RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
2 MB. Its primary purpose was to provide me with ready access to commonly needed
formulas and reference material while performing my work as an RF system and circuit
design engineer. The World Wide Web (Internet) was largely an unknown entity at
the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps
while tying up your telephone line, and a nice lady's voice announced "You've Got
Mail" when a new message arrived...
All trademarks, copyrights, patents, and other rights of ownership to images
and text used on the RF Cafe website are hereby acknowledged.
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.
About RF Cafe.
3 of the July 2018 homepage archives.
Lens-Like Antenna: Low Noise, Less Space
This is the first article I have posted from a
magazine called, simply, Electronics. It is very different from all the other
vintage electronics magazines I have used in the past. Electronics is much more
focused on military, space, and fundamental research. New issues were published bi-weekly
by McGraw−Hill from 1930 until 1988. About half the editions (this is not one of
them) had two to three times as many pages as the other half, with most of the extra
pages being advertisements. The publishers must have made a fortune on advertising revenue.
My guess is that the vast majority of the companies appearing in the early 1960s issues
I bought on eBay do not exist anymore, having either gone out of business or having been
acquired by bigger ...
Promote Your Company on RF Cafe for as Little as $35/Month
RF Cafe typically receives
10,000-15,000 website visitseach weekday and about half that on weekends. RF Cafe
is a favorite of engineers, technicians, hobbyists, and students all over the world.
With more than 7,000 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. Items added on the homepage are broadcast on LinkedIn, Facebook, and
Twitter. Banner advertising begins at $150/month ...
FCC Compliance for Human Exposure to RF Electromagnetic Fields
RF Cafe website visitor David Burger (VK2CZ /
K3HZ) sent me a great Excel spreadsheet titled, "Evaluating
Compliance with FCC Guidelines for Human Exposure to Radiofrequency Electromagnetic Fields."
As amateur radio operators learn when studying to earn a license, you are required to
perform a calculation to verify that the transmitted effective power radiating from your
antenna does not exceed a specified maximum value in areas where humans have access.
David's spreadsheet takes system parameter inputs and calculates, along with various
other values, the minimum required separation distance for both controlled and uncontrolled
human access. If your antenna is mounted up higher than the limit distance, then no action
is required to keep people away. Otherwise, you must either erect physical barriers or
reduce power output to comply with the maximum RF exposure limit ...
QuinStar Sets New Benchmarks for SSPAs Operating Above 100
QuinStar has established new power benchmarks for
SSPAs operating at frequencies above 100 GHz. We have successfully demonstrated
two GaN MMIC amplifiers operating at F-band frequencies: The first producing an output
power of 28-29 dBm from 102 to 118 GHz, while the second, a wideband design,
delivering an output power of greater than 25 dBm from 98 to 122 GHz. Lastly, we
have assembled and tested a multi-MMIC SSPA producing an output power of 2-3 W over
the 102–116 GHz band. These findings were presented at IMS 2018. This paper reports
the design and performance of two new GaN MMIC amplifiers operating at F-band frequencies ...
New Bell Telephone
Someone sent me a link to a viral video of a group
of teenagers (aka "Millennials") attempting to use an old school dial type telephone.
Two things are notable. #1: They do not remove the handset from the cradle prior to dialing.
#2: One of them asks whether it is necessary to let the dial spin all the way back to
rest before dialing the next number. It's really not their fault since except for in
dusty old places like my house, finding a dial phone is difficult. Many historians have
commented that two innovations most responsible for America's greatness in the last century
were the interstate highway system (for moving goods) and the telephone system. Bell
Telephone Labs engineers designed phones and all the equipment that connected them to
be simple, highly functional, robust, and to have ...
FSK Turbo Codes Supercharge Internet of Things
Turbo-FSK is a low-power, long-range solution for IoT. Internet of
Things networks are different beasts than traditional communication networks. Many, though
not all, IoT networks are characterized by devices that communicate very little for most
of the time, only to burst into action when they need to send - or receive - a relatively
large amount of data in a very short amount of time. That's why researchers at Leti,
the Laboratoire d'électronique des technologies de l'information in Grenoble, France,
developed a new modulation scheme to improve IoT communication. What's more, they have
developed a system ..."
