If you need a cheap, quick
lightning arrestor for your antenna or just about any type of
wired system, this idea from Mr. Burgess Brownson looks like a good idea. He
used an automotive spare plug. Voltage breakover points can be set by varying the
spark gap distance. The old vacuum tube transmitters and receivers had a better
of chance of surviving a lightning strike because the components were able to handle
much more of a shock than our modern semiconductor sets with miniature, closely
spaced components. Still, the spark plug setup is better than nothing, if for no
other reason than to protect the shelter. it should suffice. This and many
...
The
free whitepapers,
pamphlets, books, and chapter examples listed here are a small sample of a lot of
new items that are offered for FREE through TradePub. The publishers make them available
to qualifying people as a promotional campaign for their full line of offerings.
You might want to take a couple minutes to see what's new there. They are all free
downloads ...
In 1935, not much
was yet known about the
ionosphere. Its existence was first theorized in 1902 by Arthur
Kennelly and Oliver Heaviside, and Edward Appleton proved its presence in 1924 by
conducting a series of broadcast experiments, but no direct measurements were possible
until rocket-borne instruments could be launched. An Aerobee-Hi sounding rocket
was launched in 1956 as part of the International Geophysical Year (IGY) project
that made the first actual detection of ionized particles in what is now referred
to as the D-layer. It is therefore forgivable that Hugo Gernsback, normally spot-on
in his theories and postulations regarding RF propagation, incorrectly suggested
in this editorial that based on observed time
...
Just about a year ago I posted a
report on the FCC punishing an amateur radio operator (Ham) for
having an on-air conversation with another party who failed to identify himself
per Part 97 requirements. Per FCC regulations, every control operator in the
Amateur Radio Service (with few exceptions) is required to broadcast a station identification
(call sign) at least once every ten minutes during periods of communication. The
named operator properly identified himself, but was prosecuted for failing to terminate
an exchange with someone else who did not comply. This legal action was executed
by the same government which belittles honest citizens who object to its policies
of ignoring illegal aliens crossing our
...
Thanks to Joe Cahak, there are now 11 new
cardboard
calculators & slide rules added to the RF Cafe museum. Rare is the RF engineer
or technician who has been in the business more than 20 years that has not used
HP's classic Reflectometer & Mismatch Calculator slide rule. Most 'millennials'
might not even associate Hewlett Packard with test equipment unless they happen
to work somewhere with a stock of vintage gear. They have phone apps for this type
of work. A Miteq rotary Mixer Spur Analyzer is included, as are 9 others, some with which
you probably are not familiar. Old-Guy Admission: I once carried these calculators
in my shirt pocket right behind my plastic pocket protector
...
Remember when you could hold a telephone conversation
without having to allow a moment of time at the end of a sentence before responding
in order to keep from 'stepping on' the person on the other end? It used to be only
overseas phone calls or maybe communicating to astronauts on the moon suffered such
inconveniences, but talking to someone across town was like having a face-to-face
discussion. More often than not - or so at least it seems - there is a
noticeable delay between the time someone actually stops talking
on the transmitter end and the time the audio stops at the receiver end. People
who have
...
One of the few aspects of electronics that
has not changed since the early days of the craft is impedance matching and, in
particular, use of the
Smith Chart. Many an engineer, technician, and hobbyist has been
intimidated by the chart's appearance; however, after using the Smith Chart a few
times for impedance and/or admittance matching, quickly develops the knack of applying
it. If you have an affinity for mathematics and are comfortable with complex numbers,
all the arcs and circles makes perfect sense once the simple equations governing
its construction are presented. As with so many other things, you wonder how anyone
ever thought to do such a thing, and at the same time wonder why it took so long
for someone to think of it. Gary Steinhour (KF6U), who recently
...
It's always hard getting back into the swing
of the workaday routine after a long holiday weekend. Now that you've finished trading
stories with workmates about what you did - or did not - do, take one last moment
to lift your spirits by looking at these
electronics-themed comics from vintage issues of Electronics
World magazine. I particularly like the step switches. BTW, these comics make
good fodder for opening your technical presentations
...
"A scientist studies what is, an engineer
studies what never was." -
James A. Michener,
historical fiction author
.
Many thanks to author and amateur radio operator
Dan Romanchik (KB6NU) who sent this article for posting here on
RF Cafe. A lot of electrical engineers and hobbyists are familiar with Mr. Romanchik
from his stint as Senior Technical Editor for Test&Measurement World
magazine (now part of EDN), and by his popular books on preparing for taking and
passing Amateur Radio exams- including the newly released "No-Nonsense General Class License Study Guide."
Contained within are Dan's observations regarding how Amateur Radio seems to be
making a comeback in many realms including colleges, the popularity of radio displays
in museums, and a rising number of 'hackers/makers' who are exploring the
...
Today is
Memorial Day in America. When America was drawn into World War II
after the attack on Pearl Harbor on December 7, 1941, the country snapped into action
and our citizens were ready, willing, and able to help. One big immediate need was
knowledgeable electronics technicians and engineers, particularly people with experience
in radio communications. Amateur radio operators were the natural reserve source
for just that need. The FCC shut down Ham radio transmissions in January 1942 ostensibly
for security reasons, but some suspect the reason was at least partly to motivate
Hams to enter the armed services or work at government research laboratories. Still
feeling ...
