are usually the first instrument of choice when scouring for agile or unknown analog or digital signals. Modern oscilloscopes
offer impressive functionality, but operating these scopes can be a challenge. As a welcome contrast, the new R&S RTE
digital oscilloscopes from Rohde & Schwarz provide generous
measurement capabilities, minus the operating complexity. With each sporting a common-sense operating scheme, efficient
internal circuit architecture, and flexible, high-resolution touchscreen...
Have you ever heard of a "swinging choke?" I surely hadn't,
so my probability of getting
Quiz question number 5 correct was 50% at best. I guessed wrong - just my luck. As a result my score was 8/9 = 89%.
Oh, the shame. Maybe you will have a better time of it. Be careful with Q6 as well. Otherwise, if you understand the fundamentals
of inductor circuit analysis, you will have no problem.
"Need It? Rent It!"
That is what was embroidered on the baseball cap my rental store owner father-in-law used to wear. Sometimes it just just
makes sense to avoid the cost of ownership. Advanced Test Equipment Rentals
just issued their TEC Talk newsletter for May 2014. It includes hot topics in the tech news world, highlights of new or
special function test equipment they have available, and some electronics industry news.
If you are looking for a very thorough treatise on
from AC line frequency up through audio and RF frequencies, but without a lot of formulas to distract you, then this article
by Ken Gilmore is it. He begins with the fundamentals of a current setting up a magnetic field, talks about mutual coupling
and induction, step-up- and step-down transformers, autotransformers, iron and laminated core transformers, multi-tap voltage
and impedance matching transformers, and even touches on the mage-size transformers in electrical distribution system substations.
Transformers fundamentally work the same way today as...
AWR Corporation, the innovation leader in high-frequency EDA software,
offers a wide range of activities during IMS2014. As a platinum sponsor with its parent company National Instruments,
AWR will be demonstrating its newly released V11 NI AWR Design Environment™ in Booth #633 on June 3-5, 2014, presenting
numerous MicroApps presentation, hosting a customer appreciation event as well as sponsoring other IMS-related offerings.
Pulse modulation comes in many forms, including pulse position
modulation (PPM), pulse width modulation (PWM), pulse frequency
modulation (PFM), pulse amplitude modulation (PAM), and pulse
code modulation (PCM). In addition to providing a nice introduction to the concept of pulse
modulation, author Herbert Kondo covers the basics of each type and then discusses their application in various communications
systems. The first time I recall encountering
modulation was in the mid-1970s with radio control system for model airplanes. Pulse position modulation was the scheme
used in both AM...
USAF radar tech Elbert Cook has completed his scale model of
the MPN-13 GCA (Ground
Control Approach) mobile radar system that he worked on. It has an incredible amount of detail, including the ASR
(airport surveillance radar) and PAR (precision approach radar)
antennas, the VHF and UHF radio antennas, navigation hazard light, and even the gin poles that stabilize the trailers against
wind forces. Elbert's modeling skills are impressive indeed! Hopefully, this model will someday end up in a USAF museum
- maybe at Wright-Patterson AFB.
Now here is a profound ode to one of the most noble of technician
genres ever to tweak a receiver front end or to change out a transmitter magnetron -
Man! Some of you know that I worked on airport surveillance and precision approach radar in the USAF, so my bias is
established. Hmmm... now that I read the poem more carefully, I realize that it is not complimentary at all. It must have
been one of those jealous TACAN or satellite comms techs that wrote it!
The first commercial
broadcast occurred in 1954 during the Tournament of Roses Parade. By the late 1950s, color television sets were becoming
popular in homes, but the price, at around $500, was too prohibitive for most people to afford. In 2014 dollars that is
equal to around $4,200, which would allow you to hang a 70" Sharp 3D HDTV on the family room wall. This 1957 article reported
that there were only about five major manufacturers (more, actually) making color TV sets,
including RCA, Sylvania, Emerson, Westinghouse, Magnavox, Zenith, and Philco. Most or all used a common 21" round CRT. Over
the years many television manufactures came and went...
RFtronics develops both turnkey and custom solutions for
the RF telecom equipment designers and manufacturers. Currently, our product line includes
high power couplers, splitters / combiners and
filters between 1 MHz and 3 GHz. Local, ISO certified manufacturing with
a 25 000 sq. ft. facility and more than 20 years experience in the RF/microwave design and manufacture. This gives us the
best of both worlds, the agility of a small company and the production capabilities of a larger-sized, high-volume manufacture.
