See Page 1 |
2 |
3 |
4 | of the July 2023 homepage archives. Friday the 21st
 The National Science Foundation's 1000-meter
Arecibo radio telescope, carved into a Puerto Rico mountain valley, was commissioned
on November 1, 1963. Justification in funding the colossal project was partly from
the Department of Defense because of a need to characterize the Earth's upper atmosphere.
Satellites and looming threats of soon to be developed ICBM traffic were of prime
concern. One of the renowned uses of the Arecibo radiotelescope was when Carl Sagan's
team transmitted a "we are here" message toward the M13 globular cluster in the
constellation of Hercules in 1974. The amount of research and data collected over
the ensuing six decades has been invaluable from both communications and astronomical
perspectives. Tragically, on November 7, 2020, the dish suffered a catastrophic
mechanical failure in the suspension supports, resulting in irreparable damage.
Planning on the site's future is ongoing...
 Imagination and creativity is everywhere
today, and actually always has been, but now thanks to the Internet, we are able
to find it. I wish I had time to both engage in my own projects like this and to
watch endless videos of other people's endeavors.
Usagi Electric star David
Lovett designed, built and demonstrated "Building the Largest 555 Timer
in the World out of Vacuum Tubes" in this video. Not content with merely ginning
up a good-enough breadboard, he makes a CNC-routed PCB for the components and tube
sockets, but also fabricates mock-ups of IC-type pins for use as legs. As you might
expect, Mr. Lovett also has many other interesting videos - most of which feature
vacuum tubes - posted, totaling 5 million views to date. Usagi, BTW, is the Japanese
word for "rabbit."
 Most of us have heard about the neighborhood
collections for tires, glass, newspaper, cans, and cloth in order to help support
the war effort. Probably not many have also heard about the Signal Corps'
call for milliammeters! That's right, the huge, rapid build-up of electrical
and electronic equipment for radios, vehicles, and factory equipment. Many meters
were needed for monitoring status and making process adjustments. America had an
ample supply of meters in the hands of Amateur radio operators; all that was required
was to separate the Hams from their meters. Fortunately, an appeal to patriotism
was sufficient motivation back then. Numerous ads were placed by companies and special
interest groups like the ARRL encouraging milliammeters owners to part with their
cherished instruments. Here, from the November 1942 edition of QST magazine,
is a printed plea from the ARRL, and a couple examples of companies looking to collect
milliammeters...
 "Scientists in China have built a facility
to conduct cost-effective
microgravity experiments on Earth and support the country's ever-growing research
ambitions in space. The 40-metre (131-foot) tall Microgravity Experiment Facility
with Electromagnetic Launch, or MEFEL, uses a linear motor to drive objects up and
down and approximate the conditions of weightlessness for 4 seconds. MEFEL can host
up to 100 experiments every day and consumes only about 1 kilowatt-hour of electricity
for each experiment, according to Zhang Yongkang from the Technology and Engineering
Centre for Space Utilisation under the Chinese Academy of Sciences in Beijing, which
led the development of the facility..."
 If you do a search for "acoustinator," you
get a certain model of acoustic guitar speaker manufactured by the UK-based company,
Eminence. That, however, is not the same as the "Acoustinator"
developed by Motorola for their "Golden Voice" series of car radios, as shown in
this 1938 Radio-Craft magazine ad. It was essentially what we refer today
to as a tone control, or as an equalizer. Not satisfied with creating just one futuristic
sounding techno-term, Motorola also came up with the "wobbulator" for use in tuning
the receiver IF response. From what I gather in the Radio Service Data Sheet instructions,
a wobbulator is a sweep frequency generator for testing a filter response shape.
In case there never was a trademark associated with or a current trademark or trade
name assigned to "wobbulator," (or alternately "wobulator") let it be known that
I hereby formally...
 With more than 1000
custom-built symbols, this has got to be the most comprehensive set of
Visio Symbols available for RF, analog, and digital system and schematic drawings!
Every object has been built to fit proportionally on the provided A-, B- and C-size
drawing page templates (or can use your own). Symbols are provided for equipment
racks and test equipment, system block diagrams, conceptual drawings, and schematics.
Unlike previous versions, these are NOT Stencils, but instead are all contained
on tabbed pages within a single Visio document. That puts everything in front of
you in its full glory. Just copy and paste what you need on your drawing. The file
format is XML so everything plays nicely with Visio 2013 and later...