Pasternack-New-Cable-Designer-5-22-2015.htm" >
Pasternack Enterprises has just released their
newest engineering resource called the
Cable Assembly Designer which allows the user to design and
customize RF cable assemblies with an easy-to-use online web application at Pasternack.com.
Pasternack's new custom cable designer enables engineers and buyers to create customized
RF cable assemblies that meet their specifications from any combination of compatible
connectors and cables offered by the company. Over 250,000 possible combinations
Pasternack-New-Cable-Designer-5-22-2015.htm" ...
Until maybe 20 to 30 years ago, there was
still a certain amount of awe associated with new applications of technology. It
seems anymore people are so accustomed to new and amazing things - usually at affordable
prices - that the wonder is gone. Advancements are expected. The world is moving
so fast that it is difficult to absorb and fully appreciate all the work being done.
In 1947, both airplanes and electronics were still relatively new to a lot of people,
especially in more rural areas, so a whiz-bang scheme like broadcasting messages
from an airplane was
...
MECA-RF-Parts-On-Demand-5-21-2015.htm" >
MECA Electronics
announces our expedited online service center, the source for
RF Parts on Demand (RFPOD)
when you need them. RFPOD offers an expedited online service that process your order
and has it available for pick up at will call or shipment within 2 hours from order
placement to pick up time! Will Call pick up hours are 9:00 AM to 5 PM (ET) - earlier
hours are available by calling customer service in advance at (973) 625-0661. Let
us help solve your component problem, we are here when you need us, orders are accepted
24 hours a day, 7 days a week and shipments are made same or next business day MECA-RF-Parts-On-Demand-5-21-2015.htm"
...
Money in Radio Gadgets
Substitute "cellphone" for "radio" in this
title and editorial by
Hugo Gernsback in 1933 and it would fit right in with today's
market of wondrous gadgetry. Prescient as always, Mr. Gernsback describes, among
other things, what we now refer to as energy harnessing to power ancillary devices
and props. He also recommends a scheme for causing 'dancing dolls' on the surface
of a table vibrated and mobilized by the sonic waves of a large speaker - a lot
like the way years later vibrating football games were made
(remember them?) where the men danced randomly
...
This is a good week for engineer job openings.
Nokomis is seeking outstanding PhD and MS level electrical engineers, physicists
and computer scientists position will support design and enhancement of next-generation
RF/microwave devices. 3-10 years' experience is required depending on the position.
Military background is a plus. Experience should include RF/microwave design and/or
measurement with a focus on RF sensor systems and signal analysis. Experience with
receivers, transmitters, and transceivers is a plus. Test and measurement experience
as well as filter design ...
Isn't an anagram a word game where letters
of one word are rearranged to spell another word or series of words? For instance,
an anagram for 'microwave' is 'warm voice,' one for ''resistance" is "ancestries,"
and for "vector" is "covert." If so, then this puzzle is misnamed; it is really
a crossword puzzle. Maybe back in 1961 the word anagram included this type of puzzle.
Regardless of the naming error, I did learn a new word: "inertance," which means "the effect of inertia in an acoustic
system, an impeding of the transmission of sound through
...
Rohde-Schwarz-FSWP-Phase-Noise-Analyzer-VCO-Tester-5-19-2015.htm" >
The new phase noise analyzer and VCO tester from
Rohde & Schwarz enables ultrasensitive and ultra-fast phase noise measurements.
The R&S FSWP also allows users to very easily measure pulsed sources and residual
phase noise of RF components. Plus the instrument can be upgraded to a signal and
spectrum analyzer. With the new
R&S FSWP phase noise tester, users can measure
the spectral purity of signal sources such as generators, synthesizers and VCOs
more quickly than with any Rohde-Schwarz-FSWP-Phase-Noise-Analyzer-VCO-Tester-5-19-2015.htm"
...
NuWaves Engineering, a premier supplier of RF
systems, RF products, and engineering design services, is actively seeking talented
and highly motivated RF Design Engineers with 4 plus years of experience in RF system
and/or circuit design to support engineering development. NuWaves is a fast growing
RF Design Engineering firm located in Middletown Ohio – North of Cincinnati and
South of Dayton. Individuals must have knowledge of RF systems and circuit design.
Experience with PLLs, LNAs, PAs, demodulators, modulators and other communication
circuitry is essential ...
Dan Romanchik (KB6NU), author and instructor
on all things Ham radio, has just released his latest Amateur Radio exam book titled
"No-Nonsense General Class License Study Guide: (for tests
give between July 2015 and June 2019). The new question pool takes effect
on July 1st of this year and lasts for four years. It is available in both
paperback and
Kindle formats. Hopefully, Dan
(read his blog) has plans to release a new version for his
Amateur Extra study guide for the new question
pool in 2016, for which I'll be studying. See the formal Dan-Romanchik-Updated-Study-Guide-Paperback-E-Book-5-19-2015.htm" >press
release.
