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 Just about everyone who has worked in the
radar field for a long time is familiar with the name of
Dr. Robert M. Page. He was the first to come up with
the concept of monopulse radar, and he invented the familiar Plan Position Indicator
(PPI) radar display and the RF duplexer which allows one antenna to be connected
to both the transmitter and the receiver. Amazingly, I recently received an e-mail
from Dr. Page's son, John Page. An interest in his father's career
combined with insight that only growing up under the loving care of Dr. Page
can provide has afforded him some unique tidbits of information that many (most,
per John) historical accountings omit. Rather than me summarizing his letter...
 Biographical historians spend endless hours
searching old media for bits of information on their subjects. Finding useful material
on more renowned personalities is not a problem, but filtering out relevant bits
for a particular theme can be daunting. On the other hand, finding useful information
on lesser known people can be frustrating because there is so little information
readily available. Great Britain's World War II era superstar
Winston Churchill undoubtedly falls into the former category. While scanning
through my many vintage electronics and science magazines for interesting fodder
to post on RF Cafe, I'm always on the lookout for cameo appearances like this
one of Prime Minister Churchill talking on a walkie-talkie (aka "handie-talkie" at the
time) in this 1942 edition of Radio-Craft...
 Exodus Advanced Communications'
AMP20071 is a broadband 6.0 to 18.0 GHz solid-state power amplifier developed
as a modern alternative to legacy TWT technology for EMI/RFI, EMC, and laboratory
test applications. The amplifier delivers 200 W minimum saturated output power
with 53 dB minimum gain and features a Class A/AB linear design for demanding
RF environments. Excellent gain flatness, built-in protection circuits, and optional
monitoring of forward and reflected power, VSWR, voltage, current, and temperature
provide reliable operation in a compact 7U rack-mounted chassis...
 New:
Rectangular Waveguide Calculator. RF Cafe's spreadsheet-based
engineering and science calculator,
Espresso
Engineering Workbook™, is a collection of electrical engineering and physics
calculators for commonly needed design and problem solving work. The filter calculators
do not provide just amplitude, but also phase and group delay (hard to get outside
of a big $$$ simulator). It is an excellent tool for engineers, technicians, hobbyists,
and students. Equally excellent is that Espresso Engineering Workbook™ is provided
at no cost, compliments of my generous sponsors. 51 worksheets to date...
 DAS DEALS Marketplace, RF Cafe's newest
supporter, is a B2B-only marketplace, meaning we exclusively work with established
businesses in the telecom, wireless, and networking industry to buy and sell
related products such as cables, antennas, DAS systems, RF passives, accessories,
and test equipment. All submissions are reviewed and approved before any products
are listed. Most products on DAS DEALS can be purchased directly using a credit
card at checkout. Can't find it on DAS DEALS? We probably know who has it. If you're
looking for a product that's not listed on our site, visit the
In-Demand Request page and submit a request.
 I did a little research on this article
about John H. Nelson's work on how the positions of planets affect
magnetic storms on Earth. It looked a little more like astrology
than science, but as it turns out, Nelson's findings gained support in both
the astronomical and meteorological fields. Naturally, the astrology crowd claimed
him as part of their goofiness, but that wasn't Nelson's fault. He published
a book in 1974 titled ,"Cosmic Connections." Yeah, even that sound like an astrology
title - poor choice (or maybe he was trying to fool the contemporary Pharisees in
to buying his book). The book is out of print now, and I could not find any contemporary
work that leverages Nelson's work...
 If you want to know what was really going
on at some point in the past, there is usually nothing more reliable than reading
a print story or advertisement from the era. That way you're getting the news
"straight from the horse's mouth," so to speak, rather than being interpreted
or filtered by some unassociated source. This report on "The Transistor in Industry" was written in 1956 by Mr. Frank
Durat, a product manager at Raytheon, at a time when transistors were first making
inroads for replacing the venerable vacuum tube (valve) which had launched and propelled
the electronics industry since 1908 when Lee de Forest introduced the triode Audion
amplifier. Germanium and silicon were the semiconductor base crystals du jour, and
achieving the requisite purity was a primary concern for advancing the state of
the art for higher frequencies, power handling, and circuit density (for integrated
circuits)...
