Thursday the 14th
 World War II was the "necessity" that
elicited the "mother of invention" activity responsible for many huge leaps in technology
- not the least of which was electronic verbal and non-verbal communications. By
1951, when this Radio & Television News magazine article on the sate
of the art of military electronics was published, the United States was already
in the midst of another war - this time in Korea - fighting back the frontiers of
Communism and despotism. Along with radio and radar,
Loran had become a major means of ocean and air navigation. A fair description
of the operational details, including timing diagrams, is included in the text.
Loran-A, the original system as it came to be known, was fully decommissioned in
1980, thereafter supplanted by Loran-C. With the advent of GPS, Galileo, and Glonass
navigation systems and their low equipment and installation costs, Loran-C was eventually
no longer needed either, causing it to be decommissioned in the U.S. in 2010. Norway's
Loran-C stations, the last operational stations, were scheduled to close in 2016.
In case you are wondering...
 "SDR requires a complex web of circuitry
on PCBs that not only defines the device's functionality, but also the performance
of these microwave and RF systems. Various factors come into play when
designing PCBs for SDRs that must maintain signal integrity. Software-defined
radio (SDR) requires complex circuitry on printed circuit boards (PCBs) that defines
the functionality of the device as well as the performance of these microwave and
RF systems. This article discusses the factors that arise when designing PCBs for
SDRs that need to maintain signal integrity. What is an SDR? An SDR includes what's
commonly termed a radio front-end (RFE) and digital backend. The RFE boards contain
the functionality of the radio over a very wide tuning range and incorporate various
analog components such as LNAs, mixers, filters, frequency synthesizers, gain/attenuation
blocks, and other devices needed for receiving (Rx) and transmitting (Tx) functionality..."
 I could be wrong, but I'm guessing the average
audiophile in the 1950s and 1960s were probably more technically astute than modern
day audiophiles in terms of electrical and physical specifications. That is largely
due to how integrated, matched, and compatible system components (receivers, players,
amplifiers, speakers, etc.) are nowadays. Newer audio components are also more tolerant
of non-optimal configurations. In 1957 when this
Audiophile Quiz appeared in Radio-Electronics magazine, the vast majority
of electronics equipment used vacuum tubes that used lethally high voltages, so
connection and servicing mistakes could be more costly to life, limb, and hardware.
Topics like AFC (automatic frequency control), frequency response of recording and
playback devices, required technical knowledge for achieving the best performance...
 Always the consummate story teller, John
T. Frye began his writing career long before his "Carl & Jerry" electronics
adventure series that ran monthly for many years in Popular Electronics.
His style featured creating a dialog between instructor and student, serviceman
and customer, husband and wife, father and son, etc., in order to present an educational
experience with back-and-forth inquiry and responses. In the end, the reader learns
something about both sides of the situation. In this February 1955 story, electronics
service shop owner Mac McGregor reassures technician Barney Jameson that given time
and patience, he will grasp the circuit concepts of the newfangled color television
sets...
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...
 LadyBug Technologies was founded in 2004
by two microwave engineers with a passion for quality microwave test instrumentation.
Our employees offer many years experience in the design and manufacture of the worlds
best vector network analyzers, spectrum analyzers, power meters and associated components.
The management team has additional experience in optical power testing, military
radar and a variety of programming environments including LabVIEW, VEE and other
languages often used in programmatic systems. Extensive experience in a broad spectrum
of demanding measurement applications. You can be assured that our Power Sensors
are designed, built, tested and calibrated without compromise.
Wednesday the 13th
 Here is a really good introduction to
the way a laser works. In this 1961 Popular Electronics article, author
Ken Gilmore discusses a couple Bell Telephone scientists who pioneered long distance
laser communications back in 1960. Their experiments began with rather large chemical
lasers on the rooftops of buildings separated by 25 miles. Back in the day, most
people - including technical types - had never read or heard a description of how
a laser works, so this was a brand new concept. Lasers were a science fiction thing
used as weapons for battling aliens. We've come a long way since then, with laser
communications now taking place within the confines of a semiconductor integrated
circuit...
