my call for entries in the new Out of Order feature on RF Cafe, Mr. Denny Condron responded
with a great saga of his use of finely tuned (pun intended) use
of fox hunting skills to track
resolve a bad case of interference in the 2-meter amateur radio band. Although names are omitted
to protect the innocent (and the guilty) parties, it is good
to know that the offending source was remedied willingly by the owner of the equipment: a
manufacturing operation. This is a fine example of the term "unintentional radiation," and
why ignorance is usually only bliss, as the saying goes, for unaffected and usually oblivious
parties. Denny noted separately that this tale...
is a story of a real feat of RF engineering where the stakes were high for determining the
cause of the problem and effecting a solution. In this case
Bell Telephone Laboratories was solicited to figure out why a commercial broadcast station's
signal was not being received as strongly as predicted after the station had relocated its
facilities specifically to address the issue. A lot of power was being pumped into the antenna,
but inexplicably some relatively nearby listeners were getting lousy reception while reports
were coming in of good signal strength from hundreds - even thousands - of miles away in other
directions. A modern antenna design program like EZNEC...
TT Series Remote Control Transceiver is designed for reliable bi-directional, long-range
remote control applications. The module consists of a highly optimized Frequency Hopping Spread
Spectrum (FHSS) RF transceiver and integrated remote control
transcoder. The FHSS system allows higher power and therefore, longer range than narrowband
radios, reaching over 2 miles (3.2 kilometers) line of site in
typical environments with 0 dB gain antennas. Regulations in the country of operation
dictate the maximum legal output power, so the final system range may be less depending on
the country of operation...
material's first widespread application in electronics was in the form of
quartz crystals that were cut along certain axes in order to provide resonance at specific
frequencies. They are still used in modern circuits as frequency-determining devices in oscillators
and as frequency-selective devices in filters. Many high Q and tailored frequency response
applications are now using polycrystalline ceramics for surface acoustic wave
(SAW) devices where crystals used to claim an exclusive domain.
This article provides a bit of theory of operation as well as application in radio circuits
using both fundamental and overtone frequencies.
need custom-made precision metal parts - chemical etching, metal stamping, RF shielding, or
any custom part made out of metal. Fotofab can help. We've been in the chemical etching, chemical
metal stamping business for years, so we know how to make your custom part quickly, accurately,
and affordably so you can get on with your business. Our rapid prototyping service is so efficient
we can usually deliver your prototype within a few days of receiving your order, or our new
Same-day delivery might be what you are looking for.
new R&S SMW-K541
digital predistortion option from Rohde & Schwarz allows users to import predistortion
coefficient tables directly into the R&S SMW200A. The signal generator uses these delta
values to adjust the baseband signal in real-time. The option greatly reduces test times since
predistorted waveforms no longer have to be tediously recalculated and imported into the generator.
Amplifiers are most efficient when they operate near their maximum output power, which occurs
in the nonlinear range. Although more power efficient...
lot of RF Cafe visitors can't pass up an opportunity to get a peek inside vintage equipment,
especially if it is something they used to work with many moons ago. Caleb Kraft of EE
Times recently posted this short tour through a 1950s era
Eico model 425 oscilloscope. It is surprisingly clean inside and the electronics are sparse.
The chassis assembly reminds me of a single-channel, 10 MHz bandwidth kit o-scope that
I built back in the 1980s. Enjoy the trip down Memory Lane.
Corporation, the innovation leader in high-frequency EDA software, releases a new customer
success story that prominently and proudly features how the
Gift Initiative played a role in helping Dr. Dominic FitzPatrick found PoweRFul Microwave,
an engineering consultancy specializing in RF and microwave amplifier design. Upon graduation
from Cardiff University, Cardiff, UK, Dr. FitzPatrick took advantage of AWR’s Graduate Gift
Initiative program, which gifts a one-year complete AWR Design Environment™ software license
in today's world with computing devices everywhere sporting simulators and component calculating
programs, there are still times when having a good old fashioned
nomograph or chart handy can be very useful while in sitting at a bench selecting component
values for tweaking or troubleshooting a design. The advantage of such visual aids is that
they provide a big picture of what's happening as frequencies, lengths, widths, core materials,
etc. change - being able to see both the trees and the forest, so to speak. When you are working
in bands where the component physical size is a significant portion of the wavelength, things
get more complicated and a combination of trial and error and calculations...
P6T-2G18G-60-T-512-SFF-LV is a single pole, six throw, absorptive, low video transient,
solid state switch operating over the frequency range of 2.0 to 18.0 GHz. This model
has a maximum insertion loss of 4.0dB and a minimum isolation specification of 60 dB
with video transients of 2mV typically. It operates at 23 dBm CW maximum and has a survival
specification of 27 dBm CW maximum and offers a typical switching speed of 30 ns...
