See Page 1 |
2 |
3 |
4 of the August 2021 homepage archives. Friday the 13th
 This June 1945 issue of Radio News
magazine reported on the passing of President Franklin Delano Roosevelt; he
died on April 12th. While radio was building its presence as a relatively new form
of communication, Roosevelt exploited the technology often with radio speeches and
his well-known series of "Fireside Chats." At the outbreak of World War II,
many Americans first learned of the December 7th, 1941 ("a date which will live
in infamy") Pearl Harbor attack via the radio - before newspapers hit the stands.
Calvin Coolidge, Roosevelt's predecessor (and of Herbert Hoover's), actually made
the very first radio address. It also included some unwelcome news about the availability
of new radio receivers being delayed due to parts shortages. Unbeknownst to me prior
to reading this, American vacuum tube companies had been making tubes that worked
in German radio sets in order to enable use of Deutsche-made equipment already installed
in France and Belgium...
 "Now a critical part of worldwide defense
strategy,
Electronic Warfare (EW) must continually adapt in order to meet new threats.
To do so, new technology together with emerging standards must be incorporated into
EW system designs. Key elements of EW systems are now often combined within a single
component, such as the RF System-on-Chip (RFSoC), including signal acquisition,
processing, and generation. Hardware, firmware, and software have become more complex,
increasing risk and expense, and thereby increasing the need for effective, high-level
development tools. Along with emerging technology, EW systems developers must consider
emerging U.S. Department of Defense (DoD) initiatives such as Sensor Open Systems
Architecture (SOSA)..."
 The American Radio Relay League (ARRL) now
has an online "RF
Radiation Exposure Calculator" available to help amateur radio operators
assure their stations comply with FCC Part 97 regulations and
Supplement B
of OET Bulletin 65, Version 97-01. To wit: "The FCC has adopted guidelines and
procedures for evaluating environmental effects of RF emissions. Under the new FCC
rules, some amateurs need to perform routine station evaluations to ensure that
their stations comply with the RF exposure rules. This can be as simple as running
an online calculator to determine the minimum safe distance between any part of
your antenna and areas where people might be exposed to RF energy from your station.
Although amateurs can make measurements of their stations, evaluations can also
be done by calculation..."
 This vintage
Heathkit CR-1
Crystal Receiver kit is one the latest unbuilt Heathkit kits which appeared
on eBay, and can still be found there occasionally both in kit form and fully built
sets. I have been saving the images in order to preserve the history. The constantly
growing list is at the lower right. A PDF version of the Heathkit CR-1 Crystal Receiver
Manual can be found here, but I captured the pages (below) in case it disappears
someday. Note the information included on the operation of detectors and oscillators.
The copyright on the manual is 1956, and it appears in the 1958 Heathkit catalog
for $7.95 ($75.10 in 2021 money per the BLS). From the catalog page: "This crystal
radio is just the ticket for construction by young people interested in radio or
electronics - yet it is definitely not a toy. Employs high-quality standard components
throughout. It is even usable as an AM tuner in high fidelity applications. Covering
from 540 to 1600 kc...
 With more than 1000
custom-built stencils, this has got to be the most comprehensive set of
Visio Stencils available for RF, analog, and digital system and schematic
drawings! Every object has been built to fit proportionally on the provided
A-, B- and C-size drawing page templates (or can use your own). Stencils 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...
 Please take a few moments to visit the
everythingRF website to see how they can assist
you with your project. everythingRF is a product discovery platform for RF and microwave
products and services. They currently have 267,269 products from more than 1397
companies across 314 categories in their database and enable engineers to search
for them using their customized parametric search tool. Amplifiers, test equipment,
power couplers and dividers, coaxial connectors, waveguide, antennas, filters, mixers,
power supplies, and everything else. Please visit everythingRF today to see how
they can help you.
Thursday the 12th
 Here is a brief synopsis of radar (radio
detection and ranging). Today, most people who would be reading a magazine like
Radio-Craft would have at least a layman's level of knowledge of what radar
is and how it works. However, in late 1945 when the transition from a wartime society
to a "normal" existence was solidly underway, many new terms and types of inventions
previously withheld for defense security reasons were being released into the public
domain. I have mentioned previously that some people were vehemently against making
a lot of the stuff known, but government agencies wanted to get the information
out in order to promote innovation for improvement, to provide new technology for
manufacturers, and to reward citizens for the lifestyle and personal safety sacrifices
made in order to help secure victory...
 "A research team in the Nanjing, Jiangsu
province, has developed
stealth technology for small satellites to avoid radar detection. Spotting and
tracing a small satellite is difficult, even with a large telescope, but some ground-based
radar stations can identify an object as small as a pen in near-Earth orbit. According
to the Chinese researchers, the new stealth technology could reduce the strength
of radar signals by more than 80 percent, making the small satellite virtually invisible
on a radar screen. Radar operators often scan the sky for electromagnetic waves
of different frequencies, interacting with a wide range of materials to ensure they
do not miss anything..."
