|
 Windfreak Technologies is proud to announces
the availability of our
FT108, an innovative
programmable bidirectional filter bank spanning a frequency range of 5 MHz
to 8 GHz in 15 bands. Band selection can be controlled through USB, UART or
at high speeds through powerful triggering modes. Each unit is factory tested via
network analyzer with unique data stored in the device to help with its use. Crossover
frequencies are stored so the user can send a frequency command and the FT108 will
utilizes Intelligent Band Selection logic to automatically toggle the optimal
filter path based on minimum insertion loss. Readback of FT108 insertion loss at
any frequency between crossover points allows for easy amplitude leveling...
 An article title with both "radar" and "Great
Lakes" in the title is sure to catch my attention, as did this. Author Norman Schorr
reports on the state of the art of radar equipment and usage for the purpose of
maritime navigation. Research and development, along with an ample
surplus of components left over from World War II facilitated a rapid adaptation
of radar to many venues. Included among its applications were airway and waterway
navigation, rocket trajectory tracking, security systems, speed measurement, weather
observation, and aerial mapping...
 Johanson Technology (originally part of
Johanson Dielectrics), located in Camarillo, CA, has for over 25 years designed
and manufactured high quality RF & microwave ceramic chip capacitors, inductors
and integrated passives. These includes chip-format antennas, capacitors, lowpass,
highpass, and bandpass filters, couplers, inductors, baluns, power dividers, substrates,
chipsets.
 Details the evolution of infrared technology,
tracing its origins from William Herschel's 1800 discovery to its deployment in
military and industrial sectors, are presented in this 1959 Radio &
TV News magazine article. It emphasizes the shift from active, illuminating
systems to passive, sensitive detectors capable of identifying thermal signatures
in total darkness. The piece highlights infrared's superior resolution compared
to radar, noting its utility in applications ranging from missile guidance and ballistic
tracking to industrial quality control and chemical analysis. Since the publication
of this article, infrared technology has achieved remarkable sophistication, evolving
from bulky lab instruments into the invisible, ubiquitous...
 An ample supply of surplus coaxial cable
after the end of World War II provided an inexpensive and easy to use form
of transmission line. Not having to worry about cable routing and unintentional
radiation makes transitions through walls, running along metal surfaces, and routing
high power transmission lines near habitable areas a no-brainer. Issues like power
handling, bend radius, and higher attenuation need more attention during the installation
design phase, but that pales in comparison to coaxial cable's advantages. Author
Byron Goodman addresses some of the issues Hams accustomed to using
flat
transmission lines...
 Not surprisingly, there is a website dedicated
to only the
Regency TR-1 transistor radio and its history from development
through retail sales. As reported in this January 1955 issue of Radio and Television
News, The TR-1 was the world's first commercially available, fully transistorized
portable radio. A complete schematic and functional description is provided. It
used four germanium transistors and operated on a 22-1/2 volt battery, which provided
about twenty hours of listening pleasure. The unit weighed eleven ounces and cost
$49.95...
 This
is a must-read article for all persons interested in the history of wireless communications.
Seriously. Stop what you are doing and read it. I guarantee the vast majority have
never heard of this challenge to the veracity of
Mr. Guglielmo Marconi's bestowed title of "father of wireless
telegraphy." Most of us are at least passingly familiar with challenges to Samuel
Morse's, Thomas Edison's, and a few other notables' claims to being the first at
a particular technical breakthrough, but herein, as penned by of
Lieutenant-Commander Edward H. Loftin, is a first-hand account
of multiple successful challenges by the U.S. Patent Office against...
 ConductRF is continually innovating and
developing new and improved solutions for RF Interconnect needs. See the latest
TESTeCON RF Test Cables
for labs. ConductRF makes production and test coax cable assemblies for amplitude
and phased matched VNA applications as well as standard & precision RF connectors.
Over 1,000 solutions for low PIM in-building to choose from in the iBwave component
library. They also provide custom coax solutions for applications where some standard
just won't do. A partnership with Newark assures fast, reliable access. Please visit
ConductRF today to see
how they can help your project!
 This nomograph from a 1959 issue of
Radio & TV News magazine simplifies matching a source (sending - s) impedance
(Zs) and a load (receiving - r) impedance (Zr) using a
quarter-wave transmission line. To use it, locate your Zs value on the left
vertical scale and your Zr value on the right scale. Lay a straightedge across these
points; the intersection with the center vertical scale reveals the required surge
impedance - also called characteristic impedance - (Z0). Surge impedance is the
ratio of voltage to current for a wave traveling along an infinite transmission
line, dictated by the physical geometry and dielectric properties of the cable,
defined as Z0 = sqrt (L/C), where L is inductance per unit length and C is
capacitance per unit length. The quarter-wave transformer relies...