 My
50-year high school reunion is here. Tempus fugit. These images were scanned from
my 1976 yearbook for
Southern Senior High School in Harwood, Maryland. Only pages with
information on Seniors is included. A full list of all the names that go with these
photos can be found at the bottom of the page. Having them in text format (versus
a photo) will allow search engines to find your name and associate it with Southern
Senior High School. Oh, and yes, all the photos are in B&W; there are only eight
pages with color in the entire book! I used AI to colorize a couple of them - a
technology not even deemed possible in 1976.
 Anytime I see a photo or story about the
1964 New York World's Fair, I immediately think of the scene
at the end of the first "Men in Black" movie when Agents K and J face off with the
alien invader who has come to Earth in search of "The Galaxy." This story from an
April 1964 issue of Electronics magazine reports on preparations made for
the grand opening on April 22 of that year. Based on the typical three to six month
lead time for publishing magazines back in the day, this material would have been
gathered long ahead of time. Of course now that half a century has passed we hardly
consider any of the whiz-band technology presented there as being anything wonderful,
but then half a century from now our grandkids will laugh at what we consider amazing
at the present time. Here is an interesting statement..."
 Welcome to the RF
Frequency Mixers
Quiz, a technical assessment focused on the critical non-linear components that
enable frequency translation in transceivers and test equipment. Whether you are
designing heterodyne receivers, analyzing local oscillator (LO) leakage, or striving
to minimize spurious intermodulation products in your signal chain, a deep understanding
of mixer dynamics is indispensable for high-performance RF design. This quiz covers
the core principles of frequency conversion, exploring topics such as conversion
loss, isolation, port-to-port feedthrough, and the generation of mixing products.
By testing your grasp of these essential concepts, you refine your ability to optimize...
 Albert Einstein declared and proved that
time is relative and depends on the observer's perspective. To someone sixty
years old, the year 1971 seems like it was just yesterday, but to people born a
couple decades ago, it seems like ancient history. Even so, I am taken by surprise
when I read a story from a 1971 issue of Popular Electronics that has produced
a list of "early computers" and it includes models like the ENIAC and Harvard
Mark I. Instinctively, the IBM XT, Apple II, and Packard Bell, and Compaq
lines of personal computers (PCs) come to mind. In 1971, there were no PCs. However,
if you compile a list of antique computers, then the aforementioned names apply.
This article does provide a nice recounting of the evolution of digital computers
from Charles Babbage's mechanical Difference Engine through those vacuum tube-based
electronic computers...
 These two advertisements appeared in the
July 1935 edition of QST. Bliley Electric is still in business here in
Erie, Pennsylvania as
Bliley Technologies. They make crystals and frequency sources.
Gross Radio has been out of business for quite a while. I included it mainly to
illustrated how large radio transmitters used to be - these things were installed
in people's attics and basements back in the day. This particular model, the
CB-100, is a "100-Watt Radiophone & C.W. Transmitter completely housed in an
entirely enclosed floor rack of ingenious design." It operated in the 1.7, 3.5,
7 and 14 MHz bands. For comparison, iCOM makes a 1 kW power amplifier today
covering those bands...
 Dr. Lee DeForest might have had something
like National Public Radio (est. 1970) in mind when he penned this article in 1933.
In it, the famous vacuum tube amplifier inventor lamented and criticized the commercialization
of broadcasts because of all the paid product announcements (aka commercials) that
had been steadily increasing over the years. He also was critical of the "hit-or-miss,
higgeldy-piggeldy mélange program basis" of programing; i.e., the same station playing
a mix of jazz, opera, swing, syndicated story-telling, etc. The good doctor did
not elaborate on where funding for such dedicated, uncorrupted broadcasts would
originate if not from paying advertisers, and I do not recall ever reading about
a DeForest Radio Network paid for by his vast fortune. I don't like commercials
any more than the next person, but a company deserves time to pitch its products
and/or services if it helps deliver a source of entertainment to you that...