Whilst perusing the June 1934 edition of
Radio-Craft magazine, I found betwixt the pages this business card from
the Lake Chevrolet
Company, of Devils Lake, North Dakota. As you can tell by the old panel truck
on it, the year it was printed was probably sometime around 1934. While this business
card does not have the value of a 1900s era blue chip stock certificate I keep hoping
to find, it does have historic and nostalgic value - at least to me as an appreciator
of the people and institutions that built America. The handwriting on the back of
the card says, "Delivery 577. Cab box chassey[sic]," and "Let me know at least 3
weeks ahead." Although you cannot tell
...
NuWaves Engineering, a premier supplier of RF
systems, RF products, and engineering design services, is actively seeking talented
and highly motivated Engineering Manager. Reporting to the CTO, the Engineering
Manager directs the implementation of various strategic and tactical operations
by performing the following duties either personally or through direct reports.
Essential functions include: • Write and present proposals, reports and related
findings • Participate in development and deployment of NuWaves' mission and business
strategies • Perform RF Design • Responsible for leading and supervising design
engineers as they ...
nuwaves-c-band-amplifier-nasa-sbir-5-19-2015.htm" >
NuWaves Engineering, an international RF and microwave
solutions provider, announced today that the company has been awarded a Phase II
Small Business Innovation Research (SBIR) contract from the National Aeronautics
and Space Administration (NASA) to develop and prototype a
miniature linear and high-efficiency C-band power
amplifier to provide communication range extension for a variety of NASA missions
and applications, including Unmanned Aircraft Systems (UAS) integration into the
National Airspace System (NAS). Under the terms of the contract, NuWaves will, nuwaves-c-band-amplifier-nasa-sbir-5-19-2015.htm"
...
This
passive RF limiter is a simple combination of cascaded "T" type
resistive attenuators that are switched in and out of the circuit based on the power
level in the line. The design takes a bit of thinking due to needing to retain a
reasonable impedance match at the input and output throughout various stages' conduction
states. Arriving at an optimal value for resistors would require a circuit simulator
with a mathematically based optimizer, but, especially for amateur radio work, close
is good enough. That is not to say Hams are a bunch of slackers - they're not -
it's just that component and software resources are not as readily available
(aka 'prohibitively expensive') for doing the analysis
and testing. In 1966 when
...
Copper-Mountain-Technologies-High-Performance-VNAs-5-19-2015.htm" >
Copper Mountain Technologies (CMT) introduced
a new series of high-performance
vector network analyzers (VNAs) designed to efficiently
handle advanced test applications at the 2015 International Microwave Symposium
(IMS) in Phoenix on May 17-22. The Cobalt series, which presently features the C1220
and C1209 models, offers an unmatched price-performance combination for S-parameter
measurement between 100 kHz and 20 GHz. To achieve high performance and an affordable
cost, the design and production of Cobalt VNAs incorporates several Copper-Mountain-Technologies-High-Performance-VNAs-5-19-2015.htm"
...
"You're always so concerned about your reputation.
Einstein did his best stuff when he was working as a patent clerk!" - Dr. Peter
Venkman,
Ghostbusters
Sivers-IMA-East-Coast-Microwave-Distributor-5-18-2015.htm" >
Sivers IMA, a leading manufacturer of millimeter
wave products and Boston-based East Coast Microwave (ECM), today announced that
they have signed a reseller and distributor agreement for the US and Canadian markets.
ECM will represent the whole Sivers IMA product range including Converters and Customized
Transceivers, Radar Sensors and Signal Sources such as VCOs and synthesizers. “The
agreement with ECM is an important part of our expansion strategy. The North American
market naturally holds a large potential for our products and we strongly believe
that ECM is the right local partner for us to meet the interest we see”, says Robert
Ekström CEO of Sivers-IMA-East-Coast-Microwave-Distributor-5-18-2015.htm" ...
Magnetostriction is a term not seen very often
these days. It describes the physical shape change that takes place in certain ferrous
materials when subject to a magnetic field, and is responsible for most of the familiar
'hum' that comes from transformers. The effect is used in mechanical filters as
transducers between the electronic circuit and the mechanically resonant disks that
define filter bandpass characteristics. Elemental cobalt exhibits the highest room
temperature magnetostriction (units are 'microstrains').
Nickel, with about half the value as cobalt, is cheaper and more abundant and is
therefor more commonly used in modern magnetorestrictive transducers. Way back in
the 1980s while
...
Forbes just published its newest list showing
which college majors currently enjoy the highest starting salaries.
Engineering and architecture top the list at $50k US, while computers
and mathematics follow closely. Next comes health fields and then business. The
physical sciences fare worse than social sciences, which I find disturbing. For
comparison, workers with only a high school education average $22k US. What is not
mentioned, but probably implied, is whether pay for those with only a high school
diploma is for right out of school or four years later when the college graduate
would begin his/her career. That might be a more fair ...
"How to Meet Amazing People Without Sleazy
Networking" - now there's a catchy article title for you. It is one of the
career
advice offerings I found in my search for useful (mostly)
items for this go-round. Not being a 'networker,' probably ultimately to my disadvantage,
I am not fluent or knowledgeable in the art. However, a lot of engineers' livelihoods
are significantly dependent on well-honed
...
-
The 50 Happiest Companies in America for 2015
-
6 of the Best Tech Meetups in the U.S.