 Anritsu has been a global provider of innovative
communications test and measurement solutions for more than 120 years. Anritsu manufactures
a full line of innovative components and accessories for
RF and Microwave Test and Measurement
Equipment including attenuators & terminations; coaxial cables, connectors &
adapters; o-scopes; power meters & sensors; signal generators; antenna, signal,
spectrum, & vector network analyzers (VNAs); calibration kits; Bluetooth &
WLAN testers; PIM testers; amplifiers; power dividers; antennas. "We've Got You
Covered."
Thursday the 20th
 Despite a natural instinct to be suspicious
about new products claiming to to be a panacea to all problems pertaining a particular
subject, it seems magazines of all eras have been filled with advertisements pitching
such products. Not all are total scams, but the usefulness is often more narrow
in scope than implied or explicitly stated in the ad. An example is high gain vacuum
tube replacements for televisions which promised to improve picture quality in noisy
or low signal strength environments. They could potentially result in a better picture,
but often all that happened was both signal and noise levels increased to result
in a brighter image, which then required turning down the brightness control; i.e.,
no overall real improvement.
Antennas are another example of "miracle" cures for reception woes. The truth
is that unless you lived in a high quality signal area, nothing short of a high
gain directional antenna on the roof would do a really good job of pulling in a
great picture (and sound). Set-top rabbit ears or wires running up the wall and
across the ceiling were shot-in-the-dark efforts. Excluding weather and traffic
related multipath signal variations...
Werbel
Intros Ultra-Wideband Directional Coupler
 Werbel Microwave presents an impressive
array of features in our latest offering. The C-1830-10 from Werbel Microwave is
an
ultra-wideband directional coupler with exceptional performance across frequencies
from 0.3 to 8 GHz. It offers excellent coupling flatness, good directivity,
and can handle up to 20 W of power. This coupler is well-suited for lab testing
and power monitoring applications, among others. With its ultra-wide bandwidth,
spanning from 0.3 to 8 GHz, it eliminates the need to switch components for
different frequency bands in most lab testing scenarios. The coupler also provides
high directivity (24 dB typ.), minimizing detrimental effects from output mismatches.
Additionally, it offers excellent coupling flatness of ±0.8 dB typ., eliminating
the need for compensation circuits in many cases...
 The year 1935 could be considered the beginning
of a new paradigm in communications thanks to the introduction of
metal-encased vacuum tubes. They facilitated a move into higher frequency circuit
design and denser component placement (smaller volume). Prior to then, vacuum tubes
were almost exclusively encased in a glass envelope with no innate guard against
the emission or absorption of electromagnetic fields from nearby components. Metal-encased
tubes provide benefits like better heat dissipation, smaller physical size, ruggedness,
inherent RF shielding, and lower parasitic values of capacitance and inductance
due to smaller plate areas and shorter lead lengths, respectively. The highest barrier
to widespread adoption of metal tubes, history would show, was the higher cost of
production that made consumer products more expensive at a time when not every household
saw the need for a radio or, eventually, a television...
 Antenova Ltd, the UK-based manufacturer of
antennas and RF antenna modules for M2M and the IoT, has published a whitepaper
entitled, "A
Guide to Matching Circuits, Transmission Lines and Antenna Tuning." It begins:
"Designs thrive in environments with the least restrictions and minimal risk of
product failure. Part of creating a product is analysing the risk associated with
individual components, identifying and selecting the ones with the most desirable
functions. Wireless antennas are not like these other electronic components. Whilst
you can predict antenna performance to a certain level, it is highly likely you
will face serious compromise if you choose to integrate it at the latter stages
of development. Antenna performance is wholly a product of the operating environment.
In every different scenario, the performance of an antenna will vary - be that in
free space or whilst embedded within...
 Today is the July 20, 1969 anniversary of
Apollo 11's landing on the moon, so I figured this article would be a timely
reminder of the contributions made to electronics technology as part of the immense
effort. The thumbnail to the left is the front page of my hometown newspaper on
July 21, 1969 (my father was the classified ad department manager there - see inset).
Apollo 16 launched on April 16 of 1972 and landed on the moon on April 19.
By then, as with Space Shuttle flights, moon landings were no longer front page
news; The Evening Capital carried the story on page 2. Popular Electronics
magazine editor Snitzer wrote this short piece extolling the critical role that
electronics played in mission success. Apollo 17 flew next and December 10,
1972, marked the last time mankind ever set foot on the moon. President Trump has
asked NASA to explore the possibilities of returning to the moon by 2019, possibly
as a next step toward a mission to Mars. It is now 2023 and we're not there yet...
 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!