Frequency-to-Meter Conversion Chart for Hams & SWL's
As with your school and college days where once
there was no longer any reason to memorize physical constants, conversion formulas, and
names of people, places, and things, much of the noggin's gray matter was repurposed
to remember topics of more immediate need. You can always look up what you have forgotten.
While studying for your Ham radio or FCC license, being able to be able to quickly convert
between wavelength and frequency is essential. Recalling on demand
frequency-wavelength pairs is a real time saver on a timed exam. Even being able
to perform the conversion on a calculator during the test takes up valuable time that
could be better used on other tasks. This handy-dandy chart for converting ...
RF Front End Module Market to Show
Promising Growth up to 2023
"According to a recent report published by Yole
RF front-end module market is expected to reach US $35.2B by 2023.
The Yole Group of Companies including KnowMade, System Plus Consulting and Yole, combined
their expertise to work on a comprehensive analysis of the RF front-end module industry.
They have mixed their knowledge of the RF FE ecosystem, their understanding of the IP
landscape and their analysis of the today's RF technologies to detail the industry evolution
and highlight the technology trends. Yole Group of Companies has created a set of four
reports dedicated to the RF FE sector. The RF FE modules market, along with the WiFi
connectivity sector, will show an impressive 14% CAGR between 2017 and 2023 ..."
Empower RF Systems to Hold 1 kW Live Demo at EMC Symposium
Empower RF Systems is once again conducting live
demonstrations of broadband, high power amplifiers with compelling performance, industry
leading small size, IOT interface, and user selectable functionality that dares to challenge
legacy products offered in the market. Next appearing at EMC+SIPI 2018 at the Long Beach
Convention Center, we will be showcasing one of our popular models, the 2170, operating
from 1 to 3 GHz at 1 kW in a 5U chassis. The 2170 is a member of Empower's
Next Gen family of high power amplifiers that is the result of a visionary design combining
advances in RF components, digital loop control, real time software, HTML GUI, thermal,
and electro mechanical design ...
B&K Manufacturing Co. Advertisement
Until solid state electronics had supplanted the
majority of vacuum tube type televisions and radios,
portable tube testers were essential equipment to successful, efficient troubleshooting
and repair in businesses and people's homes. Yep, believe it or not the stories told
about doctors and electronics repairmen visiting homes are not just fables. I remember
as recently as the 1960s having our family doctor make house calls when I or one of my
fours sisters got sick. Both doctors and TV servicemen ceased the practice at about the
same time - probably the result of a Brotherhood of Electronics Technicians and General
Practitioners collective bargaining agreement ;-) Many column inches of editorials, articles,
comics, and letters to the editor were devoted to the trials and tribulations of in-home
servicemen and the experiences ...
SpaceX's 2nd Launch in 3 Days Lofts 10
More Iridium Satellites
"Firing through a veil of fog blanketing California's
Central Coast, a Falcon 9 launcher climbed into orbit Wednesday with 10 more satellites
Iridium's voice and data relay constellation, pushing the upgraded
network closer to completion as SpaceX accomplished another landing of the rocket's first
stage booster. The 229-foot-tall launcher lit its nine Merlin main engines after a problem-free
countdown and lifted off from Space Launch Complex 4-East at Vandenberg Air Force Base
at 4:39:30 a.m. PDT. Riding 1.7M pounds of thrust, the slender, two-stage launcher turned
southward from Vandenberg ..."
Engineering Crossword Puzzle w/Weekly Headlines July 29
For the sake of all the avid cruciverbalists amongst
us, each week I create a new
technology-themed crossword puzzle using only words from my custom-created list related
to engineering, science, mathematics, chemistry, physics, astronomy, etc. At least 10
clues with an asterisk (*) in this puzzle are pulled from the past week's
"Tech Industry Headlines" column on the RF Cafe homepage. 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, see someone or something in the exclusion list
directly related to this puzzle's theme, such as Hedy Lamar or the Bikini Atoll, respectively.
