1996 - 2016
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...
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This collection of video and a few audio files represents files that have been featured on the RF Cafe homepage. Every week or so a new file is added that should be of interest to RF Cafe visitors.
Please send me an e-mail if you have a good subject. Note: "Videos for Engineers" formerly went by the name "Cool Videos."
you are going to play a public joke on your boss, especially when he is a Nobel Prize winner, you had better
be certain that he has a good sense of humor. Evidently co-workers of 1978 physics laureate Arno Penzias were
pretty confident that he was the jovial type. Penzias and fellow scientist Robert Wilson, you may recall,
famously discovered the primordial background cosmic radiation while attempting to get rid of low level noise
in a high sensitivity radio telescope receiver that they designed for a horn antenna at Bell Labs. According
to the credits at the end, in 1990 Bell Labs engineers Rob Pike and Dennis Ritchie (C language inventor)
arranged with magicians Penn (Gillette) and Teller to devise a trick where they would convince Mr. Penzias
that they had developed an artificial intelligence software program that was capable of answering his
questions after speaking to the computer. It was to represent leading edge voice recognition. Keep in mind
that this is 20+-year-old technology, so don't expect anything
too whiz-bang. The video is displayed on what appears to be a monochrome, SVGA CRT, and the jerkiness of the
motion is reminiscent of the Max Headroom type production typical of futuristic movies of the era...
A friend who has been an RF design engineer working in the smart meter industry since its inception sent me this video of Itron's (a competitor of his) smart meter production facility in Oconee, South Carolina. My first response upon viewing the video was gratitude to Itron for actually locating the plant in the U.S.! Then, I settled in to enjoy the high quality of the video production by the crew from How It's Made.
If you have never been in an electronics assembly environment, you cannot fully appreciate the capability of these automated machines. Bare printed circuit boards have solder paste silkscreened onto them via an automated process that guarantees repeatability, and then are moved to the assembly area. BTW, equally amazing is the process used to manufacture the PCB itself (at another factory). The speed and accuracy of the pick-and-place machines is mesmerizing; I find myself staring in awe while watching the head pick up the component from the feed tape (sometimes after visually verifying the component by its markings), position itself over the PCB, rotate for proper orientation, deftly place the component into the screened-on solder paste footprint pattern, then zip over to pick up the next part and repeat...
It is amazing how much of what was merely science fiction a few decades ago is now reality. This video of a swarm of 20 nano quadrotors developed by researchers at the University of Pennsylvania's General Robotics, Automation, Sensing and Perception (GRASP) Lab is reminiscent of something out of Star Wars or The Matrix. Not only are the tiny flying machines autonomously stable, but they can fly in formation either as a fixed shape moving simultaneously from location to location, but they also move in a dynamic formation like marquee lights. Their multiple electric-powered propellers make a high speed droning sound like bees, adding to the ominous presence that a militarized version would present to an aggressor. IT's quite cool and quite spooky at the sme time. A company called Kmel Robotics is credited with building the nano quadrotors. I want some.
In case you missed the big event, last Sunday Google launched what they consider a disruptive technology with their new Gmail "Tap" cellphone app. Google claims that this new concept is more efficient by virtue of its simpler user interface that uses just two keys rather than the 40 or so normal keys that include one for each letter of the alphabet, numbers, and special characters. Because only two keys are needed, they can be made large enough to press blindly, even while in the user's pocket. Just as texting shortcuts (omg, lmao, cul8r, etc.) speed up typing by fewer characters requires you to learn a new "language," Gmail Tap also requires you to memorize a character set. Once you commit it to memory, though, you're gtg (good to go). This is on the Tap app homepage to extoll its virtues: "Two keys: dot and dash. Space bar: added to increase typing speeds. Multi-email mode: dual threaded keyboard. (Warning: power users only) Predictive text mode: autocomplete re-imagined. Optional audio feedback: engage all your senses." Widespread adoption of the new technology will drive future improvements in the app, like: "Ship to shore mode: activates your phone's flash to communicate with other power users across an ocean (of people). Table tap: microphone enabled off...
I personally don't understand the i-Everything craze, but then idol worship has never been my bailiwick. The religion is as alive and well in China as it is everywhere else. Maybe it's partly due to national pride since most- if not all - of Apple's products are made there. The problem is that workers who make the products usually cannot afford to buy them. It's like the old story about the Chinese workers who cannot afford the Barbie dolls and Nike sneakers that they spend long hours manufacturing. Our government hands out free cellphones, complete with service plans, to welfare recipients who do no work at all for their bounty, while many of the honest workers of China have none. As with any other product or service in high demand but largely unaffordable, there is a thriving black market for iPhones in China. Trafficking "mules" gamble on their livelihood (and maybe their lives) while smuggling iPhones into mainland China from Hong Kong. According to this report, iPhones cost $150 more in China than in Hong Kong, so for a profit of a few dollars each (they would have to sell for far below market value on the black market), the smugglers risk a run-in with a Communist, totalitarian government police force...
