These archive pages are provided in order to make it easier for you to find items that you remember seeing on the RF Cafe homepage. Of course probably the easiest way to find anything on the website is to use the "Search RF Cafe" box at the top of every page.
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"U.S. Air Force researchers are asking industry to develop power sources and antennas for future high-power microwave weapons and for other aerospace and defense uses. Officials of the Air Force Research Laboratory at Kirtland Air Force Base, N.M., released a solicitation Tuesday for the source and antenna portion of the High-Powered Electromagnetics (HPEM) research program. The overall HPEM project seeks to develop high-power electromagnetics technologies not only for directed-energy weapons, but also for cyber warfare, EW, electronics-killing weapons ..."
Cobham Antenna Systems announces the launch of a dual-band, Gooseneck addition to the 'Universal' spring mount range of omni-directional antennas. The Gooseneck antenna, along with a selection of the 'Universal' spring mount antennas, will be available to view on Cobham's booth #1319 at (AUVSI's) XPONENTIAL 2016 in New Orleans, Louisiana. The OA2-2.3V-5.2V/2358 is a ground plane independent, dual band antenna which covers the frequency ranges 2.10 – 2.60 GHz and 4.40 – 6.00 GHz, offering 4 dBi gain in the higher frequencies ...
"API Technologies offers a standard line of rotary joints, formerly manufactured by Sage Labs, suitable for use in commercial and military applications. The term rotary joint describes a device used to transmit energy from a stationary RF line to a rotating RF line." The 345 and 351 series covers DC to 40 with VSWRs in the 1.2:1 to 1.75:1 range. Peak power handling is 500 W. Max rotation rate is 100 rpm. SMA & 2.92 mm connectors. WOW is the per revolution variation, same as with audio equipment ...
How well received do you think this social concept would be in today's easily offended world: "To bring together socially the Wives and Mothers of Dallas Radio Amateurs; to promote mutual sympathy, counsel, and interest in our husband's and our son's hobby; and with a realization that theirs is an outstanding, fascinating, far-reaching and educational hobby, it is our desire to further their interests in whatever way may present itself." It would be roundly criticized as a backward, misogynistic, 1930-era mindset intended to subject women to yet another form of domestic slavery beyond housekeeping and child rearing - no doubt thought up by a man. Anyone thinking so ...
I've said before that if you want a place to see great engineering-related slideshows, it's hard to beat the subjects that Charles Murray and Rob Spiegel come up with on the Design News website. Motorheads will definitely appreciate these images of some of the most high-tech production engines ever built. The blue anodizing on Ford's 1.0-liter, turbocharged, three-cylinder EcoBoost engine is incentive to do like in the 1950s-70s and cut a hole in the hood to show off the craftsmanship. However, its diminutive size would allow it to fit into an airplane's overhead luggage compartment so the effect would not be as impressive as a big block Chevy engine with a raised intake manifold, blower, and four-barrel Holley carburetor sticking out ..."
My introduction to a tesseract was during an episode of Carl Sagan's "Cosmos" series in the 1980s, where he was demonstrating how beings in of dimension N would perceive items of dimension N+1. The tesseract, Sagan explained, is a 3-dimensional projection of 4-dimension hypercube. Watch the embedded video for more information. The Tesseract website, which has nothing to do with a hypercube as far as I can tell, deals in some very cool antique scientific instruments. I learned of it from an article in Astronomy magazine where an editor recommended it when researching the potential value of a collectible telescope. Run by Drs. David and Yola Coffeen, Tesseract has a huge inventory of items ...
Well it's about time this antiquated rule was abolished! "Expert maintains that the 15 dB gain limitation is an unneeded holdover from the days when amplifiers were less efficient and the FCC was attempting to rein in the use of Amateur Service amplifiers by Citizens Band operators (aka CBers). While the FCC proposed in its 2004 Notice of Proposed Rulemaking and Order in WT Docket 04-140 to delete the requirement that amplifiers be designed to use a minimum of 50 W of drive power and subsequently did so, it did not further discuss the 15 dB gain limit in the subsequent Report. 'There is no technical or regulatory reason an amplifier capable of being driven to full legal output by even a fraction of a watt should not be available to Amateur Radio operators ..."