 Temwell is a manufacturer of 5G wireless communications filters
for aerospace, satellite communication, AIoT, 5G networking, IoV, drone, mining
transmission, IoT, medical, military, laboratory, transportation, energy, broadcasting
(CATV), and etc. An RF helical bandpass specialist since 1994, we have posted >5,000
completed spec sheets online for all kinds of RF filters including helical, cavity,
LC, and SMD. Standard highpass, lowpass, bandpass, and bandstop, as well as duplexer/diplexer,
multiplexer. Also RF combiners, splitters, power dividers, attenuators, circulators,
couplers, PA, LNA, and obsolete coil & inductor solutions.
Wednesday the 19th
 Interference takes on many forms and can
be caused by nearly an infinite number of sources. In 1960 when this article appeared
in Radio-Electronics magazine, most
manmade interference (QRM) originated in electrical machinery, faulty contacts
in switches and lighting, improperly shielded and/or filtered RF generators, and
arcing transmission lines. Natural interference (QRN) has not fundamentally changed
since the same process continue to occur - lightning, meteoric ionization of the
atmosphere, solar particles, etc. It was nearly all caused by analog processes.
Nowadays, ambient noise both conducted and induced is as likely - or even more likely
- to come from digital circuits. The base level (noise floor) of electromagnetic
(EM) signals in a typical urban or suburban environment is significantly higher
than it would have been in 1960. Fortunately, the same group of engineers and scientists
that generated the condition have also figured out ways to mitigate the issues -
for the most part. Some forms of increased EM interference...
 Since 1996, ISOTEC has designed, developed
and manufactured an extensive line of RF/microwave connectors, between-series adapters, RF components
and filters for wireless service providers including non-magnetic connectors for
quantum computing and MRI equipments etc. ISOTEC's product line includes low-PIM
RF connectors components such as power dividers and directional couplers. Off-the-shelf
and customized products up to 40 GHz and our low-PIM products can meet -160 dBc
with 2 tones and 20 W test. Quick prototyping, advanced in-house testing and
high-performance. Designs that are cost effective practical and repeatable.
 A
polygon is a two-dimensional
geometric figure that is formed by connecting a sequence of straight line segments
to create a closed shape. The segments are called sides, and the points where the
sides intersect are called vertices. Polygons can have any number of sides, but
they must have at least three sides. The word "polygon" has its origins in the Greek
words πολύς ("many") and γωνία (gōnia), meaning "knee" or "angle." Polygons are
classified based on the number of sides they have: Triangles: Triangles are polygons
with three sides and three vertices. They are further classified into: Equilateral
triangle: All three sides are equal in length. Isosceles triangle: Two sides are
equal in length. Scalene triangle: All three sides have different lengths. Right
triangle: One angle is a right angle (90 degrees). Quadrilaterals: Quadrilaterals
are polygons with four sides and four vertices. They include: Square: All four sides
are equal in length, and all angles are right angles. Rectangle: Opposite sides
are equal in length, and all angles are right angles. Parallelogram: Opposite sides...
 In this wanton example of virtue signaling,
NASA is attempting to extol the virtue of transporting astronaut crews to the launch
pad in an
e-vehicle ... to be launched into space in a rocket that will put millions of
pounds of exhaust products into the atmosphere. All methods of producing hydrogen
fuel (H2) are energy intensive, including extraction from
fossil fuels
(95%) and
electrolysis. It's a greater breach of integrity than a dieting 500-pound (227 kg,
0.25 ton, 36 stone) person at a table full of donuts, with a diet Coke
to wash it all down. As stated many times before, I have been a life-long proponent
and champion for the development of alternative energy sources and implements for
exploiting its use, but what I object to is the shameless lying and deception by
politicians, media, and, most unforgivably, the science community, for personal
aggrandizement. Prove me wrong.
 Here is yet another treatise on the subject
of
reactance and resistance. Considering that the date on this Radio-Craft magazine
is 1931, it was probably amongst the first to publically discuss such newfangled
topics outside of a formal university setting. The layman just was not accustomed
to being bothered with such esoteric concepts. After all, not many decades previous
a person might be burned at the stake for exercising such witchcraft as speaking
of "imaginary" numbers as is required for a complete analysis of alternating circuits.
This article, however, does not actually get into complex numbers, but future ones
did...
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...
 SF Circuits' specialty is in the complex,
advanced technology of PCB fabrication and assembly, producing high quality multi-layered
PCBs from elaborate layouts. With them, you receive unparalleled technical expertise
at competitive prices as well as the most progressive solutions available. Their
customers request PCB production that is outside the capabilities of normal circuit
board providers. Please take a moment to visit San Francisco Circuits today. "Printed
Circuit Fabrication & Assembly with No Limit on Technology or Quantity."
