Solutions has introduced a new 0.02 – 4 GHz, high isolation,
single pole four throw absorptive switch with 50 Ω terminations
and excellent isolation performance. The symmetrical
SKY13392-359LF is ideal for military communications, test and
measurement and GSM/CDMA/WDCMA/LTE cellular infrastructure applications
requiring feedback, channel and filter-bank switching where very
high isolation (>50 dB) and low
loss (1 dB) are needed. The device
contains integrated logic.
is an interesting story where the FCC issued a citation of violation
incidental radiation due to a malfunctioning well pump. The
noise was evidently being generated by the motor and radiated from
the AC power wires. The interference was affecting local MF and
HF amateur radio operation.
used direction finding equipment to locate the source
('fox hunting' in Ham terms). The owner
was threatened with a $16,000 fine unless corrected immediately,
with up to $112,500 levied if he screwed around. Replacing the AC
line filter did not solve the problem, so he probably ended up replacing
the entire pump. Being in Florida where the water tables are typically
near the surface, it was likely not a submersible type pump, so
the entire assembly would have had the opportunity to radiate. Submersible
pumps use brushless induction motors deep within the metal casing
lining the well hole (a nearly ideal RF shield),
but depending on the vintage of the resident's above-ground pump
it could be brushed, with arcing causing the problem.
are a few recent articles from our industry's leading magazines
that you might find useful.
Choosing Optimal Cables &
Connectors, J. Browne
Designing MRI Coils with Aid
of Simulation, A. Bitz,
J. Felder, T. Wittig
Unused RF Spectrum May
Ease Wi-Fi Traffic Jams,
Manage Growing EM
Radiation Levels, J. Browne
Input Third Order Intercept
Point for Crystal Filters (p.22)
Measuring the Thickness of
Coated Shields, K. Wyatt
controls, evaluation kits and master development systems feature
straightforward hardware configuration and clear documentation,
making it simple for engineers and hobbyists to integrate wireless
features without the hassle and expense of engineering RF functionality
from scratch. They also offer design services including board
layout assistance, programming, certification advice and packaging
design. "Wireless Made Simple"
a break and work this week's
wireless engineering themed crossword puzzle. All the words
are pulled from a hand-built list of terms, names, and abbreviations
that have only to do with science, mathematics, and engineering.
If you want a crossword with names of movie stars and obscure countries,
try the local newspaper. If you want to exercise your nerd knowledge,
this is the one for you.
1985, Apex Wireless has offered
and design services focusing on high-performance, cost-optimized
products that employ wireless RF transmitters, receivers, and transceivers.
To complement our RF design expertise, we work with local experts
in DSP, ultra low power design, packaging, certification, and manufacturing.
Consumer, defense, aerospace, power, transportation, industrial,
sports, and other industries served.
you ever heard of a 'nuvistor?' It didn't seem familiar to me right
away until after I looked it up.
Nuvistors were high mu (high gain) tubes, manufactured originally
by RCA, used in sensitive receiver front ends. They came in about
a dozen different varieties. This particular NASA-136 receiver for
satellite reception uses a 6CW4 triode. Per Wikipedia, "Most nuvistors
are basically thimble-shaped, but somewhat smaller than a thimble,
and much smaller than conventional tubes of the day. Triodes and
a few tetrodes were made. The tube is made entirely of metal and
ceramic. Making nuvistors requires special equipment, since there
is no intubation to pump gases out of the envelope. Instead, the
entire structure is assembled, inserted into its metal envelope,
times I have extolled the high quality of QST authors' knowledge
and writing skills.
H. Ward Silver writes the "Hands-On
Radio" column which usually features circuit and system design
and theory topics. It often includes, gasp, mathematics. His July
2013 article is titled "Phasors, Part One." It promises to be a
good series. The last paragraph says, "There is a final way to describe
the signal - the exponential form in which it is represented as
V ejΘ. This form comes from the mathematics behind
Euler's equation in which the coordinates
of our points are miraculously shown to be equivalent to ejΘ=cosΘ
+j sinΘ. The serious and beautiful math behind this equation
lies at the heart of much electrical engineering and leads to the
jaw-dropping Euler's identity: ejπ
= -1 which unites the two most widely used transcendental number
imaginary numbers (j), negation and unity. Not bad for a moving
point in a simple circle, huh?" Beautiful. After reading it Melanie
asked why my eyes were suddenly red. "Allergies," I explained.
PS-500M2G-8B-SFF is a Stare-of-the-Art, 8-Bit Digitally Controlled
Phase Shifter that operates over the 500 MHz to 2.0 GHz
frequency range. This model has a typical insertion loss of
10dB and offers 360 degrees of phase shift via 8-Bit TTL control.