 Each week, for the sake of all avid cruciverbalists
amongst us, I create a new
technology-themed crossword puzzle using only words from my custom-created
lexicon related to engineering, science, mathematics, chemistry, physics, astronomy,
etc. You will never find among the words names of politicians, mountain ranges,
exotic foods or plants, movie stars, or anything of the sort. You might, however,
see someone or something in the exclusion list who or that is directly related to
this puzzle's theme, such as Hedy Lamarr or the Bikini Atoll, respectively...
 John T. Frye's monthly "Mac's Radio Service Shop" techno-drama, written in story form
- was usually an incognito lesson on circuit functionality or troubleshooting, how
to deal with customers, industry regulations and news, or an introduction to new
components and equipment. As the "Unusual New Equipment" title suggests, this time
Mac described a few new items added to the service shop to aid in their work. Often
when reading one of the episodes, I do a Google search on specific components or
equipment mentioned in the article. He describes a special-purpose CRT (Sylvania's
new 5AXP4 Television Receiver Check Tube) that could be used universally for troubleshooting
in place of a wide variety of installed picture tubes. I found one for sale on eBay
for $39.95. There is not much you cannot find on eBay if you watch long enough...
 This is a different type of
electronics-related quiz from Quizmaster Robert P. Balin.
Mr. Balin created many monthly quizzes for Popular Electronics magazine.
Here you are provided a series of images and a list of men's first names, and you
need to match the image to the name. There are nine in all. Sure, it's kind of hokey
(especially B and I), but it is a good end-of-the-work-day challenge challenge to
help pass the time until the weekend begins...
 While not a second-hand store junkie, I
do like to occasionally make the rounds of the local Salvation Army, Goodwill, and
other independent shops to see what kind of relics are donated. Since eBay, Etsy,
and their kind have gained immensely in popularity, it is getting harder to find
anything useful other than clothes and kitchen wares. A few months ago Goodwill
had a 1910s vintage
cabinet -style Edison disc phonograph (as opposed to wax cylinder)
that was in very good condition, complete with a handful of styli and a couple old
records. The original finish over smooth mahogany and burl veneers had only a few
scratches and could easily be polished to look practically new. The metal hardware
could have stood a fresh coat of black paint due to nearly a century of oxidation.
Even the original nomenclature plate looked factory-new, and a clearly legible paper
plaque...
 Bell Labs, having been responsible for creating
the first positive amplification point contact transistor just before Christmas
1947, continued to lead the way in semiconductor research and new product announcements
for many decades. This little tidbit was tucked away at the bottom of page 120 in
the May 1954 issue of Radio & Television News magazine. It reported on "the
purest substances in the world" being created there in the form of 99.99999999%
(aka 10N)
pure germanium crystals, which are used as seed for growing boules
for device production. That's one rogue impurity atom in ten billion germanium
atoms. Modern monocrystalline silicon boules are typically 7N or better...
 This
Attenuator Calculator
is probably unlike any you have seen. Not only does it calculate resistor values
for both balanced and unbalanced Pi and Tee topologies, but it also calculates the
power dissipated by each resistor, and calculates the input and output VSWR when
1% tolerance resistors are used rather than ideal values. Another page provides
all equations and schematics for all four configurations.
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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.
 Since I am currently planning a loudspeaker configuration
to replace the original speaker in my 1941 Crosley 03CB floor model AM / shortwave radio
set, this article made for a good refresh on
audio frequency crossover networks. A very nice set of design charts is provided.
Of course today there is no need to design and build your own since commercial units
are very good and cost less than what I could build myself. Many moons ago while serving
in the USAF at Robins AFB, Georgia, I did actually build my own crossover circuit for
use in custom speaker cabinets I built in the base woodshop. The speaker that came in
the Crosley has a 12" cone, which is still in good condition, but it uses an electromagnetic
voice coil rather than a permanent magnet like modern speakers use...
 Electronics World magazine editor W.A.
Stocklin commemorated the fortieth anniversary of the publication's existence with a
long look back to 1919 when it debuted as Radio Amateur News. Two months previous
to this July 1959 issue was the first instance of the name change from Radio &
Television News, which was known as simply Radio News from June 1920 through
July 1948. Finally, in 1972 Electronics merged with and became Popular Electronics.