Tuesday the 18th
 If I have ever heard of a "trigistor"
(aka "dynaquad") before seeing it in the 1960 Radio-Electronics magazine article,
I don't remember it. It is a p-n-p-n silicon switch device that is essentially the
same as a thyristor in that conduction can be turned on or off with separate control
signals that can be removed once the switching action is initiated. According to
the Wikipedia entry for the thyristor, it was first introduced in 1956, not so long
before this article. The Howard W. Sams Transistor Circuit Manual, 1961, by
Allan Lytel provides information on not just the "trigistor," but also the "binistor,"
another bistable on/off silicon switch. Other process control devices such as unijunction
transistors, avalanche diodes, silicon controlled rectifiers (SCRs), and cryostats
(used for temperature control) are discussed. The electronics industry was in the
early stage of transition from vacuum tubes to solid state devices...
 Duh. Astronomers warned of both visible
light and radio frequency electromagnetic
interference from the massive satellite constellations being launched by SpaceX,
Starlink, and others. Experts who have no direct vested interest in the astronomy
assured everyone that once all the birds were "on orbit," their footprints would
be too small to matter. A skeptic might be inclined to suspect they have a financial
incentive to make their claims - akin to medical "experts" who told us the unvaccinated
would all be dead by now and the weather experts who told us the polar ice caps
would be gone 10 years ago. Astronomers called "BS" from the beginning; to wit:
"Astronomers Stand
up to Satellite Mega-Constellations," "Satellite
Constellations Are an Existential Threat for Astronomy," "Satellite
Megaconstellations Are Threatening Astronomy." As the numbers grow, the true
impact will become increasingly evident. At least, though, Internet service will
be available at every point on Earth, with heavily government-subsidized subscriptions.
 Here are handy formulas for some of the
most commonly used
cylinders,
cones, and spheres, all with symmetry about the axis of rotation. Equations
for surface area, volume, and circumference are provided. They were gotten from
CRC Standard Math Tables, 1987...
 "A modular quantum computer with multiple
separately cooled processor nodes could solve this. However, single microwave photons
- the particles of light that are the native information carriers between superconducting
qubits within the processors - are not suitable to be sent through a room temperature
environment between the processors. The world at room temperature is bustling with
heat, which easily disturbs the
microwave photons and their fragile quantum properties like entanglement. Such
an entangled quantum state of two photons is the foundation to wire up superconducting
quantum computers via room temperature links. This has implications not only for
scaling up existing quantum hardware but it is also needed to realize interconnects
to other quantum computing platforms as well as for novel quantum-enhanced remote
sensing applications..."
 As the advertisement for membership in the
Official Radio Service Men's Association says, structured organizations for
people of like mind and interests have long been the hallmark of an advanced society
where there is a need for directed socialization and the 'strength in numbers' benefit.
I suppose most people reading this piece belong to at least one such association
like the Institute for Electrical and Electronics Engineers (IEEE), American Radio
Relay League (ARRL), Armed Forces Communications and Electronics Association (AFCEA),
Association of Old Crows (AOC), Electronics Technicians Association (ETA), etc.
Having significant representation in government in the form of lobbyists is essential
these days in order to obtain and retain fair treatment and consideration of your
professional, hobby, and personal interests. If you don't defend your territory,
somebody else WILL take it. I liken the predators to Sentinels in the Matrix movie
series that are incessantly and tirelessly seeking out to subdue and destroy the
Human Resistance...
 Banner Ads are rotated in all locations
on the page! RF Cafe typically receives 8,000-15,000 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.
Your 728x90-px and 160x600-px Banner Ads are displayed on average 225,000 times
per year! 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...
 Alliance Test Equipment sells
used / refurbished
test equipment and offers short- and long-term rentals. They also offer repair,
maintenance and calibration. Prices discounted up to 80% off list price. Agilent/HP,
Tektronix, Anritsu, Fluke, R&S and other major brands. A global organization
with ability to source hard to find equipment through our network of suppliers.
Alliance Test will purchase your excess test equipment in large or small lots. Blog
posts offer advice on application and use of a wide range of test equipment. Please
visit Allied Test Equipment today to see how they can help your project.