 The Remington Rand "Univac" (UNIVersal
Automatic Computer) computer was delivered on March 31, 1951.
Its main memory consisted of liquid mercury delay lines arranged in 1000 words of
12 alphanumeric characters each. A Univac famously calculated the first presidential
race forecast - Eisenhower vs. Stevenson - and was correct! This 1957 report in
Radio & Television News magazine mentions how "giant electronic computers
no longer rank as laboratory curiosities or frightening science-fiction robots."
The Unisys company is today's descendant of Remington Rand...
 In 1957, only a top-of-the-line automobile
deserved a radio containing 13 discrete transistors and four crystal diodes. Only
buyers of such a top-of-the-line vehicle could afford the luxury offered by an electronic
marvel that promised instant-on music with superior sensitivity and selectivity
over the vacuum tube models that lesser humans endured. As shown in this 1957 issue
of Radio & TV News magazine,
Delco's Model 7268085 was up to the task as it populated the dashboards of Cadillac's
Eldorado Brougham. Modern day radios use a single IC for performing all reception,
filtering, amplification, and tuning functions, with superior performance compared
to the Delco without all the interstage tuning transformers, Rs, Ls, and Cs. Most
of the rest of the circuitry in your car radio is for microprocessor control...
 Triad RF Systems, a leading designer and
manufacturer of innovative RF/Microwave amplifiers and integrated radio systems
for challenging environments, presents their newest Blog entry entitled, "3
Practical Steps to Begin the Custom RF Power Amplifier Design Process." It outlines
the process to Research and Plan with Size and Performance in Mind; to Design, Simulate,
Manufacture; and to Test, Tune and Repeat. "It takes years of expertise to push
the boundaries of linearizing RF Solid State Power Amplifiers (SSPAs) while maintaining
a price structure that allows RF amplifier solutions to meet cost targets. So, due
diligence is crucial. Please feel free to contact us with any question." You can
also download our paper entitled "Key Considerations for a Successful Custom RF
Amplifier Design."
 RF Cafe typically receives 8,000-15,000
website visits each 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 16,000 pages in the Google search index, RF Cafe returns in favorable
positions on many types of key searches, both for text and images. New content is
added on a daily basis, which keeps the major search engines interested enough to
spider it multiple times each day. Items added on the homepage often can be found
in a Google search within a few hours of being posted. I also re-broadcast homepage
items on LinkedIn. If you need your company news to be seen, RF Cafe is the
place to be.
 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. Products are designed
and manufactured in the USA.
Wednesday the 11th
 Major Eugene Skinner (a mere Captain when
the previous two parts were written) wrote many articles about radar and microwave
technology for Radio-Craft magazine. In 1945 he provided a three-part series
entitled "Microwaves." This third part focuses on
antennas and radiators, including waveguides and feedhorns. The discussion is
high level covering the basic operation of basic circuit elements, so it is excellent
fodder for people new to the field - hobbyists, students, technicians, and engineers.
The previous two parts are also available if you want to start at the beginning...
 If you have not yet discovered the Engineering
and Technology History Wiki (ETHW) website, now would be a good time to surf on
over and take a look at the vast resources there - particularly the "Oral-History"
series of in-person interviews of our field's top scientists and engineers. Among
them are Dr. Harold Beverage, Dr. Ulrich L. Rohde (N1UL), Harold S.
Black, Harold A. Wheeler, Dr. Irwin Jacobs and Dr. Andrew Viterbi,
and of particular significance to me,
Dr. David B. Leeson (W6NL), founder of California Microwave and Ham
radio contesting champion. Many of the oral interviews were conducted in the pre-Internet
era and some of the people are no longer with us. A few days ago, I had the honor
of being contacted Dr. Leeson as part of his search for information he wants
for some work he is doing. His name is familiar to amateur radio contesters who
participate in DX (long distance) events. Most Hams do their part from home-based
"shacks" while others join in during Hamfest gatherings. Some adventuresome and
hardy souls set up temporary (and sometimes fixed) stations in remote locations
around the world in order to provide rare and exotic contact opportunities, where
coveted QSL cards can be collected...
 Here is a million dollar idea for you to
consider. I hereby dub it the "Drone-Based Field
Measurement System™"(dB-FMS™). The concept came to me while reading a column
in QST magazine discussing the use of the EZNEC antenna radiation pattern prediction
software. As you know unless an antenna is situated in a perfect, unobstructed environment
like in the middle of a desert with a perfectly uniform ground or on a space-based
platform, physical obstacles and variations in surface conductivity can significantly
alter the 3-dimensional field distribution. Columnist Joel Hallas (W1ZR) is a master
at EZNEC and is routinely called upon to model antenna systems for people. As important
as length and orientation of antenna elements are, the ground plane configuration
can have a profound impact on the radiation pattern, particularly when the antenna
is less than a wavelength above ground. Areas of low soil conductivity require placement
of conductive wire radials below, on top of, or above the ground surface, at specific
lengths (or not), arrayed in various spacing...