Maybe I suffer from cranial rectumitis at the moment, but I'm having a hard time with a statement made about coaxial feedline impedance, to wit, "102-ohm line (52-ohm lines in series)." I must be missing something because I don't understand how placing two 52-ohm transmission cables in series results in twice the impedance. Aside from that, author John Avery presents an interesting article on multi-impedance dipole antennas. Empirical data is presented on how the feedpoint impedance of a dipole varies with distance above the ground. His results are very close to theoretical values which assumes non-sagging elements, perfectly linear alignment, a perfectly conductive ground, etc. He then extended his investigation into 2-wire (4x impedance) ...
MACOM Technology Solutions Holdings, a leading supplier of high-performance analog RF, microwave, millimeterwave and photonic semiconductor products, today announced that it has initiated legal action against Infineon Technologies and International Rectifier (acquired by Infineon in 2015), to defend its rights to use the pioneering and patented GaN technology developed by Nitronex (acquired by MACOM in 2014) in MACOM's core markets. GaN is a next-generation technology that promises to improve network data service and cell coverage of 4G/LTE and 5G basestations while reducing their energy consumption and associated carbon footprint ...
Free downloadable whitepaper from Anritsu. "This paper outlines some high-speed standards for next-generation communications and describes some physical-layer measurement techniques, targeting the era of 5G and IoT. • Need for 5G/IoT Generation • Wired Networks Faster • Wired Communications Measurement Challenges in Next-Generation Interconnects ..."
"EPFL scientists have built a single-atom magnet that is the most stable to-date. The breakthrough paves the way for the scalable production of miniature magnetic storage devices. Magnetic storage devices such as computer hard drives or memory cards are widespread today. But as computer technology grows smaller, there is a need to also miniaturize data storage. This is epitomized by an effort to build magnets the size of a single atom. However, a magnet that small is very hard to keep 'magnetized,' which means that it would be unable to retain information for a meaningful ..."
Windfreak Technologies was created with the vision of providing low cost, quality, innovative RF products that can be used in a wide range of highly technical applications for a wide range of customers, from hobbyists to education facilities to government agencies. Windfreak designs, manufactures, tests and sells high value USB powered and controlled radio frequency products such as RF Signal Generators, RF Synthesizers, RF Power Detectors, RF Mixers, RF Upconverters and RF downconverters. Worldwide customers include Europe, Australia, and Asia. Please visit Windfreak today!
"Martin Thuo likes to look for new, affordable and clean ways to put science and technology to work in the world. His lab is dedicated to an idea called frugal innovation: 'How do you do very high-level science or engineering with very little?' said Thuo, an assistant professor of materials science and engineering at Iowa State University and an associate of the U.S. DoE's Ames Laboratory. 'How can you solve a problem with the least amount of resources?' That goal has Thuo and his research group their materials expertise to study soft matter, single-molecule electronics and renewable ..."
"Do you think that F.C.C. would be engaged in the present terrific expense and effort of getting our fingerprints and citizenship histories if there were intention of shutting us down shortly?" That statement was printed by the QST magazine editor in the issue that preceded the December 7, 1941, attack on Pearl Harbor by thirteen months. A few things about it are troubling. First, the FCC was collecting fingerprints of licensed amateur radio operators. Second, the FCC was assimilating information about licensed amateur radio operators' citizenship histories. Third, a combination of short-sightedness and apparent naiveté concerning the FCC's willingness to shut down amateur radio operations once ...
"Hydrogen atoms can induce magnetism in graphene and be used to create a uniform magnetic order across the 1D material. That is the finding of researchers in Spain, France and Egypt, who also demonstrated that it is possible to atomically manipulate hydrogen atoms on graphene to control the local magnetic state. Graphene is a sheet of carbon just one atom thick that has a number of unique properties. But it is not magnetic. 'The incorporation of magnetism to the long list of graphene capabilities ..."
"The Congress shall have Power … To promote the Progress of Science and useful Arts, by securing for limited Tımes to Authors and Inventors the exclusive Right to their respective Writings and Discoveries." - United States Constitution, Article I, Section 8. Therein lies the authority for legislation and prosecution of rights for virtually every human creation within the jurisdiction of the country. Each nation has it own version, and international agreements help assure universal protection of a creator's rights of ownership; e.g., the "Convention for the Protection of Literary and Artistic Works" of 1886 and the World Intellectual Property Organization. America has the U.S. Copyright Office. Those of us involved in presenting information and referring to legally protected ...