"A self-taught signals & electronics hacker from Helsinki,
Finland. Fond of mysteries, codes and ciphers, and vintage tech. Absorptions is a blog about my hobbies." That is the tag line for Ms.
Oona Räisänen's website.
Thanks to QST's "Eclectic Technology" column author Steve Ford for bringing this impressive story to the public.
Oona's article tells of her adventure in tracking down the source of a mysterious element of an audio clip from a video
of a news station helicopter following a police chase. After multiple efforts, the embedded digital signal was decoded and
then confirmed to be accurate by the transmitting equipment manufacturer. It's a quick read, complete with good graphics,
that you'll enjoy.
Printed MIMO Antenna Engineering, by Mohammad Sharawi. Wireless communications
has made a huge leap during the past two decades. The multiple-input-multiple-output (MIMO)
technology was proposed in the 1990's as a viable solution that can overcome the data rate limit experienced by single-input-single-output
(SISO) systems. This resource is focused on printed MIMO antenna system design. Printed antennas
are widely used in mobile and handheld terminals due to their conformity with the device, low cost, good integration within
the device elements and mechanical parts, as well as ease of fabrication.
you like good old fashion
3Ø, high voltage generator and transformer stories with troubleshooting and analysis, then you
won't want to miss this one. Having started my career as an electrician with tech school and field experience, I am always
drawn to such topics even though I seldom have a chance to tinker with it anymore. The comments section at the end already
has quite a few posts, including responses from the author. There's usually one obnoxious person who wants to demonstrate
superiority and call names, and there's one here, too. I give Mr. Hardy a lot of credit for his ability to deal with an
aspect of electrical engineering for which he was not necessarily trained in depth.
Here is a short tutorial on how to construct a
stub "trap," or filter to attenuate even-order harmonics from transmission lines, be they antennas or sections of track
running on a microwave substrate. The article appeared in a 1960 edition of Popular Electronics.
"Far better an approximate answer to the right question, which
is often vague, than an exact answer to the wrong question, which can always be made precise." -
John Wilder Tukey, statistician and developer
of the Fast Fourier Transform (FFT).
Werbel Microwave is a designer and manufacturer
of RF and microwave passive components that operate up to 18
GHz. Products and designs are for the commercial wireless industry, featuring power dividers & combiners, directional
and hybrid couplers, bias Ts, and resistive dividers. An expansion is planned for business year 2014 that include high power
directional couplers, weatherproofed enclosures, and miniature drop-in packages. Typical turnaround time from concept to
manufacture is within four to six weeks after receipt of order.
John H., of Tucson, AZ, is the April
winner! He selected
Microwave and Millimeter-Wave Electronic Packaging, by Rick Sturdivant. John was not only a
purchaser of RF Stencils for Visio,
but he also pointed out an error on on of the pages, so he was awarded his choice of a book. Two other people had been notified
on May 1 and again on May 3, but neither responded, so they lost the chance. Graciously provided
by Artech House
For the sake of avid cruciverbalists, 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).
This particular puzzle has lots of abbreviations and acronyms.
Hide me. My predicament started out as a mere curiosity, but
then over time the phenomenon seemed to occur with greater and greater frequency. I tried to dismiss it as being a "coincidence"
that was only noticeable because I was subconsciously monitoring and listening for it. After today, however, the time has
clearly come to take action. The disturbing events are
instances where I am reading or writing a particular word or phase and at the exact same instant I hear that exact word
or phrase spoken on the radio. Now, I have to admit that I spend practically my entire waking life either reading or writing,
while simultaneously listening to a variety of talk and music radio in the background. Melanie will attest to the alarmingly
large number of times I remark...
For over 20 years Z-Comm has employed
the latest in proven technology to achieve low phase noise, wide tuning ranges and higher operating frequencies in our VCO
and PLL modules. Our state-of-art, high speed SMT manufacturing facility is located in
San Diego, CA. Our solutions
can be tailored to address any VCO or PLL need with the highest performance available in today's demanding market. Z-Comm
can also provide custom solutions for customers with short deadlines.