 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
job openings. HR department employees and/or managers of hiring companies are welcome
to submit opportunities for posting at no charge (of course a gratuity will be graciously
accepted). 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 ...
 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.
Tuesday the 10th
 I frequently refer to magazine editor, inventor,
author, and futurist Hugo Gernsback as a genius who accomplished as much in his
lifetime as just about anyone has. He often noted in his magazines, including as
in the 1945 issue of Radio-Craft, where products, methods, and events he
predicted ended up coming true. It might seem like a case of "blowing his own horn,"
so to speak, but the fact is that then, as now, you have to publicize your successes
because competitors and those who wish to cause you harm will not do it for you.
Here, he had described a year previous a "Radio
Bomb" which had the capability of radio controlled guidance, including onboard
navigation for pinpointing targets in the final phase of flight. An onboard transmitter
provided telemetry enabling tracking and correction...
 We know, many times you want to just buy
your RF assemblies to plug in to your
Circular D38999 Connector or your VITA67 module. Well know ConductRF offers
multiple solutions for both styles of Multi-Port connector all available on short
lead times based on our on hand materials stock.D38999 integrates BMA, SMPM &
SMPS Connectors, also other #8, #12 & #16 coax contact solutions. VITA67.1/2
uses SMPM solutions, but the new VITA67.3 also offers SMPS and NanoRF to support
your coax. These are 100% factory tested to exacting VSWR and Loss standards because,
We know, Results Count!
 "Even though quantum computers are a young
technology and aren't yet ready for routine practical use, researchers have already
been investigating the theoretical constraints that will bound quantum technologies.
One of the things researchers have discovered is that there are limits to how quickly
quantum information can race across any quantum device. These speed limits are called
Lieb-Robinson
bounds, and, for several years, some of the bounds have taunted researchers.
For certain tasks, there was a gap between the best speeds allowed by theory and
the speeds possible with the best algorithms anyone had designed. It's as though
no car manufacturer could figure out how to make a model that reached the local
highway limit..."
  This
is big news from EZNEC antenna
simulator creator Roy Lewallen, (W7EL) for both Amateurs and Professionals: "On
January 1, 2022, I will be retiring. I'll be nearly 76 and want to spend more time
at other things. EZNEC is and always has been developed, sold, and supported only
by me, so all development, sales, and support will end at that time. For several
reasons there is no practical way to sell or transfer ownership to someone else,
so here's what will happen on that date: EZNEC
will be released to the public domain and become free of cost and can be freely
copied and distributed..." Until then, you can support Mr. Lewallen
with the purchase of his industry-changing
EZNEC software.
 Long before digital communications was widely
adopted, there was a great need for stable frequency-determining devices / systems.
That is to say, low bit error rates (BER) for digital communications are not the
sole motivation for
oscillators with low short-term and long-term stability and low levels of jitter.
One obvious need for precise frequency control is radar, in order for accurate ranging
(the second "R" in radar) and in the case of Doppler systems, for accurate radial
velocity reporting and clutter cancellation. Those capabilities existed long before
digital systems came online. Aside from radar, precise frequency was needed in order
to reduce guard band width between assigned channel assignments, thereby enabling
more broadcast stations (commercial and military) to coexist in an allotted frequency
band...
 Without warning, a couple days ago our hot
water heater became just a cold water storage tank.
Our A.O. Smith GCV 40 100 HWH had been functioning perfectly
since we acquired it with the house in 2008. Being a gas hot water heater, I had
a bit trepidation about messing with it since gas has a way of exploding at the
most inconvenient times - like when your face is staring into a burner chamber.
I attack electrical problems with near-reckless abandon from having dealt with AC
and DC supplies and controls for nearly five decades. Nevertheless, last December
when our Trane VX95 gas furnace decided it was time to be a cold air storage container,
I sought advice on the Internet for how to exact a repair - and found it. The problem
was a dirty flame sensor element. I cleaned it per recommendation and it has work
just fine ever since. I wondered, therefore, whether the gas hot water heater might
be experiencing the same phenomenon. After all, it was exhibiting the same sort
of behavior...
 This assortment of custom-designed themes
by RF Cafe includes T-Shirts, Mouse Pads, Clocks, Tote Bags, Coffee Mugs and Steins,
Purses, Sweatshirts, and Baseball Caps. Choose from amazingly clever "We Are the World's
Matchmakers" Smith chart design or the "Engineer's Troubleshooting Flow Chart."