 Here is a batch of
electronics-themed comics that appeared in the January 1949 edition
of Radio & Television News. The scene seen (hey,
homonyms) on the page 138 comic was commonplace in the 1940s when televisions
were relatively new and not every household had a set. The scenario repeated itself
in the 1960s when color sets were hitting the consumer market. Now, people can watch
TV on their smartphones while not at home so gathering 'round the television display
in a store is relegated pretty much to little kids watching the Disney movies that
seem to always running on them. There is a growing list of other comics at the bottom
of the page...
 December
1942 was just a year into America's "official" involvement in World War II.
Already, both wired and wireless communications had made major advances and were
indisputably vital in both the logistical and strategic aspects of troop movement,
supply chains, fighting battles, and evacuation of wounded personnel. It also played
a large part in propaganda campaigns. This was all true for both Axis and Allied
forces. Ham radio operators provided a huge boost to the Signal Corps
because they came at least partially trained for the jobs. These dozen and a half
photos from the field exhibit the state of the art at the time. Maybe you'll
recognize a father, grandfather, or uncle in one of them. For that matter, you might
even recognize a mother, grandmother...
 Exodus Advanced Communications, is a multinational
RF communication equipment and engineering service company serving both commercial
and government entities and their affiliates worldwide. Exodus'
AMP20026 is a rugged 2.0 to 6.0 GHz solid state amplifier delivering a
minimum of 200 W with clean, stable 53 dB gain. It offers excellent gain
flatness, a 20 dB control range, and full protection circuitry. Built for EMI/RFI,
lab, CW/pulse, and EW environments, it delivers instantaneous bandwidth, superb
reliability, rack mount configuration...
 In April of 1952 when this article appeared
in Radio & Television News magazine, the
bipolar junction transistor (BJT) had only made it out of the
experimental laboratory of Messrs. Bardeen, Shockley, and Brattain at Bell Labs
a mere three years earlier in December of 1948. It did not take long for commercial
production to begin. Along with being a great primer for anyone new to transistors,
herein is also some background on how the now ubiquitous BJT schematic symbol was
created. Interestingly, only Dr. William Shockley is mentioned, making me wonder
whether the contributions of Dr. John Bardeen, and Dr. Walter H. Brattain was
not widely publicized early on. Not to worry, though, because all three were duly...
 Mac's Service Shop captures here a moment
of technological transition in 1961 where a new "Loud-speaking
Telephone" impresses his right-hand man, Barney. The device utilizes vacuum-tube
amplifiers and a bulky external control box to allow hands-free communication, enabling
Mac to work while handling customer inquiries. Mac, ever the mentor, contrasts this
tube-based unit with the emerging technology of transistorized speakerphones, which
eliminate the need for external control boxes, external power supplies, and warm-up
times. The 1961 "Loud-speaking" setup, occupying significant space under a workbench,
has been completely replaced by modern smartphones and integrated VoIP systems...
 As with all
RF Cafe
crossword puzzles, this one uses only words pertaining to engineering, science,
mathematics, mechanics, chemistry, astronomy, etc. 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., Hedy Lamarr or the Bikini Atoll). The technically inclined cruciverbalists
amongst us will appreciate the effort. Enjoy!
  The microwave klystron was invented in 1937
by brothers
Russell and Sigurd Varian. If you have been in the microwave design
business for a couple decades, you undoubtedly recognize the company name of Varian
Associates, especially if you worked in the aerospace or defense electronics business.
There is a video on YouTube of a segment on Varian done sometime around 1990 by
Walter Cronkite. There is also a historical piece on Varian Associates on the Communications &
Power Industries website. This circa 1952 article covers the fundamentals of klystron
operation and reports on the increasing use of klystrons in high frequency application
- including by amateur radio operators exploring...
 Werbel Microwave began as a consulting firm,
specializing in RF components design, with the ability to rapidly spin low volume
prototypes, and has quickly grown into a major designer and manufacturer with volume
production capacities. The
WMRD02-7.2-S is a resistive splitter that covers up to 7.2 GHz with ultra-wide
bandwidth. This design is useful when there are many low power signals within a
wide spectrum. By design, the nominal insertion loss and isolation is 6 dB,
hence it is often referred to as a "6 dB splitter." Its small size makes it
easy to integrate into compact systems. Designed, assembled, and tested in the USA.
"No Worries with Werbel!"
