|
 This week's
Science & Engineering Crossword Puzzle has a special message included that has to do
with why you might be off work on Monday for a holiday. Oh, and it also happens
to be the world's most revered religious time of commemoration, which to the
delight of some and to the sorrow of others, is rapidly fading into the shadows
of time. The colorful "no-letter" squares were inspired by the type of candy I
am eating as I make the puzzle. As always all the other words are from a hand
assembled file of thousands of terms from science, engineering, mathematics,
chemistry, astronomy, etc. 7 Across + 15 Across to all...
 It really was not all that long ago when
wiring images for news stories literally meant
transmitting photographs over a twisted pair of telephone lines
either to a fax machine or to a computer on standby waiting for incoming files.
Videocasts were being regularly performed via satellite of ground relay microwave
stations since the 1960s, but most still shots were sent via phone lines. For the
last decade and a half, both still shots and videos have been transmitted as a routine
matter via camera-equipped cellphones, and as with most technologies we have quickly
become so accustomed to the convenience that memories of the old ways are quickly
(even thankfully) forgotten. This article from a 1936 edition of Radio-Craft
magazine
describes one of the really early systems. Notice that coupling to the telephone
line is...
 On
sale through the end of June! Werbel's new
WM3PD-6-18-S, 3-way Wilkinson divider that operates from 6 to 18 GHz.
It is part of Werbel Microwave's catalog of splitters that offer a wide range of
port count and frequency ranges. Its compact aluminum enclosure measures 1.57 x
1.57 x 0.38 inches. The device is RoHS compliant, however it may be specially
ordered with lead solder. Return loss 14 dB typical input, 15 dB typical
output. Insertion loss above 4.8 dB is 0.3 dB typical. Isolation 23 dB
typical. Phase balance 3.4° typical. Designed and assembled in the USA. "No Worries
with Werbel!"
 Velocity modulation, aka deflection modulation,
of electronic images was evidently considered by some engineers to be potentially
disruptive technology when this article was published in a 1951 issue of Radio &
Television News magazine. You can see from the pictures that the result is
an image that today's digital software would render with an "emboss'" technique.
More vertical relief seems to be generated with the analog velocity modulation technique
compared to what my graphics program does when embossing the original photo. At
the bottom of the page is a velocity modulation video demonstration found on YouTube...
 Windfreak Technologies designs, manufactures,
tests and sells high value USB powered and controlled radio frequency products such as
RF signal generators, RF synthesizers, RF power detectors, mixers, up / downconverters,
and a 15-band programmable filter (5 MHz-8 GHz). Since the conception
of WFT, we have introduced products that have been purchased by a wide range of
customers, from hobbyists to education facilities to government agencies. Worldwide
customers include Europe, Australia, and Asia. Please contact Windfreak today to
learn how they might help you with your current project.
 Fortunately, there is a constant flow of
people newly interested in electronics who are seeking information on basic principles.
Some will find an article this one on
Ohm's law fundamentals and decide maybe being just a user of electronics
is good enough. Others will, as did you and I, read this kind of material and be
amazed at how ultimately predictable electrical circuit parameters are. If he or
she continues and launches into a career in electronics or electrical engineering,
it won't be long before he or she will, as do you...
 Whilst reading this Carl Kohler technodrama
entitled "Thin Air My Foot!," I happened upon this word new to me: "din,"
as in "It was dinned into me." OK, maybe you already knew that, but surely I should
have been aware of its alternate meaning other than being a loud noise ("the agitated
cat made quite a din."). Fortunately, I am not subject to a household of people
who refuse to put things back in their respective places when through with them,
but this tale of woe tells what might be a familiar scenario to you. To be honest,
this could have been written about me as a boy - before the U.S. Air Force taught
me a thing or two about organization and neatness - since I continually frustrated
my father by leaving his tools (and hardware and lumber and paint) scattered in
forgotten places around the house and yard...
 Antenna radiation (beam) patterns published
by manufacturers are obtained under ideal - or close to ideal - conditions with
a carefully prepared and calibrated open air test site (OATS) or an enclosed anechoic
chamber. Multipath, imperfect earth ground, obstacles both manmade and natural,
misshapen elements, poor VSWR, antenna orientation (in both azimuth and elevation)
are among the many factors which produce real-world operational results that do
not jive with a manufacturer's datasheet. Without employing some far field 3-dimensional
field strength scheme see
Drone-Based Field Measurement System™), there is no way to obtain
a complete picture of how your antenna performs in all directions...