The inestimable Hugo Gernsback, a prolific writer and inventor, was the progenitor of
this magazine series - and many other magazines, fiction, and non-fiction books. Stocklin
had taken over as editor a couple decades earlier as Gernsback moved on to other projects...
 Home entertainment is as big of a deal (or bigger)
today as it was in the 1960's and 1970's when high fidelity personal sound gear was coming
into the mainstream. Capability and features were going up while the price was coming
down on really nice equipment. In order to achieve theater quality sound from your stereo
and/or large screen television, thought and planning is essential or you will end up
with a confusing mess of directed and reflected sounds. This article contains very valuable
information on room configuration and sound absorbing materials and strategies. A fairly
extensive table of common floor, wall, and ceiling sound absorption coefficients is provided,
as are charts of reverberation times of various venues and volumes...
 At least 10 clues with an asterisk (*)
in this
technology-themed crossword puzzle are pulled from this past week's (6/25 - 6/29)
"Tech Industry Headlines" column on the RF Cafe homepage. For the sake of all the avid
cruciverbalists amongst us, each week I create a new technology-themed crossword puzzle
using only words from my custom-created related to engineering, science, mathematics,
chemistry, physics, astronomy, etc. You will never find among the words names of politicians,
mountain ranges, exotic foods or plants, movie stars, or anything of the sort. You might,
however, see someone or something in the exclusion list who or that is directly related
to this puzzle's theme, such as Hedy Lamar or the Bikini Atoll, respectively. Enjoy...
 Here is the 46th quiz I have posted from 1960s
and 1970s issues of Electronics World and Popular Electronics magazines.
Most of were created by Robert P. Balin. I like to save these for Friday afternoons.
Guys like me who cut our teeth on analog meters read these indications like a second
language. Even novices usually do a good job on the meter needles, but reading a mechanical
micrometer (#9) might be more of a challenge, especially if you have never used one before.
The same goes for a dial caliper. Can you read the dials on a mechanical gas or electric
meter, where some spin CW and others spin CCW?...
 This feature appeared at the end of a larger article
titled, "RF Induction Heating." A notable difference between the type of induction heating
in the other article and the type described here is that rather than directly heating
a metallic substance to be treated (melted, bent, tempered, etc.), a "susceptor"
(graphite crucible) is used to absorb the field and heat up to melt by conduction (via
a quartz liner) the silicon material within. Pure silicon cannot absorb the RF energy
sufficiently to be heated directly. Interestingly, if you go to the Wikipedia susceptor
page, it has an image of Hot Pockets, which are wrapped in a type of susceptor that produces
a crispy exterior while heating the interior. As you are probably aware...
 If you are interested in the ingenious machines
and methods manufacturing engineers dream up for quickly and reliably producing parts
and assemblies in large volumes, then you will definitely appreciate this article on
RF induction heating. This process of course only works with metallic objects, unlike
microwave type heating schemes that work with liquids. Induction heating requires the
generated electric, magnetic, or RF field to invoke electrical currents within the metals
to increase its temperature. Ohm's law applies here. Have you ever used a torch to heat
a metal bolt, wire, car fender, etc., and noticed how it usually discolors the surface
and might even produce a crusty oxide layer? An extreme temperature rise as is required
for soldering, brazing...
 In 1967, when this parody was published in
Popular Electronics, the Iron Curtain of Communist Russia and the Union of Soviet
Socialist Republic (USSR) was still firmly in place. Constructing faux
Russian-sounding words was common at the time. All a comedian needed to do to have
their audiences rolling in the aisles was to append "ski," "ovitch" or "skov" to the
end of any word, or add lots of "z"s and "k"s in the middle of words. Tim Conway and
Harvey Korman did many hilarious skits on the 1970s' Carol Burnett show where they feigned
speaking in German, Japanese, and Russian tongues. Nowadays...