My "Matchmaker's" design has been ripped off by other people and used on their products,
so please be sure to purchase only official RF Cafe gear. My markup is only a paltry
50¢ per item - Cafe Press gets the rest of your purchase price. These would make
excellent gifts for husbands, wives, kids, significant others, and for handing out
at company events or as rewards for excellent service. It's a great way to help
support RF Cafe. Thanks...
 TotalTemp Technologies has more than 40 years
of combined experience providing thermal platforms.
Thermal Platforms
are available to provide temperatures between -100°C and +200°C for cryogenic cooling,
recirculating circulating coolers, temperature chambers and temperature controllers,
thermal range safety controllers, space simulation chambers, hybrid benchtop chambers,
custom systems and platforms. Manual and automated configurations for laboratory
and production environments. Please contact TotalTemp Technologies today to learn
how they can help your project.
Monday the 9th
 Don Hoefler, widely credited for being the
first author to use the term "Silicon Valley" in print* to refer to the rapidly
building semiconductor region of the San Francisco Bay area, published a series
of articles in the 1944-1945 timeframe in Radio-Craft magazine about radio
and television broadcast equipment. This particular installment is part XII, covering
broadcast antenna towers. At the time, commercial installations were few and
far between as priority was given to scarce resources for military applications.
He discusses the tradeoffs involved in various vertical antenna designs, including
the tower structures: top-loading, center-loading, etc. When I first looked at the
traditional tapered tower design I thought about how labor-intensive such calculations
might be and sure enough, he mentions that constant-cross-section towers were gaining
favor due to the relative ease of computations for predicting radiation patterns
and impedance matching. Still, it required a lot of slide rule work...
 "Using an unconventional fabrication technique,
researchers have created ultra-thin, ultra-flexible, high-performance electronics
including active devices.
Flextronics - meaning flexible electronics including the active and passive
devices as well as their carrier (akin to a PCB) - is an attractive and hot area
of interest, especially for wearables and even some IoT applications. However, developing
such a carrier and components with superior flexibility and ruggedness, as well
as sufficient electronic performance, has been a challenge. Thus far, the primary
engineering impediment has been the formation of these almost impossibly thin devices:
It requires a process that’s far too heat-intensive for their flexible plastic substrates.
These flexible materials..."
 A surprising number of people write to me
wanting to know what happened to Gary Breed's RF Design magazine. Recently,
there was an interest in this "Mathematical
Basics of Bandlimited Sampling and Aliasing" article, authored by Vladimir Vitchev
of Maxim Integrated Products (aka Maxim), which appeared in the January 2005 issue
of RF Design. Fortunately, Archive.org has a copy of it on its website.
It begins: "Modern applications often require that we sample analog signals, convert
them to digital form, perform operations on them, and reconstruct them as analog
signals. The important question is how to sample and reconstruct an analog signal
while preserving the full information of the original..." BTW, here is a webpage
with many downloadable
RF Design articles (also
here).
 Anyone visiting RF Cafe (other than by accident)
almost certainly knows of
Drs. Bardeen, Brattain and Shockley fame for their transistor invention while
jointly working at the Bell Telephone Laboratories. The trio shared The Nobel Prize
in Physics in 1956. Bell was so proud of their employees' efforts that they ran
full page advertisements to boast of the accomplishment. This one appeared in the
February 1957 edition of Radio & Television News. Alas, Ma Bell's moment
of glory was a bit diminished by needing to add a footnote admitting that Drs. Bardeen
and Shockley no longer work there. Note that while the ad says the transistor was
announced in 1948, the first demonstration to Bell managers was in December of 1947...
With more than 1000
custom-built stencils, this has got to be the most comprehensive set of
Visio Stencils available for RF, analog, and digital system and schematic
drawings! Every object has been built to fit proportionally on the provided
A-, B- and C-size drawing page templates (or can use your own). Stencils 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...
 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 are serviced around the world. Please take a couple minutes
to visit their website and see how IPP can help you today.
Sunday the 8th
 This
Engineering Theme crossword puzzle for August 8th, 2021, contains only words
and clues related to engineering, mathematics, chemistry, physics, and other technical
words. As always, this crossword contains no names of politicians, mountain ranges,
exotic foods or plants, movie stars, or anything of the sort unless it/he/she is
related to this puzzle's technology theme (e.g., Hedy Lamarr or the Bikini Atoll).
The technically inclined cruciverbalists amongst us will appreciate the effort.
Enjoy!
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.
Homepage Archive Pages
2024:
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec
2023:
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec
2022:
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec
2021:
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec
2020:
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec
2019:
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec
2018:
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec
2017:
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec
2016:
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec
2015:
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec
2014:
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec
2013:
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec
2012:
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
13 (no archives before 2012)
|
