RF Cafe Software
About RF Cafe
1996 - 2022
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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These images have been chosen for their uniqueness. Subject matter ranges from historic events, to really cool phenomena in science and engineering, to relevant place, to ingenious contraptions, to interesting products (which now has its own dedicated Featured Product category).
Cool Pic Archive Pages
Making the Modern World website is a great collection of photos exemplifying devices that helped form the
world in which we live. A good example is John Fleming's
valve shown here. He invented it in 1904 while at the Marconi Company. Add a grid to control electron flow and
you've got Lee De Forest's signal-amplifying
triode valve (Audion). Edison's Earth-destroying
filament lamp is another example. Have you seen a picture of
radiometer rather than just a sketch in your second-semester physics textbook? Here is Faraday's original
and coil from which he formulated his laws of electromagnetic induction., This is another one of those websites
where once you start browsing through the images, you will find it hard to stop. You'd better save this one for
Maybe I should pay more attention to what is on the shelves when going grocery shopping with Melanie. Whilst strolling through the produce section of the local Wegmans supermarket, I noticed an impressive example of mathematics in nature called Romanesco broccoli. Its shape just screams "fractals" at you when you see it. The apparent order and symmetry is amazing. In all the reading I have done over the years on fractals and Mandelbrot sets, for some reason I do not recall ever seeing Romanesco broccoli as an example in nature. Tree leaves, ice crystals, lightning bolts, and even continental shorelines are often offered, but broccoli? Heretofore when I thought about broccoli, the stuff that looks like a brain stem came to mind - not much order apparent in that stuff. While in general my food preferences were formed and have remained pretty much unchanged since about age 15, I think sampling some Romanesco broccoli is in order, almost required. Who knows, perhaps it is a real brain food like fish and seeds and may even improve my math skills.
Steve Jobs worship is such an established religion that I'm surprised Apple Computer never received 501(c)(3) status with the IRS. Buying Apple products could have been deductible as a charitable expense if the accountants on staff had put a little effort into it. Just like with the over-zealous religious fanatic in the office break room, I have always felt a little embarrassed for the person who dotes over his new iPhone or has to constantly remind us infidels how our PCs running Windows (excuse the bad language) pale in every aspect compared to his Mac-this, or i-that. When a new version of the MacOS is released, it is as if a new chapter of the Bible had just been discovered in a cave in Jerusalem. Now, I wish the best of health for Mr. Jobs, and truly admire his accomplishments, but let us admit here and now that a large part of his success is due to the unwavering dedication of iBots. Prosecuted computer hackers are on record for specifically <more>
you seen the strange patterns imaged over China's Gobi desert by the Google Earth satellite? It first hit the news
cycle late last week. Unlike the Martian "canals"
sketched and reported by Percival Lowell, these surface marking are not artifacts of a faulty interpretation. The
tin hat crowd immediately concluded that it is evidence that China has been visited by space aliens
(too far for illegal aliens from Mexico to travel), and that is why China has
been able to build up its infrastructure so rapidly in the last decade. Theories also abound about how the Red Army
(red = Communist, yes they are) has heretofore secret ICBM launch facilities spread
throughout the western mountains, just waiting for another American aerospace company to provide the final
technology needed to launch an offensive against the U.S. In reality, real experts say they are likely calibration
targets for Chinese spy satellites. The 65'-wide, silver-painted lines follow natural drainage channels in the landscape.
Of course, the U.S. can also use them for alternative calibration to learn how China sees the world. If you pan
widely around the area, you will find all kinds of other interesting structures.