"Engineers at the University of Wisconsin-Madison have found an inexpensive, easy way to make flexible transistors. The manufacturing method can easily be repeated and scaled up, but the most exciting development is the transistor itself. It is faster than any other silicon-based flexible transistor, and it is capable of wirelessly transferring data or power. The transistor operates at a record 38 GHz, and the researchers estimate that it could even operate as fast as 110 GHz, which would give computers incredibly fast processing speeds. The transistor's record-setting performance is because of a unique, 3-D current-flow pattern that makes it ..."
Nova Microwave, located in Clearwater, Florida specializes in the design, engineering and manufacturing of a broad range of Ferrite Circulators and Isolators. Nova Microwave is a leader in technically differentiated electronic and radio frequency Ferrite circulators and isolators that connect, protect and control critical systems for the global microwave electronics market place including commercial and military wireless telecommunications. Our staff is dedicated to research and development of standard and custom design quality ferrite circulators and isolators from 380 MHz to 26.5 GHz ...
"Using fiber optic cables as waveguides for transmitting light that is ultimately converted into voice calls or data has been a mainstay for the telecommunications industry for decades. But it's been a massive struggle to adapt this kind of technology to the scale of a microchip so that photons carry data through an integrated circuit instead of electrons. Now researchers at Karlsruhe Institute of Technology (KIT) in Germany have tackled a major problem in making integrated optical circuits a reality by creating nanoscale photonic emitters with tailored optical ..."
"We are an operational squadron. We are supposed to be flying jets, not building them." - Lt. Col. Harry Thomas,, commanding officer of VMFA-312, a Marine Corps F/A-18 squadron based at Beaufort, remarking in a story about how only 30% of the USMC air fleet is actually air worthy.
It is always nice to read an article that encompasses more than one of my hobbies, whether it be amateur radio and amateur astronomy like this one, amateur radio and model rocketry, or amateur radio and radio controlled airplanes. I don't recall ever seeing an article that combined astronomy and model airplanes. In this QST piece, author Hollis French expounds on the necessity for Hams to understand the effects that atmospheric phenomena, caused primarily by our sun's periodic and intermittent activity, have on radio signal propagation. Properties of the ionospheric layers had by 1943 been pretty well surmised based on cause and effect relationships since at the time no sounding rockets had been launched into the upper atmosphere to obtain in situ ...
"FCC Jessica Rosenworcel told a group of industry representatives that the 5.9 GHz band is "our best near shot for having more WiFi" and called for tests to ensure that it can be effectively used for this purpose. Rosenworcel was speaking at the WiFi Now conference held at the Sheraton Hotel here. The conference featured looks at some innovations in WiFi as well as new ways to monetize this primarily free service. Perhaps the most important innovation came from Edgewater Wireless, which has developed a means for producing radio chips with three discrete ..."
When Melanie's mother needed to be moved into an extensive care facility, we inherited the family's antique dining room table. It was manufactured by the James Pleukharp company, located in Ohio. Similar models were made sometime in the late 19th and early 20th centuries. The rounded end panels drop down and the center section expands to hold up to six leaf panels to a total of 105". With no leaves the table is nearly round with a 45" diameter. A very greenish poplar comprises the solid 3/4" tabletop and turned legs, with oak used for the sliding expansion mechanism. Surprisingly, a thick walnut plank ran across the frame to support the center leg ...
"The Vice-Chairman of the Joint Chiefs of Staff is taking a "very serious" look at to making the electromagnetic spectrum a formal "domain" of military operations, a top aide to the Pentagon’s chief information officer told me this morning. The move would elevate the ethereal realm of radio waves and radar to the same level of importance as land, sea, air, space, and cyberspace, with ramifications rippling across the military's budget, training, and organization. We’ve written for years about the military’s anxiety that it has "lost the electromagnetic spectrum" to increasingly sophisticated adversaries like Russia and China, who can jam or spoof ..."
A little over a year ago, I posted photos and info on a few really cool-looking RF devices that make me wish I had a use for them, or at least had examples to put on display as conversation pieces. Usually the components look the way they do purely due to functional necessity, but sometimes I think the designers intentionally add a little bit of 'wow' factor to them. Waveguide components tend to dominate. At the time, I could not find a hyperlink to Sage Millimeter's Space Qualified 26.8 GHz Integrated Transmitter Module; however, thanks to a recent e-mail from a nice lady from the company, there is now a link to the datasheet ...