 It has been quite a while since posting
a
Carl & Jerry adventure tale. The teenage-neighbors-cum-Ham-radio-operators-cum-electronics-hobbyists-cum-amateur-detectives-cum-pranksters
are the creation of John T. Frye. He published a monthly episode in Popular
Electronics magazine. Mr. Frye is also the author of the
Mac's Radio Service Shop series of instructional stories
that ran in Radio & Television News magazine. This adventure is quite
a digression from the typical storyline in that the boys actually engage in a bit
of deceit in order to save face based on a bet...
 Exodus Advanced Communications is a multinational
RF communication equipment and engineering service company serving both commercial
and government entities and their affiliates worldwide. Power amplifiers ranging
from 10 kHz to 51 GHz with various output power levels and noise figure
ranges, we fully support custom designs and manufacturing requirements for both
small and large volume levels. decades of combined experience in the RF field for
numerous applications including military jamming, communications, radar, EMI/EMC
and various commercial projects with all designing and manufacturing of our HPA,
MPA, and LNA products in-house.
 Is
the
BOMARC an airplane or a rocket? If it is an airplane, then it is the pilotless
type (aka "drone"). If it is a rocket, then it is the ultimate in controlled trajectory
hardware - at least in its day. The DoD referred to it as a surface-to-air guided
missile. The name is a combination of "BOeing Airplane Company"
and "Michigan Aeronautical Research
Center." Clever, non? If memory serves me correctly (it's been
30+ years), the AN/TPX-42 IFF (Identification Friend or Foe) secondary radar system
(built by Gilfillan) I maintained as an air traffic control radar technician reserved
a special "X" bit in its data packet to designate the BOMARC - and maybe other guided
missiles. That might have been a military secret at the time...
 "Israel's Iron Beam laser weapon that can
destroy drones for a few dollars 'a pop' are being developed and introduced into
combat service. The Chinese
Hurricane 3000 system is another new weapon developed to tackle the growing
use of drones in combat. However, unlike the laser-based Israeli system, the Hurricane
3000 system uses microwaves to disable drones and drone swarms at ranges exceeding
3 kilometers (1.9 miles). This is a similar weapon to the US Army's Leonidas microwave
weapon, although China claims that the 3000's reported three-kilometer-plus range
is over a kilometer more than the Leonidas system...
 This is interesting. The title for the
General Motors S1B radio says it is a 25-cycle model, as compared
to the S1A, 60-cycle model. According to an IEEE Xplore paper, "At 8:53 PM on 12
October 2006, a 66-kV circuit breaker tripped and locked out at the Harper Substation
in Niagara Falls, New York, due to downed transmission conductors near Buffalo,
New York. That event marked the end of over 111 years of 25-Hz alternating current
(ac) electric power service on the American side of the Niagara Frontier." 25 Hz
was considered a good, low frequency for...
 Here is a good
quiz that tests your knowledge of classifications of science fields.
It appeared in a 1949 edition of The Saturday Evening Post magazine. Even
if you do not particularly know the relationships, you should be able to get most
if not all twelve correct with a combination of surety, recognition of word roots,
and a process of elimination. Good luck...
 ConductRF is continually innovating and
developing advanced solutions for RF cable assembly and various RF through millimeterwave
interconnect requirements. We'll be posting their latest RF cables and technical
articles here at RFcafe.com, but to stay abreast, you're encouraged to visit their
Updates section at https://www.conductrf.com/blog
and sign up for their monthly news releases.
 During the early 1960s, Short-Wave Listening
(SWL) was a remarkably popular era-defining hobby, as enthusiasts worldwide competed
to pull in distant broadcasts from London, Moscow, or Hong Kong. "How
to DX Satellites" challenged these listeners to advance beyond Earth-bound stations
to the ultimate frontier: intercepting signals from orbiting spacecraft. While skeptics
dismissed satellite DXing as impossible due to extreme distances, low power, and
elusive verification, the author maintained it was achievable for those with the
right patience and gear. Successful monitoring required sensitive communications
receivers, crystal calibrators...