International Electronics Quiz
Test your knowledge of the
country of origin of the inventors responsible for these ten inventions. In some
cases the inventor was born in another country but then emigrated to the U.S. or another
country before his/her invention or discovery. This is a pretty tough quiz even for someone
who has done a lot of reading on the history of technology. Guessing the country of origin
for the inventor of the voltaic pile might be easier if you recall the guy's name (hint:
his name is in the caption), and for the TV antenna take note of the configuration of
the elements (hint: there was nobody named Log Periodic). I'm too embarrassed to divulge
my score, but if you do better 50% or better, you've beaten me ...
World's Fastest Human-Made Spinning
"Researchers have created the fastest human-made
spinning object in the world, which they believe will help them study
material science, quantum mechanics and the properties of vacuum. At more than 60 billion
revolutions per minute, this machine is more than 100,000 times faster than a high-speed
dental drill. 'This study has many applications, including material science,' said Tongcang
Li, an assistant professor of physics and astronomy, and electrical and computer engineering,
at Purdue University. 'We can study the extreme conditions different materials can survive
in.' Li's team synthesized a tiny dumbbell ..."
Symbolism in the FCC Seal
Dave Casler, KE0OG, has a YouTube channel titled,
Radio Answers" where, as the name implies, he fields questions from viewers. This
Symbolism in the
FCC Seal episode was featured in the August 2018 issue of QST magazine. As one who
explores the history of radio communications and electronics, I found this interesting.
Electronics-Themed Comic, February 1972 Popular Electronics
This is a great
electronics-themed comic from a February 1972 issue of Popular Electronics.
It encompasses the essence of the stereotypical salesman ruse, especially in that era
when people were sure that electronics repair services were out to rip them off by selling
unneeded services and replacement parts. Aspiring TV technicians who couldn't grasp the
technology moved on to working as mechanics in a garage, poking tiny holes in brake lines
to scare owners into paying for complete braking system rebuilds. I usually like to post
multiple comics on each page, but at the moment only this one is available ...
RF Stencils for Visio v3.1 Available!
- Your Support Keeps Me off Welfare ;-)
With more than 780 custom-built symbols, this
has got to be the most comprehensive set of
available for RF, analog, and digital system and schematic drawings! Every object has
been built from scratch to fit proportionally on the provided A- and B-size drawing page
templates (you can use your own page if preferred). Components
are provided for equipment racks (EIA and ETSI) and test
equipment, system block diagrams and conceptual drawings, and for schematics
Electronic Stickers to Streamline Large-Scale
"Researchers have developed a new fabrication
method that makes tiny,
thin-film electronic circuits peelable from a surface. The technique
not only eliminates several manufacturing steps and the associated costs, but also allows
any object to sense its environment or be controlled through the application of a high-tech
sticker. Billions of objects ranging from smartphones and watches to buildings, machine
parts and medical devices have become wireless sensors of their environments, expanding
a network called the 'internet of things.' As society moves toward connecting all objects
to the internet - even furniture and office supplies ..."
Spot News - Electronic Industry News
Television broadcast stations were quickly growing
in number in the post-Korean War era and the FCC needed to devise a scheme for
accommodating more channels. There were only 13 channels (only 2-13 used) allocated
in the VHF spectrum with 6 MHz-wide bands. Even though VHF propagates primarily
in a line-of-sight mode, reflections and earth-bounce can extend the range fairly significantly,
limiting density in closely spaced cities. The military refused to yield any spectrum
so a decision was made to add new channels (14-83, also 6 MHz wide) in the UHF band.
UHF presented its own problems with more difficult equipment manufacturing issues and
higher atmospheric attenuation. It never really caught on because cable TV was being
widely installed in metro areas ...
Global OTA Testing Market to Reach $3 Billion
in Revenue by 2025
over-the-air testing industry is projected to reach $3B in revenues
by 2025, growing at a CAGR of 9.4% from 2018 to 2025. This industry was valued at $1.5B
in 2017. At present, North America dominates the global OTA testing market with a revenue
of $630.5M in 2017, and is projected to reach $1.2B by 2025, growing at a CAGR of 8.7%
from 2018 to 2024. However, the Asia-Pacific region is anticipated to exhibit the highest
CAGR of 11.7% during the forecast period. Over the Air (OTA) testing is a mandatory test
to get the cellular telecommunications and internet association (CTIA) certification ..."
