) systems are precise
and versatile RF instruments that have become indispensable for many industries,
playing a significant role in shaping the modern world. From military operations
to air traffic control, these systems are now the main tools for monitoring and
tracking objects in motion. Naturally, development of novel radar techniques and
devices requires significant resources. However, complex techniques involving multiple
channels and anti-jamming waveforms can’t be easily performed using traditional
RF transceivers..."
 The
U.S. Army's Signal Corps was set up to "exercise supervision over signal communications
literally from the Pentagon to the foxhole." Created in 1860 at the suggestion of
a military doctor, the Signal Corps originally used a system of flag waving for
messaging dubbed "wigwag" and graduated to overseeing the nationwide telegraph network
six years later. By 1870, members were tasked with establishing and operating a
weather forecasting service, so in 1907 when they created an aeronautical division
it was just in time for facilitating the nation's rapidly growing cadre of aircraft
pioneers (recall the Wright brothers had flown four years earlier at Kitty Hawk)
by providing en route weather information. Having already mastered the state of
the art that was radio and telephone by 1937, the Signal Corps then undertook the
challenge of a sophisticated new technology called "radar." Their motto is "Watchful
for the Country." This is the first of four articles...
 Innovative Power Products (IPP), with more
than 30 years of experience designing & manufacturing RF & microwave passive
components, introduces a line of
RF Feedback Resistors for Solid-State Amplifiers. IPP's line of Feedback Resistors
are designed to support wideband RF/Microwave solid-state transistor power amplifiers,
which require resistive feedback. Using negative resistive feedback is a simple
way to improve transistor amplifier stability and frequency gain sloping. These
feedback resistors are flange mounted and designed to fit directly over the RF/microwave
transistor using the same mounting holes as the transistor. This mounting configuration
utilizes normally unused space above the transistor without taking up valuable PCB
area adjacent to the transistor. This also decreases parasitic inductance associated
with resistor leads...
 This story reads like an infomercial for
IBM, which it just might be. Infomercials were still a little used marketing scheme
in 1957 when this piece appeared in Popular Electronics magazine, so IBM
was ahead of its time. The answer to the article's title, "How
Far Can You Go in Electronics Without a Degree?" was the same 66 years ago as
it is today: As far as your intellect and ambition will take you. Back then, as
with today, few people could rise to the level of design engineer without a college
degree. However, there are many aspects of electronics that require no formal education
at all if you possess the requisite skills - with or without the title of engineer.
However, I disagree with the feel-good line that "you can be anything you want to
be." Some people simply cannot achieve the mastery necessary to do a particular
job, regardless of how hard they try...
 This assortment of custom-designed themes
by RF Cafe includes T-Shirts, Mouse Pads, Clocks, Tote Bags, Coffee Mugs and Steins,
Purses, Sweatshirts, and Baseball Caps. Choose from amazingly clever "We Are the World's
Matchmakers" Smith chart design or the "Engineer's Troubleshooting Flow Chart."
My "Matchmaker's" design has been ripped off by other people and used on their products,
so please be sure to purchase only official RF Cafe gear. My markup is only a paltry
50¢ per item - Cafe Press gets the rest of your purchase price. These would make
excellent gifts for husbands, wives, kids, significant others, and for handing out
at company events or as rewards for excellent service. It's a great way to help
support RF Cafe. Thanks...
 Exodus Advanced Communications is a multinational
RF communication equipment and engineering service company serving both commercial
and government entities and their affiliates worldwide. Power amplifiers ranging
from 10 kHz to 51 GHz with various output power levels and noise figure
ranges, we fully support custom designs and manufacturing requirements for both
small and large volume levels. decades of combined experience in the RF field for
numerous applications including military jamming, communications, radar, EMI/EMC
and various commercial projects with all designing and manufacturing of our HPA,
MPA, and LNA products in-house.