 Contributors to the Wikipedia article on
the
Yagi–Uda antenna credit Japanese professor Shintaro Uda primarily for the antenna's
development, with Hidetsugu Yagi having played a "lesser role." Other sources assign
the primary role to Yagi. Regardless, history - and this article's author, rightly
or wrongly, has decreed that this highly popular design be referred to commonly
as the Yagi antenna and not the Uda antenna. I don't recall seeing advertisements
for "'Uda" television or amateur radio antennas. Harold Harris, of Channel Master
Corporation, does a nice job explaining the fundamentals of the Yagi antenna. Another
Yagi article appeared in the October 1952 issue of QST magazine...
 Established in 1990,
dB Control supplies mission-critical,
often sole-source, products worldwide to military organizations, as well as to major
defense contractors and commercial manufacturers. dB Control designs and manufactures
high-power TWT amplifiers, microwave power modules, transmitters, high- and low-voltage
power supplies, and modulators for radar, ECM, and data link applications. Modularity
enables rapid configuration of custom products for a variety of platforms, including
ground-based and high-altitude military manned and unmanned aircraft. Custom RF
sources and receivers, components and integrated microwave subsystems as well as
precision electromechanical switches. dB Control also offers specialized contract
manufacturing and repair depot services.
 The production of high-performance transistors
necessitated new methods to achieve extreme purity levels, far beyond standard industrial
capabilities. To reach the required purity of
one part in ten billion, engineers adopted zone melting, a sophisticated technique
pioneered by W. G. Pfann. In this process, radio-frequency heating coils melt a
narrow zone of a semiconductor rod, which is then moved along the crystal to sweep
impurities to one end. Beyond purification, zone melting allows for the precise,
uniform introduction of "dopants" like antimony or indium, which are essential for
creating p-type and n-type semiconductor characteristics. By refining these methods
through continuous processing and floating-zone techniques, manufacturers significantly...
 Here's another advertisement that you probably
wouldn't see in a contemporary RF / microwave engineering magazine. For that matter
you probably wouldn't see it on a contemporary RF / microwave engineering website
... except on RF Cafe where political correctness gets no respect.
Adson Radio & Electronics was located on Fulton Street in New York City,
just a block from the 911 Memorial. the original building might have been destroyed
when the...
 My first thought when seeing the cover for
this edition of Radio-Craft magazine was that it was an April Fools gag,
but it turns out the "hat" being worn by the radio receiver's designer is a
loop antenna for AM reception. Ya' know, he does look like he
could be a suicide bomber. In a way it is the opposite of a tinfoil hat in that
this headgear invites electromagnetic energy around the wearer's head rather than
shielding it. Back in 1936, being seen in public donning a contraption like this
radio would have been akin to Google Glass today - you'd be a superhero to fellow
nerds, and just be confirming your otherworldly nerd status to non-nerds...
 Vreeland Corporation was an early radio
manufacturer located in Hoboken, New Jersey, with multiple patents on file for innovative
circuits. The
Vreeland band selector system mentioned here was originally filed
in the U.S. Patent and Trademark Office in August of 1927 and had not been awarded
by the time of this November 1929 article in Radio-Craft magazine. In fact,
it wasn't until five years later, in 1932, that the patent was finally assigned.
The official description reads in part, "The general purpose of the invention is
to receive the component frequencies of such a band with such uniformity as to avoid
material distortion of the modulated wave, and to exclude frequencies outside of
the band which the system is designed to receive. Another purpose of the invention
is to provide means for shifting the position of the band...
 In this 1959 Radio-Electronics
magazine promo, Bell Telephone Laboratories showcased its advanced
radio-inertial guidance system, a technological breakthrough enabling precise
long-range missile flight. Developed for the Air Force's Ballistic Missile Division,
this innovation proved its efficacy by guiding a Thor-Able nose cone to a precise
target five thousand miles away, allowing for a successful aerial and maritime recovery.
The system utilized a missile-borne transmitter to feed continuous data to ground-based
radar and a Remington Rand Univac computer, which calculated real-time steering
corrections. By keeping the primary command equipment on the ground...
|
 • Ham
HOA Antenna Protection in Indiana
• FCC Expands
Use of Broadband Spectrum
• UK's
Fractile Chip Facility Gets £100m Expansion
• Choosing an
Antenna for Compliance Testing
• Huawei
Wins 8 GLOMO Awards at MWC Barcelona
 The
RF Cafe Homepage Archive
is a comprehensive collection of every item appearing daily on this website since
2008 - and many from earlier years. Many thousands of pages of unique content have
been added since then.
 As reported in this 1967 Electronics World
magazine piece, lasers were still the things of science fiction to most people.