The phase shift error is less than ±10 degrees and the amplitude
error is less than ±1 dB. The switching speed is 500 nsec
Technologies' new low-cost gold plated connectors are now available
from Linx, adding new options to our already diverse connector line.
The gold jacks are available in
Reverse Polarity SMA styles in straight or right-angle versions.
In addition, the 50-ohm connectors are available as PCB mount or
surface mount components offering a variety of mounting options
for your design.
the time you read this it will probably be too late to be an original
owner of this very limited edition 'Codebreaker'
watch, made by the prestigious UK Bremont Watch Company. Each Codebreaker
watch will incorporate a piece of pine wood from the iconic Hut
6 and numbers from some rare, original punch cards used in wartime
machines that carried out rapid analysis of encrypted message
systems to assist the
Each watch will also have incorporated into its rotor, material
from an original Enigma machine
Bletchley Park news, the WWII era
Electronic Delay Storage Automatic Calculator
(Edsac) restoration project recently
reached a key milestone. Edsac is built of 3,000 valves
(vacuum tubes) spread across 140 separate
the early 1930s, QST magazine (ARRL's monthly
publication) usually ran a line at the bottom of every page
in the back half of each issue that said, "Say
You Saw It in QST - It Identifies You and Helps QST." They even
got the capitalization correct (all lower
case short prepositions and conjunctions, but I digress).
The December 1933 edition was a bit different, however, in that
all the left-hand pages had the message translated into one of fourteen
different languages while the right-hand pages used English. I deemed
that discovery cool enough to scan and post here. Since the only
languages I speak with any fluency are English and Pig Latin, I
took the trouble of entering the English sentences into the Google
Translator engine for each language...
1933 "Century of Progress" World's Fair, held in Chicago, was
a big deal on many fronts. Life in America and around the world
was changing rapidly due to the widespread introduction into homes
a decade earlier of electrical and telephone service, indoor plumbing,
and associated appliances. The state of the art was a modern wonder.
Transportation had been made affordable to many families, and leisure
time was becoming more abundant. If it were not for the advent of
the stock market crash in 1929, economies would be thriving because
there was so much cool stuff to be had. Many people had taken up
the hobby and/or profession of wireless communications, so a display
was included on the fairgrounds for the craft. An interesting consequence
of a combination of noisy (electrically)
electromechanical wonders being promoted and the desire to demonstrate
working amateur radio equipment was a necessity to locate the two
as far apart as possible...
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DTS Series and EUR Series
RF transceiver modules combine a low power wireless transceiver
with a powerful multipoint-to-multipoint protocol controller to
form an effective UART-to-antenna wireless communication solution.
The modules use a wide band digital modulation technique known as
Digital Transmission System (DTS) and are capable of replacing wires
in almost any RS-232/422/485 application. This system has a higher
output power, giving it a range of up to 1 mile / 1.6 km
line of sight without having to limit duty cycle, hop channels or
the expense of a DSSS system.
National Company, of Malden, MA, which made this cesium-based
Atomichron in the mid-to-late 1950s, began life as a toy manufacturer.
It had an output frequency at the nominal resonance frequency of
cesium - 9192.631830 MHz - and was accurate to better than
a second in 600 years. The unit was 7 feet tall and weighed 500
pounds. Modern cesium standards are more stable and are portable.
As of January 2013, the NIST-F1 cesium fountain primary frequency
standard is accurate to within one second every 100 million years!
CDT-2M18-30-BB Options DE, D is a threshold detector that operates
over the 2 MHz to 18 GHz frequency range. This model has
a low insertion loss of 2.5 dB maximum and operates over an
input power range of -30 to 0 dBm. The threshold level is adjustable
and the output signal is TTL positive logic. In addition to the
threshold detector, this unit offers an analog detected output voltage
of 0 to 2.5 VDC.
new technology could be a relatively simple and inexpensive method
of creating permanent, high density records storage. Using an
electron beam, the planar hexagonal carbon
of graphene (2-dimensional by definition)
is disturbed and replaced by a 3D clump of carbon atoms that provide
a discernable relief easily recognized as printing under a microscope.
While the print could be similar to a normal printed page, it might
be more useful to encode the information in some other form that
will require decryption to read. Magnetic and optical digital storage
media is notoriously non-permanent due to cold flow and migration
of localized storage domains. This process eliminates that problem.
have probably heard proposals for 'smart guns' that will only fire
when owners wearing special rings are in possession. Here is a near
ring that permits only its wearer to use a cellphone, tablet,
or other NFC-enabled device linked to its code. Doing so eliminates
the need to enter a password for access. According to an
NFC World report, the ring contains an IC that can
store personal contact information as well allowing the wearer to
voluntarily "share" certain details about him/herself
(why would you do that?) simply via
proximity contact. Initially, the ring will only work with Geak's
devices, but plans are in the works for more widespread adoption.
