Out of Order: Tracking
Down a Mystery Signal
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
skills to track down and
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...
Solving a Broadcaster's
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...
Linx TT Series R/C Transceiver
Low Power &
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
Phenomena Underlying Radio:
material's first widespread application in electronics was in the
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.
Many Thanks to Fotofab
for Continued Support
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 machining,
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
R&S SMW200A Digital Predist.
Shortens Test Time
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.
AWR Student Gift Helps PhD
Corporation, the innovation leader in high-frequency EDA software,
releases a new customer success story that prominently and proudly
features how the
AWR Graduate 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 to graduates...
Chart Gives You All You Need
to Know About
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
PMI Intros 2-18 GHz, 1P6T,
Transient, SS Switch
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...
Thanks to Nova Microwave
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
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
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
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
Current Reuse Gains UWB
LNA (Michael Hopkins at
has been into current reuse for a
Low Battery in Multimeter
= High Voltage
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...
Sherlock Ohms: Corroded
Copper Stops Dial
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
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
A New Arm of the Law
my judgment, it will be only a few years before
all police 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
Ford C-Max Energi Hybrid horseless carriage, along with an in-depth
accounting of his carefully-analyzed...
Book of the Week
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 concept...
IMS 2014: June 1-6
Tampa Bay, Florida
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...
EDI CON 2014 RF & High Speed
and EDA in China
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.
A Radio Dream Come True
is a fortuitous discovery. While perusing a 1930 edition of Radio
News magazine, I ran across an article written by none other than
Senatore 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...
Will You Pay for TV?
1950s was a time of transition in the television watching business.
Broadcasters were experimenting with
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
The Art of Technology
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...
Radio & Radar Crossword
for February 9, 2014
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.
Out of Order:
Tech Trials & Tribulations
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..."
Super Selectivity with Crystals
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
1957 Auto Radios: Ford
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...
The Packard-Bell Color TV Line
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.
Carl & Jerry:
The Hot Dog Case
hot dog, not hotdog. In this third installment in the adventures
of John T. Frye's much-anticipated monthly exploits of teenage electronics
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.
AWR Magazine Goes Digital
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.
Practical Techniques of
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
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. -
Please Welcome Ophir RF
as a New Advertiser!
1992, Ophir RF has been designing and manufacturing
for military, T&M, EMC and scientific research applications.
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.
The Los Boludos
Vacuum Tube Family
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
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
Thanks to Steatite Q-Par
Antennas for Support!
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
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 available."
Red and Fuzzball
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...
What We Hear
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.
U.S. Air Force's New
Radar Height Finder
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 for a
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...
Map of the Internet
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...
Congrats to Dean S. as Winner
of the January
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
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." -
Musk, CEO and chief product architect, Tesla Motors
and SpaceX (engineering degree from
U. of Penn., business degree from Wharton).
Congrats to My January 2014
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
USAF Radar Tech Jim Rice
Added to Vaunted
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
engineering-themed 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.