 Radio Shack,
like so many of America's original great companies, was born and lived long and
prospered during its glory days, then eventually waned into insignificance and obsolescence
within the last decade or so. It is not always simply an unwillingness to adapt
to new technologies and methods that dooms them. The forces behind those life cycles
are often beyond their control because start-ups vying for market share do not carry
the burden of and have to deal with established investments in people, facilities,
and infrastructure...
 Although obviously (but getting less so)
before my time, the mention of this airborne radar surveillance system having been
built by
General Electric, in Utica, New York, struck a chord since that
is where I had my first engineering job after having graduated from the University
of Vermont with a BSEE degree. It seems to me the work at the time was all done
in the converted textile complex on Broad Street. They were the glory days of GE,
Westinghouse, Collins, Raytheon, and other electronics titans whose engineers, technicians,
assemblers, and program managers...
 The June 1949 issue of Radio & Television
News had four
television-themed comics. Television at that time was a relatively
new home appliance, so there was a huge amount of interest in the technology. It
hadn't really been all that long since the public got used to hearing sound (i.e.,
'talkies') in the movie theater, so the mystique that surrounded television made
it the subject of a lot of puns and jokes. 1949 was a mere four years after the
end of World War II, and the post-war economic boom was primed by a surplus
of left-over electronic components along with lots of available talent both in the
areas of design and assembly...
 Temwell is a manufacturer of 5G wireless communications filters
for aerospace, satellite communication, AIoT, 5G networking, IoV, drone, mining
transmission, IoT, medical, military, laboratory, transportation, energy, broadcasting
(CATV), and etc. An RF helical bandpass specialist since 1994, we have posted >5,000
completed spec sheets online for all kinds of RF filters including helical, cavity,
LC, and SMD. Standard highpass, lowpass, bandpass, and bandstop, as well as duplexer/diplexer,
multiplexer. Also RF combiners, splitters, power dividers, attenuators, circulators,
couplers, PA, LNA, and obsolete coil & inductor solutions.
 Both my father and grandfather were
stamp collectors - philatelists is the technical word - who dabbled
in a recreational way with commemoratives from foreign countries. Nearly all were
canceled (used) stamps that today, as back in their
day, have no real value other than to someone interested in history. Of course none
are the rare types. I now possess many of those stamps in an album that was painstakingly
hand-illustrated and assembled to arrange each stamp according to its country and
issue date. At one time I, too, dabbled in the hobby, having collected many plate
blocks and special issue U.S. stamps in the 1970s and 1980s, along with purchasing
a few designs of special purpose such as those with aerospace and communications
themes...
 Exodus Advanced Communications offers a
scalable portfolio of
high-power solid-state RF amplifiers designed for electronic warfare, GPS/GNSS denial,
and counter-drone applications. These systems are engineered to support high-power
RF denial architectures capable of disrupting control, navigation, and payload links
across multiple frequency bands. Integrated into mobile, fixed, and expeditionary
platforms, Exodus amplifiers enable reliable, long-range electronic attack performance
in complex and evolving threat environments. These solutions are deployed within
high-power RF denial systems across mobile and fixed counter-UAS platforms, as illustrated...
 "Measuring low-frequency electric fields
with high precision remains a significant challenge. Existing sensing technologies
often cannot deliver traceability, compact design, and the ability to detect field
direction all in one system.
Rydberg atoms are gaining attention in electric-field quantum metrology because
they have large electric dipole moments and their behavior can be tied to well-defined
atomic properties. Most current methods for detecting low-frequency or DC electric
fields using Rydberg atoms rely on vapor-cell electromagnetically induced transparency
(EIT) spectroscopy. However, this technique is limited..."
 Here are the
Majestic Chassis Models 380 A.C. T.R.F., and 400 A.C.-D.C. Superheterodyne
and
Delco 32-Volt Radio Receiver Chassis Radio Service Data Sheets
as featured in a 1933 edition of
Radio-Craft magazine. As mentioned many times in the past,
I post these online for the benefit of hobbyists looking for information to assist
in repairing or restoring vintage communication equipment. Even with the availability
of SAMS Photofacts, there are some models that cannot be found anywhere other than
in these vintage magazines...