This story reminds me of carefully scripted 'tours' given by Communist regimes to outside agencies to demonstrate how humane and open their society really is. "A few minutes past 9 a.m. at Pegatron Corp.'s vast factory on Shanghai's outskirts, thousands of workers dressed in pink jackets are getting ready to make iPhones. The men and women stare into face scanners and swipe badges at security turnstiles to clock in. The strict ID checks are there to make sure they don't work excessive overtime. The process takes less than two seconds. This is the realm in which the world's most profitable smartphones are made ..."
The weekend is over and it's time to hunker down for five long days of grueling work. Most of the electronics-themed comics that appeared in QST magazine were associated directly with particular columns. For example, the cartoons featuring 'Jeeves,' the overtaxed manservant of a never-seen house master, was part of the "How's DX" feature. Drawn by artist Phil Glidersleeve (aka 'Gil'), W1CJD, poor Jeeves was often found doing his boss's will in the most precarious situation with intemperate weather making his assignments tough to complete. Situations involving Podunk Hollow Radio Club were frequent subjects of Gil's drawing pen as well. Enjoy ...
Keysight EEsof EDA has released a series of five RF power amplifier (PA) design videos intended to provide engineers with the building blocks to design more complex PA classes (i.e., A, AB, B, F, E and J). While PAs are used everywhere, their large signal nonlinear nature makes designing them difficult. Moreover, the idealized waveforms that define textbook classes of operation are problematic, if not impossible, to realize using a real device ...
"The antennas for smartphones capable of operating anywhere in the world at 4G and in the future at 5G, are becoming progressively more difficult to design with all the different frequencies they must transmit and receive. The answer, already being used in advanced design is multiple-input multiple-output (MIMO) antennas (also called multi-port antennas) that can dissect the frequency band cheaply and efficiently. Unfortunately, today's experienced antenna designers use "black magic" (their experience and savvy) to guess at what ..."
Res-Net Microwave manufactures a complete line of precision RF & microwave components including microwave attenuators, microwave terminations, microwave resistors, and now diode detectors for commercial, military, and space applications. The company is a leader in development and production of the films required for these type of RF/microwave components. In addition to an extensive selection of standard products, Res-Net offers custom designed and manufactured products using their state-of-the-art CAD/CAM resources for all their ...
"Full-duplex radio ICs that can be implemented in nanoscale CMOS to enable simultaneous transmission and reception at the same frequency in a wireless radio were first invented last year by Columbia Engineering researchers. That system required two antennas, one for the transmitter and one for the receiver. Now the team has developed a breakthrough technology that needs only one antenna, thus enabling an even smaller overall system. 'Our circulator is the first to be put on a silicon chip ..."
NuWaves Engineering, an international RF and microwave solutions provider, announced the upcoming release of an upgraded broadband RF PA for VHF to S-band transmitters and data radios, the NuPower™ 11B02A model, featuring high power efficiency and multi-octave operation in a compact package. The NuPower 11B02A model, part number NW-PA-11B02A, will replace the NuPower Mini Multi-Octave Power Amplifier model, part number NW-SSPA-MINI-10W-0.225-2.6, delivering a minimum of 7 Watts, and typically 10 Watts, of RF power from 225 to 2600 MHz when driven with a 3 dBm RF input signal ...
"The microscopic world is governed by the rules of quantum mechanics, where the properties of a particle can be completely undetermined and yet strongly correlated with those of other particles. Physicists from the University of Basel have observed these so-called Bell correlations for the first time between hundreds of atoms. Their findings are published in the scientific journal Science. Everyday objects possess properties independently of each other and regardless of whether we observe them or not. Einstein famously asked whether the moon ..."
Kite- and balloon-lifted antennas are very popular in the amateur radio realm. They are primarily used for short-term activity such as during a contest or during an emergency; however, some operators use them on a more extended basis. A really good series of articles on the use of balloons and kites for suspending antennas can be found here. Equations for calculating necessary balloon and kite sizes and predicting wind effects are included along with lists of 'Dos' and 'Don'ts.' This is not a new phenomenon. A 1940 edition of QST magazine described how to employ weather and sounding balloons to provide needed antenna configurations ...
"Buried in the wilderness between microwaves and infrared light is part of the electromagnetic spectrum known as the terahertz gap. The term comes from the relative lack of wireless technology that is capable of transmitting or receiving these ultra-high frequency bands. Now, researchers from the Ecole Polytechnique Federale de Lausanne (EPFL) and University of Geneva have invented a graphene filter that could make terahertz antennas more efficient and practical. The new microchip blocks out rouge signals that interfere ..."