 "Synchrotrons and many board games have
at least one thing are common - objects are accelerated in a circle but going round
and round is not the main point of either. In board games, the object is fun and
in 'Diamond:
The Game,' [print, cut out, play - free] there is also an educational element.
Developed by Mark Basham and Claire Murray at the UK's Diamond Light Source synchrotron
and Matthew Dunstan at the University of Cambridge, the game puts players in the
role of a researcher at Diamond. By visiting different beamlines while progressing
round the board, participants learn about the diversity of science that is done
at the facility - including physics, chemistry, cultural heritage, and more..."
 Even in the year 2022, there is a huge cadre
of turntable aficionados out there whose players can only be taken from them by
prying them from their, cold, dead hands. Look at all the buying and selling of
turntables that takes place on eBay if you have any doubt (the search I just did
turned up more than 800 items). I remember in my U.S. Air Force days, the only time
ever lived in mass group quarters (no college dorms for me), guys were in heated
competition against each other over who could accumulate the most extensive and
expensive hi-fi gear. A large percentage in my barracks were mobile communications
types, and they seemed to spend about as much time adjusting their turntables, reel-to-reel
tape decks, and receivers for ultimate performance. Entire beer and pizza parties
were centered around topics like balancing tone arms. As with most subjects where
many "experts" debate, no two could agree on the best method. Here's a little sage
advice from a 1960 issue of Popular Electronics magazine in case you're
not a seasoned
tone arm balancer...
 For many years I have been scanning and posting
schematics & parts lists like this one from a 1936 issue of Radio-Craft
magazine. It features the
Kadette Jewel Model 40 Chassis 3-Tube Ultra-Midget Receivers Model 41, 43, 44
and 48 radios in graphical format. It is able to be "miniature" because only three
vacuum tubes are used - although a 12A7 diode / tetrode effectively makes it a 4-tube
radio. I'm guessing the Kadette Midget might have only worked well in strong signal
areas. Often times I run OCR on them to separate the textual content. The radio
shown in the thumbnail is currently being offered for sale on eBay†; the price seems
a bit steep. The case appears to be in fine physical condition, but the electronics
could stand some rework. There are still many people who restore and service these
vintage radios, and often it can be difficult or impossible to find schematics and/or
tuning information. I will keep a running list of all data sheets to facilitate
a search. † Usually when I find an item like this on eBay, I have Archive.org's
Wayback Machine grab a page snapshot of it and link to it rather than the original
eBay page because it will soon disappear...
 New Scheme rotates
all Banners in all locations on the page! RF Cafe typically receives 8,000-15,000
website visits each weekday.
RF Cafe is a favorite
of engineers, technicians, hobbyists, and students all over the world. With more
than 12,000 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.
 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.
Tuesday the 12th
 It took a couple times reading through this
"Rectifying
Without Rectifiers" article to get the gist of what author H.B. Conant
was talking about. He begins by pointing out the negative aspects of using nonlinear
metallic rectifiers in a bridge circuit for an electric meter, then goes on to describe
an improved "translator" circuit that uses - wait for it - nonlinear metallic rectifiers
(or nonlinear resistors made of Thyrite material). If my interpretation is correct,
basically the new and improved circuit incorporates a bias voltage that forces the
nonlinear element (be it a metallic rectifier or a nonlinear resistance) to operate
in a region which passes a higher current level to the meter movement when low values
are being measured. One of the drawbacks mentioned of a traditional (at the time)
bridge circuit was the need for separate calibration / marking of the meter's scale
on the front panel, but then he says the translator meter also does not have uniform
scales on all voltage ranges. I are a bit confused...
 Cabe Atwell has an interesting piece on the
EE|Times website entitled, "Transatlantic
Communication in the Digital Age," where he does a brief comparison of cable
types used at the middle of the 19th century (i.e., 1850+) to those used
today. In both eras, inserting amplifiers at intervals was/is necessary in order
to maintain an acceptable signal-to-noise ratio. Using optical fiber instead of
copper helps matters, but does not eliminate the need for amplifiers. Insulation
and protective armor has vastly improved as well since
gutta-percha on submarine
telegraph cables. Mr. Atwell begins: "Communication between nations and at
great distances was not always as available, and certainly not as fast, as it is
in many places today. The site of the first transatlantic communication via cable
is Valentia Island, Ireland, where over 160 years ago the first telegram was sent
between the United States and Great Britain. Sent on Aug. 16, 1858, it read: 'The
queen is convinced that the president will join with her in fervently hoping that
the electric cable, which now connects Great Britain with the United States, will
prove an add..."
