Featured Product Archive
The inventions and products featured on these pages were chosen either for their
uniqueness in the RF engineering realm, or are simply awesome (or ridiculous) enough
to warrant an appearance.
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past few months, this full-page BridgeCom advertisement has been running
in the American Radio Relay League (ARRL) magazine QST. When I
first saw it I though it might be one of those research laboratory
hydraulic apparatuses for generating the kind of pressure found at the
center of the Earth. Scientists use such devices to synthesize diamonds by
compacting coal. In actuality, the four cylinders are part of the
BCD-144250 Rack Mount VHF Duplexer. Per their website: BridgeCom
Systems' BCD-144250 Duplexer for amateur and commercial applications. The
BCD-144250 utilizes four high-quality cavities that results in
uncompromising duplex isolation. It will handle up to 250W continuously
for the most demanding applications...
It has been a long time since I've
citizens band (CB) radio in my car. Back in the 1970s when the CB craze
was at its peak, with songs like C.W. McCall's "Convoy"* topping Casey Kasem's
American Top 40 (AT40) charts, my high school compadres were all installing
23-channel CBs (standard at the time) in their cars and pickups. I joined
in with a Radio Shack unit (don't recall the model number). In those days
the FCC required operators to register and mail a check for a few bucks -
same with radio control (R/C) systems for model airplanes also operating in
the same 26-27 MHz radio band - in return for a "Citizens Radio Station
License" document to carry in your wallet. Most CB channels were spaced at
10 kHz, but the R/C frequencies were in−between some CB channels spaced
at 20 kHz. For instance, my 3-channel OS Digitron R/C system was at 27.195 MHz,
which resided between CB channels 19 (27.185 MHz) and 20 (27.205 MHz).
Some electronically savvy CBers would illegally modify their radios to include
operation on those in−between frequencies (e.g. Ch 19A at 27.195 MHz),
thereby creating a scenario where merely keying up the transmitter could "shoot
down" a model airplane if close enough...
Dr. Scott Best, of SiberSci RF
engineering services, sent information about the FREE general purpose
DISLIN scientific and engineering
plotting software library that includes Smith Chart support. The graphics library
was initially created at the Max Planck Institute for Solar System Research beginning
in 1985 by Mr. Helmut Michels. Its continual series of upgrades is as recent
as May 2020. The DISLIN library is available for Unix, Linux, FreeBSD, Windows,
Mac OSX, and MS-DOS systems. It supports a variety of public domain and commercial
compilers for Go, Perl, Python, Java, Ruby, TCL, Julia, FreeBASIC, Free Pascal,
R, C/C++, and Fortran (77, 90, and 95). If you are a software developer, you probably
know that most development platforms are supplied with either no plotting components
or very rudimentary versions of for-purchase products. Many cost hundreds or even
thousands of dollars...
NI (National Instruments) has made their
LabVIEW Student Edition software product available as a free download for students
needing it for school projects. The license is good for 6 months. You can always
download a trial of standard LabVIEW, but it only has a 30-day license. The LabVIEW
Student edition includes most of the same features as the full LabVIEW suite but
adds a watermark on the front panel and block diagram. The download screen requires
some personal information if you do not already have a NI account set up, but that
is not unusual or unreasonable when a company is offering you trials software. I
did the download and was going to set it up and get some screen shots, but after
15 minutes or so it was still installing (and that's on a solid state hard drive,
SSHD), so I killed the process and figured I'd find a video that someone else had
done. If I had a use for the program I would have let it go ahead and complete the
installation, but otherwise I didn't want that much new stuff on my SSHD. Even though
it is called Student Edition, there is no requirement that you prove that you are
As this is written, we in the U.S. are
nearing the end (hopefully) of the virtual house arrest period most of the country
has had imposed upon us by overzealous politicians. Part of the "comeback" plan
being bandied about by governors is requiring subjects/citizens to don
cloth face masks
when in public places where the arbitrarily conjured up six-foot "social distancing"
rule cannot be easily maintained. There is no foreseeable end to this "new normal"
imposed upon most of the world. Contrary to what many people believe, the mask's
purpose is not to prevent the wearer from inhaling COVID-19 (aka Wuhan Virus, China
Virus - pick your favorite) particles, but to arrest the body fluids emanating from
the wearer's mouth and nose from being spewed into the air and/or onto surfaces.
