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5 of the January 2019 homepage
archives. Friday 4
 When I first read the title for this article,
"A Look at the PC Market," I was thinking personal computers, not
printed circuits. It being from a 1972 issue of Popular Electronics, my assumption
was that the photos of circuit boards were from early kit format computers, but
then it finally dawned on me that there were no personal computers in 1972 - not
even in kit form. Actually, that is not entirely true since there were advertisements
for hokey contraptions called "computers" that combined some switches, logic gates,
and LEDs for implementing simple multiple choice true/false testing boxes or rudimentary
(with emphasis on "rud[e]") calculators. Getting to the real story, though, the
1970s was the decade where printed circuit boards (PCBs) were replacing point-to-point
wiring wherever possible. If you opened a radio or television...
 Chapter 12 of the U.S. Navy's basic electronics
training course discusses
electromagnetism. It follows on the heels of the sections introducing
magnetism and electrical currents. The Navy (and the Air Force, I must add) is renowned
for its high quality training and for turning out graduates that perform highly
in both their service duties and in private industry after separation. It describes
the electromagnet as being like a natural or artificial magnet in its attractive
force, is tremendous and can hold tons of iron. Because this magnet is powered by
an electric current, the magnetism can be turned on and off with the flick of a
switch. Electrically-powered magnets are called electromagnets. Electromagnets come
in all sizes and shapes...
 Infinite Electronics, a global supplier of RF
and Microwave components and assemblies, is looking for a Technical Support Representative.
We have an exciting opportunity for a technically savvy individual with proven customer
facing and team skills to round out our Sales and Tech Support team. Job Summary:
The Technical Support Representative's duties and responsibilities include, but
are not limited to: (80%) Resolving customer technical questions directly through
telephone, email, chat or other methods of communication, or via the Sales and Service
Representative. The TSR will identify customer needs and resolve routine customer
technical questions by identifying the appropriate RF/Microwave part, recommending
additional or alternative...
 "A new electronic
skin with magnet-sensitive capabilities developed by researchers
in Germany can turn someone into a human compass, providing opportunities for navigation
as well as virtual-reality and other applications. Researchers at Helmholtz-Zentrum
Dresden-Rossendorf (HZDR) developed the e-skin, which can detect and digitize body
motion as it corresponds to the Earth's magnetic field, they said in an HZDR news
release. An ultra-thin golden foil on the middle finger is all that's needed to
control a virtual panda with the help of the Earth's magnetic field, thanks to new
research to develop an electronic skin by researchers in Germany. The e-skin is
extremely thin and malleable, which means..."
 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...
Thursday 3
 Have you ever used any of these
voltage-variable capacitor (VVC) types: varicaps, epicaps, minicaps,
voltacaps, capistors and varactrons? If you answered "no, but I have used varactor
diodes," then the more correct answer would have "yes, I have, but by a different
name." Construction was similar for all variations. This article from a 1969 issue
of Radio-Electronics magazine reports on some of the earliest forms of
diodes specifically designed to use a reverse bias on the PN junction to control
the effective capacitance of the device for use in frequency tuning circuits. The
first uses were for electronically tuning local oscillators in mixing stages, and
then for making tunable filters. Capacitance ratios greater than 10:1 with some
VVCs allowed tuning over a very wide range. At the time the article was written,
there was not universally agreed upon schematic symbol for the VVC, as illustrated
in Figure 2. Varactor-tuned television channel selectors...
 Do a WWW search for
filter equations and you will find thousands of pages, including
a few here on RF Cafe. However, if you want an example of how to implement the transfer
functions in a spreadsheet or software, examples of actual code are elusive (other
than maybe a Matlab or MathCAD worksheet). As one who has incorporated equations
for Butterworth, Chebyshev Type 1, Chebyshev Type 2, and other filter
functions in many spreadsheets and software over the past few decades, I figured
it might be useful to post snippets of my code so that someone else can copy and
paste it directly into other work. BTW, I do not consider myself to be a filter
expert by any means and there is no ground-breaking knowledge here; it's just hopefully
easier to find. Writing a macro to use in a spreadsheet is the preferred...