-
How to Meet Amazing People Without Sleazy Networking
-
Storytelling 101: How to Inspire, Influence and Get Results
(interesting approach)
Please bear with me again as I post these
six radio service data sheets for the benefit of hobbyists and archivists who might
be searching for such information either in a effort to restore a radio to working
condition, or to collect archival information. Putting links on the homepage helps
get them registered fast in search engines.
Hetro Air-Ace Series M, 9-Tube 4-Band Superhet,
Crosley Model 1155, 11-Tube 4-Band Superhet,
Canadian Westinghouse Model 175, 7-Tube Dual-Range Superhet Radio
Service Data Sheet,
Arvin Model 35, 8-Tube Car-Radio Receiver,
Philco Models 39 and 39A, 6-Tube Dual-Range Battery Superhet,
Philco-Packard Deluxe, 7-Tube Superhet Car Radio
everythingRF Providing IMS 2015 Coverage
everythingRF-Providing-IMS-2015-Coverage-5-18-2015.htm" >everythingRF will be covering the everythingRF-Providing-IMS-2015-Coverage-5-18-2015.htm" >IMS
2015 in Phoenix, Arizona. A link to the live coverage can be found
here. This is a non-bias coverage unlike most
of the other journals where they only publish what their sponsors are showcasing.
This page will be updated as and when new products
and announcements are made at the event. Visit
www.everythingRF.com
to learn more everythingRF-Providing-IMS-2015-Coverage-5-18-2015.htm" ...
There was a time when having a career in any
field of electricity or electronics work was an enviable mark of a person's technical
prowess that conveyed a degree of respect. The whole
controlling of electrons thing boggled the minds of most people,
whether it meant wiring homes and buildings for lights, receptacles, and motors,
or designing 'all wave' radio sets for listening to the evening broadcast of "The
Lone Ranger." Today, with nearly everyone alive having grown up with such conveniences,
the 'wow factor' is pretty much gone, except maybe with those of us who still chose
to engage. If an electronics appliance or device stops working nowadays, it is discarded
rather than repaired. This 2-page advertisement
...
Have you had a rough week? If so - and even
if not - take a few minutes to get a laugh from these
electronics-themed comics from the pages of vintage Radio
News magazines. Beginning sometime in the late 1930s and early 1940s, single-panel
topical comics began appearing frequently in many hobby and even professional magazines.
Sure, comics showed up in magazine before that time, but they generally did not
necessarily have to do with the main subject of the publication. The Saturday
Evening Post, for example, had many single-panel comics, but they were on any
random theme. The Saturday Evening Post, for example, had many single-panel
comics, but they were on any random theme. I can't go without commenting on the
April 1946 comic since it reminds me of a situation
...
As radio frequencies moved up into the UHF
realm of 30 MHz (through 3 GHz), designers
noticed that the old methods and equations for winding inductors
(aka coils and chokes) no longer performed as predicted.
The culprit was
stray capacitance created by the wire itself and the insulation
between windings. To some extent, the length of leads running from the inductor
windings to connection points (terminal strips and lugs at
first and then later printed circuit boards) generated enough extra inductance
to add noticeably to total inductance. New methods were developed to help mitigate
the effects of these stray (aka parasitic) reactances.
Much new knowledge in this area was gained through the war efforts with many radar
...
Long-time RF Cafe visitor and contributor
Joe Cahak's article entitled "Pondering on Power Measurements"
(it begins on page 22) just made the cover of
High Frequency Electronics magazine's May edition (IMS2105
preview). Joe's expertise lies in many areas of electrical engineering, with
an emphasis on RF. He has authored many articles, such as "Measurements with Scattering Parameters" and "Searching for the Q," appearing here and elsewhere. Joe's other
interests include amateur astronomy, cycling, hiking, and mineral / rock collecting.
His Sunshine
Design Engineering Services company is located in Ramona, California.
The good folks at
IMS ExpertServices have published an interesting
short article highlighting the increasingly difficult technical issues being brought
before courts in intellectual property (IP) cases.
Attorney
Ryan Thompson, who holds degrees in both law
and journalism, tells here about a recent court ruling that places severe restrictions
on the ability of an expert witness to cite and admit as evidence material based
on the work of another non-testifying expert witness. Known in the legal realm as
'bootstrapping,' the practice has greatly burdened efforts required
to rebut massive volumes of opinions admitted as evidence based solely on the endorsement
of an expert who is physically present and testifying in the courtroom. This strategy,
used extensively in patent cases, is especially
...
Please welcome
James Stanton as the
newest USAF radar tech to be inducted into the Radar Shop Hall of Fame! James served
in the 3rd Combat Communications Group (3CCG) at Tinker
AFB, Oklahoma. He's an 'old school' guy with 'new school' technical expertise, having
served 8 years as a cadet in Civil Air Patrol, 9 years in the USAF as an Air Traffic
Control Radar Technician, and earning an AAS degree in Electronic / Electrical Engineering.
James now owns and operates James' TV and Audio Repair shop in Milton, DE,
servicing cellphones, computer monitors, wide screen TVs, speakers, appliances,
and more.