A lot of people view the videos I post of giant scale radio controlled model airplanes, so this one should be of interest. It shows a Russian Antonov AN-225 performing a mid-air launch of a piggybacked Buran spaceplane (which by pure coincidence looks like the U.S. Space Shuttle). Drama ensues during the separation phase. As is often the case, we thank our German modeling brethren for for this magnificent craft ...
"The Army has been speeding up its global satellite constellation, designed to give soldiers quick access to global communications using portable equipment, into service. The Wideband Global Satellite, or WSG-1, operates at 12 times of the speed of the legacy Defense Satellite Communications System. Users in the western Pacific recently transitioned to WSG-1 following six months of testing, the Army said in a release. DSCS, which has been in operation since the 1960s, with the latest versions launched in the 1980s and '90s, transmitted ..."
"A team of researchers from across the country, led by Alexander Spott, University of California, have built the first quantum cascade laser on silicon. The advance may have applications that span from chemical bond spectroscopy and gas sensing, to astronomy and free-space communications. Integrating lasers directly on silicon chips is challenging, but it is much more efficient and compact than coupling external laser light to the chips. The indirect bandgap of silicon makes it difficult to build a laser out of silicon, but diode lasers can be built ..."
Anatech Electronics (AEI) manufactures and supplies RF and microwave filters for military and commercial communication systems, providing standard and custom RF filters, and RF products. Standard RF filter and cable assembly products are published in our website database for ease of procurement. Custom RF filters designs are used when a standard cannot be found, or the requirements dictate a custom approach. Please visit Anatech today to see how they can help your project succeed!
KR Electronics has introduced a new 1100 MHz bandpass filter design, part number 3260-1100. The filter has a minimum 2 dB bandwidth of 400 MHz. An elliptic type filter is used for high selectivity. Typical insertion loss is 1 dB . The filter is supplied in a small surface mount package measuring .2" x 0.38" x 0.25". Other frequencies and bandwidths are available. Please visit KR Electronics today to see whether their products can be of use to you.
"Pentagon-funded researchers have achieved a breakthrough that could double the capacity of wireless communications, leading to faster Web searches and downloads, by allowing devices to send and receive signals with a single antenna. Smartphones and tablets tend to use at least two antennas for transmitting and receiving signals. But Columbia University electrical engineers, working as part of DARPA's Arrays at Commercial Timescales (ACT) program, have managed to miniaturize the electronic components and get radio frequency signals to work in ..."
Sci-fi writer William F. Jenkins, who went by the pen name "Murray Leinster," wrote a short story titled A Logic Named Joe, that appeared in March 1946 issue of Astounding Science Fiction. In the story, an amazingly prescient description of the modern Internet is laid out. The works is copyrighted so I will not replicate the entire thing here, but these are a few excerpts that sound a lot like Mr. Leinster was in cahoots with DARPA during the development ...
Many great new RF-type magazine articles that have appeared in the trade magazines in the last couple weeks. Since the majority of people no longer receive paper copies of the magazines, I try to drive a little traffic to their websites by highlighting titles that appeal to my interest and like-minded RF Cafe visitors ...
Virtual Thru-Reflect-Line (TRL)
Calibration, J. Penn
• Process Wide Bandwidths in
• Multi-Tone Testing Multiplies Test
Solutions, C. DeMartino
• First Pass Success with ASICS,
A. Rehman <more>
Peregrine Semiconductor has created a quiz titled "What's Your RF Integration IQ?" that tests your knowledge on RF SOI (RF Silicon on Insulator), MCMs (Multi-Chip Modules), Intelligent Integration, the Ron Coff figure of merit, MPAC (monolithic phase and amplitude controller), and other topics. The winner, which will be announced at IMS 2016, gets awarded $500. Attendees at the IMS show can submit their information at the Peregrine booth (#2129) for another entry into the $500 giveaway.
PMI Model No. PEC-53-12-10-15-SFF is a 1.0 to 2.0 GHz LNA. This amplifier has a minimum gain of 53 dB with ±0.75 dB flatness, OP1dB of +16 dBm minimum and a noise figure of 0.7 dB typical. PMI Model No. P4T-100M50G-100-T-RD is an absorptive, SP4T PIN diode switch operating over 0.1 to 50.0 GHz, with low insertion loss, high isolation, and a TTL compatible. Specifications include insertion loss of 5 dB @18 GHz and 14 dB @ 50 GHz, Isolation of 80 dB @50 GHz, switching speed of 50 ns max, input power 20 dBm CW ...