ConductRF Low PIM RF Cables for DAS and Cellular
ConductRF provides 3 styles of solution for
DAS applications in Stadiums,
Malls, Campuses, Hotels and more. Straight & R/A Low PIM Connectors are available
for 7/16, N, SMA, QMA, 4.1/9.5 and 4.3/10 interfaces. We also offer Low PIM Adapters
and PIM Test Cables for all these series. Utilizing ConductRF's new Low PIM Direct Solder
Attachment Connectors, we provide high performance solutions for Low PIM interconnect
including Straight, Right Angle, Bulkhead and Panel attachment. Performance better than −155 dBc
is validated through 100% testing ...
The Ubiquitous Ham
You probably need to be a
Ham radio operator to fully appreciate the humor in some of these comics. The first
one, for instance, is a poke at a guy proudly pointing out his QSL cards from distant
(DX) stations "right near the city limits," "on the other side of town," etc., basically
what you can pull in with a home Citizens Band (CB) radio base station and a rooftop
antenna. In another, the "73" signoff code is from the
Western Union telegraph standard meaning "Best regards." "88" means
"Love and kisses," hence the guy's unnerved response. The others don't really require
an insider viewpoint. Let me know if you need any more help ;-) ...
RF Test Technician Needed by Empower RF Systems
Empower RF Systems is a leading provider of high-power
ultra-broadband radio frequency (RF) amplifier solutions. The company and designs and
manufactures solid-state, high-power RF amplifier systems and modules for commercial,
scientific, and military customers worldwide. RF Test
Technician Position Summary: Reporting to the Production Test Manager and
partnering closely with engineering teams, the RF Test Technician is responsible for
developing and performing test solutions for RF products from concept through manufacturing
release. He/she supports product development evaluations and final product characterization
testing, and works with the development team to provide testability planning, strategies
and methodologies ...
A Photonic Circuit for Quantum Computers
"Getting photons to interact is a key step toward
using them as qubits. The foundational element of quantum computers is the qubit.
Qubits can be any kind of particle that has quantum properties, such
as an electron or a photon. For these qubits to accomplish their job in a quantum computer,
they need to interact with each other in a quantum process known as entanglement. While
photons would make for great qubits because of their speed, they don't like to interact
with each other, or anything else for that matter, making it difficult to achieve quantum
entanglement. Now researchers at the University of Maryland and the Joint Quantum Institute
have managed ..."
Electricity from Atoms
Dr. Linder's patented AC and DC generators
exploited alpha (proton) and beta (electron) particle emissions from radioisotopes contained
within. The device is basically a metallic sphere concentric to an enclosed mounting
platform for polonium (α particle emitter), phosphorous
(β particle emitter),
or similar elements. With just a gram of radioactive material, the charge which accumulates
on the outer sphere generates a very high voltage (~1 MV) driving a low current
(~1 mA). Georg Ohm's work tells us that is equivalent to 1 kW of power - quite
a lot for a fairly compact device. Dr. Linder envisioned multiple
atomic generators combined in series and/or parallel to obtain the required power.
No mention was made of the effective internal resistance, which would ultimately determine
the terminal voltage when connected to a load ...
RF Cascade Workbook 2018
- Your Support Helps Keep Me off Welfare ;-)
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 ...
everythingRF Adds 6 New Component Search Categories
everythingRF has created the largest database of
searchable RF and microwave components, equipment and services. everythingRF has recently
added six (6) new categories to their
parametric search tool: DRO's, PL-DRO's, VCSO's, SAW Resonators, DLVA's, and Pick-Off
Tees . The parametric search tool makes it easy to find products across multiple manufacturers
based on the user's requirement. For example, the user can enter the frequency, voltage
and other parameters and the tool scans multiple manufacturer catalogs to find the product ...
Flat-Screen TV Has 52,900 Picture Elements
A 720-line HDTV display is made up of 1,280 vertical
lines and 720 horizontal lines of pixels, which gives a total of 921,600 pixels. A 1080-line
HDTV has 1,920 vertical lines and 1,080 horizontal lines, for a total of 2,073,600 pixels.