Microwave is a leader in technically differentiated electronic and radio frequency ferrite
circulators and isolators
connect, protect and control critical systems for the global microwave electronics market
place including commercial and military wireless telecommunications. Dedicated to R&D
of standard and custom design quality Ferrite Circulators and Isolators from 380 MHz
to 23.6 GHz.
The February 5, 2014 edition of
The Ohm is now online. The editor of Kansas State University Department of Engineering's
newspaper contacted me asking permission to reprint one of my
puzzles in their monthly publication called The Ohm. You will find their alma
matter's name buried in the word clues. Like always, all of the words are technology related.
As time permits, I'll be glad to do a custom crossword for your school's newsletter.
Enterprises, an industry leading manufacturer and global supplier of RF and microwave products,
recently launched its new website which boasts best-in-class site search functionality, one-page
checkout and an updated user friendly interface. The new 2014
Pasternack website is the first major
redesign since the Company’s previous 2012 website overhaul. Most noticeable to the average
user is the sites simplified, stripped down look and feel of the new homepage. Pasternack's
main objective with the new site was to provide engineers and buyers...
month has passed already, which means a whole new bunch of good tech articles are being posted
on magazine website like MW&RF and T&M. If you're like me, you don't even look at
the print versions anymore. Do you have an article written that you would like to have published
on RF Cafe (and that has not been published elsewhere)? If so,
please send it to me for review.
GaN Enables RF Where
LDMOS and GaAs Can't
Measure Small Impedances
with Rogowski Current
Offers Exciting Possibilities
SoCs Bring High-End RF
Devices from Lab to Sofa
Reuse Gains UWB
(Michael Hopkins at
has been into current reuse for a
very first submission for RF Cafe's new
Out of Order feature has been received
from Joe Birsa. His experience is one that many of us (including me)
has been bitten by at some point in our electronics and/or electrical pursuits. Unfortunately,
this type of situation occurs so infrequently that by the time it happens again, we've forgotten
about it and are prone to getting bitten again.
Low Battery in
Multimeter = High Voltage Scare, by Joe Birsa. Last year when I was adding a
new accessory to my ham radio station at home, I noticed that the power supply I use for accessories
was putting out 16 VDC instead of the nominal 12 volts I expected...
upon seeing the title of this newest Sherlock Ohms adventure, I thought of my own experience
with a telephone dial tone problem. In A. David Boccuti's case the culprit turned out to have
an entirely different cause than mine. Read about Mr. Boccuti's issue resolution here. My
dial tone dilemma was caused by corrosion as well, but mine was inside the phone itself. Being
a lifelong avid fan of Charles Schulz's Peanuts comic strip, I decided to purchase a
1976 vintage Snoopy and Woodstock
telephone from someone on eBay. It was promoted as being in working condition, but I discovered
'working' was a subjective term in this case. Indeed, it was possible to hold a conversation,
but the volume in the earpiece was very low, and the dial tone was weak and intermittent.
I have a more detailed description...
my judgment, it will be only a few years before
departments will be equipped with radio," Superintendent A. A. Carroll, Grand Rapids Police
Department. Such a statement could have been deemed risky - or even career-ending back in
the late 1920 to early 1930s when radio communications was still in its infancy. A lot of
public figures denounced radio for anything other than a means of receiving entertainment
at home. After all, the equipment was physically large and very power hungry. It was considered
folly by many people to believe that an automobile's electrical generation capability would
ever be able to power a vacuum tube receiver, much less a transmitter that would have enough
range to be useful. Still, police and fire...
engineers can usually be identified by their tendency to deal with all aspects of life through
a combination of pragmatism and objectivity. Every object and objective presents a challenge
that requires consideration of both the initial assessment of each situation and the careful
analysis of how it might be improved for personal optimization and utilization. You know the
type; you probably are one of 'them' if you're reading this... one of 'us,' I probably should
say. Be assured, you are among friends here. This latest installment in Joe Cahak's creative
series offers a quantitative analysis of his new
C-Max Energi Hybrid horseless carriage, along with an in-depth accounting of his carefully-analyzed...