In response to the shortage of N95 type masks that are supposed to stop up to 95%
of virus particles, many private citizens - mostly women - worked with health care
personnel to design cloth masks that are comfortable to wear for long periods of
time and are reusable by washing them...
Phil Salas, AD5X, published an extensive
review of the NanoVNA
vector network analyzer in the May 2020 issue of the ARRL's QST magazine.
Unfortunately, the article is not available to non-members, but if you are a member
or know someone who is, it would be worth reading. He compared measurements by the
NanoVNA with those obtained using an Array Solutions VNAuhf, which yielded very
favorable results. There are many knock-offs of the NanoVNA available, which is
typical since most of these low-cost, high-performance electronics devices are built
using widely available block-level components that make replication relatively easy.
Variations in the quality of coaxial connectors, internal batteries, switches, etc.,
can and often does make a big difference in the quality and ruggedness of the equipment
you buy. Firmware and support software can vary significantly as well. It's a roll
of the dice to some extent...
Randy Rogers*, AD7ZU, mentioned in the May
2020 issue of QST magazine the Smith Chart software called "SimSmith," by Ward
Harriman, AE6TY. SimSmith first appeared around 2011. Being written in Java, it
will run on any operating system that supports Java (Win64, Win32, Apple Mac OS
X, Solaris, and Linux). If you are using Win64 as I am, you will want to download
the "windows64-with-JRE.exe" file. Windows security will try to block it, but it
is safe to run after your antivirus program scans it and gives a green light. AE6TY
recommends using the installation files rather than just downloading the "SimSmith.jar"
file even if you already have a version of Java installed. When launching the program,
the window might not be very large, so grab a corner and stretch it out so the components
are easier to see. After playing around with SimSmith for a while, you might want
to click on the "SimSmith->preferences" menu selection...
RF Cafe visitor Mike M. reminded me
of "Madman Muntz," who was a widely
known television commercial personality on the West Coast from the 1950s through
the 1970s. Earl William "Madman" Muntz's zany live and animated commercials were
used highly successfully in selling cars, including one he himself designed and
manufactured called the Muntz Jet. Along with being a master salesman, Madman Muntz
was also a self-taught electronics engineer of sorts. He is credited with developing
the first 4-track stereo tape deck for cars, which was a precursor to the 8-track
tape deck. What Mike mentioned specifically was the line of Muntz television sets.
Not satisfied to merely manufacture TV sets, Muntz created an entire service shop
and fleet of mobile television trucks. It was kind of an early version of the Nerd
Herd. Based on the Madman's trademark method of minimizing the number of components
used in his products...
Dr. Michael Steer, Lampe Distinguished Professor
of Electrical and computer Engineering at the NC State University, has released
half a dozen of his books on RF system and circuit design in the form of OpenAccess
eBooks, and are downloadable at no cost on the NC State website. Dr. Steer
is a prolific author whose books are chock full of highly useful illustrations and
photographs. The first five "Microwave and
RF Design" books, volumes 1 through 5, cover a wide swath of ground with concentrations
in radio systems, transmission lines, networks, modules, and amplifiers and oscillators.
The final book, "Fundamentals of Microwave and RF Design," is a summary of the first
five that will prove useful to newcomers in the field. Excerpts of the books' contents
are quoted ...
Fellow amateur radio enthusiast Russ Keller
(KM4RHK), of Wake Forest, North Carolina, has designed and is selling his
DMMCheck Plus test device for verifying
the accuracy of digital multimeters, oscilloscopes, or other instruments which measure
the provided parameters. This compact (2.5" x 2.2"), inexpensive board is battery
powered and can be used to verify the accuracy of seven primary DMM functions. A
very complete description of each function is provided on the DMMCheck Plus
website. A certificate of measured values for each function is provided with the
DMMCheck Plus. Re-measurement, if desired, is free for the first two years ...
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 en 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.
Since according to a popular saying a picture reportedly paints a thousand words ...
Those of us whose were around in the RF industry
in the 1990s and remember a very fine magazine entitled "Applied Microwave &
Wireless." It was published by Noble Publishing Group. The Archive.org
(aka the Wayback Machine, a la from Sherman and Mr. Peabody cartoon) website
has an archive of 410 published articles (as of this writing) on a variety of topics
including antennas, oscillators, filter design and tuning, direct conversion receivers,
microstrip and stripline, RF link calculations, shielding, co-channel interference,
power amplifiers, lightning protection, SAW devices, GPS, dielectric measurement,
circuit and system computer simulation, transistor biasing, RF transformers ...