 For the sake of avid cruciverbalists amongst
us, each week I create a new
crossword puzzle that has a theme related to engineering, mathematics, chemistry,
physics, and other technical words. You will never be asked the name of a movie
star unless he/she was involved in a technical endeavor (e.g., Hedy Lamar). Clues
in this week's puzzle with an asterisk (*) are directly from this week's "High Tech
News" column on the RF Cafe homepage (see the Headline Archives page if necessary)...
 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 354,801 products from more than 2478 companies
across 485 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.
 In 1961, when these
tech-themed comics appeared in Electronics Illustrated magazine, the
"Space Race" was in full swing. That, along with home hi-fi stereo equipment, newfangled
color televisions, and - gasp - transistors, filled the headlines. They were also
the subject of many forms of humor. These four comics touch on many of those aspects,
all centered on the Space Race. Of course, everything is noticeably dated. "Flunking
the code test" means not much to Amateur radio licensees who earned their first
license (like me, in 2010) after the 5 WPM Morse code requirement was removed. Building
something in "kit form" was a good way to save some money and learn something...
 In our present "No user serviceable parts
inside" world of electronic products, it is easy to understand why very few people
have an appreciation for the technical prowess needed to troubleshoot and repair
them. When reading through these episodes of "Mac's Radio Service Shop" that appeared in mid last century editions
of Radio & Television News magazine, I am inspired to envy the skills
that small electronics repair shop owners had for working on the old vacuum tube
based radio and television sets. Digital electronics has its own unique set of quirks
and special knowledge requirements to troubleshoot, but when everything is analog
rather than merely being required to be a "0" or a "1"...
|
 • Amazon
Might Buy Globalstar
• AI Could End
Online Anonymity (or falsely identify)
• How
Test and Measurement Will Evolve in 2026
• AI
and Geopolitics Forge Memory Market Crisis
• European
Electronics Distribution Gains Momentum
 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.
 Radio control (R/C) systems operating in
the 2.4 GHz ISM band, using one of or a combination of frequency hopping and
direct sequence spread spectrum scheme, have been in widespread use since the early
2000s. As with any new technology, there was a lot of reluctance to adoption of
the systems based on a few reports (valid or not) of performance issues - primarily
lack of control range where communications between the transmitter (Tx) and receiver
(Rx) with a pilot and aircraft was lost and a crash ensued. Tx power was already
at the FCC-mandated maximum, so manufacturers quickly improved receivers by adding
diversity with a second Rx antenna. The receiver microprocessor continuously monitors
signal integrity from both antennas and uses the best one. It is the same scheme
that was already being used by WiFi routers also operating at 2.4 GHz...
 The word prefix "para" can mean "above and
beyond" or "resembling" or "abnormal or incorrect." Ward Products probably preferred
first two be inferred by potential customers when naming their
PARA-CON television antenna, although it actually is a shortening of "parabolic."
The "con" part is a shortening of "conical." After reading the text of this full-page
advertisement from a 1951 issue of Radio & Television News magazine, I'm inclined
to assign the third prefix meaning of "para" to it. Then, add in the "con" part
where "con" can take on either the noun form meaning of "disadvantage" or the verb
form definition of "to trick or defraud," and you get what this antenna truly represented
in terms of achieving superior performance. At best the PARA-CON exhibited the characteristics
of a phased pseudo-[bi]conical antenna. The allusion to a parabolic antenna...
 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...
 There are probably few baseband and IF
delay lines these days that are constructed from a chain of inductor-capacitor
(LC) sections as described in this 1953 Radio-Electronics magazine article.
SAW and MEMS devices are the more likely choice for many reasons including cost,
weight, and volume savings. The preferred implementation of measured delays nowadays
would be in software after sampling with an analog-to-digital converter (ADC). There
are still applications for coaxial delay lines such as phase matching or adjustment
between system elements, and many companies offer custom designs with delay precision
in the tens of picoseconds. I once worked on part of a VHF/UFH transceiver unit
that used precise lengths of coax cable as part of a signal cancellation circuit
for enabling multiple radios to function in close proximity. I was not the designer...
 I have been scanning and posting schematics
and parts lists like this one featuring the Admiral (full name Admiral Continental
Radio & Television Co., located in Chicago, IL) models
7T06 and 7T12 in graphical format. It appeared in a 1947 issue of Radio News
magazine. Publications of the era provided this service data for the sake of both
professional repairmen and hobbyist do-it-yourselfers because the manufacturers
did not make it available to entities that were not official representatives. Sams
Photofact made more detailed documentation available for sale, but it was expensive.