De-Embedding: From Theory to Applications, by Giovanni Crupi and Dominique Schreurs. This
groundbreaking book is the first to give an introduction to microwave de-embedding, showing
how it is the cornerstone for waveform engineering. The authors of each chapter clearly explain
the theoretical concepts, providing a foundation that supports linear and non-linear measurements,
modeling and circuit design. Recent developments and future trends in the field are covered
throughout, including successful strategies for low-noise and power amplifier design. This
book is a must-have for those wishing to understand the full potential of the microwave de-embedding
IEEE MTT International Microwave Symposium
(IMS) is the premier annual international meeting for technologists involved in all aspects
of microwave theory and practice. It consists of a full week of events, including technical
paper presentations, workshops, and tutorials, as well as a full set of social events. The
symposium also hosts a large commercial exhibition featuring over 550 companies. The IEEE
MTT-S Microwave Week has several conferences that are co-located at the same venues. Besides
the flagship IMS Conference, Microwave Week also hosts the IEEE RFIC and ARFTG conferences...
Journal Editor, David Vye moderates a round table panel discussion among leading EDA vendors
as they consider the state of
IC design in China and the challenges for organization’s looking to develop a world-class
EDA design flow infrastructure and adopt design automation tools. Panelists will discuss design
entry and management, PDKs, EM simulation / modeling, various types of RF specific analyses,
third party integration and the role of EDA companies in providing engineering support/training
programs. Visit EDI CON 2014.
is a fortuitous discovery. While perusing a 1930 edition of Radio News magazine, I ran across
an article written by none other than
Guglielmo Marconi himself - 28 years after the first transatlantic radio communication
had occurred. It's hard to imagine having lived in an era when radio was looked upon with
awe - and even fear - by most of humankind. Its seemingly magical operation was matched at
the time only with the fledgling air travel revolution. Mr. Marconi here provides a brief
history of his work in making that first radio contact between Poldhu, England, and Cape Cod,
Massachusetts, with the assistance of the BBC and NBC, respectively. This is the type of resource
that credible historians love since it is a first-hand account of an event...
1950s was a time of transition in the television watching business. Broadcasters were experimenting
pay-TV systems to replace or supplement over-the-air service. Much as people today think
that everything on the Internet should be free, the same mindset prevailed then regarding
television programming. Early coding and decoding schemes seem really hokey by today's standards,
using computer-type punch cards. I remember the area around Annapolis, Maryland, where I grew
up, had both over-the-air and cable-based subscription services in conjunction with the open
broadcasts. I spent at least a little time playing with the horizontal and vertical picture
sync settings on the back of the TV set that, if lucky...
trust an atom. They make up everything." - Anon
is Colossal, really, it is. That's the name of a website that features, among other things,
amazing works of art with high technology themes. There are hundreds of pages containing thousands
of images, so after spending an inordinate amount of time sifting through pages in an orderly
manner looking for for items of interest, I finally discovered the Search box. I then spent
my valuable time looking only of for topics like radio, technology, computers, etc. This first
example, titled "Antenna Telescopes on the Streets of Birmingham,
UK," is classified loosely as street art and was done to camouflage some satellite television
dishes mounted to the side of a building. It would be interesting to see if the artist planned
for the images to look right from...
week's crossword puzzle, like last week's crossword puzzle, and all the weeks before that,
was custom made by me and contains only words and clues pertaining to science and engineering.
Print it out and take it to your next diversity in the workplace meeting so you can honestly
say you got some mental stimulation out of it. Enjoy!
do many of you, I enjoy and learn from reading online anecdotes submitted by engineers, technicians,
and hobbyists that have faced and resolved situations which are sometimes daunting, sometimes
impossible, and sometimes just ridiculous. Sherlock Ohms and Made by Monkeys from DesignNews,
and Tales from the Cube from EDN are the most notable sources for such stories, but the topics
cover a very wide range of subjects that are more often than not unrelated to RF and microwave.
Lately, the stories have been pretty lame and uninspiring. I like tales of work and hobby
related situations with a good description of the problem and its symptoms, followed by a
fairly detailed explanation of the steps taken to resolve it. If you appreciate such articles
and would like to make your own contribution for the edification and teaching of fellow techies,
I will be glad to create an area for posting them on RF Cafe and title it "Out
of Order: Tech Trials & Tribulations..."
article on crystal filters will probably be more useful to people responsible for maintenance
on old RF systems than for new designs. The technology has come a long way since 1957.