Thursday the 27th
 Ever the enthusiastic futurist, Radio-Electronics
magazine editor Hugh Gernsback laid out the need for and predicted the implementation
of an electronically broadcast form of newspaper publishing. He states, "In this
electronic-automation age, physical newspapers, that must be printed at a central
plant, then distributed by trucks to newsstands, or mailed or transported by rail
or air to distant cities, are an anachronism. They are wholly unnecessary and economically
suicidal." That was in 1963, when he discussed the technology "RAFAR" (from
Radio Automated Facsimile And Reproduction). Facsimile (fax) machines were already
in use with signals being transferred over telephone lines. My first question was
how is the entire newspaper content made available on demand by multiple users?
There was no means of electronically storing that much information other than on
magnetic tape. The RAFAR scheme had a miniature version of the newspaper printed
on paper, then the reader scrolled through the paper while viewing a magnified image
projected on a glass screen - akin to a microfiche machine. Magnetic storage could
have been used...
 "The golden parts of the device depicted
in the above graphic are transformable, an ability that is 'not realizable with
the current materials used in industry,' says Ian Sequeira, a Ph.D. student. UC
Irvine physicists have discovered
nano-scale electronic devices that can change shapes and sizes in solid states,
potentially revolutionizing electronic devices and atomic-scale quantum material
research. The devices, made of graphene sheets and gold wires, enable flexible and
dynamic movement on van der Waals material surfaces. The nano-scale electronic parts
in devices like smartphones are solid, static objects that once designed and built
cannot transform into anything else. But University of California, Irvine physicists
have reported the discovery of nano-scale devices that can transform into many different
shapes and sizes even though they exist in solid states..."
 I challenge you to find a calculus lesson
in a modern-day electronics magazine. In 1932, not all that long after Isaac Newton
developed differential calculus (that's a joke), Radio News magazine ran
a series of "Mathematics
in Radio" articles that included, among other topics, a few lessons in calculus.
Anyone who has taken college-level science or engineering courses knows how indispensible
calculus is in working out many circuit, physics, and chemistry problems. My appreciation
for calculus came when I realized that it actually allowed me to derive the kinds
of standard equations that are commonly seen in lower level applications. For instance,
if you needed to know the volume of a sphere, you could look up the familiar Volume = 4/3 π r3
formula, or you could write the equation Volume =
 . Area, mass, center
of mass, and length of a spiral line, are other examples of problems that can be
solved by knowing the fundamental mathematics behind the equations...
 Modelithics, the leading provider of highly
accurate RF/microwave simulation models, and MathWorks, the leading developer of
mathematical computing software, announced the launch of the new
Modelithics SELECT+ Library for free use to MATLAB® and Simulink® customers.
This product is a direct result of Modelithics joining the MathWorks Connections
Program, a group of third-party organizations that develop and distribute commercially-available
products that are complementary to the MathWorks product line. The Modelithics SELECT+
Library is a collection of Modelithics Microwave Global Models™ for passive devices,
including capacitors, inductors, and resistors. Microwave Global models are highly
scalable models that are developed using specialized measurements covering a range
of test conditions. All Modelithics models contain a detailed model datasheet that
lists recommended model validity parameters, measurement and test fixture details,
and model-to-measurement data comparisons...
 Did you know that the
Hallicrafters line of radios is named after founder Bill Halligan (W9WZE)? Hallicrafters,
founded in 1932, was a major manufacturer of amateur radio gear. During the years
of WWII they ruggedized some of their products to survive the harsh environments
of battle. Hallicrafters was sold to Northrop Corporation in 1966, at which time
the product line essentially ceased. Their gear is still very collectible by aficionados
of vintage Ham equipment. This story from the February 1943 QST magazine
provided an inside look at the production floor at Hallicrafters. Having cut my
figurative electronics teeth on radar and radio equipment built with tubes and point-to-point
wiring while in the USAF, and then later as an assembly/test technician at Westinghouse
Electric building sonar equipment for the Navy which included wiring chassis and
building large complex cable harnesses, I can personally relate to the photos accompanying
the article. When, for readers in the U.S., is the last time you saw a company touting
its "expert American craftsmen...