The development of radar by the British and Americans during World War II was undoubtedly a key factor in preventing Hitler's forces from destroying and dominating the world. Once his ground forces had invaded western and southern Europe and spread toward the eastern seaboard, the main task remaining was to take England and Ireland. The English Channel prevented a relatively simple land invasion, so the Luftwaffe undertook an air campaign both in the form of massive bombing raids and the terrible V1 Buzz Bombs and V2 rockets developed by Werner von Braun's team. Scotsman Robert Watson Watt was commissioned to create a microwave "death ray" to shoot down the German aircraft and rockets, but his investigations showed that microwaves would be more effective employed in the form of radar to give advanced warning of approaching squadrons. That gave RAF pilots time to get airborne and go out to meet the enemy before it could reach British shores. Of course, Hitler then made bombing the radar installations a priority. Just as Admiral Kurita made a fatal strategic decision during the Battle of Leyte Gulf by turning his fleet around, Göring... <more>
junk is becoming more of a problem on a daily basis. It is not necessarily that a new satellite or part of its
launch system is added each day, it's that there is so much junk floating around up there now that collisions
between existing components are continually creating new junk. In fact, if you look at the chart to the right
that appeared in the April 2012 edition of Scientific American ("Space Age
Wasteland: Debris in Orbit Is Here to Stay"), you will see that the multiplication effect will continue
to produce more space junk even if all new launches are halted immediately
(the lower line). The upper line extrapolates growth of space junk at the current rate of satellite
launches. Of course the dots shown are not in scale to the volume of space represented, but we know
empirically that collisions occur frequently. The North American Aerospace Defense Command
puts a lot of work into tracking space debris in order to predict reentry hazards, orbital collisions, and to
be able to differentiate between benign projectiles and hostile military projectiles. We hear a couple times a
year about the need to adjust the orbit of the International Space Station in order to avoid potential
collisions with orbiting space junk. Back when the U.S. wasn't a 3rd-world nation from the manned space
Product teardowns are a common part of the engineering cycle. Rarely are teardowns performed by the manufacturers (or at least not made public) since the truth is, they would prefer that nobody know how they do things. I don't blame them for not wanting their materials and methods known since a lot of money is invested in the process that leads to the end product. Fortunately for the rest of us, there is no law against performing and publicizing teardowns. I have a confession: I spent six years doing teardowns of competitors' products at my last job. Electrical parametric testing including RF performance and even ESD survival levels, identification of components used and estimating costs, x-raying and decapping IC packages, and even sanding down LTCC substrates layer-by-layer to determine construction of distributed and buried element values, generating schematics of ICs and complete assemblies, then writing sometimes extensive reports was my daily routine. It was the best job I've ever had as an engineer. So, when I see teardown reports and, in this case, a teardown video, my interest piques. In this video, a team of Avnet-sponsored Drive for Innovation engineers and technicians completely disassemble a Chevrolet Volt electric vehicle. The time-lapse video compress a couple full days of work into a little under 5 minutes. It is both instructive and entertaining to...
Dr. Francesco Fornetti has posted a very nice collection of tutorials on his RFMicrowave channel on YouTube. AWR's Microwave Office and Mathworks' Matlab serve as the simulation and calculation platforms. In the video represented by this thumbnail, a simulation demonstrates how a slotted line is used to find the maxima and minima, and how to model it in MWO. If you are relatively new to using Microwave Office, these videos are a great way to quickly learn where to find a lot of the parameter setting screens for building schematics and for making measurements. The entire presentation is narrated and real-time annotations are added on the workspace to aid in understanding the material - much like being in a college classroom. Topics include Microstrip Line, Coaxial Line, Basics of RF Simulations, and Introduction to AWR Microwave Office. Dr. Fornetti also runs Explore RF, which produces webinars like the upcoming Wide Bandgap Semiconductor Materials and Microwave PAs, on February 16.
2/15/2012Church of Apple congregants, please take no offense at this week's subject. No sacrilegious insult is intended (well, maybe just a little). In the continuing saga of "Will It Blend?" videos, the Blendtec Guy subjects a spanking new iPhone 4s to the rigors of a Blendtec Total Blender blender (is there an echo in here?). Watch for yourself as normally mild-mannered Tom Dickson casually ignores Siri's plea to spare his/her/its life, and without human emotion or compassion pushes the Smoothie button on the blender. That's right, a split second after a final entreaty to not "commit a terrible error," the gruesome disintegration ensues. What results is not a pretty sight - unless you happen to be trying to sell blenders that have the power to pulverize almost anything that can be crammed into them...
A few weeks ago, I posted a video of a manufacturing plant that builds smart meters. It is always cool to watch the automated pick-and-place machines pick surface mount components from tape reels and precisely place them on the printed circuit board. This video shows the assembly line for microprocessor-controlled motor controllers for brushless electric motors at Castle Creations. Business development manager Lee Estingoy starts out showing the silkscreening process for the solder mask, then moves on to the tape reels where the electronic components are fed to the pick-and-place machine. You get to see the amazing speed at which the robotic head places the parts onto the PCBs. He tells how a vision system verifies that each part is the right size and value and is oriented properly for placement. This particular speed controller has a daughter board assembly that gets inserted by a separate machine because of its relatively large size and weight. Some parts still need to be hand-assembled because they do not lend themselves to automated assembly (although there are machines to do the job if the budget can be justified). After all the parts are on the board, the assembly is fed into a reflow oven that melts and then cools the solder paste according to a temperature profile that has been optimized to assure proper flow and adhesion...
The SNL (Saturday Night Live) crew recently did a parody on Verizon's new 4G LTE commercial. A lot of people have been critical of the confusing, non-committal commitments to the glorious features of their new service. Of course most 4G LTE users have no idea what either 4G or LTE stands for, so that doesn't help matters. Good luck finding a succinct explanation of 4G LTE on the 3GPP website (there is no 4GPP, BTW). Even that global governing body cannot seem to provide a clear definition, so it's no wonder the carriers' messages are so garbled and obfuscatious. For the record, 4G stands for 4th generation cellphone standards, and LTE stands for Long Term Evolution, which is self-explanatory (if not excusatory). Verizon offers a web page for an OWS-level introduction to 4G LTE. Basically, 4G LTE boils down to "blazingly fast speeds." Truthfully, that's all the average user wants or needs to know. Well, there is one more thing he/she needs to know - the potentially very high phone bill when he/she chooses to ditch all other media services, including TV and wired Internet, to do everything via his/her smartphone.