In 1969, a 230 vertical line by 230 horizontal line
electroluminescent (EL) flat-screen television display with 52,900 pseudo-pixels
was considered a big deal - and it was since it was the starting point for digital flat-screens
of today. Interestingly, while the "pixel" distribution was square, the actual display
retained the standard 4:3 aspect ratio, meaning horizontal element width was 33% greater
than the vertical element. Since each EL element was addressed individually, there was
no ability of a picture element to be shared by adjacent "pixels," so displaying a circle
would result in a very pixelated picture ...
Nanoparticles Enable Molecular
"Last week, researchers at IBM Research-Zurich
in Switzerland, and the Universities of Basel and Zürich announced in a Letter published
in Nature a new method for creating electrical contacts to
individual molecules on a silicon chip. The advance could open up
a promising new way to develop sensors and possibly other electronic or photonic applications
of manipulating single molecules. When, in the mid-1970s, researchers discovered single
molecules with interesting electronic properties such as that of a diode, hopes
were high that this would spur the development of a new semiconductor technology that
might compete with silicon-based electronics ..."
"Eventually," Dr. Herwald said, "we believe it
will even be possible to automatically and continuously produce actual electronic equipment,
such as radio receivers and amplifiers, starting from a pool of molten semiconductor
materials." That was in early 1960 in an Electronics World article titled, "Molecular
Electronics." The term "molecular" references what eventually became integrated circuits
(IC), the first of which was realized in 1958 by Texas Instruments engineer Jack Kilby.
Kilby's IC incorporated one transistor, one capacitor, and three resistors on a germanium
substrate. Building on that success, researchers envisioned single-chip semiconductors
which contained hundreds, thousands, and even millions of transistors, diodes ...
Space, Not Brexit, Is Final Frontier
for Scottish Outpost
"Never mind Brexit: For a remote peninsula in
the Scottish highlands, the buzz is all about hi-tech rocket launchers firing satellites
into space. In just three years' time, rockets will send satellites into orbit from the
rugged stretch of coastline, under British government plans unveiled this week. The sleepy
county of Caithness and Sutherland has been selected as the site of the country's first
space port, Britain announced at the Farnborough Airshow, a showpiece
event for the global aerospace sector ..."
EDI CON USA 2018 Announces EDI CON University
Electronic Design Innovation Conference and Exhibition
(EDI CON) USA, the industry event that brings together RF/microwave and high-speed digital
design engineers and system integrators, is pleased to introduce its
University 2018 program at its event this October 17 and 18 at the Santa Clara Convention
Center. These 2-hour sessions offer in-depth training in a particular topic, such as
MIMO Test, Amplifier Design, and Measuring Impedance. All conference pass holders are
eligible to attend, but pre-registration happens during the registration process. After
attending an EDI CON University course, attendees can earn IEEE Continuing Education
Unit/Personal Development Hour ...
Comes the Revolution - or - "40 Million Frenchmen Can't Be
Popular Electronics printed in April 1966 its
first notice of
new frequency units to be used beginning with the June edition. The May issue included
piece titled, "Comes the Revolution - or - '40
Million Frenchmen Can't Be Wrong'." Predictably, not everyone liked it. With the June
issue came the promised change and along with it the first in a series of reader responses.
I also found a reader's opinion from the
August issue as well. Evidently, not everyone wanted to honor Heinrich Hertz by naming
the base unit of frequency in his honor ...
Installing an Android Radio and GPS into an
Paul Rako, over at Electronic Design, has posted
many pieces over the years about his DIY projects. This one details his exploits while
retrofitting his 1992 Honda Accord with an Android radio and GPS. The finished product
look like a factory-installed option. "Like a lot of engineers, I enjoy working on my
own cars. I take pride in keeping my old 1992 Honda Accord running. I have replaced a
bad ignition module inside the distributor, and the cracked radiator. I did take it to
a mechanic to replace the axle half-shafts, but try to do all the lighter work myself.
Lately that has included fixing a broken key lock on the passenger side, as well replacing
the lug nuts so that ..."
China Plans 2 New Gravitational-Wave Missions
This is worth looking at just for the cool image.