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. An Admiral
7T06 radio recently came up for sale on eBay...
 Ever heard of the revolutionary
Graphechon Tube, by RCA? Neither
had I, until I saw it mentioned in an ad for RCA televisions in a 1950 edition of
The Saturday Evening Post. My curiosity was piqued enough to do some research.
First, here is the text of the ad: "Scientists at RCA Laboratories work with split-seconds
of time too infinitesimal for most of us to imagine. Their new electron tube, the
Graphechon, makes it possible. For instance, in atomic research, a burst of nuclear
energy may flare up and vanish in as little as a hundred-millionth of a second.
The Graphechon tube oscillograph, taking the pattern of this burst from an electronic
circuit...
 Necessity
is the mother of invention, according to a popular saying, and perhaps there is
no greater need that the one for survival as a nation. It cannot be denied that
most of our advanced technology has been invented for the sake of defending the
country against the threat of invasion from a formidable enemy who intends to use
its advanced technology against you. Whether you love, hate or are neutral on the
military, you have benefitted from its existence both in the form of enduring freedom
and from everyday products and methods produced due to its existence. Human nature
being what it is, history has shown that simply being willing to lay down your arms
and play nice with the rest of the world does not result in peace - only in your
being subject to somebody else's control. Missile technology - particularly the
intercontinental range type - was the primary concern...
 J-pole antennas (aka "J" antennas) are so
named due to their physical shape. The basic "J" antenna is a half-wave
vertically polarized antenna that has an integrated parallel feed quarter-wave
tuning stub. It is very popular with amateur radio operators and is still used
with some commercial radio installations. The azimuth radiation pattern and gain
are very similar to the half-wave dipole antenna, as shown in the Wikipedia plot
below. The J-pole was invented in 1909 for use on the German Zeppelin airships
as a trailing wire antenna. Variations of the J-pole have evolved over the years
that in some cases significantly change the radiation pattern, but the
characteristic quarter-wave stub match is retained in all of them...
 Until seeing this Bell Telephone Laboratories
promotion in a 1960 issue of Electronics World magazine, I never considered
that programming an autonomous missile for long distances and long flight times
in the days before GPS required compensation for the Earth's rotation. Also, even
though an intercontinental ballistic missile (ICBM) would spend a relatively small
amount of time in the atmosphere during boost and reentry / terminal phases, wind
effects would also need to be factored in to the onboard
inertial guidance system's navigation program. Bell Labs was evidently tasked
to design a system which could launch from the U.S. and fly to a target 6,000 miles
away, and hit a designated spot closely enough to do the intended damage. According
to the online great circle distance calculator, the trajectory from Lincoln, Nebraska,
to Moscow, Russia (USSR in 1960) is 5,258 miles, so it is reasonable to assume the
chore had similar start / stop locations in mind...
 Many people end on RF cafe as a result of a Google
(or other) search about electronics, so even though regular visitors might find this
primer on
Ohm's law to be redundant review, it will be valuable to the aforementioned people.
Electronics technology has moved forward at lightning speed in the last century, but
the fundamentals of Ohm's law remain unchanged. Indeed, we would be in trouble if voltage
no longer equaled the product of current and voltage (E = I x R).
National Radio-TV News magazine was published monthly by National Radio Institute,
a correspondence school that did business from 1914 through 2002. A bonus electronics-themed
comic is included...
 Narrow-band frequency modulation (NFM) was
a relatively new technology in 1947, having been advanced significantly during World
War II. Amateur radio operators were just getting their gear back on the air
after having been prohibited from transmitting for the duration of the war (see
"War Comes," January 1942 QST). Few were probably thinking about adopting
and exploiting new modulation techniques, but for those who were and recognized
FM as the path to the future of radio, QST published this fairly comprehensive
treatment of both frequency modulation (FM) and phase modulation (PM). Mathematically,
FM is the time derivative of PM. Both modulation schemes vary the carrier frequency
in some proportion to the baseband signal. Author Byron Goodman provides some insight
into the techniques...