"Nikola Tesla conjured up all sorts of interesting experiments for his famed 'Tesla Coils.' Today, however, their main use has been relegated largely to impressing visitors at science museums. That is about to change. Researchers at Rice University have used Tesla coils to get carbon nanotubes to self-assemble into long chains, a phenomenon the scientists have dubbed 'Teslaphoresis.' Controlled assembly of nanomaterials from the bottom up could be useful in applications including regenerative medicine where the nanotubes would act as nerves as well as fabricating electronic circuits without touching ..."
At first I thought maybe this was intended to be an April Fools joke, being that it appeared in an April issue of QST, but it is probably just a coincidence. One of the two topics refers to a 'door knob for UHF,' which in reality was a glass-encased vacuum tube that was shaped a lot like one of the old glass door knobs. The author penned a humorous take-off. On second thought, maybe this is a Fool's edition now that I have read the second item. All kidding aside, "Strays" concludes with a poem dedicated to those who became 'Silent Keys' as a result of World War II ...
"University of Tokyo researchers have developed an ultrathin, ultraflexible, protective layer and demonstrated its use by creating an air-stable, organic light-emitting diode (OLED) display. This technology will enable creation of electronic skin (e-skin) displays of blood oxygen level, e-skin heart rate sensors for athletes and many other applications. Integrating electronic devices with the human body to enhance or restore body function for biomedical applications is the goal of researchers around the world. In particular, wearable electronics need to be thin and flexible to minimize impact where they attach to the body ..."
Peregrine Semiconductor, founder of RF SOI (silicon on insulator) and pioneer of advanced RF solutions, introduces two UltraCMOS® MPAC–Doherty products—the PE46130 and PE46140. These monolithic phase and amplitude controllers (MPAC) join the PE46120 in offering maximum phase-tuning flexibility for Doherty PA optimization. Designed for the LTE and LTE-A wireless-infrastructure transceiver market, the MPAC–Doherty product family now extends from 1.8 to 3.8 GHz with three separate, pin-compatible parts. "Phase and amplitude control is critical to the future of communications, where everything from LTE and 5G to radar will rely on the efficient exchange of data ...
"The U.S. military is pouring money into hypersonic research, and it’s making China and Russia - which have their own similar programs - nervous. But the accelerating effort to build missiles that fly at speeds between Mach 5 to Mach 19 is also alarming some in the nonproliferation community. Despite Pentagon officials' assurances that superfast weapons will carry only conventional warheads, some believe that other nations may well treat any hypersonic launch as a potential nuclear strike ..."
This quiz is based on the information presented in Spectrum and Network Measurements, 2nd Edition, by Robert A. Witte. "This comprehensive treatment of frequency domain measurements successfully consolidates all the pertinent theory into one text. It covers the theory and practice of spectrum and network measurements in electronic systems. It also provides thorough coverage of Fourier analysis, transmission lines, intermodulation distortion, signal-to-noise ratio and S-parameters."
"The Aerospace Corp. the people who brought you the concept for GPS, are launching GPS 2.0. It all began when two Aerospace Corps scientists J.R. Woodford Woodward and H. Nakamura penned a little-known briefing In 1966, 'Navigation Satellite Study,' that paved the way. Tomorrow, the Aerospace Corp. will issue a new study it hopes will pave the way for the next wave of GPS, one much more resilient, much more resistant to jamming and tampering but boasting accuracy that is at least as good as the current satellite-dependent system ..."
"The map below tracks what we know, based on press reports and publicly available documents, about the use of stingray tracking devices by state and local police departments. Following the map is a list of the federal agencies known to have the technology. The ACLU has identified 61 agencies in 23 states and the District of Columbia that own stingrays, but because many agencies continue to shroud their purchase and use of stingrays in secrecy, this map dramatically underrepresents the actual use of stingrays by law enforcement agencies nationwide. Stingrays, also known as 'cell site simulators' or 'IMSI catchers,' are invasive cell phone surveillance devices that mimic cell phone towers ..."