 New Scheme rotates
all Banners in all locations on the page! RF Cafe typically receives 8,000-15,000
website visits each weekday.
RF Cafe is a favorite
of engineers, technicians, hobbyists, and students all over the world. With more
than 17,000 pages in the Google search index, RF Cafe returns in favorable
positions on many types of key searches, both for text and images. New content is
added on a daily basis, which keeps the major search engines interested enough to
spider it multiple times each day. Items added on the homepage often can be found
in a Google search within a few hours of being posted. If you need your company news to be seen, RF Cafe is the
place to be.
 Withwave manufactures an extensive line
of metrology quality coaxial test cable assemblies, connectors (wave-, end-, vertical-launch,
board edge, panel mount), calibration kits (SOLT), a
fully automated
4-port vector network analyzer (VNA) calibrator, between- and in-series connector
adaptors, attenuators, terminations, DC blocks, torque wrenches, test probes &
probe positioner. Special test fixtures for calibration and multicoax cable assemblies.
Frequency ranges from DC through 110 GHz. Please contact Withwave today to
see how they can help your project succeed.
Wednesday the 26th
 Electronics industry trade magazines used
to like to print what I refer to as technodramas, which were stories that had a
plot centered around a technical issue. Sometimes it was circuit troubleshooting,
design, customer interaction, component reliability, availability of technical information,
supply chain problems, hired help troubles, finances, or any other thing involved
in the operation of an electronics service business. Mac's Radio Service Shop is
probably the most well-known example, but there was also Carl and Jerry and similar
regular series. This "The
Technician Who Knew Too Much" story from a 1968 issue of Radio-Electronics
magazine is an example of a random technodrama that was not part of a series. The
moral of this story involves not being too proud to concede to the possibility that
someone you regard as being lesser in experience than yourself might be capable
of solving a problem which evaded your first attempts...
 "The researchers have for the first time
succeeded in demonstrating a device, based on a 2D magnetic material, in room temperature.
The
2D magnetic crystal is shown as the blue, yellow and white balls and is a mix
of Iron, Tellurium and Germanium atoms. The big turquoise arrow indicates the magnetization
direction of the 2D magnet. The crystal with gray color is the carbon atoms of the
graphene channel. The smaller turquoise arrows indicate the spin-polarized electrons
injected from the 2D magnet into the graphene channel. Here, the 2D magnet act as
a source for spin-polarized electrons and the graphene channel for spin transport
and communication. The discovery of new quantum materials with magnetic properties
are believed to pave the way for ultra-fast and considerably more energy efficient
computers and mobile devices. So far, these types of materials have been shown to
work only in extremely cold temperatures..."
 Most visitors to RF Cafe are either engineers,
technicians, or hobbyists who deal with watts in terms of electrical power. This
article from the January 1957 edition of Popular Electronics magazine deals
primarily with
watts in terms of acoustic power, but it also addresses how obtaining acoustic
watts relates to electrical watts. Audiophiles will appreciate the table of speaker
watts needed based on your room volume as well as rules of thumb for selecting the
amplifier power required to deliver that sound effectively. You will note that back
in the day the common abbreviation for decibels was all lower case (db) ad opposed
to how we do it today (dB). A tech-related comic was on a page in the article so
I included it as well...
 John W. Schultz's latest book from Artech
House, "Wideband
Microwave Materials Characterization," is a practical engineering guide to microwave
material measurements for both laboratory and manufacturing/field environments,
including nondestructive inspection (NDI) and nondestructive evaluation (NDE). The
book, published by Artech House, covers topics including Electromagnetic Materials
Properties, Free Space Methods, Microwave Non-Destructive Evaluation, Focused Beam
Methods, and more! This book is a practical engineering guide to microwave material
measurements for both laboratory and manufacturing/field environments, including
nondestructive inspection (NDI) and nondestructive evaluation (NDE)...