Please support RF Cafe through
Amazon.com purchases! By clicking this link or
logo when initiating an Amazon shopping spree, RF Cafe (a
one-man operation - me) earns a small commission and it does NOT
affect the price you pay in any way. Most items qualify for free shipping when you
spend more than $35. Melanie and I always check with Amazon for a price comparison
prior to buying anything we don't need immediately or cannot be bought through the
mail (like groceries). Your support is definitely
needed and appreciated. Thanks!
NI-AWR-Design-Environment-V12-Pre-Release-5-12-2015.htm" >
NI (formerly AWR Corporation),
announces that NI AWR Design Environment™ V12 - the first major software release
in 2015 - is now available as a pre-release to select customers, partners and evaluators.
Previewing for the first time at International Microwave Symposium 2015
(IMS2015) in NI booth #2431, this latest release boasts
new load-pull and antenna- and radar-specific features, as well as ease-of-use improvements,
speed enhancements and third-party integration flows.
BOSH Global Services has an opening for an experienced
RF engineer who would like to work in the small unmanned aerial systems
(sUAS) realm. I know there are a lot of engineers
who fly radio controlled model airplanes and the current crop of drone platforms.
This would be an excellent opportunity to get paid while enjoying your hobby passion.
If you happen to be an Amateur radio type as well, then it's a twofer.. Read about
the qualification and duties in this RF Engineer III job listing.
Many of these magazines have websites that
I visit on a daily basis in search of up-to-the-minute industry headlines.
Free subscriptions
are offered to qualified applicants. 'Qualified' usually means that you are currently
employed in a field related to the primary theme of the magazine, and often you
also need to be a decision maker for buying products represented within the pages.
Technical magazine coffers, like mine here at RF Cafe, get filled by advertisers
and therefore we/I need the public to support those companies by purchasing their
products and/or services. If you believe you meet the qualification(s) and can use
a subscription ...
This is one of a multi-part series of articles
that appeared in Popular Electronics magazine on using an
o-scope to analyze signal waveforms. An introduction to square
waves and how to accurately measure them is covered here. Frequency-compensating
the o-scope probe is always an important step prior to sampling just about any waveform
other than a pure sinewave, because per Fourier series analysis, every periodic
waveform can be defined by a series of sinewave and various frequencies, phases,
and amplitudes. The author demonstrates with a square wave being composed of the
fundamental frequency and its odd harmonics. I remember being amazed to learn whilst
in engineering school that
...
Empower-RF-Systems-Patent-Approval-5-10-2015.htm" >
United States Patent 9,007,125 B2, recently awarded
to Empower RF Systems, validates the uniqueness of the hardware architecture in
use on Empower's high power,
next generation amplifiers. The ability to deliver
1 kW CW broadband power in an air cooled, 5U chassis requires innovation and engineering
breakthroughs that are described and protected in this patent award. "We are pleased
to receive this recognition and patent protection for our next generation amplifiers,"
said Jon Jacocks, CEO. "The hard work and creativity of our design teams, leveraging
this architecture for standard products and customer configurations, continues to
Empower-RF-Systems-Patent-Approval-5-10-2015.htm" >..."
Just as modern high power semiconductor amplifiers
are composed of cascoded (connected in parallel) lower
power amplifier units, so too a
super-high-power vacuum tubes. In the case of tubes, a requisite
number of triodes (typically) are arranged around
the perimeter of the tube enclosure with the inputs and output connected to power
dividers and combiners, respectively. Vacuum tubes are still used in high power
applications, although it is rare that you will find them with glass enclosures;
most are metal and/or ceramic. Over-the-air radio and television broadcasting stations
are major users. Richardson Electronics is a major distributor for
...
Many thanks to website visitor Joe Birsa
(N3TTE) for donating three vintage cardboard slide
rule calculators to the RF Cafe Slide Rule Museum. Reflecting off of Joe's history in
the nuclear power industry, one is
Radiation
Measurement Calculator from Ohmart, another is a
Valve Sizing Calculator from Control Components, and the other
is
Air-Gas Orifice Flow Calculator from Daniel Industries. Any similar items you
might care to donate would be very welcome and appreciated.
"Scientists will eventually stop flailing
around with solar power and focus their efforts on harnessing the only truly unlimited
source of energy on the planet: stupidity. I predict that in the future, scientists
will learn how to convert stupidity into clean fuel." - Scott Adams, creator of
Dilbert
anatech-product-update-5-12-2015.htm" >
Anatech Electronics offers the industry's largest
portfolio of high-performance standard and customized RF and microwave filters and
filter-related products for military, commercial, aerospace and defense, and industrial
applications up to 40 GHz. Anatech has released three new designs: a 2 to 18 GHz
connectorized directional coupler, a 2027-2108 MHz & 2452-2484 MHz
connectorized band combiner filter, and a 80-225 MHz connectorized circulator.
All can be ordered directly through their AMCrf web store.
Hams Go Video
Ironically, an RF Cafe visitor just within
the last couple days wrote about possibly getting his Amateur radio license in order
to permit live broadcasting of his
kite-borne video camera system (known as
"Kite Aerial Video" [KAV]), or Kite Aerial Photography [KAP]). Slow scan
television SSTV has long been a popular facet of Ham radio since prior to broadband
Internet connections, it was the only practical method available. Older equipment
was large, heavy, power hungry, and relatively expensive, but today you can buy
a much improved camera for a few bucks that transmits real-time via an unlicensed
2.4 GHz wireless link. That data stream can be recorded for later use of streamed
real-time to the Internet. As with so many other things, easy availability take
some of the challenge out of it, but the world benefits from
...