Real-world applications seemed to be far off in the future, but in fact, work was
underway setting the stage for today's blazingly fast communications systems. The
author here references attaining 5 THz optical transmission speeds through
fiber and through the air. At the time, a laboratory filled with bulky prototypes
chassis and optical tables were required to get those results. I can remember reading
articles in the 1970s when laser power output was measured in "Gillette
power," referring to the beam's ability to burn through a number of razor blades
(a big deal at the time). In 2020, devices that greatly surpass 5 THz are available
in consumer quality IC packages...
 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, and
more. Page templates are provided with a preset scale (changeable) for a good presentation
that can incorporate all provided symbols...
 This advertisement from a 1949 issue of
Radio & Television News would never pass muster with the politically
correct crowd of today! Even though, as with the Washington Redskins football team,
Red Man chewing tobacco, Indian Motorcycles, Land O'Lakes food company,
American Indians are without exception used as a depiction of strength, high
quality, high integrity, and beauty, there is a very, very, very tiny minority of
rabble rousers who are having their way with the vast, vast, vast majority (there
seems to be a lot of that these days). Somehow that has become the norm in society
today. If the goal is to upset everyone and to pit good people against each other,
then it has been a resounding success. For the record, I reject the idiocy and buck
their efforts whenever possible...
 Here is the final installment
of C.W. Palmer's "Microwaves"
series of article in Radio-Electronics magazine. Topics for all seven parts
are shown below. Unlike the previous parts, this one discusses uses for waveguide
below its cutoff frequency for switching and attenuation purposes. Of course there
is also the filter application as well which exploits the high attenuation in the
cutoff region. Since these pieces were written in the pre-solid state semiconductor
era, vacuum tubes appear as control and amplifier devices rather than diodes and
transistors, but don't let that deter you from benefitting from the useful waveguide
characteristics lessons presented...
 It's time for another pop quiz (does
that line give you a fearsome flashback to your school days?). Whenever I have
one available, I like to post quizzes from vintage electronics magazines, like
this one on
diode circuit functions which appeared in the August 1965 issue of
Popular Electronics. Many from that era include vacuum tubes, but this one
has the solid state symbols so the under-40 folks won't be uncomfortable. Your
job is to look at the diode circuits and match them with the names of the
functions. A couple of them will probably cause some head scratching, but you
should do well. Don't jump to a quick conclusion with circuit "E" without
noticing the two signal generators attached to it. If you like diode quizzes,
here is another...
 This custom RF Cafe
electronics-themed crossword puzzle for March 12th contains only words and clues
which pertain strictly to the subjects of electronics, mechanics, power distribution,
engineering, science, physics, astronomy, chemistry, etc. If you do happen see names
of people or places, they are directly related to the aforementioned areas of study.
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.
 Thanks to RF Cafe visitor / contributor
Michael M. for letting me know about an update to
CNES RF Propagation
Calculations DLL download hyperlink. In the four months since posting the information,
CNES moved the file. This very handy RF propagation software tool is 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...
 Considering that not much more than a year
before this article was written in 1950 for Radio & Television News
magazine that the transistor had been invented, it is impressive that already Raytheon
was producing a commercially available
CK703 "crystal triode." That nomenclature was a natural extension of the preceding
crystal diode already being widely adapted in circuit design. If you have wondered
how the transistor schematic symbol came to be as it is, you will learn why here
where the emitter and collector symbols actually both have arrows on the ends that
contact the base, indicating the "point contact" physical arrangement of the semiconductor
junctions. Shortly thereafter the arrow on the collector port was eliminated, primarily,
I suppose to avoid confusion when the E, B, and C labels are not present...
 Eastern Amplifier's history is well hidden
on the Web. The best clue I could find regarding their history is from this interview
on Ralph Baer who says Eastern Amplifier Company became Loral. (see p13. The title
of "It's Spring... and the Plants Are Booming!" was a double entendre playing off
the drawing of a mother and her daughter standing in a field, but actually referring
to the industrial war machine cranking out weapons and supplies for our troops "Over
There." It reminds me of an older radio host who would remark that he could remember
"the bees buzzing" as heard from his back yard on Long Island. He was alluding to
the 'B-' series bombers taking off and landing from Mitchel Field near his home.
Note: Amazingly, the grandson of Eastern Amplifier company founder Leonard Meyerson,
Matt Meyerson, saw this page and wrote the following...