 Here is a good quiz on calculating total
equivalent capacitance for circuits containing various combination of series,
parallel, and series-parallel connections. It appeared in the June 1968 issue of
Popular Electronics magazine. To help in calculation, all of the individual
capacitor values are the same. Many of them you can probably solve in your head,
especially if you mentally rearrange the circuit into a more readily recognizable
configuration. For instance, circuit #1 can be redrawn having two parallel branches
across the source. One branch has just a single capacitor while the other has two
parallel capacitors in series with one capacitor. The equation is then C + (2C2/3C)
= C + 2/3C = 5/3C. For C = 6 pF, Ctotal = 5/3*6 pF = 10 pF...
 With more than 1000
custom-built stencils, this has got to be the most comprehensive set of
Visio Stencils available for RF, analog, and digital system and schematic
drawings! Every stencil symbol has been built to fit proportionally on the included
A-, B-, and C-size drawing page templates (or use your own page if preferred). Components
are provided for system block diagrams, conceptual drawings, schematics, test equipment,
racks (EIA 19", ETSI 21"), and more. Test equipment and racks are built at a 1:1
scale so that measurements can be made directly using Visio built-in dimensioning
objects. Page templates are provided with a preset scale (changeable) for a good
presentation that can incorporate all provided symbols...
 The leading website for the PCB industry.
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.
Tuesday the 25th
 In the February 1967 issue of Radio−Electronics
magazine, editor Forrest Belt wrote about the up-and-coming
Pay TV scheme. At the time, nearly everyone received over-the-air (OTA) broadcast
programming, and cable TV was getting its beginnings in metropolitan and nearby
suburbs. As originally envisioned, Pay−TV would be delivered OTA on allocated frequencies
within the UHF band. This 1969 article provides some updated information. Many people
were already paying separately for cable television, so Pay−TV targeted the others.
Two of the main marketing pitches were no commercials during movies, and availability
of shows not presented anywhere else. History has shown that not only will people
gladly pay to watch TV programming, but they'll pay for it while also being required
to endure an ever-increasing amount of commercials. Access via the Internet has
greatly accelerated the "cord cutting" movement not just to telephones, but for
music and TV...
 Here is a little insight into early speech
processing research by the Bell Telephone Laboratories. 1957 was the early era of
real-time digital processing where the need to cram more calls into less signal
space (bandwidth) led to sampled systems - 1:6 in the case of this advertisement
from Bell that appeared in Radio & Television News magazine. Engineers
of the day would be amazed at how the state of the art has advanced since then,
both in mathematical techniques and in miniaturized hardware. Waaaaay back in the
early 1990s while working at Comsat Laboratories, in Germantown, Maryland, one of
the Intelsat earth station modem transceivers I worked on used groundbreaking software
algorithms to reduce call bandwidth by replacing certain parts of spoken word sounds
with shorter segments of code that would then be reassembled at the receiver end.
I specifically remember the software guys have a hard time getting the "s" sound,
"ess," working properly. That issue and many others were conquered long ago...
 "For monitoring X-ray does in patients undergoing
radiotherapy for gastrointestinal cancer, a group of researcher have created a prototype
swallowable dosimeter capsule that also measures gut pH and temperature. SAIT
CAS xray dose capsule 'The researchers found that the dosimeter was approximately
five times more accurate than standard methods for dose determination,' according
to the Chinese Academy of Sciences, whose Shenzhen Institute of Advanced Technology
(SIAT) worked with the National University of Singapore and Tsinghua University.
NUS xray dose capsuleThe 18mm long 7mm diameter capsule has an optical fibre encapsulated
with X-ray persistent lanthanide-doped nano-scintillators whose glow can be used
to estimate radiation dose, and a colour-changing pH-sensitive polyaniline film..."
 By 1950, says the author of this Radio &
Television News magazine story, "No longer are 'aerials' merely required to
transfer electromagnetic energy into space," in reference to airborne platforms."
Following great advancements in radio and radar technology during World War II,
great interest lay in what would later become referred to as 'stealth' technology
and in secure communications. The transition of aircraft speeds into the realm of
supersonic also mandated that projections beyond the main airframe outline be either
eliminated or very much minimized. The
long cable aerials that stretched from the cockpit area to the tip of the vertical
fin, and the round direction finding antennas hanging from below could not be accommodated
at airspeeds above about 300 knots. The aerodynamic drag would be excessive
and the forces would tear the antennas apart. Douglas Aircraft set up one of the
first antenna measurement laboratories...