Hobbyists in the technical realm have in many ways contributed mightily to
the advancement of professional scientific knowledge and practice. This is partly because many hobbyists are also career
technologists, but the majority are tinkerers, experimenters and otherwise participants who come from all walks of life
geographically, economically, professionally, and socially. Just as with university and corporate laboratories, some of
the discoveries are the result of structured, preconceived plans of action and designs of experiments with certain goals
in mind; many, however, are due to serendipitous events that are recognized by their participants as being significant.
Such is the case of 'TV DX' as related in this story. TV DX is the use of...
Dow-Key Microwave is the world's largest
manufacturer of electro-mechanical RF switches in coaxial, waveguide, and rack switching matrix formats. We are
certified and committed to providing unparalleled
customer service, competitive pricing, on-time delivery and products that are distinguished by quality and reliability.
Dow-Key offers the largest switch product line in the world with over 10,000 unique configurations.
OK, time again for weekly links
to RF and microwave magazine articles. I wish HFE
would make their PDF format with bookmarks so I could link directly to an article page, but unfortunately you have to view
the online version and thumb through to the page.
Give Science a Boost,
• Möbius Coupling Approach
Drops SMD DRO Phase
Noise, A.K. Poddar,
• The Quirks of
an ADC's Offset
and Gain Error,
A. Chakravarty, S. Jain
• Multiband Doherty
Amplifiers for Wireless
and SSN, M. Dunn
• How Trends
(p.22), B. Stanton
The proper care and feeding of
was - and still is - a big topic amongst audiophiles. As with so many things, phonographs and platters have experienced
a resurgence in popularity in the last decade or so as the world gets nuttier and people crave for a simpler, saner time
- imagined or otherwise. I remember back in the barracks at Robins AFB, GA, where there was always at least one guy who
would have a very extensive (pronounced "expensive") stereo setup complete with an equipment
rack, reel-to-reel tape player, dual cassette tape deck, super-sensitive AM/FM receiver with a huge tuning knob on the front,
a turntable with a precisely balanced and weighted tone arm (with a stylus that cost two month's
pay for an enlisted man)...
Established in 1987, Pulsar Microwave
is a supplier of high quality RF and microwave passive components
in the frequency range of DC to 85 GHz. Because of our large
library of designs, we are able to provide
custom products with little effort and in most cases with no additional price increase above the standard catalog item.
New products are introduced on an almost monthly basis, the most recent of which are high power directional couplers and
power dividers. Coming shortly are high power switches and low power resistive power dividers.
A good technician, knowing what sine-wave signals
are simultaneously applied to the horizontal and vertical inputs of an oscilloscope, can predict what the displayed
Lissajous pattern will be. In this quiz, the same signal is applied to both amplifiers, but through combinations
of impedances that cause differences in the phase angle and amplitude of the actual AC voltages reaching the inputs. All
resistances and reactances have the same ohmic impedance at the applied frequency, the gain of both amplifiers is equal,
and positive-going voltage deflects the spot upward, or to the right...
API Technologies' Transmit and Receive
L-Band Antenna Arrays are designed for military
and commercial markets and applications including point-to-point communications, satellite communications, and RF transmitters
and receivers. This low profile, high gain, linearly polarized planar antenna array achieves wider bandwidth than similar
sized antennas. API utilizes an in-house proprietary mix of substrate materials which allows wider than normal bandwidth
for an antenna of this size and frequency range.
I love these kinds of stories. It has the perfect
combination of situational humor, irony, and a very important lesson about relying on subjective measurement versus objective
measurements. If you have a great tale to tell about one of your work or hobby experiences that no respectable publisher
will print, you're welcome to send it to me for consideration in the RF Cafe "Out of Order" series.
a bit far-fetched, this
Carl & Jerry saga has the two amateur radio hobbyists cum detectives applying their knowledge of standing
waves and an invention called SNARE (Signal Net for Actuating Radio-sensitive Explosives, by Irwin Ehlmann) to thwart an
assassination attempt on a visiting foreign dignitary. The choice by author
John T. Frye of a halo antenna on their mobile shortwave rig was probably no coincidence given the
guardian angel role it played in the adventure.
AWR Corporation has extended its 2013 ADF tour well into 2014. The final venue stops
being added to this tour are located in Israel. Late addition dates and locations include May 20th in Haifa and May
21st in Tel-Aviv. The agenda details as well as registration are
all online and available now. AWR Design Forum is a free and open
event where designers of microwave and RF circuits and systems can network, share useful information and resources pertinent
to high-frequency design, and collaborate on industry issues
openings for non-engineers result from industry growth and shortage of skilled men." Thus goes the subtitle for a magazine
article pitching the promises of a
career in electronics technology. It came at a time that predated throw-away everything rather than attempting
to repair stuff. It was before the term 'personal device' (aka 'throw-away') had been coined.