"China has revealed plans for two space-based missions to study
gravitational waves. The National Space Science Center, Chinese Academy
of Sciences (CAS), announced on 4 July that the country will launch a mission in 2020
to monitor gamma-ray bursts associated with gravitational-wave events. The CAS also gave
the go-ahead for a fully-fledged gravitational-wave detector to be sent into space in
2033. Gravitational waves are distortions of space-time that occur when massive bodies,
such as black holes, are accelerated. Since their first direct detection in 2015 by the
Laser Interferometer Gravitational-Wave Observatory (LIGO) detectors ..."
Electrical Shock: Fact and Fiction
Any time I see
an article that references causing limb movements by poking the brain with electrical
signals, I think of the old The Far Side comic. Artist Gary Larson drew quite
a few hilarious operating room scenarios.
Electrocution is of course not a laughing matter - unless it happens to someone else
and it is not serious and no harm is done. Then - and only then - can it be funny. I've
laughed at myself many times after receiving a good jolt due to stupidity. Sometimes
after such an experience I wonder how I never killed myself from getting zapped as the
result of being too lazy to turn off a circuit breaker before servicing a light switch
or receptacle. The sad thing is that I'll probably do it again some day ...
25 Charts on Spectrum Ownership in
the United States
"Licensed spectrum remains the lifeblood of the
cellular industry. But which companies actually own all those
spectrum licenses? More importantly, which spectrum licenses do they
own, how much did they pay for them, and where is the market heading? This report aims
to answer these questions. We've collected the below charts from a variety of sources
including spectrum management companies, Wall Street analyst firms and boutique analysis
companies such as Allnet Insights & Analytics. Our goal is to provide an overview
of licensed spectrum ownership in the United States ranging from low-band licenses like
600 MHz to high-band holdings up to 40 GHz ..."
Foreign Tube Substitution Data
I suppose a more appropriate title for this chart
would be "Foreign
Valve Substitution Data," considering that most (if not all) of Europeans refer(red)
to vacuum tubes as "valves." As with having posted scores of Radio Service Data Sheet
pages for the benefit of hobbyists who restore and service vintage radio equipment, I
also post other hard-to-find reference resources when I find them. Sure, the number of
people looking for this information is extremely small, but they are extremely grateful
for this when in the throes of finding replacement tubes (valves). Posting a hyperlink
to this page on the RF Cafe homepage will assure that ...
Corner Press QSL Card Printing Services
Barry Rimer (WA2WAO), proprietor of Corner Press,
has been printing
QSL cards since 1961. QSL cards are cards Amateur Radio Operators (HAMS) send to
each other to confirm a QSO (talking to each other on the air). QSL's were our first
product; it's how we started in 1961. In 1971 we changed the company name to Corner Press
to reflect a more diverse product line, not just HAM radio specific. There are more than
70 standard designs to choose from, or submit your own custom design. We produce QSL's
in many styles: Flat printed in one or two spot colors, Raised printed in one or two
spot colors, Full bleed full color. Please contact Barry for your QSO printing needs ...
Experts and Engineers Explain 10 Steps
of Design Process
"The 10 steps of the engineering design process
are fundamental knowledge for all budding engineers. If you're hoping to become an engineer,
one of the most crucial things you need to learn are the 10 steps of the
engineering design process. This process lays out the correct protocol
for any project, allowing everything to go seamlessly. No matter which area of engineering
you intend to work in, the 10 steps will always be important. They're a fundamental part
of engineering, and can always provide a solid foundation for your work. Let's take a
look at each step, and hear what the experts have to say about the importance of the
Engineering Crossword Puzzle w/Weekly Headlines, July 22
At least 10 clues with an asterisk (*)
technology-themed crossword puzzle are pulled from this past week's (7/16 - 7/20)
"Tech Industry Headlines" column on the RF Cafe homepage. For the sake of all the avid
cruciverbalists amongst us, each week I create a new technology-themed crossword puzzle
using only words from my custom-created list 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, see someone or something in the exclusion list who or that is directly related
to this puzzle's theme, such as Hedy Lamar or the Bikini Atoll ...
Please Support RF Cafe by purchasing
my ridiculously low−priced products, all of which I created.