KR Electronics has introduced a new 1550 MHz bandpass filter design, part number 3260-1550. The filter has a minimum 1.5 dB bandwidth of 500 MHz, with stopband rejection maintained to 9 GHz. Typical insertion loss is <1 dB. The filter is supplied in a small surface mount package measuring 0.88" x 0.38" x 0.235". Other frequencies and bandwidths are available. Please visit KR Electronics today to see whether their products can be of use to you.
"Don't get me going on this, or we'll be here all day, trust me." - Justin Trudeau, Prime Minister of Canada, after responding to a snarky comment by a reporter who asked, "I was going to ask you to explain quantum computing, but - when do you expect Canada's ISIL mission to begin again, and are we not doing anything in the interim?" Trudeau slapped him down by answering, "Very simply, normal computers work by either there's power going through a wire, or not. It's 1, or a 0, they're binary systems. What quantum states allow for is much more complex information to be encoded into a single bit." He then talks about matter being both particles and waves at the same time, etc. This, from a politician? Whoa.
"Scientists at Rice University have discovered that the strong force field emitted by a Tesla coil causes carbon nanotubes to self-assemble into long wires, a phenomenon they call 'Teslaphoresis..' The team led by Rice chemist Paul Cherukuri reported its results this week in ACS Nano. Cherukuri sees this research as setting a clear path toward scalable assembly of nanotubes from the bottom up. The system works by remotely oscillating positive and negative charges in each nanotube, causing them to chain together into long wires. Cherukuri's specially designed ..."
Here is a fairly major treatise on folded and loaded antennas that appeared in a 1953 issue of QST magazine, with "Suggestions for Mobile and Restricted-Space Radiators." It is not for the faint of heart or anyone with mathphobia. Integral calculus is part of the presentation, although an understanding of calculus is not required to get the gist of the article. Equations for calculating the antenna configuration radiation resistances are given for the 3λ/4-wave folded dipole, the λ/8-wave folded monopole, the bottom-, center- and top-loaded λ/8-wave monopole, the bottom-loaded λ/16-wave monopole, and the λ/4-wave monopole folded twice, to name ...
"Facebook's goal of networking the world means extending communications to everyone on the planet. Facebook has started to test new approaches to ground-based systems. And it's continuing to work on its futuristic drone-based communications system, Aquila. At the company's F8 developer conference held in San Francisco today, Facebook vice president of engineering Jay Parikh talked a little more about Aquila's development, and how it would use laser links to bring the internet to rural areas in developing countries. According to Parikh, Facebook's UAV platform looks like a giant boomerang. 'We need to fly ..."
Cobham Antenna Systems is pleased to announce the FPA-0.7-2.7R/2319,, which is the first in a new range of high power, directional spiral antennas. The FPA-0.7-2.7R/2319 offers high power, high gain and circular polarisation within a compact, low profile, rugged housing. It is suitable for multi-band communications as well as cellular countermeasure and security applications. The low profile housing means that this antenna can be used to replace much larger and more expensive, Log-Periodic, Horn or Conical spiral antennas and also be used in situations where height/profile is critical ...
""'A revolution is happening in the textile industry,' said engineer Professor John Volakis. 'We believe that functional textiles are an enabling technology for communications and sensing, and even medical applications like imaging and health monitoring.' While looking into using fabric techniques to make brain implants with scientist Asimina Kiourti, he and she decided to apply their ideas to create wearables antennas. 'We asked, how can we functionalise embroidered shapes? How do we make them transmit signals at useful frequencies?' said Volakis ..."
Author Howard Wright takes the opportunity here to distill the concept of modulation down to its basic operation while dispensing with the garbled mix of "graphs, formulas, charts, vectors, diagrams, and Greek letters which often enter into various discussions of modulation". Wright describes how to the uninitiated radio dial spinner, the culmination of events occuring behind the scenes in an AM reception is akin to knowing "that, to be reproduced, the picture [in a magazine] was broken down into its primary colors, if all we had to go by was the original print and the magazine?" That is a very apt comparison ...
""Because we're nearing the end of tax season here in the United States, I decided to examine the often volatile combination of tax policy and IT systems. Tax-related problems are some of the most painful IT failures, because they tend to hit citizens right where it hurts most: their bank accounts. Below you'll find some of the most noteworthy operational glitches of the past decade, but as with previous timelines, the incidents listed here are merely the tip of the iceberg, and should be veiwed as being representative of tax-related IT problems rather than comprehensive. It doesn't even include incidents of tech-assisted fraud, data breaches, or failed modernization projects ..."