 Mac's staff service technician, Barney, asked
a great question when he mentioned that Pittsburgh radio station KDKA made the country's
first commercial broadcast in 1920: "Who
was listening?" It is a reasonable question since prior to the beginning on commercial
radio broadcasts there would have been no reason for there to have been a lot of people
to own a radio for receiving commercial broadcasts. The answer, of course, is that there
were plenty of multi-band radios in homes and businesses for listening in on shortwave
broadcast from around the world - a very popular pastime in the era. Just as today we
are bombarded with admonitions to not stare at computer monitors or cellphone screens
for too long lest we suffer near-sightedness or worse, radio listeners of yore who used
headsets were told, "Youths of this generation will never have as protruding ears as
some of their older brothers." I suppose...
 I recently created a new reference page titled
"Resistivity (ρ) & Conductivity
(σ) of Metals, Alloys, Rocks, and Soils." Values for materials are pulled from my
copy of Reference Data for Radio Engineers, Sams Publishing. Resistivity, also
referred to as specific resistance, is dependent on the nature of the material as well
as its volume definition (shape and size). Resistivity is expressed in units that are
the product of resistance and length; e.g., Ω·cm. As an example of calculating a volume's
resistance, consider the drawing to the left. Assume 12 AWG copper wire with a resistivity
of 1.72x10-6 Ω·cm, a cross-sectional area...
 As an influential member of the Internet media
;-) , I feel an obligation of sorts to make information I have access to available to
fellow vintage electronics aficionados, even if it pertains to a narrow field of interested
parties. Not many folks are frantically seeking assistance with
troubleshooting cathode ray tube (CRT) problems, but those who are in need greatly
appreciate locating content someone else took the trouble to make available. The surest
way to have Google, Bing, and other search engines discover and register it is to place
a link on the RF Cafe homepage. The main search engines usually grab my content within
a couple hours of it being posted; that is one of the perks associated with having been
around for 20 years. Many companies I have posted items about...
 It is a rare occasion that Barney bests
Mac when it comes to electronics prowess. Good natured back and forth often goes
on between them during troubleshooting sessions and impromptu discussions about
business practices, industry trends, and customer interactions; indeed, John
Frye depends on it to make his "Mac's Service Shop" stories, featured in
Electronics World magazine, interesting. This time, underling Barney
exploits knowledge gained from a recently purchased electronics reference book
to trip up shop owner Mac over which of two metals has the
lowest resistance. Mac's choice is one many people would instinctively make
- and be wrong as Mac was...
 With even a modicum of familiarity with vacuum
tube terminology, you will fairly easily complete the custom crossword puzzle. This
Electron Tube Crossword Puzzle appeared in the May 1959 issue Electronics World,
which was the first sporting the name change from Radio & TV News. If you
are a hard-core crossword puzzle worker, then check out my weekly RF Cafe crossword puzzles
that draws upon a custom dictionary of thousands of engineering, science, chemistry,
and other technical words, along with words from current news items. Bon chance...
 Germanium was "the" semiconductor of
choice in 1959 even though advances were being made with silicon. Most of the newer semiconductor
devices were being fabricated with germanium as the central transducer element. Temperature
sensors, strain gauges, "sensistor" variable resistance units, Hall effect sensors and
gyrators and circulators, torsional (twist) transducers, displacement sensors, and even
neutron detectors were done in germanium. Even though silicon is referenced as being
applicable to all the devices, it was not until the 1960s that silicon began to dominate
semiconductor fabrication. This paper titled ,"From Germanium to Silicon, A History of
Change in the Technology of the Semiconductors...
 At least 10 clues with an asterisk (*)
in this
technology-themed crossword puzzle are pulled from this past week's (7/2 - 7/6) "Tech
Industry Headlines" column on the RF Cafe homepage. For the sake of all the avid cruciverbalists
amongst us, each week I create a new technology-themed crossword puzzle using only words
from my custom-created related to engineering, science, mathematics, chemistry, physics,
astronomy, etc. You will never find among the words names of politicians, mountain ranges,
exotic foods or plants, movie stars, or anything of the sort. You might, however, see
someone or something in the exclusion list who or that is directly related to this puzzle's
theme... |