Believe it or not, the International Microwave
Symposium (IMS2015) is almost upon us; it is next
week. Having been to a few of the shows, I can tell you if you have never been to
one that there is a lot to take in and it is easy to miss something you would liked
to have seen if you don't do a little research ahead of time. Tom Perkins wrote
an article for High Frequency Electronics magazine titled "Maximizing Your Symposium Experience"
(page 32) that provides a bit of guidance in that
regard. There are a lot of other great articles out now. Is it my imagination, or
are there an inordinate number of guys
...
Side-looking airborne radar started out using
a narrow beam formed by reflectors, like traditional radars, as opposed to the synthetic
aperture type most often (maybe even exclusively)
used today. Both types of side-looking radars rely primarily on the physical movement
of the airborne platform for effective azimuthal scanning rather than steering the
beam either mechanically or electronically. Modern computer-controlled synthetic
radar beams can be segmented and directed off-axis for detected areas of interest
as required, but the early systems simply gathered radar return data and presented
it real-time, with some level of analog processing, to operators
...
When I first saw this article from a 1946
edition of
Radio News, I did a double-take on the author's name, thinking
it was written by long-time model aviation author and magazine editor William 'Bill"
Winter. It was actually done by a fellow named Winters, not Winter. An enthusiastic
radio control (R/C) evangelist in his day, Bill Winter
wrote many pieces for electronics magazines such as
Popular Electronics. As I have noted in the past,
hobbyists in the electronics realm, as well as in the fields of aircraft and rocket
design, contribute mightily to the state of the art. Such is also the case in many
other arts and sciences. Here we have a report of some of the earliest radio controlled
flying 'drones,' as we call them today. They are a far cry from the
...
Magnetic ceramics have been with us for a
long time - probably forever as far as most people that use them these days are
concerned. When this article was published in 1953, ferrites for use at RF frequencies
were a new, breakthrough phenomenon. Take a look at inductors used in vintage radio
equipment and you will find either air or solid iron as the permeable filler elements
in most instances. Whereas iron might have a permeability of 100-150, the new magnetic
ceramics exhibited
permeabilities up to 4,000 at 1 MHz, and even higher for
lower frequencies. Modern alloys and compounds provide permeabilities of more than
50,000 for special applications. Such high values allow physical size and weight
of inductors and transformers
...
Narda-Safety-Test-Solutions-Wide-Area-Data-Collection-5-6-2015.htm" >
New on the market from Narda Safety Test Solutions
is the Narda-Safety-Test-Solutions-Wide-Area-Data-Collection-5-6-2015.htm" >AMB-8059,
a wideband Area Monitor that monitors electromagnetic fields up to 7 GHz in conformance
with the ITU-T Recommendation K.83. The data can be accessed via Ethernet or GSM/UMTS.
The “EMF Observatory” software integrates several Area Monitors into a wide area
coverage monitoring system. The new type
AMB-8059 Area Monitors monitor electromagnetic
fields in accordance with the ITU-T Recommendation K.83: Monitoring of electromagnetic
field levels. Depending on the probes used, they capture electric field strengths
in the frequency range 100 kHz to Narda-Safety-Test-Solutions-Wide-Area-Data-Collection-5-6-2015.htm"
...
James ilton Clapp in 1948 first published
details on an oscillator that used positive feedback obtained from an LC
(capacitive & inductive) voltage divider to initiate
and sustain oscillations. Thus was born the now familiar Clapp oscillator. It had
an advantage over both the Colpitts and Hartley oscillators because the feedback,
not being dependent on a simple capacitive or inductive voltage division, respectively,
made it more reliable as a variable frequency oscillator
(VFO). This article does a nice job of explaining the operation of the Clapp
oscillator. Just as the Colpitts and Hartley oscillators handily provide an easy
mnemonic for being based
...
Many
thanks to Empower RF Systems for helping to deliver RF Cafe to the world!
Founded in 1999, Empower RF Systems is a global leader in
power amplifier
solutions that are critical to defense, commercial, and industrial market applications.
With our origins in the design of broadband and band-specific solid state power
amplifiers, Empower continues to advance the science of RF power amplification to
produce rugged, power efficient, and cost-effective solutions in the industry. Empower
RF Systems will be in Booth #3226 at the IMS 2015 how in Phoenix. See you there!
Many thanks to Kevin, of Roanoke, VA, for
sending me a link to this documentary video covering the entire
production
chain for radio crystals as filmed by Reeves Sound Laboratory, in New York,
NY. It was produced during World War II so the methods used are not anywhere
near what is common today. What is the same, fundamentally, is the ingenuity and
hard work that goes into developing a new technology, and particularly the effort
needed to move to high volume production. As with most of these vintage factory
films, a few aspects of normal practices of the era are immediately apparent. First
is the near utter lack of personal safety devices on machinery and accessories for
workers. Fingers run perilously close to diamond-impregnated crystal dicing blades,
unprotected hands and arms are submersed in oils and cleaning solutions, no ear
protectors ...