 This could be a headline for today, tomorrow,
or from 89 years ago when this article appeared in QST magazine. It was
the latter, following the magnitude 6.4 earthquake that hit the Long Beach, California
region. Per Wikipedia, "An estimated $40M worth of property damage resulted, and
between 115 and 120 people died. Many of these fatalities occurred as people ran
out of buildings and were hit by falling debris." That paled, though, in comparison
to the
magnitude 7.8 San Francisco earthquake in 1906, where massive destruction occurred
and upwards of 3,000 people died. As usual, radio amateurs were some of the first
emergency responders on the scene, setting up essential communications centers to
assist with search and rescue operations. The Federal Radio Commissions (FRC), precursor
to the FCC, issued a note of appreciation...
 Back in the early days of radio - and then
later television - companies used big-name media personalities to promote their
wares. To a lesser extent some of that happens today as well. Advertisements like
this one for
RCA's Radiotron vacuum tubes appearing in a 1934 issue of Radio News
magazine is typical of what you would have seen in the era. In it, none other than
Bing Crosby was joined by a trendily dressed woman who was rejoicing in her decision
to buy a new radio that contained those newfangled "Micro-Sensitive" receiver tubes.
Radio was considered a mystical entity by most people, and in 1934 there were still
many households that did not yet host a radio of any sort. Rural residences often
did not have AC service and relied on storage batteries to power machinery and appliances.
Farmer Brown had to haul a wagon loaded with heavy lead-acid batteries to town to
get them recharged. Some of the more prosperous ruralites had windmill- or water-driven
generators to produce the necessary power. In fact, in 1934 a complete power generator
setup...
 All RF Cafe Quizzes make great fodder for
employment interviews for technicians or engineers - particularly those who are
fresh out of school or are relatively new to the work world. Come to think of it,
they would make equally excellent study material for the same persons who are going
to be interviewed for a job. The subject of
Quiz #16 is Antennas. You don't
need to be an antenna expert to score well, but if you do or plan to work with antennas
and cannot answer a question like, "What does dBi, the most often used unit for
antenna gain (or directivity), stand for?," then maybe it is time for some review...
 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 stencil symbol has been built to fit proportionally on the included
A-, B-, and C-size drawing page templates (or use your own page if preferred). Components
are provided for system block diagrams, conceptual drawings, schematics, test equipment,
racks (EIA 19", ETSI 21"), and more. Test equipment and racks are built at a 1:1
scale so that measurements can be made directly using Visio built-in dimensioning
objects. Page templates are provided with a preset scale (changeable) for a good
presentation that can incorporate all provided symbols...
 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.
Monday the 11th
 Hmmmm.... at the time I marked this
stereo tape playback preamp project for posting I must have had a really good
reason for it, but now I can't recall what that really good reason was. Maybe it
was simply to mark the point in time when stereophonic electronic equipment was
just beginning to be mainstream. Oh well, somebody somewhere will do a Google search
on the topic someday and will be elated to find this. Besides, even though the use
of vacuum tubes and magnetic tape is way outdated, there is a discussion of hi-fi
audio that is still relevant. The article appeared in a 1958 issue of Radio-Electronics
magazine. Thanks for your indulgence.
 "The invention of the transistor by Bell
Laboratory in 1947 ushered in an era of electronic devices that were smaller and
ran cooler using far less power than their bulky and fragile vacuum tube counterparts.
Transistors function as a binary switch to facilitate electrical current from off
to on states. Radios, calculators and telephones were among the first wave of instruments
to replace vacuum tubes with the new semiconductor technology. As the technology
scaled smaller and smaller, subsequent decades saw the steady integration of silicon
transistors into devices, and today's computers, cell phones, watches, pacemakers,
and virtually every kind of electronic device relies on them for high-speed processing
and memory. Enter the
memristor, an electronic device that emulates the binary switch using a two-
and also three-dimensional matrix configuration, or cross bar array, to regulate
states of conductivity based on current resistance..."