Crystal filters were heralded as godsends as airwaves became more crowded and simple LC
filters could not provide the required Q to prevent cross-channel interference. Of course
the problem is many times worse today, but components are better now than then with low-cost
integrated circuit front ends that handle a lot of the selectivity issues and SAW filters
with better performance than many crystals.
was part of the hey day of the newfound
radio-in-your-car craze, and the public was voraciously consuming all the high tech equipment
it could afford. Rock and Roll music was on every teenager's mind and many guys for the first
time were able to have their own wheels and were outfitting them with sound systems that could
blast the latest works of Buddy Holley, Chuck Berry, Elvis Presley, and Fats Domino. Those
machines were the first babe magnets used for cruising the strip on Saturday nights. Radio
stations were popping up all over the country, enabling cross-country travel with non-stop
music, news, and variety show entertainment. Ford and Chevrolet were not going to miss an
opportunity, so they delved into the high end mobile radio manufacturing business. As the
quality of broadcasts increased, noise...
if you are even old enough to remember the Packard Bell line of desktop computers that appeared
during the PC revolution of the late 1980s, you probably do not know that before making PCs,
Packard Bell made television sets. Before that they made radios. Herb Bell and Leon Bell
formed the company in 1933, then marketed their first radio model, the 35A. Packard Bell was
sold to Teledyne in 1968, then in 1986, an American businessman named Beny Alagem and a group
of Israeli investors bought the Packard Bell name from Teledyne. Because of a failing brand
name, Packard Bell left the U.S. altogether in 2000. If you visit the Packard Bell homepage
today, you will not find the U.S. or Canada...
have been very popular as an affordable space platform for experimental electronics systems.
Their small size presents an issue with signal strength both for uplink and downlink channels.
Heretofore, some form of rigid dipole or even a ¼-wave stub, with 1 dB or so best-case
gain and relatively low directivity (which subjects it to interference)
is all that was available. MIT engineers are developing an
inflatable parabolic antenna made of thin Mylar that will stow onboard in a small space
and then deploy with a powered that turns into pressurized gas to form the antenna. CubeSats
typically have short lifespans due to limited space and weight allowance for batteries and
solar panels (and their usually lower orbits degrade in weeks to months),
so the antenna does not need to have a long life expectancy.
hot dog, not hotdog. In this third installment in the adventures of John T. Frye's much-anticipated
monthly exploits of teenage electronics investigators
Carl Anderson and Jerry Bishop, pet mutt Bosco has developed a case of hot paw pads. Using
a makeshift Geiger counter and a homemade radio homing device, the two boys set out to discover
the source of Bosco's warmth. A buried, as-yet undiscovered lode of uranium is high on their
suspect list, and visions of untold wealth dance through their heads. Read on to find out
what they found out.
Corporation has released a digital edition of its AWR Magazine that’s a culmination of news
and events over the past year. Widely distributed at major trade shows and AWR-hosted
seminars, the AWR magazine is now offered online in a new interactive format that’s PC, tablet
and smartphone compatible. The digital edition of
AWR Magazine, as well
as previous static PDF issues, can be found on line.
you work with oscilloscopes on a regular basis, you know know one of the first things you
do (or should do) is to calibrate the frequency response of the
probe by hooking it onto the
squarewave port and tweaking the probe capacitor for no overshooting or undershooting
at the waveform edges, and then verify that the displayed amplitude is correct. I remember
being amazed during engineering courses at learning that any periodic waveform can be described
mathematically as the sum of sinewaves at various frequencies, amplitudes, and phases. Knowing
the theory behind those waveforms - particularly standard ones like squarewaves, trianglewaves,
sawtooths, etc. - really helps...
1992, Ophir RF has been designing and manufacturing
RF/Microwave Amplifiers for military,
T&M, EMC and scientific research applications. Products range
to 40 GHz. Power levels 1 W to 25 kW. Ophir RF's specializes in replacing radar
tube technology with solid state. Whether RF amplifier systems or modules, Ophir RF is your
RF power source. Ophir RF designs and manufactures its products in the USA. We are well-known
in the industry for successfully adapting our amplifiers or custom designing new solutions
to meet your application requirements.
might be a bit of a risk telling you this, but I saw an advertisement appear on the RF Cafe
homepage that struck me as so funny that I had to investigate. The risk involves the terms
of use agreement with the ad serving company that prohibits bringing attention to a particular
ad that might encourage clicks. So, rather than providing a screen capture of the banner ad,
let me describe what I saw. An imaginative guy named Ramiro Cairo, who lives in Brooklyn,
NY, created a "family" of electronic novelty characters called
Los Boludos that are made from salvaged vacuum
tubes, colorful rubber computer keyboard spring cones, clothing snaps, and toothed metal clasps.
According to Mr. Cairo's bio, he was born in Buenos Aires...
Process Engineering Inc., a full service company specializing in process systems and solutions,
is seeking people with the following skills. We were established in 1974 and promote an environment
where all employees are valued and treated with respect.