To look at this drawing of the path
Venus takes across the sky, the casual observer might never expect
that it actually follows a simple elliptical orbital progression around the sun.
No wonder the word 'planet,' meaning 'wanderer,' was assigned to the bright, rapidly
moving night sky objects like Mercury, Venus, Mars, Jupiter, and Saturn. In fact,
until the middle of the 16th century when Nicolaus Copernicus promoted his heliocentric
model of the solar system, a vast majority of 'experts,' 'professionals,' 'learned
scholars,' etc., held fast to a belief that Earth was the center of the universe
and everything moved relative to it. Sophisticated mathematical and mechanical models
were created by some of the smartest minds of the day to explain the circuitous
movement of the planets. Indeed, and to their great credit, observed phenomena
...
NuWaves-bidirectional-s-band-linear-ofdm-amplifiers-5-5-2015.htm" >
NuWaves Engineering, an international RF and microwave
solutions provider, today announced a new linear bidirectional amplifier for OFDM
radios at the Association for Unmanned Vehicle Systems International Unmanned Systems
2015 Trade Show. The
NuPower Xtender™ 12E06A model is a broadband,
small, lightweight and cost-effective solution for high-performance S-band OFDM
transceivers with Mobile Ad hoc Networking (MANET)
and/or Multiple-Input and Multiple-Output (MIMO) technology
NuWaves-bidirectional-s-band-linear-ofdm-amplifiers-5-5-2015.htm" ...
Today is the 78th anniversary of the
Hindenburg disaster at the Naval Air Station in Lakehurst, New
Jersey. It is the RF Cafe logo theme for today (see upper
left page corner). Ironically, last night while looking through the July
1936 edition of
Radio-Craft magazine, I saw this news article reporting on
preparations being made in the onboard radio and direction finding equipment for
Hindenburg's maiden voyage from its home base in Frankfurt, Germany to North America.
No one at the time of this article suspected such a terrible fate was looming les
than a year later. Theories abound regarding the cause of the fatal fire, but there
is no doubt that a combination of highly flammable hydrogen gas and an also highly
flammable graphite dope
...
Handbook of Microwave Component Measurements:
with Advanced VNA Techniques, by Joel P. Dunsmore, provides state-of-the-art
coverage for making measurements on RF and Microwave Components, both active and
passive. A perfect reference for R&D and test engineers, with topics ranging
from the best practices for basic measurements, to an in-depth analysis of errors,
correction methods, and uncertainty analysis, this book provides everything you
need to understand microwave measurements. With primary focus on active and passive
measurements using a vector network analyzer, these techniques and analysis are
equally applicable to measurements made with spectrum analyzers or
...
It is a pretty good bet that most
multi-element TV aerials you find on rooftops and even on ancient
towers were decommissioned years ago. They have been replaced either with cable
(whether via CATV or Internet) or satellite dishes.
A few hold-outs still use them for local over-the-air broadcast stations and/or
even FM radio reception. There was a time, though, that photographs taken looking
across a vast expanse of house roofs showing an endless array of antennas and guy
wires was a sign of 'modern' living. Most were erected by Harry Homeowner types
or minimally qualified service technicians, and were well-known for toppling, twisting,
bending or un-aligning when stiff winds were imposed upon them. This story-lesson
from the March 1953 edition "Mac's Radio Service Shop,"
...
Melanie's mother, Mary Goodwin, has four (4)
gravesites at Mount Rose Cemetery in York, Pennsylvania, that she would like
to donate to the families of U.S. military veterans. They
are located in the "Defenders of the Flag" area of the grounds, near the flagpole
and cannon. Being in this reserved section, only honorably discharged veterans and
their immediate family members are eligible to be laid to rest there. A qualified
veteran is welcome to any or all of them for free. Mount Rose
...
ΞΞ
RF Cafe App v1.00 ΞΞ Now Available
It's
been a lot of work with a steep learning curve, but at long last the first
RF Cafe App
is now available for download from the Google Play website! An iPhone version will
probably be created if my motivation level is elevated enough by a huge number of
downloads for this Android version. This first release is meant to 'test the waters'
for the usefulness of an app whose purpose is to provide reference material rather
than a collection of calculators. Whether you are in the lab, at your desk doing
design work, or operating in the field, there are times when you need data. These
first few screens are some of the most often needed information. If enough support
is received, the RF Cafe App can be greatly expanded into a vast volume of formulas,
sketches, tables, definitions, and other encyclopedic content not
...
Microwave-Journal-EDI-CON-2016-USA-4-5-2015.htm" >
Horizon House Publications and Microwave
Journal announce that their annual RF/microwave, EMC/EMI and high-speed digital
Electronic Design Conference and exhibition, EDI CON, is expanding into the U.S.
market after three successful events in Beijing, China. EDI CON China drew more
than 2,600 attendees at the April 2015 event held at the China National Convention
Center (CNCC). Thefirstfirst EDI CON USAEDI CON USA will take place September 20-22, 2016
at the Hynes Convention Center in Boston, Mass. Boston has an extensive electronic
design industry especially in the RF/microwave area where many industry leading
companies reside in the New England region. Horizon House president Microwave-Journal-EDI-CON-2016-USA-4-5-2015.htm"
...