 While reading through these vintage electronics
magazines, I often wish I could have lived in the era and owned an
electronics repair shop. Radios, televisions, record players, tape recorders,
amplifiers, etc., were very serviceable with plug-in vacuum tube active components
and point-to-point wiring with all leaded passive components (capacitors, resistors,
inductors, lamps, etc.). I know this from first-hand experience working on a 1960's
air traffic control radar system while serving in the U.S. Air Force. As with today,
servicemen often get a bad rap undeservedly because of the low morals of some fellow
practitioners. While it is unfortunately true that bad eggs exist in the service
world, a lot of customers are rotten and try to take advantage of or outright rip
off the technician. This story from a 1952 issue of Radio-Electronics magazine
is a tongue-in-cheek parody from the viewpoint of a self-righteous customer looking
to get his radio repaired...
 Maybe it isn't so anymore, but according
to Centralab the ceramic raw materials available in abundance in America were electrically
superior to those being used in Europe since the early 1900s when German scientists
first discovered the dielectric properties of the material. Ceramic capacitors represented
a major advance in capacitor technology over liquid and paste dielectric types in
most areas of electrical and mechanical specifications such as vibration, aging,
vibration and shock, temperature, value stability, voltage and current handling,
etc.
Centralab ran this advertisement in Radio & Television News magazine
spelling out all the virtues of ceramic capacitors that had accumulated due to their
research efforts. Philips Electronics' Components division bought Beyschlag and
Centralab and merged the two into "BCcomponents," whereupon in 2002 Vishay
bought them...
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...
 Lotus Communication Systems began in 2009,
setting up CNC machine shop and RF/microwave assembling and testing lab in Middlesex
Country, Massachusetts. Lotus is committed to highest quality and innovative products.
Each RF/microwave module meets
exceedingly high standards of quality, performance and excellent value, and are
100% MADE IN USA. Lotus' RF/microwave products cover frequency band up to 67 GHz.
Lotus also offers an COTS shield enclosures for RF/microwave prototyping and production.
All products are custom designed. We will find a solution and save your time and
cost. Lotus has multiple 4 axis CNC machines and LPKF circuit plotters.
Sunday the 10th
 With few exceptions, I, RF Cafe webmaster
Kirt Blattenberger, have for more than two decades designed a custom crossword puzzle
every week for the benefit of website visitors. This
Electrical Engineering Theme Crossword Puzzle was created for July 10th, 2022.
All crossword puzzles use a personally built dictionary of thousands of words and
clues related to RF, microwave, and mm-wave engineering, optics, mathematics, chemistry,
physics, and other technical subjects. As always, this crossword puzzle 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., Reginald Denny or the Tunguska event in Siberia). The technically inclined
cruciverbalists amongst us will appreciate the effort. Enjoy!
 Anatech Electronics (AEI) manufactures and
supplies RF and microwave filters for military and commercial communication
systems, providing standard LP, HP, BP, BS, notch, diplexer, and custom RF filters,
and RF products. Standard RF filter and cable assembly products are published in
our website database for ease of procurement. Custom RF filters designs are used
when a standard cannot be found, or the requirements dictate a custom approach for
your military and commercial communications needs. Sam Benzacar's monthly newsletters
address contemporary wireless subjects. Please visit Anatech today to see how they
can help your project succeed.
Friday the 8th
 Many thanks to RF Cafe visitor Michael M.
for sending me a note about a very handy RF propagation software tool provided free
of charge by the French organization Centre National d'Études Spatiales (CNES, National
Centre for Space Studies). The
PROPAGATION dynamic
link library (DLL) contains functions to compute propagation losses according
to ITU-R P.† recommendations. Versions are available for both 32- and 64-bit
Windows and Linux operating systems, as well as for the C and Visual Basic programming
languages. Very conveniently, the DLL functions can be referenced from within an
Excel spreadsheet as well*, and a demo (demoprop.xls - see screen shot at right)
is provided for reference. To access the DLL contents, add the "Propa" module to
your VBA (Visual Basic for Applications) code and call away. A full list of the
functions is given below, including ones for gaseous, cloud and rain attenuation
that factors in temperature, precipitation intensity, and atmospheric noise, as
well as for inputting geographic location (latitude, longitude, and elevation) and
antenna parameters...