If you visited the good folks at the
QuinStar Technology booth at the IMS
show in Boston this year (2019), you were probably offered one of the T-shirts shown
here. As you might expect from a company of engineers and scientists, the design
on the T-shirt includes a thinking exercise. Rumor has it that this is the first
question put to interviewees. Can you decode the license plate message? I asked
Ms. Carol Clasby, who probably handed you your T-shirt at IMS2019 (if you got
one), whether someone at QuinStar actually has the license plate and she responded
not yet, but maybe in the near future. I went to the California Department of Transportation
website to see what such a license plate might look like. It allowed me to reserve
the plate, although of course ...
It seems impossible that you can buy
Visio Professional 2019 and Microsoft Office Professional Plus 2019 for less
than $10 each, but according to the research I did the offers seems to be legitimate.
Evidently, sellers buy corporate subscriptions and then are licensed to distribute
copies to it agents (we, the buyers). This is nothing new because I have seen it
done for many years. After purchasing a product, you are provided with a hyperlink
for downloading the software directly from the Microsoft.com website, and also an
activation key. Heeding te old saying about if something seems too good to be true,
it probably isn't, I decided to test the system. Back in March, I purchased one
copy each of Visio Professional 2019 and Microsoft Office Professional Plus 2019
for $5.99 and $9.99 ...
My daughter, Sally, in addition to owning
and operating a very successful horse riding school named Equine Kingdom Riding
Academy, has a rather large eBay store she uses as a venue for selling items purchased
at the local Goodwill "Bins" store. She often buys vintage toys with electronics
features - sometimes working and sometimes not. A properly functioning vintage toy,
be it a stuffed animal or a game of some sort, can make a huge difference in the
resale price. When that is the case, she sends them home with me to attempt a repair.
Many times the problem is corroded contacts from leaky batteries. A dental pick
and some isopropyl alcohol usually solves the problem. When that doesn't work, it's
time to open 'er up for a deeper look. Over the years I have found problems ranging ...
There's a new online interactive Smith chart
s-parameter plotter in town, and it goes by the name of
QuickSmith. Justin Coulston, designer of QuickSmith, sent me an
e-mail asking that I take a look at it. I did, and I like what he has done. Assuming
that anybody reading this is already at least somewhat familiar with the Smith chart,
this report will concentrate on the features of QuickSmith. Keep in mind while checking
out QuickSmith for yourself that it is still in Beta phase, so your feedback to
Justin will be appreciated ...
Coilcraft has been around
as long as I can recall since beginning my electronics career in the 1970s. In fact,
Coilcraft was founded in 1945 near Chicago to make custom coils for television sets.
They began manufacturing a line of standard products in the 1970s - no doubt with
supporting my budding career in mind ;-) Inductors and magnetics are their
primary focus. Coilcraft has been an industry leader in surface mount components,
and was one of the first to provide packaging that could be used by pick-and-place
automatic PCB assembly ...
A couple days ago I posted an update on the
Watkins-Johnson databook page that had an unauthorized gag graph titled, "WJ-G1/SMG1
Phase vs. VCTL vs. Frequency vs. Phase of the Moon." When RF Cafe visitor and sometimes
contributor Dr. Marek Klemes* read
that, he sent me a note about remembering this "Delayed
Light Turn-Off" circuit from the Signetics 555/556 Timer Databook. It took a
bit of creative Googling, but he managed to find the datasheet (to the right). The
text was a bit washed out from the original low resolution scan, so I reproduced
the labels (green). This Rube Goldberg-ish contraption works thusly: After a delay
determined by the values selected for R1 and C1, the output
of the NE555 timer goes high and causes resistor RL to heat up enough
to ignite match M1. M1 subsequently lights the fuse on firecracker
FC1, which has tied to its body a string that wraps around a pulley and
holds a rock (which weighs precisely 2π pounds ...
Longtime RF Cafe visitor, electrical engineer, and occasional contributor Alan
Dewey sent me a note yesterday saying a book for which he helped provide a large
amount of research data has been published by authors Iain Dey and Douglas Buck.