It was before placards warning "No user serviceable parts inside" were routinely stuck on practically every item purchasable
in a department store. It was a time when people took stuff apart to see how it works, and were actually able to figure
it out because parts were large enough to see and actually moved, and even printed circuit boards...
Long distance communications
(DX) thrives on ionized atmosphere. It causes boundary layers at various altitudes that function
as reflecting surfaces and thereby facilitate the 'bouncing' of radio waves off the sky so that they bend around the curvature
of the Earth. Early sounding rocket experiments verified that indeed ionized layers of atmosphere did exist as suspected
based on theories of aurora activity during periods that correlated with observed solar flare activity. Intense solar flare
periods are associated with large numbers of sun spots, since coronal mass ejections (CMEs)
are produced which supply enormous amounts of electrons traveling at high speed earthward. CME matter of course shoots in
Filter Synthesis Using
Genesys S/Filter (Artech House)
Hardcover, by Randy Rhea. S/Filter includes tools beyond direct synthesis, including a wide variety of both exact and approximate
equivalent network transforms, methods for selecting the most desirable out of potentially thousands of synthesized alternatives,
and a transform history record that simplifies design attempts requiring iteration. Very few software programs are based
on direct synthesis, and the additional features of S/Filter make it a uniquely effective tool for filter design. This resource
presents a practical guide to using Genesys software for microwave and RF filter design and synthesis.
It's time for another helping of
job hunting and career advice stories. There seems to
be no limit to the amount of advice available by helpful 'experts.' Many of these particular bits of guidance for your life
come from authors on LinkedIn, which typically does have good content. Considering, however, the quality of helpful suggestions
offered by your friends and acquaintances in the real world, it would be wise to learn a little about the source before
potentially risking your future. With that bit of my own advice in mind...
Your Present Job Costing
You Your Retirement?
Why to Skip the Fancy
Preparing for the Financial
Roller Coaster of
Baby Steps That Lead to a
Successful Career Change
Innovative Power Products has more than
30 years of experience designing and manufacturing RF passive
components. Our couplers, combiners, resistors, and terminations incorporate
the latest technology in materials
available, which equates to unrivaled product performance. Products include 90° couplers (30 MHz to 4.2 GHz), directional
couplers (20 MHz to 6 GHz), combiners (20 MHz to 4 GHz), RF resistors and terminations (DC to 8.5 GHz, up to 800 W CW)
Engineering college rankings for 2014 have been out for a while now, so
I'm a bit late reporting the results. All the ranking entities have their own set of criteria and claim to be objective,
but unless there is a mutually agreed upon standard, let's face it, they all have a component of subjectivity in the ordering.
I'm not going to tackle the validity of methods used, but instead will present the data. Note, however, that it is worth
doing a quick read through the stated methods since some are based on institutional research and others rely solely on student
surveys. Some rate only schools whose highest degree offered is a Bachelor's, while others include graduate and post graduate
schools. Being that RF Cafe is viewed by a worldwide audience, I have included...
it was established in 1979, Reactel has become one of the industry leaders in the design and manufacture of RF and Microwave
filters, diplexers, and sub-assemblies. Through a continuous process of
research and development, we have established
a full line of filters of all types. We offer the generally known tubular, LC, cavity, and waveguide designs, as well as
state of the art high performance Suspended Substrate models. We use the latest in CAD/CAM methods and equipment in all
of our design and manufacturing processes. We feature a modern, well-equipped machine shop...
If you are familiar with Saunder Harris'
stories for Popular Electronics, you know they were written in the form of a story that describes a mentor mentoring
a mentee (yes, mentee is a real word). "The Load Line
Story" presents a quick lesson on how to determine the operational points of in this case a vacuum tube, but it applies
equally well to a transistor. If you have had a difficult time conceptualizing the usefulness of I-V curves a load line,
then this might be just what you need to get you going. Sure, all the designers out there do this in their sleep, but remember
that every day there are new people getting into electronics and this is what they are looking for to help get them on the
path to where you are.