 It was a lot of work, but I finally finished
a version of the "RF & Electronics Schematic & Block Diagram Symbols" that
works well with Microsoft Office™ programs Word™, Excel™, and Power Point™.
This is an equivalent of the extensive set of amplifier, mixer, filter, switch,
connector, waveguide, digital, analog, antenna, and other commonly used symbols
for system block diagrams and schematics created for Visio™. Each of the 1,000 or
so symbols was exported individually from Visio in the EMF file format, then imported
into Word on a Drawing Canvas. The EMF format allows an image to be scaled up or
down without becoming pixelated, so all the shapes can be resized in a document
and still look good. The imported symbols can also be UnGrouped into their original
constituent parts for editing. Check them out!
 Empower RF Systems is the technological
leader in RF & microwave power amplifier solutions for EW, Radar, Satcom, Threat
Simulation, Communications, and Product Testing. Our air and liquid cooled amplifiers
incorporate the latest semiconductor and power combining technologies and with a
patented architecture we build the most sophisticated and flexible COTS system amplifiers
in the world. Solutions range from tens of watts to hundreds of kilowatts and includes
basic PA modules to scalable rack systems.
Monday the 24th
 Mathophobes beware; I cannot be held accountable
for instances of hyperventilation, fainting, intense sweating or nervousness, post
traumatic stress, etc. When in high school and junior high, I suffered from the
common malady. However, after setting my sights on earning an electrical engineering
degree, I embraced mathematics as a necessary skill to be successful. In fact, I
did very well in all my math classes even up through calculus, differential equations,
and even higher levels. It soon became evident that my fellow students who struggled
the most - even failed - at engineering courses were those who never had a handle
on math. Since becoming comfortable with higher mathematics, my appreciation for
its abilities to describe the physical world has constantly grown. It is also nice
when reading technical articles to at least somewhat understand the math behind
the concepts. Author Norman Crowhurst attempts in this 1960 Radio−Electronics magazine
article to sooth the pain of
complex numbers a bit...
 "As automobile electrification speeds up,
the world faces an overwhelming need for
critical metals and minerals to make atmosphere-saving electric vehicles possible.
The demand for battery-grade lithium, nickel, cobalt, manganese and platinum will
climb steeply as nations work to reduce greenhouse gas emissions through mid-century,
but will likely set off economic snags and supply-chain hitches, according to new
Cornell research published April 11 in Nature Communications. 'Electrification
and decarbonizing fuel production are critical for adequately mitigating greenhouse
gas emissions from road transportation,' said Fengqi You, the Roxanne E. and Michael
J. Zak Professor in Energy Systems Engineering, the senior author on 'Trade-off
Between Critical Metal Requirement and Transportation Decarbonization in Automotive
Electrification..."
 Here are a few
tech-themed comics from the April 1967 edition of Popular Electronics
magazine depicting the perception of techies during the era. I took the liberty
of colorizing them. As mentioned before, stereo equipment was a big deal in the
era, back before most people listened to music through ear buds attached to smartphones.
When in the USAF in the early 1980s, a sure sign of hipness was to have 19" equipment
rack in your barracks room, stuffed full with a reel-to-reel tape deck, a high end
AM/FM receiver ("tuner," to the audiophile), power amplifier that could deliver
at least 200 W per channel, a dual cassette deck, turntable (referring to it
as a "phonograph" revealed your squareness). Of course no self-respecting stereo
aficionado would be caught dead with an 8-track tape deck in the rack. Things really
haven't changed much when it comes to serious audiophiles, except now a CD/DVD player
will be included...