 Elite Electronic Engineering, of Downers
Grove, Illinois, if offering as a free download this whitepaper titled, "Guide to FCC Certification for Part 15C Wireless Transmitters."
Elite is a recognized Telecommunication Certification Body (TCB) for the FCC, Foreign
Certification Body (FCB) for Canada, and Notified Body (NB) for the European Union
under the Radio Equipment Directive. These credentials assure the speedy and convenient
processing of your approval. FCC Certification Elite is designated by the United
States government as an accredited Telecommunication Certification Body (TCB). We
provide FCC compliance testing services to manufacturers of radio-frequency transmitting
devices...
Triad RF Systems, a top-tier designer and manufacturer of RF and microwave amplifiers,
announces the introduction of their
TTRM1210 bi-directional amplifier, a wideband GaN Bi-Directional
Amplifier (BDA) that operates from 30 MHz to 2700 MHz and produces over
8 W of transmit power. The receive side has over 20 dB of gain to overcome
losses between the antenna and the radio. The noise figure is 2 dB which makes
the BDA practically invisible to the system. Switching between transmit and receive
can be done either automatically when RF is sensed at the radio port, or manually
switched by the radio or user. One of the smallest BDAs in the industry measuring
only 3.25 x 2.12 x 0.53 inches, this feature rich BDA is also one of the most efficient.
While producing 8 W of RF power...
 "The Physics World 2018 Breakthrough of the
Year goes to Pablo Jarillo-Herrero of the Massachusetts Institute of Technology
(MIT) in the US and colleagues for making the discovery that led to the development
of 'twistronics,' which is a new and very promising technique for adjusting the
electronic properties of graphene by rotating adjacent layers of the material. The
technique was first used by the team to create 'magic-angle graphene,' which behaves like a high-temperature superconductor.
Nine other achievements are highly commended in the Top Ten Breakthroughs of 2018
and cover topics ranging from the first full body PET/CT scan to a zero-carbon aeroplane
propelled by a jet of ions. Graphene is a layer of carbon just one atom thick that
has a honeycomb lattice. Bilayer graphene..."
 Innovative Power Products (IPP) has over
30 years of experience designing & manufacturing RF & microwave passive
components. Their high power, broadband couplers, combiners, resistors, baluns, terminations and attenuators
are fabricated using the latest materials and design tools available, resulting
in unrivaled product performance. Applications in military, medical, industrial
and commercial markets. Take a couple minutes to visit their website and see how
IPP can help you today...
Wednesday 2
 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...
 RF Cascade Workbook 2018 is the next phase in the evolution
of RF Cafe's long-running series, RF Cascade Workbook. 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...
 An ancient legend tells us that nearly 5,000
years ago an Emperor of China had a small statue of a man mounted on his chariot.
This statue was pivoted at the base and one outstretched arm always pointed to the
south. In those ancient times, this action must have seemed truly miraculous - probably
the Emperor used his statue more to impress his subjects than he did to find his
way. This legend is the first report of man's use of a black or lead-colored stone
called
magnetite. About the time of Christ, magnetite was rediscovered
by a Grecian shepherd. He noticed that the iron of his staff was attracted to certain
stones. But for nearly another 1,000 years, no particular use was made of this discovery...
 A while back I mentioned that Mr. Glen Robb,
owner of
Antenna Test Lab, had an article in the October 2018 issue of
Microwaves & RF magazine titled, "Assemble
Antennas with 3D Printing." He told me a future issue of the ARRL's QST
magazine would also be running an article on his 3D antenna printing project. It
just showed up in the January 2019 edition. Unfortunately, QST does not have a publically
accessible version of the magazine, but for ARRL members you can find the article
under the title of , "3D-Printed Antennas," on page 67. It is featured in Paul Wade's
monthly "Microwavelengths" column. "3D printers have become quite inexpensive, and
many hams have acquired one. Printing hard-to-machine horn and antenna feeds is
a natural task for 3d printers ..."