 Mac and Barney discuss with some degree of trepidation
the alarmingly increasing rate at which new
electronics technology is being developed and marketed. As service shop owner and
technician, respectively, they needed to constantly educate themselves on new components
and circuits in order to stay current and be efficient enough to turn a profit. Mac recounts
his lengthy background beginning with the days of mainly battery-powered AM radios, and
progressing through AC-DC, FM and all-band (shortwave) radio, B&W television and
the color TV, CB radios, and a new breed of appliances with electronic controls...
 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. This "A Smorgasbord
of RF Topics" quiz touches on a wide range of subjects ranging from Bluetooth
to WLAN and ESD testing standards.
 There are still many old-timers and beginning
nostalgic collectors out there who nurse heirloom and otherwise procured vacuum
tube radios - like this
Arvin Models 150TC, 151TC combination radio / phonograph - back to health (operating
condition) and/or keep them in good health. While it is possible to purchase schematics,
parts lists, and service instructions from many different models, there are still
some that have escaped the scanners of those publishers. For those kindred spirits
in search of such reference materials, I happily scan, clean up as necessary, and
post this collection (see complete list at bottom of page). I have dozens more that
will eventually be added over time, so check back later or send me an e-mail if
I have an issue (check the lists first, please) of Radio News, Radio-Craft, etc.
known to contain the information you need...
 When up in a small airplane or helicopter,
I have never had any sense of fear of heights, but when at the top edge of a really
tall building or at the precipice of a high cliff, the need to control the panic
sensation is required. It is not strong enough to prevent me from going there, but
I'm definitely not one of those fearless types that will go anywhere with reckless
abandon. Even seeing a photo like this one on the IEEE Spectrum website invokes
the fight or flight emotion. You need to click on the thumbnail to see the larger
version to really get a sense of the height at which the technicians are working.
The story is about China's
Changji-Guquan ultrahigh-voltage direct-current transmission link along the
Yangtze River, in Anhui province. Arguments abound over whether DC or AC is better
overall for electrical distribution, but the main reason for this DC line is to
accommodate energy storage at locations throughout the country...
 This
vacuum tube shaped crossword puzzle appeared in the April 1964 issue of
Popular Electronics magazine. It won't take you more than a couple minutes
to complete - just a short trip, with a pencil, to the John ;-) Like with
all my custom-made RF Cafe Crossword Puzzles, every clue and word in this crossword
by Stephen Nelson has an application to electronics technology. Unlike with my crosswords,
the across/down grid is very simple with few groups of adjacent empty squares. That
makes creation an easier task, especially when your word selection list is constrained
to a particular topic. Still, it's a good puzzle. Have fun.
 The newest release of RF Cafe's spreadsheet
(Excel) based engineering and science calculator is now available -
Espresso Engineering Workbook™. Among other additions, it now has a Butterworth
Bandpass Calculator, and a Highpass Filter Calculator that does not just gain, but
also phase and group delay! Since 2002,
the original Calculator Workbook has been available as a free download.
Continuing the tradition, RF Cafe Espresso Engineering Workbook™ is
also provided at no cost,
compliments of my generous sponsors. The original calculators are included, but
with a vastly expanded and improved user interface. Error-trapped user input cells
help prevent entry of invalid values. An extensive use of Visual Basic for Applications
(VBA) functions now do most of the heavy lifting with calculations, and facilitates
a wide user-selectable choice of units for voltage, frequency, speed, temperature,
power, wavelength, weight, etc. In fact, a full page of units conversion calculators
is included. A particularly handy feature is the ability to specify the the number
of significant digits to display. Drop-down menus are provided for convenience...
 Banner Ads are rotated in all locations
on the page! RF Cafe typically receives 8,000-15,000 visits each
weekday. RF Cafe
is a favorite of engineers, technicians, hobbyists, and students all over the world.
With more than 17,000 pages in the Google search index, RF Cafe returns in
favorable positions on many types of key searches, both for text and images.
Your Banner Ads are displayed on average 225,000 times per year! New content
is added on a daily basis, which keeps the major search engines interested enough
to spider it multiple times each day. Items added on the homepage often can be found
in a Google search within a few hours of being posted. If you need your company
news to be seen, RF Cafe is the place to be...
 My first thought when seeing the cover for
this December 1936 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 wearing
Google Glass (a failed concept) a few years ago - you'd be a superhero to fellow
nerds, and just be confirming your otherworldly nerd status to non-nerds. Note the
very nicely done drawings... |