Files: How the Inventor of the Microchip Put Himself in the KGB's Sights," is
an extensive delve into the background of Dr. Dudley Allen Buck, whose son,
Douglas, conducted an extensive investigation into his father's mysterious death
that happened to coincide with the death of his colleague and two other scientists
just days after being visited by Soviet computer experts. Dr. Buck was a superconductivity
researcher during his short, highly productive life. A cryotron, BTW, is a superconducting
switch that would make for very low power supercomputers if it could be made practical
in IC form ...
An advertisement for Mini-Circuits' DIY
Network Analyzer Kit appeared in the October issue of Microwaves & RF
magazine. It is evidently the first of a planned series of University Projects.
Billed as an attempt to "Bridge the gap between textbook theory and real-world measurement,"
Project No. 1-UVNA-63 targets college laboratories as low-cost means of procuring
a high performance vector network analyzer (VNA) at a reasonable cost ($2,495.00).
The frequency range is 100 MHz to 6 GHz. Having the student build the
1-UVNA-63 provides a familiarity with a block diagram level understanding of 2-port
VNAs and gives hands-on experience with assembling RF components. Included are filters,
directional couplers, a transceiver PCB (made by Vayyar) ...
Take a look at this
ARRA (Antenna & Radome Research Associates)
attenuator advertisement that appeared in the September 2018 issue of Microwaves & RF
magazine a tell me if it reminds you of something you might have seen in the 1960's
through 1980's. That might not have been the intention, but seeing it sure triggered
my nostalgia mechanism. Even the tag line, "When it comes to attenuators, nobody
- but nobody - can fill our shoes," idiom, being somewhat dated, conjures up memories
of vintage company slogans. Of course the black and white format feeds the perception.
Maybe I'm wrong, but if it appeals to me for any reason, the ad designers have done
their job ...
Rohde & Schwarz has been publishing a
series of good old-fashioned printed (aka hard copy) Pocket Guides on RF test and
measurement topics. This latest one titled, "Key Characteristics of Signal Generators and Modulation Methods: Pocket
Guide," arrived in my mailbox (the physical one at the curb, not Outlook). There
are 116 pages chock full of an amazing amount of descriptions, equations, tables,
and graphs. The main topic areas are analog, vector, and arbitrary (ARB) waveform
generators, and analog and digital modulation methods. It also reviews associated
topics like phase noise, VSWR, intercept points, etc. A sampling of them are reproduced
below. You can get your own free copy by filling out the form on the R&S website ...
Sitting in the waiting room in the local Jeep
dealership, waiting for the technicians to do the annual inspection on the 2011
Patriot, I noticed a 12 volt car battery sitting on a table. At first I assumed
it was just a sales pitch for a new battery, but then I noticed a bunch of small
cables coming from its bottom edge. As you can see in the photo I took of it, those
cables are mobile device charging cords with mating connectors for Apple, USB, and
miniUSB ports. An Internet search did not turn up any of these things, so maybe
Mopar engineers came up with it. Times sure have changed from when ...
Rohde & Schwarz is offering at no cost
a variety of reference charts (posters) for hanging on your lab or office wall,
and some handy-dandy Pocket Guides. In the current age of (seemingly) paperless offices
and laboratories, opening a cardboard package from R&S containing the pictured
items caused me to wax nostalgic over the days when sales reps handed out such materials
during workplace meetings and at trade shows. Wall charts are still fairly easily
obtained, but the spiral-bound pocket guides are more rare. Maybe soon we'll be
seeing the resurrection of cardboard slide rule calculators ...
Mr. Oleg Sakharov, Director of the Center
of Telecom. Technologies, LLC, recently sent me information on the
MLinkPlanner software for performing microwave communications
link design. Judging only from the provided screenshots and the online documentation,
MLinkPlanner looks to be very user friendly and loaded with features. I downloaded
the 7-day free trial and did a quick fictitious link between my house in Erie, PA,
and the WBEN AM radio station in Buffalo, NY. My route is mostly over Lake Erie,
so there was not much in the way of obstructions, other than the curvature of the
Hyperlinks all around the Internet pointing
to Hittite's infamous Mixer Spurious Product Calculator broke suddenly when Analog
Devices swallowed up Hittite in 2014. The good news is that if you still want to
use it, you can find it as the ADI Mixer-Spur Graphical Representation tool on the
ADI website. However, Marki Microwave now has a much nicer
Spur Calculator that you will want to consider. It provides both
a Spur Web format and a Spectrum Analyzer format for presenting mixer spurious products.