Corporation announces a new eBook,
RF Electronics: Design and Simulation, which is available free
of charge to students, graduates, professors and industry professionals
through AWR’s new
Professors in Partnership™ web portal. Developed by adjunct
associate professor C. J. (Keith) Kikkert of James Cook University
School of Engineering and Physical Sciences, Townsville, Queensland,
Australia, the book describes the use of AWR's
Microwave Office® and
AXIEM® software to design RF electronic devices for applications
such as amplifiers, radar, mobile phones, Bluetooth, and WLAN.
regular RF Cafe visitors will probably not be too interested in
this article, but there are a lot of people who build and/or repair
vintage radio gear and search the Internet for helpful information.
Having built a couple
crystal radio sets as a kid, I've always been amazed at how
a few picowatts of RF energy can be received, processed, and heard
through an ear plug without the need for external power from a battery.
Speaking of crystal radios, I remember one time while working as
an electrician in Annapolis, MD, (prior to
entering electronics) I had a telephone handset for use in
communicating with other electricians in a building I was wiring,
and it picked up the local AM radio station. A pair of the old style
stupidity. It's worse than stupidity: it's a marketing hype campaign."
- GNU founder
Richard Stallman on embracing Cloud Computing for its ostensibly
"free" data storage on uncontrolled servers rather than on your
Matrix's newest addition to the
QuickSyn® line of microwave frequency synthesizers is a 10 GHz
synthesizer housed in a very compact package, only 4 x 4 x 0.8 inches. The
new synthesizer, model
FSL-0010, employs the revolutionary phase-refining QuickSyn®
technology. The new Quicksyn® Lite synthesizer is less than
half the size of the full featured 10 GHz and 20 GHz QuickSyn® synthesizers,
yet it performs with wide coverage (0.65 to
10 GHz), fine resolution (0.001 Hz
resolution), fast frequency switching
(100 μs), and exhibits instrument-grade
folks at Rev Response have a pretty big collection of white papers
on a very wide range of subjects that are free for downloading.
Well, not quite free - they do require you to sign in, but no $$$
is involved. I make a few pennies on each download, so you're helping
to support RF Cafe if you participate. Here are a few of the newer
ones that might interest you:
Laptop Buying Guide
Rapid Color 3D Modeling
Your Guide to Create
Scientific Instrument and
Medical Device Makers
Exploiting 3D Interactive
Bring Your Own Device (BYOD) Policy Guidebook
a break and work this week's
engineering-themed crossword puzzle. All the words are pulled
from a hand-built list of terms, names, and abbreviations that have
only to do with science, mathematics, and engineering. If you want
a crossword with names of movie stars and obscure countries, try
the local newspaper. If you want to exercise your nerd knowledge,
this is the one for you.
searching occasionally for many years for another Crosley 03CB radio
in a location close enough to drive for pick-up, I finally saw one
on Craigslist in Harrisburg, PA, about 300 miles from my home in
Erie, PA. Melanie and I picked it up yesterday. It needs - and will
receive - a total restoration for both the cabinet and the electronics,
but it appears to be in better condition that my first pre-restored
Crosley 03CB. This radio is Chassis #95. If you look at the
photo of the first radio , you will notice that the tuning dial
has no cover over it. I never knew there was supposed to be a glass
bezel in front of the dial...
the illegal alien problem is just made up? Here is the
2012 fraud report showing more than $86 million sent to just
10 addresses. See
Figure 5 on page 17. In Atlanta alone, a single address for
23,994 'Unauthorized' (aka Illegal) Aliens received payments totaling
$46M. This crap is costing our economy jobs by requiring working
citizens to pay the tab for this. It also feeds into the massive
fraudulent voting scheme for one party and suppression of voting
by the other party. We now have a politico-economic
oligarchy, folks. Congratulations.
are a few more useful stories on the tech job market and job hunting.
5 Negotiation Tips from
Google Says GPAs Are
Meaningless for Recruiting
9 Qualities of Truly
TWC Offering New
Teleworker Support for
13 Must-Have Mobile Apps
4 Extreme Habits of Highly
Successful Remote Teams
I will be travelling on Friday
with limited e-mail access. Responses will probably be delayed for
a few hours. I apologize for any inconvenience.
is a fairly simple quiz on
AC circuit analysis. If you are not already comfortable with
adding series and parallel circuits containing resistors, capacitors,
and inductors, you will appreciate the simple formula presented
that will keep the sweat level down ;-) OK, pick up you pencils...
hobbyists are always anxious to hear the announcement of a new device
that is forecast to revolutionize the tech world. In the late 1950s
something as relatively tame as a
crystal photocell satisfied that urge. Today it takes something
like a negative refractive index metamaterial to invoke the same
sense of awe and wonder. Those were simpler times, but then again
even today's beginners in the world of electronics circuit designing
and building have to start somewhere, and these types of circuits
are as good as any place.
wasn't able to verify Dr. Baker's (VP
of GE) prediction in 1957 of what the state of the television
industry would be by 1960. He said 10 million sets would be sold
in 1960 vs. 7.5 million in 1957. Some recent sources claim there
were as many as 52 million TV sets total by 1960, so he might have
been right. Transoceanic scattering techniques were thought to be
the method of choice for television broadcasts, but we know that
ultimately relay satellites would win out. It wasn't until 1962
that the Telstar bird carried the first TV signals, however. "Truly
portable" transistorized TVs would be appearing...
is a little insight into early
speech processing research by the Bell Telephone Laboratories.