 The first RF Cafe Poll for the new year asks,
"Do you Plan to Change
Jobs in 2019?" Voting is totally anonymous and does not require registration.
I also will not hit you with a full-page advertisement, require you to submit an
e-mail to view the poll results, or set a cookie with the poll code. My cardinal
rule on RF Cafe is to never subject visitors to any form of treatment I despise
when going to a website. Thanks for your participation...
"Engineers have succeeded in fabricating
topological LC circuits arranged in a honeycomb pattern where
electromagnetic (EM) waves can propagate without backscattering even when pathways
turn sharply. These circuits may be suitable for use as high-frequency electromagnetic
waveguides, which would allow miniaturization and high integration in various electronics
devices, such as mobile phones. NIMS succeeded in fabricating topological LC circuits
arranged in a honeycomb pattern where electromagnetic (EM) waves can propagate without
backscattering even when pathways turn sharply. These circuits may be suitable for
use as high-frequency EM waveguides, which would allow miniaturization and high
integration in various electronics devices, such as mobile phones..."
Since 2003, Bittele Electronics has consistently provided low-volume, electronic
contract manufacturing (ECM) and turnkey PCB assembly services. It specializes in
board level turnkey PCB assembly for design engineers needing low volume or prototype
multi-layer printed circuit boards.
Free Passive Components: Bittele Electronics is taking one further
step in its commitment of offering the best service to clients of its PCB assembly
business. Bittele is now offering common passive components to its clients FREE
of Charge...
Tuesday 1
 Although "Citizens Band" (CB) is the common reference to these unlicensed
two-way radio service transceivers, the official name for the spectrum allocated
by the FCC to their operation is "Citizens Band Radio Service" (CBRS). It was originally
called just "Citizens Radio Service," but the popular use of "Band" caused the FCC
to incorporate the additional term later on. Early Part 95 Class D citizens band
radios offered up to 23 channels in the 11-meter band from 26.965 MHz through
27.255 MHz. CB radio channels increased to 40 in 1977 due to the immense popularity
at the time (long before cellphones) - recall the "Convoy" song. The 11-meter band
was re-allocated from the amateur radio spectrum in 1958 (to the great dismay of
Hams). CB radios are still used heavily by truckers who don't like the idea of "Big
Brother" listening to and recording conversations...
 Not everyone is an ardent observer of astronomical
events, but most people are still as awestruck as were primitive peoples when a
lunar eclipse or solar eclipse occurs, or when a massive meteor shower happens.
Centuries ago most of those phenomena were not predicted because the mathematics
and mechanics of gravity were not known. The kings' best astronomers and astrologers
leveraged ignorance to influence ruling policy similar to how politicians and activists
do today. The folks at the Telescopic Watch website created this infographic titled
"Must-See Stargazing Events for 2019" which highlights the 10 most
significant astronomical events of the new year. First up is a total lunar eclipse
on January 21st...
 "The inconvenient truth of future
5G networks is that their increased high-speed bandwidth, and
the use of the millimeter wave spectrum (the radio spectrum above 30 GHz) to achieve
it, comes at a price: Those radio signals barely propagate around the corners of
buildings. To overcome this issue, the strategy has been a combination of small
cells with massive multiple-input multiple-output (MIMO) antennas to increase coverage.
Small cell deployment will be so extensive that the Small Cell Forum predicts 5G
small cell will overtake 4G small cells by 2024. The total installed base of 5G
or multimode small cells will reach 13.1 million by 2025, constituting more than
one-third of the total small cells..."
 Windfreak Technologies designs, manufactures,
tests and sells high value USB powered and controlled radio frequency products such
as RF signal generators, RF synthesizers, RF power detectors, mixers, up / downconverters.
Since the conception of WFT, we have introduced products that have been purchased
by a wide range of customers, from hobbyists to education facilities to government
agencies. Worldwide customers include Europe, Australia, and Asia. Please contact
Windfreak today to learn how they might help you with your current project...
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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