 Technodrama stories were a popular means
of teaching valuable lessons back in the mid-twentieth century. Carl and Jerry,
Mac's Radio Service Shop, Sally the Service Maid - even Hobnobbing with Harbaugh
- et al, were very popular features. Popular Science magazine's Gus
Wilson's Model Garage was a gearhead equivalent. An occasional non-regular
feature appeared, as with this "Pedro
and the Swami" troubleshooting adventure in a 1959 issue of
Radio-Electronics magazine. You will like the ending. As a long-time
troubleshooter of electrical, mechanical, and hydraulic systems, I always read
these kinds of things. Pull up a chair and take a read through it; you will
appreciate the combination of reductio ad simplicitatem, reductio ad absurdum...
 Since there does not seem to be service-related
trade magazines - at least for electronics - anymore, most people have never gotten
first-hand experiences of the kinds of travails endured by servicemen as imposed
by customers. Radio News, Radio-Electronics, Popular Electronics,
Radio-Craft, and other such magazines regularly carried articles and sometimes
regular monthly columns with content contributed by guys in the repair shop and
in homes. Some were actual scenarios and others were fictional based on typical
experiences. The most entertaining were told in story form, and were undoubtedly
embellished a bit in order to increase the drama factor. This Serviceman's Experiences
feature ran in Radio News for a few years. I have to admit to not quite
getting the "Leg Department" comment, unless it means he was treated as a gofer
(i.e., go for this and go for that, using his legs). Optional theories are welcome...
 Homepage
Archives for March 2024. Items on the RF Cafe homepage come and go at a pretty
fast rate. In order to facilitate fast page loading, I keep the size reasonable - under a megabyte (ebay, Amazon, NY Times, etc., are multiple
megabytes). New items are added at the top of the content area, and within a few
days they shift off the bottom. If you recall seeing something on the homepage
but now it is gone, fret not because many years I have maintained
Homepage Archives.
 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...
 Hughes Aerospace has many openings for qualified
design engineers in Culver City, California. High power airborne transmitters, low
noise receivers using parametric amplifiers, solid state maser component development,
radar processing systems, crystal oscillators, telemetering, and high efficiency spaceborne
power supplies are among the kinds of specialties needed by Hughes to support military
and civilian projects. If you have been looking for just such an opportunity, then the
wait is finally over... provided you happened to see this advertisement in Electronics
magazine back in the fall of 1965. Quiz question: What is the difference between
a geosynchronous orbit and a geostationary orbit?
 This is the first of a three-part series
on
radio detector circuits by Mr. Robert Scott. It appeared in the August 1945
issue of Radio-Craft magazine. He begins in this article with describing
diode action and progresses to uses in various types of signal detectors in radio
receivers. A discussion of modulation and distortion sources is included as well.
The strange-looking round schematic symbols are vacuum tubes, which used metallic
elements separated by space as functional elements rather than fused sand containing
traces of impurities. Don't be intimidated, though; just think of them as field
effect transistors (FETs) where the plate is the drain, the grid is the gate, and
the cathode is the source. The next article in the series discusses hi-fidelity
triode detectors; the plate rectifier, infinite-impedance detectors, grid rectification,
and regenerative circuits...
 It was a little difficult to make out the
shape within the
crossword puzzle grid from this December 1960 issue of Popular Electronics
magazine, so I got out my blue Crayon and filled in the hashed squares. It appears
to be a transistor schematic symbol. Unlike the weekly RF Cafe crossword puzzles,
not all of the clues and words are specifically related to science and engineering,
but a large percentage of them are. Admittedly, I have the advantage of a software
program to help place the words within the grid. Margaret LeFevre did not. Doing
it by hand is a lot more work. I can't imagine how the people who created the
New York Times' Sunday-size puzzles were able to do it without computer
assistance!
 High quality
test equipment (TE) typically costs more than the knockoff stuff, but a lot more
of the former is still around in regular use compared to the latter. The retained value
of vintage TE can be quantitatively measured on eBay - as can most things for that matter.
An item is worth what the market will bear. Hewlett Packard (HP), Tektronix, Bird, Simpson,
B&K, Triplett, even Heathkit, typically sell for often surprisingly high prices when
in working order. Accordingly, a lot of people are looking for specifications on the
older equipment as well as schematics and alignment manuals. A Google search almost always turns
up what you want. The information presented in this 1966 article from
Popular Electronics magazine will probably be found by someone doing just
such a search...
 Now here is a profound ode to one of the
most noble of technician genres ever to tweak a receiver front end or to change
out a transmitter magnetron -
The Radar Man!! It appeared in a 1960 issue of Popular Electronics magazine.
Some of you know that I worked on airport surveillance and precision approach radar
in the USAF, so my bias is established. Hmmm... now that I read the poem more carefully,
I realize that it is not complimentary at all. It must have been one of those jealous
TACAN or satellite communications technicians that wrote it! |