1957 was the early era of real-time digital processing where the
need to cram more calls into less signal space (bandwidth) led to
sampled systems - 1:6 in the case of this advertisement from Bell
that appeared in Radio & Television News. Engineers
of the day would be amazed at how the state of the art has advanced
since then, both in mathematical techniques and in miniaturized
sends out an e-mail every week or so with links to stories on job
hunting. Here are a few of the most recent.
20 Questions to Ask
Yourself Before You
Relocate for a Job
The 10 Best Cities for
STEM Jobs Right Now
Didn't Get the Job?
You'll Never Know Why
Messages Galore, But
No Time to Think
has won in two categories in the first annual Microwaves & RF
of Microwaves & RF" awards. The company won the Best Training
and Education category and was first runner up in the Best Supplier
Industry Blog category. The winners were determined through
a recent survey that went out to readers of Microwaves & RF
magazine inquiring about their favorite online tools for keeping
up to date within the microwave/RF industry.
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. They have more than 20 years experience in the RF/microwave
design and manufacture, with the agility of a small company and
the production capabilities of a larger-sized, high-volume manufacture.
RFtronics will usually deliver prototype quantities
(less than 50 pcs) directly and for
larger orders the design will be transferred to our manufacturing
NY Times article reported on a
court ruling in favor of a couple interns who claimed they were
not fairly paid for their work. Author Steve Greenhouse points out
that while it could be a victory for the litigants, ultimately it
could bode poorly for internship programs. Legal precedence is widely
referenced and applied by legal teams, and is notoriously difficult
to overturn. This particular internship involved work on a movie
production set, but expect the decision to ripple through to even
engineering and science business programs. An estimated 1,000,000
internships are hosted each year in America, a significant portion
of which could be eliminated out of an abundance of caution and
fear of being sued. Is this another "careful what you wish for,
you might just get it" scenario?
Lines and Slotlines, by Ramesh Garg, Inder Bahl, and Maurizio
line technology has progressed considerably due to developments
in UWB communications, imaging, and RFID applications. In addition,
the simultaneous demands for compactness of wireless electronic
devices while meeting improved performance requirements, necessitates
increased use of computer-aided design, simulation, and analysis
by microwave engineers. This book is written to help engineers successfully
meet these challenges. This book was used as the basis for
RF Cafe Quiz #50.
might have read about the recent U.S. Patent and Trademark Office
(USPTO) law that changes policy from
a 'first to invent' to a 'first
to file' system. It was meant to reduce the amount of work required
by patent examiners and to reduce litigation by eliminating the
heretofore potentially subjective nature of determining who was
the 'real' inventor of an idea. Previously, if a person could prove
via formal dated notes, witnesses, etc., that he was the first to
manifest an idea in the form of a working model, there was a good
chance that an existing patent could be reassigned. Now, it is almost
purely a matter of who gets the earliest timestamp for having been
received at the USPTO. This short piece in Inc magazine discusses
patent filing issue.
1994, leading wireless electronics companies have relied on 3Gmetalworx
to deliver cutting edge solutions for advanced
RF/EMI PCB-level shielding requirements. From prototyping
and design services to JIT manufacturing supply, our clients depend
on us to provide a seamless service pathway supporting entire product
lifecycle. All shields can incorporate
these features, as well as your custom needs:▪Engagement tabs, trace/component
relief, tuning/access openings, thermal relief.
Wolfgang has a good article in the May 2013 edition of QST
to Science." In it he recalls a few examples of how
amateurs have helped professional
scientists and engineers advance the state of the art in wireless
communications. For instance Pat Dyer, WA5IYX, conducted an 11-year
study of mid-latitude
sporadic E, and Dave Olean, K1WHS, built a
magnetometer to predict aurora to aid in 144 MHz DX. Hams also
trans-equatorial propagation. Mr. Wolfgang suggests that pursuing
a meaningful scientific investigation of your own or maybe by your
club would be a worthwhile and satisfying endeavor. BTW, while writing
this I happened upon a resource for current QST articles on
EBSCO Host website, which is significant because non-members
of ARRL cannot access their online editions.
take a moment and vote in this poll. No sign-in-required. Results
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