 As part of the immense amount of work that
goes into publishing RFCafe.com, I regularly visit science and engineering websites
to gather relevant headlines and stories. Most - far more than half - present pop-up
advertisements and/or cookie acceptance screens, all of which must be responded
to before being able to use the website. Don't get me wrong, I appreciate the services
provided by them, but do find the imposition very inconvenient. Some are so bad
that I have stopped including them in my lists of headlines and stories. You will
please note that RF Cafe never has and never will subject you to sure an intrusion
to your browsing endeavors. I also make far less income than they do because of
refusing sponsors who want to use that form of advertising. Click on the above thumbnail
to see some of the offender website screen shots.
 My father used to refer to the "sweet-voiced
lady predicting the weather over and over again" as my girlfriend because I would
call the "WEather 6-1212" phone number (936-1212) so often. It really wasn't
because I was infatuated with her voice, it's that I was obsessed with weather forecasting.
Most of my free time as a kid and teenager was spent building and flying model airplanes
and rockets, and at eighteen years of age I began taking full-size aeroplane flying
lessons, so my world revolved around a zone extending from terra firma up to about
5,000 feet AGL. This collection of communications news items in a 1940 edition of
National Radio News includes the creation of that very recorded weather
forecasting service (we lived about 30 miles east of Washington, D.C.). Now, I admit
to having a bit more of a problem explaining my frequent calling of the local time
annunciator lady at "TIme 4-1212" (844-1212)...
 This is incredible, and the best is yet
to come. "We're less than one week away from the July 12, 2022, release of the first
science-quality images from NASA's
James Webb Space Telescope, but how does the observatory find and lock onto
its targets? Webb's Fine Guidance Sensor (FGS), developed by the Canadian Space
Agency, was designed with this particular question in mind. Recently it captured
a view of stars and galaxies that provides a tantalizing glimpse at what the telescope's
science instruments will reveal in the coming weeks, months, and years. FGS has
always been capable of capturing imagery, but its primary purpose is to enable accurate
science measurements and imaging with precision pointing. When it does capture imagery,
it is typically not kept: given the limited communications bandwidth between L2
and Earth, Webb only sends data from up to two science instruments at a time. But
during the week-long stability test in May, it occurred to the team that they could
keep the imagery that was being captured because there was available data transfer
bandwidth. The engineering test image - produced during a thermal stability test
in mid-May..."
 In this 1953 QST magazine article, Authors
Cohen and Hessinger warn about the need to consider the
capacitive loading effects of shielded and closely-space test leads when measuring
other than direct current or very low audio or line frequencies. Lead capacitance
is especially likely to affect measured values when the frequency is high and/or
the source and load impedances are high. As was common in the day, capacitance units
of μμfd (micro-micro farads = 10-6 x 10-6 = 10-12 F) are cited, which is equivalent
to units of pF (10-12 F)...
 Cooling devices based on the Peltier effect
were first demonstrated by French physicist
Jean Charles Athanase Peltier when he noted the presence of heating or cooling
at an electrified junction of two different conductors types (opposite of a thermocouple).
Widespread commercial use depended on finding efficient materials that could be
produced inexpensively. Music synthesizers, to be practical, needed to await the
availability of miniaturized electronics like transistors and memory elements. Light
amplification similarly depended on affordable sources to be anything more than
a laboratory curiosity. Fortunately, by the mid 1950s such entities were becoming
reality. This 1955 Popular Electronics magazine article reports on a few
of those items...
New Scheme rotates
all Banners in all locations on the page! RF Cafe typically receives 8,000-15,000
website visits each weekday.
RF Cafe is a favorite
of engineers, technicians, hobbyists, and students all over the world. With more
than 12,000 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.
 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.
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