"Gentlemen, that is surely true, it is absolutely
paradoxical; we cannot understand it, and we don't know what it means. But we have
proved it, and therefore we know it must be the truth." -
Benjamin Peirce, on Euler's identity, as quoted by R. C. Archibald
in his book Benjamin Peirce, 1809-1880 : Biographical Sketch and Bibliography.
Also on the topic: "What could be more mystical than an imaginary number interacting
with real numbers to produce nothing? The equation contains nine basic concepts
of mathematics - once and only once - in a single expression. These are: e
(the base of natural logarithms); the exponent operation;
π; plus (or minus, depending on how you write it);
multiplication; imaginary numbers; equals; one; and zero." -
Robert P. Crease, in "The greatest equations ever" at PhysicsWeb
(October 2004) <Quote Archive>
Kanwal F., of Fullerton, CA, is the second
winner in the April 2015 RF Cafe Book Drawing. Kanwal selected
Precision FMCW Short-RangeRadar for Industrial
Applications
. Each month I randomly draw one or two people's names from
my 'electronic hat' (an Excel spreadsheet) to receive
his/her choice of a book. This book was graciously provided
by
Artech House.
NI-QuickSyn-Lite-Synthesizer-Extended-Millimeter-Wave-4-30-2015.htm" >
NI Microwave Component's popular
QuickSyn Lite frequency synthesizers are now extended to millimeter
wave. The new synthesizer modules employ the same revolutionary phase refining technology
that all QuickSyn products use to enable fast switching speed, low phase noise,
compact size, and low cost. The modules are available in three popular bands - 27
to 40 GHz, 50 to 67 GHz, and 76 to 82 GHz - and are designed to supply medium power
output. These new products present a very cost effective solution NI-QuickSyn-Lite-Synthesizer-Extended-Millimeter-Wave-4-30-2015.htm"
...
U.S. News & World Report has released
its engineering school
rankings for 2015. The usual suspects are still at the very top of the list,
with a couple swapping positions each year. However, what might be surprising is
the number of state universities that occupy most of slots 8 through 24. Some that
you would expect to see heading the list - like Cornell, Harvard, and Johns Hopkins
- are beaten by State U. My guess is that holding a degree from MIT
(#1 spot) is still a sure ticket to your job of choice,
but news reports for the last few years show that institutional names do not hold
the weight they used to as compared to a graduate's proven capability. A very strong
mood of entrepreneurship is gaining popularity with college students who start businesses
prior ...
A mere five years elapsed from the time Echo,
a gas-filled metallized plastic sphere that passively reflected radio signals back
to Earth, was launched and the time that 35
television cameras had been launched into space. The
Space Race was at a fever pitch. Although the Ruskies beat us
in being the first to launch both an active satellite (Sputnik)
and a man (Yuri Gagarin) into space, America's deep
pool of intellectual resources, consisting of both native scientists and many of
the world's top scientists who chose to flourish in freedom here rather than oppression
behind the Iron Curtain, fostered the advantage that in short order established
the United States as the leading super power both in space
...
Stephen M., of Midland, Virginia, is a winner
in the April 2015 RF Cafe Book Drawing. Stephen wisely selected
Envelope Tracking Power Amplifiers for Wireless
Communications, by Zhancang Wang.
This book was graciously provided by
Artech
House. I sent a notice to a second winner, but have not heard back yet,
so check your e-mail!
This week's
crossword puzzle has a 'directional coupler' theme in that many
of the words are related to the devices. All of the other words are, as usual, pulled
from a custom-built dictionary containing only terms pertaining to engineering,
mechanics, astronomy, mathematics, chemistry, and names of companies that make components
for the aforementioned fields. Even Dilbert characters appear sometimes. You will
not, however, find names of numbnut Hollywierd celebs or TV shows here.
The advent of
FET-input multimeters greatly reduced reading accuracy errors
due to not taking into account the impedance of devices being measured. A certain
amount of familiarity with how to interpret the indication on a meter movement on
analog meters is still required based on the multiplier switch position and scale
selected, but for most users simply reading the number beneath the pointer - or
interpolating its position between two numbers - is good enough. Mirrored scales
take the some of guesswork out of that by reducing parallax issues. Finally, digital
multimeters (DMMs) hit the scene and made slackers
out of just about all of us when it comes to making voltage, current, and resistance
measurements. With few
...
Sivers-IMA-Launches-Radar-Development-Kit-4-30-2015.htm" >
Sivers IMA, a leading manufacturer of millimeter
wave products, today announced its launch of a
Radar Development Kit (RDK) an easy-to-use platform
for those who need to measure distance or speed of an object. “At Sivers IMA
we have a long experience of developing complete Sivers-IMA-Launches-Radar-Development-Kit-4-30-2015.htm" >radar
sensor solutions and a portfolio of FMCW Radar sensor front-ends. For the RDK that
we are now launching, we have taken some of our know-how and developed and packaged
hardware and software to simplify for customers that are interested in including
radar technology in their products Sivers-IMA-Launches-Radar-Development-Kit-4-30-2015.htm"
...