 "China is building sophisticated cyber weapons
to
seize control of enemy satellites, rendering them useless for data signals or
surveillance during wartime, according to a leaked US intelligence report. The U.S.
assesses that China’s push to develop capabilities to 'deny, exploit or hijack'
enemy satellites is a core part of its goal to control information, which Beijing
considers to be a key 'war-fighting domain.' The CIA-marked document, which was
issued this year and has been reviewed by the Financial Times, was one of dozens
allegedly shared by a 21-year-old US Air Guardsman in the most significant American
intelligence disclosures in more than a decade. A cyber capability of this nature
would far exceed anything Russia has deployed in Ukraine, where electronic warfare
teams have taken a brute-force approach with little effect. These attacks, first
developed in the 1980s, attempt to drown out signals between low-orbit SpaceX satellites
and their on-ground terminals by broadcasting on similar frequencies..."
 This continuation of Part I of the three-part
"Detector
Circuits" series covering the basics of diode detectors delved into some of
the specific circuit configurations and their applications. Here in Part II,
author Robert Scott touches on regenerative and superregenerative feedback "tickler"
circuits that are able to detect very low level signals. You have no doubt heard
of "quenching" but how about "squegging?" The nonlinear devices used in the article
happen to be vacuum tubes, so stay away if you suffer from thermionophobia (a term
I just created). Imagine a generic semiconductor diode in place of the tube if it
makes you feel better ;-) Part I appeared in the August 1945 issue, and Part III,
the final article in the series, was published in the October 1945 edition...
RF Cascade Workbook is the next phase in the evolution of
RF Cafe's long-running series, RF Cascade Workbook. Chances are you have
never used a spreadsheet quite like this (click here for screen capture). It is a full-featured RF system
cascade parameter and frequency planner that includes filters and mixers for a mere
$45. Built in MS Excel, using RF Cascade Workbook 2018 is a cinch
and the format is entirely customizable. It is significantly easier and faster than
using a multi-thousand dollar simulator when a high level system analysis is all
that is needed. An intro video takes you through the main features...
 Lotus Communication Systems began in 2009,
setting up CNC machine shop and RF/microwave assembling and testing lab in Middlesex
Country, Massachusetts. Lotus is committed to highest quality and innovative products.
Each RF/microwave module meets
exceedingly high standards of quality, performance and excellent value, and are
100% Made in the USA. Lotus' RF/microwave products cover frequency band up to 67
GHz. Lotus also offers an COTS shield enclosures for RF/microwave prototyping and
production. All products are custom designed. We will find a solution and save your
time and cost. Lotus has multiple 4 axis CNC machines and LPKF circuit plotters.
In stock, 1-day free shipping.
Sunday the 23rd
 As always, this week's
crossword puzzle for April 23rd sports an electronics 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 (e.g.,
Reginald Denny, Hedy Lamarr, or the Tunguska event in Siberia). The technically
inclined cruciverbalists amongst us will appreciate the effort. Enjoy!
This assortment of custom-designed themes
by RF Cafe includes T-Shirts, Mouse Pads, Clocks, Tote Bags, Coffee Mugs and Steins,
Purses, Sweatshirts, and Baseball Caps. Choose from amazingly clever "We Are the World's
Matchmakers" Smith chart design or the "Engineer's Troubleshooting Flow Chart."
My "Matchmaker's" design has been ripped off by other people and used on their products,
so please be sure to purchase only official RF Cafe gear. My markup is only a paltry
50¢ per item - Cafe Press gets the rest of your purchase price. These would make
excellent gifts for husbands, wives, kids, significant others, and for handing out
at company events or as rewards for excellent service. It's a great way to help
support RF Cafe. Thanks...
 Anatech Electronics (AEI) manufactures and
supplies RF and microwave filters for military and commercial communication
systems, providing standard LP, HP, BP, BS, notch, diplexer, and custom RF filters,
and RF products. Standard RF filter and cable assembly products are published in
our website database for ease of procurement. Custom RF filters designs are used
when a standard cannot be found, or the requirements dictate a custom approach for
your military and commercial communications needs. Sam Benzacar's monthly newsletters
address contemporary wireless subjects. Please visit Anatech today to see how they
can help your project succeed.
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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