The interface is very user friendly both for the input and the output specification.
The Spur Web screen uses a format pioneered ...
QuickSmith, a creation of Nathan Iyer, has
been around for a long time. It is without a doubt one of the most feature-filled
examples of RF design software around. Nathan recently released a Web-based version
of QuickSmith on a GitHub server, which means it works on any platform with a browser
- desktop or mobile. Access is free, and you can save and reload your design files
rather than losing your work once you leave the website. Being online also means
that the latest version is always available. The screenshot to the right illustrates
where to place series and parallel components, and where to access the sweep ...
You might think the world doesn't need another
RF basics book, but the fact is there are so many new people coming into the field
that there is always room for one more - particular a well-done edition like "RF Basics Handbook" from Rigol Technologies. The PDF download
is free, but you do need to fill out a submission form. A replication of the table
of contents give you an idea of all the topics covered. The photos and drawings
are very good quality. Of course the equipment used in the publication are representative
of Rigol's product line, but that's to be expected ...
Amateur radio operators take note: Heathkit,
which in years past was a prime supplier of homebuilt ham radio gear, has just announced
plans to manufacture its first piece of test equipment in three decades. "Now there's
the Heathkit® HM-1002: Intuitive, intelligent, affordable, accurate measurement.
Heathkit® HM-1002 Precision RF Meter™ picks up where our venerable
SWR / wattmeters of yesteryear -- and everyone else's -- stopped. Incredible new
features, yet simple for beginners to assemble and understand. And you can build
and maintain it yourself." ...
Dr. Andrei Muller, progenitor of the
world's first 3D Smith
Chart software program, has teamed with a handful of able colleagues to release
this commercial version of this paradigm-changing design and analysis tool. 3D Smith
Chart enables you to visualize S-parameter data in ways not possible from the Flatland
dweller's perspective that is the traditional 2D Smith chart. Flatland existed
in a plane, and from an observer's perspective a 3-dimensional object entering the
plane from along the Z-axis seemed to appear out of nowhere ...
This back-page advertisement by
Model Rectifier Corporation (aka MRC) appeared
in the January 1972 issue of American Aircraft Modeler magazine. Note the
cool collection of [now] vintage test equipment shown
in support of testing the R/C system. The advertisement shows a rhombic antenna,
the Dana 8015 RF frequency counter, Tektronix 7904 oscilloscope, HP spectrum analyzer,
RF communications synthesizer RF generator, Anritsu precision field strength meter.
I was 13 years old at the time, and anxiously watched for in the mailbox each month ...
RF Cafe visitor Tony C., who is an engineer
working for on of America's great, longtime manufacturers of green farm equipment,
sent me a link to this unique memory IC released by Signetics on April 1, 1973.
Being April 1, 2017, it seems to be an appropriate day to post the Signetics 25120
Fully Encoded, 9046 x N, Random access Write-Only Memory datasheet that per Wikipedia,
"...was created 'as a lark' by Signetics engineer John G 'Jack' Curtis and was inspired
by a fictitious and humorous vacuum tube datasheet from ..."
April 1, 2017
How many times have you dug through a drawer
of coaxial connector adapters and found what
seemed like every possible combination of TNCs, Ns, SMAs, TNCs, UHFs, SMBs, and
<fill in the blank>s except the one you really
need? Sometimes the reason is simply because all on hand are being used for something
else and cannot be 'borrowed' for your use. Other times it is because the need never
existed before. Usually, a quick search on the Internet will turn up exactly want
you want, but for decent a quality adapter you will pay a stiff price - especially
if it is a rare combination of connector types. The truth is, not often is a combination
like QMA-Male-Right-Angle-to-TNC-Female-Bulkhead adapter or
Just as the paperless office, predicted to
quickly become a reality when personal computers were beginning to dominate the
workplace and home in the 1980s, has yet to occur, neither has desktop software
for high-end applications totally replaced online equivalents. Microsoft has made
good progress in the last few years in moving part of their Office suite online,
you still need a local copy of Visio, Project, and even their Visual Studio software
development tools if you want to use them. Graphics and video editing software cannot
be used efficiently online. The problem is mostly due to time latency between user
input and software display response. Speed on the host server end is addressable
with pumped up computing power and extra