Instrumentation & Controls
Field Service Technician
like Q-Par Antennas (now owned by Steatite) underwrite the publication
of RF Cafe, so if you have a need for products or services my advertisers
please check with them first. "Steatite Q-par Antennas designs and manufactures
antennas, positioners, components and subsystems
across the radio frequency spectrum, with specialisation in microwave & millimetric systems.
We design, build and calibrate our products to the highest engineering standards. Custom products
not sure when storytelling as a style of
technical writing went the way of vacuum tubes (probably about the
same time, come to think of it), but this article from the January 1958 edition of
Radio-Electronics is a prime example of how such prose was utilized. Two characters, Red and
Fuzzball, meet at a coffee counter and discuss the intricacies of color convergence in color
television sets. Such issues are not a concern with today's electron-beam-less displays, but
back in the day, it made the difference between an acceptable picture and frustrating images
with color fringing. Maybe you remember those days. After having...
Multiple Target Tracking, by L.D. Stone, R.L. Streit, T.L. Corwin, and K.L. Bell. This
book views multiple target tracking as a Bayesian inference problem. It develops the theory
of single target tracking, multiple target tracking, and likelihood ratio detection and tracking.
In addition to providing a detailed description of a basic particle filter that implements
the Bayesian single target recursion, this resource provides numerous examples that involve
the use of particle filters. With these examples illustrating the developed concepts, algorithms,
and approaches -- the book helps radar engineers track when observations are nonlinear...
are lots of
audiophiles in the RF Cafe audience who might appreciate this article on the characteristics
of human hearing and ways in which stereo hi-fi equipment attempts to reproduce realistic
sound, as if from a live performance. A handy-dandy chart is provided that shows the characteristics
of various audible frequency ranges, and the kinds of
speakers best suited for reproducing the sound. It was published in 1955, but still should
be applicable today.
from the photos of cool radar antennas, "Made by General Electric of Syracuse, N.Y.," caught
my attention because I actually spent a couple years there (it was a
different company by then) in the mid 1990s as an engineer working with a design team
weather radar for the FAA. It was a kludge of left-over components and assemblies from
other cancelled programs. The phased array antenna came from a Navy shipboard program, and
the components for the RF, analog, and digital portions were cobbled together mostly from
parts that were in the company stock room inventory. Very little money was budgeted for new
parts or personnel. I handled all the RF and analog design and the equipment rack power supplies,
plus RF plumbing out of the building and into the phased array antenna...
and part-time digital artist Jay Simons has created his first version of a
Map of the Internet, where an attempt is
made to cram in as much information as possible on most often used browsers, most often used
social networks, NSA surveillance, worldwide Internet penetration, a list of Alexa's top 500
websites, a timeline Internet history, and top software companies. The base world map is done
in old-world format and coloring with faux names like Sea of Archives, Ocean of Information,
the country of Google and island of Bit Torrent. LinkedIn and its capital city of Hoffman
(for LinkedIn's founder, Reid Hoffman) resides just south of...
winners of January's RF Cafe Book Drawing
actually responded this month - woo-hoo! None of the four winners notified for November and
December responded after three separate e-mail notifications (their
loss is possibly your gain). Dean S., of Owensboro, Kentucky, selected Introduction
to Modern EW Systems, by Andrea De Martino. This book was graciously
provided by Artech House.
path to the CEO's office should not be through the CFO's office, and it should not be through
the marketing department. It needs to be through engineering and design." -
Elon Musk, CEO and chief
product architect, Tesla Motors and SpaceX
(engineering degree from U. of Penn., business degree from Wharton).
A., of Ontario, Canada, is one winner in the January 2014
RF Cafe Book Drawing. Mostafa selected
Design of CMOS Operational Amplifiers, by Rasoul Dehghani. Each month I randomly
draw one or two names from my electronic hat (an Excel spreadsheet),
and then mail it/them at my expense. Some months nobody responds to my e-mail notifications.
I usually try 2-3 times, but give up after that. This book was graciously
provided by Artech House.
radar technician Jim Rice checked in today with
his service record for adding to my list of honored service members who have spent time taming
the often fickle beasts - both fixed and mobile ground-based units. Jim served America for
20 years and then worked for 25 years as an inspector at Boeing. Recently retired, he's enjoying
life in the Robins AFB area.
editor of Kansas State University Department of Engineering's newspaper contacted me asking
permission to reprint one of my
crossword puzzles in their monthly publication called The Ohm. You will find
their alma matter's name buried in the word clues. Like always, all of the words are technology
related. As time permits, I'll be glad to do a custom crossword for your school's newsletter.