Monday the 17th
 Here we go with four more
electronics-themed comics, this time from the May 1964 issue of Radio-Electronics
magazine. Man-made satellites were a relatively new phenomenon, so they were fair
game for ridicule. A lot of people were afraid of a satellite falling from orbit
and crashing through their roofs or strike them down on the golf course. In the
ensuing 66 years since Sputnik was launched in 1957, as far as we know Lottie Williams,
of Tulsa, Oklahoma, is the only person ever to have been confirmed to have been
hit by a piece of satellite debris. Another comic makes fun of the trend in the
day of vacuum tubes being designed with an ever-increasing number of pins. The pin
counts on most tubes were typically between 4 and 8. A diode tube had two pins for
the heater element and one each for the cathode and anode, for a total of 4. A duotriode
like the 12AT7 sported 8 pins. The 6AV11 Compactron Three Triode contained 3 triodes
(a triotriode) and had 12 pins, three for each triode, two for the heater, and one
N/C. Some cathode ray tubes (CRTs) had 14 or more pins. Attempts were made to build
vacuum tube integrated circuits...
 This is the
electronics market prediction for West Germany, circa 1966. It was part of a
comprehensive assessment by the editors of Electronics magazine of the
state of commercial, military, and consumer electronics at the end of 1965. West
Germany was intent on being a player in the Space Race with Siemens and Telefunken
providing expertise. Bochumer Verein was pushing the electronic computer frontiers
forward. The article states that only about 5% of West Germany's factories including
heavy industry have anything approaching the automation of American industry. Factory
automation was viewed as a threat to the German workers. Unless you can find a news
story on the state of the industry, detailed reports must be purchased from research
companies like Statista. Their website has a lot of charts on Germany's current
electronics market showing revenue in the consumer electronics segment amounts of
US$2,948M in 2018...
 "A new family of ferroelectric materials
could be used to make more energy-efficient microelectronics devices. This is the
finding of researchers at Carnegie Mellon University and Pennsylvania State University,
both in the US, who studied how the polarization of crystalline materials called
wurtzites switches when an electric field is applied. The recent observation
of ferroelectricity in wurtzites contradicted a 100-year-old belief that these materials
were pyroelectric and piezoelectric, and that their polarization could thus not
be switched with an electric field. The discovery also sparked interest among electronics
engineers because wurtzite-based switches could have applications in logic, memory,
high-power, acoustic and electro-optical devices. A further attraction is that wurtzites
would be easy to integrate with mainstream semiconductor platforms..."
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...
 This Radio Service Data Sheet for the
Motovox Models 10A All-Electric and 10E Battery-Operated "Moto-Tetradynes" is
an example of the dozens of similar schematic and alignment instruction sheets that
have been posted on RF Cafe over the years. It appeared in a 1933 issue of Radio-Craft
magazine. There was also a small image and brief description of this "motor-car
receiver" (moto "moving" + vox "voice") in the August 1933 issue of Radio News
magazine. Obtaining technical information on most things, even readily available
items, prior to the Internet era was often very difficult - if not impossible. Service
centers had what was needed by manufacturers and distributors, but if you wanted
to find a part number or service data on a refrigerator, radio, lawn mower, garage
door opener, etc., and did not have the original paperwork, you were usually out
of luck. Nowadays a Web search will quite often get you what you need thanks to
people (like me) who go to the trouble of making the information available. The
stuff doesn't just magically appear or get posted by benevolent governmental entities...
 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. 50 Ω and 75 Ω models are available, along with
a full line of precision calibration and connector adaptors.
Sunday the 16th
 This custom RF Cafe
electronics-themed crossword puzzle for July 15th contains words and clues which
pertain exclusively to the subjects of electronics, science, physics, mechanics,
engineering, power distribution, astronomy, chemistry, etc. If you do see names
of people or places, they are intimately related to the aforementioned areas of
study. Being that "O" is the 15th letter of the alphabet, it is used as the first
and/or last letter of many words in today's crossword puzzle - as well as in-between.
Those clues are marked with an asterisk (*). 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.
/jobs.htm">![Engineering Job Board - RF Cafe]() RF
Cafe's raison d'être is and always has been to provide useful, quality content for
engineers, technicians, engineering managers, students, and hobbyists. Part of that
mission is offering to post applicable
/jobs.htm">job openings. HR department employees and/or managers of hiring
companies are welcome to submit opportunities for posting at no charge. 3rd party
recruiters and temp agencies are not included so as to assure a high quality of
listings. Please read through the easy procedure to benefit from RF Cafe's high
quality visitors...
Reactel has become one of the industry leaders in the design and manufacture
of RF and microwave
filters, diplexers, and sub-assemblies. They offer the generally known tubular,
LC, cavity, and waveguide designs, as well as state of the art high performance
suspended substrate models. Through a continuous process of research and development,
they have established a full line of filters of filters of all types - lowpass,
highpass, bandpass, bandstop, diplexer, and more. Established in 1979. Please contact
Reactel today to see how they might help your 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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