Innovative Power Products introduces their Model IPP-2247,
a 150 watt 90 Degree Coupler in a Drop-In package style that operates from 20 - 1000 MHz. The IPP-2247 will combine two
signals up to 150 Watts CW of total output power. This coupler has a remarkable amplitude balance of ±0.25 dB across
the whole band. This design is a 3 port device with an internal Termination capable of handling 50 watts. Insertion Loss
is less than 0.90 dB, VSWR is less than
"There are two possible outcomes: if the result confirms the hypothesis, then
you have made a measurement. If the result is contrary to the hypothesis, then you have made a discovery." Enrico Fermi.
Caveat: This quote is widely repeated on the Internet and in printed material. I could not find an original source, but
it sounds good and he could easily have said it considering his other sourced quotes.
This entry level introduction of
as it applies to electronic circuit analysis appeared way back in a 1932 edition of Radio News. It was written
by none other than Sir Isaac Newton himself (just kidding, of course). Author J.E. Smith
created an extensive series of lessons that began with simple component and voltage supply descriptions and worked up through
algebraic manipulations and on finally to calculus. I remember not being the best math student in high school
(OK, one of the worst), but once I got an appreciation for the power of mathematics for analyzing
RF Engineering crossword puzzle,
like all my crossword puzzles, uses only words that I personally placed into a custom dictionary of words relating to science,
mathematics, engineering, chemistry, astronomy, electronics, and other technical fields, plus you are likely to find a few
company and engineering schol names that your recognize as well. Contact me if you would like to have your company or school
name added to the dictionary terms.
"Are we killing the broadcasting goose, layer of many golden eggs?"
Dr. Lee de Forest
asked in his inaugural address, upon his election to the presidency of the Institute of Radio Engineers. So went the opening
editorial in a 1930 edition of Radio News magazine. It was directed at the question of whether excessive, "gratuitous" advertising
was going to be so offensive to listeners that they would turn off the set and go back to their former silent worlds. Remember
that many, if not most, households, and certainly not automobiles, even had radios at the time. Building an audience was
essential to nurturing the new phenomenon of radio, and to saturate the listeners with commercials would surely doom...
PMI Model No. P2T-1G1R1G-25-R-TFF-40W
is a single pole, two throw, hermetically sealed, reflective switch designed to operate over the 1.0 to 1.1 GHz frequency
range. This model is designed to handle 40 watts average input power and 4 kW peak having a 3usec pulse width and 1%
duty cycle. The switch offers fast switching speeds of 300 nsec maximum, low insertion loss of 0.4 dB typically
and high isolation of 37 dB typically
Not very long ago I mentioned
Jean Shepherd (original
asignee of W9QWN and later K2ORS call signs) as being one of my favorite old-time radio broadcasters
(1960s-1970s). Jean was famous for recounting stories of his own life and for reporting news
of the time in a way that could hold you in rapt attention from beginning to end. His humor, wit, and command of the English
language was acknowledged by his contemporaries. If you listen to enough of his broadcasts you will notice the frequent
mention of electronics and his experiences as a licensed amateur radio operator beginning at a tender young age. Just recently
I listened to him recount his first day in high school when a SNAFU in the computer-generated (must
have been a UNIVAC) class schedule mistakenly had him reporting to the girls' swimming pool...
This article by Bob Ambrogi,
IMS Expert Services, reports on the 10th U.S. Circuit Court of Appeals' addressing the need for a more
objective means for testing whether
expert testimony should be allowed
during litigation. The action was taken as the result of an IP theft case whereby
a software engineer was accused of stealing code from his former company and using it to help start a new competing company.
Precedence is given a lot of weight when courts consider testimony and in determining the rules of engagement before the
bench. I am innately dubious of simply regarding precedence as settled law because of how often decisions are overturned
on appeal. When precedence is used to sidestep the need to make a courageous ruling...
My father used to refer to the "sweet-voiced lady
predicting the weather over and over again" as my girlfriend because I would call the 'WEather-1212' phone number (936-1212)
so often. It really wasn't because I was infatuated with her voice, it's that I was obsessed with
Most of my free time as a kid and teenager was spent building and flying model airplanes and rockets, and at eighteen years
of age I began taking full-size aeroplane flying lessons, so my world revolved around a zone extending from terra firma
up to about 5,000 feet AGL. This collection of communications news items in a 1940 edition of National Radio News includes
the creation of that very recorded weather forecasting service. Now, I admit to having a bit more of a problem explaining...