This is a test. One of these offices belonged to Albert Einstein at the Institute for Advanced Study, at Princeton, New Jersey. The other belonged to Bob Pease at National Semiconductor. Both photos were taken very soon after their owner's departures. Don't bother trying to guess the answer based on an assumption that Pease's office will be easy to spot because there will be a computer on the desk. Bob notoriously detested computers, and desktop computers had not been invented in Albert's time. Both men used the same form of PowerPoint presentations - transparencies on an overhead projector. Both men carried out most of their laboratory computations with a paper and pencil. The Princeton Professor had no choice; the Sage of National did so because he believed that new generations of engineers were quickly losing or never had the ability to analyzed circuits without the help of a computer. This, of course, invokes the old adage, "If a cluttered desk is the sign a of a cluttered, mind, what is an empty desk the sign of?"
A familiar pipe on an open book, a cluttered desk and a blackboard covered with mathematical equations surround the empty chair in Dr. Albert Einstein’s office at the This photo was taken on April 18, 1955, the same day that the famous physicist died of a gall bladder ailment at age 76.
If you appreciate vintage military radios, then you will definitely be interested in the collection at the Duxford Radio Society's display at the Imperial War Museum, England. Racks and shelves there are densely packed with HF, VHF and UFH radios, oscilloscopes, signal generators, meters, power supplies, and intercom systems. There is even a flight navigator training simulator. Most of the gear is British, but there are a few examples of captured German equipment. Many photos of restored (from non-working condition) and conserved (cleaned and shined) radios are available, as well as some work in progress. One of the earliest airborne radar systems, the APS-4, which was mounted under the nose of a Fairy Firefly of the Royal Navy Fleet Air Arm, is being restored. The frequency used was approximately 9 GHz with a pulse duration 0.6 μS and the pulse repetition frequency adjustable to either 600 or 1000 cps. The peak RF output power was 40-70 kW. That's pretty advanced for 1943! I swear the old dude sitting in the chair is sound asleep. I'm guessing he actually operated or designed some of that equipment.
idea is interesting, but I believe the results as presented fall woefully short of real science - certainly not
worthy of a full page in Scientific American without a disclaimer. "Physics or Fashion? What Science Lovers Link
to Most" shows interconnections between Internet visitors to 600 different science and math related websites and
where they are likely to go from there. The chief scientist at "bitly" (they create shortened
URLs) plotted information gleaned from their users to conclude, for instance, that people who frequent technology
visit fashion website upon leaving, while visitors of religion, chemistry, and statistics websites have little interest
in fashion (ok, well, we don't need a formal study for that conclusion). Many
problems with the methodology are apparent, the most glaring of which is the extremely limited sample size (<0.0000001%
of Internet users) over an extremely limited time (2 days = 0.6% of year), using only their clients' data. My guess
is most paths to fashion and health websites come from Google type banner ads. What are those ads likely to show
in August? Girls in swimsuits and halter tops, and pharmaceuticals offering miracle 4800Å pills. Click, click, click.
Let's face it, most patrons of tech websites are male, many of which are held captive inside labs and cubicles all
day and all week long. It's a nice picture, but we need more data.
Warning to Apple supremacist sycophants (Ass): This smartphone story does not feature an iPhone. It is about an amputee who had a custom prosthetic arm made to hold his Nokia C7. Trevor Prideaux was born without a left arm. Being the manager of a catering service, he relies heavily on his smartphone for schedules and contacts. As you can imagine, holding the phone with a claw while pressing buttons was cumbersome and time consuming. So, Trevor solicited the assistance of Nokia and prosthetists at the Exeter Mobility Centre. "My Nokia C7 sits within my forearm between my stump socket and the single knob rotary that holds my limb attachments in place. Now when I get a call, I can either hold my arm up to my ear or put it on speakerphone. I can also take it out if I need to." Apple, btw, was contacted first but refused to help; Nokia assisted gladly. If you are an Ass and read this anyway, you might need to take a pill and lie down now.
20 Companies. 30 Years. 575,457 Jobs. That is the title of this chart published by Inc. magazine demonstrating how fast-growth start-ups are major job creators. It's not just the Oracles - 38 employees in 1984 to 104,500 in 2011 - that have given thousands of people work over the years. Papa Johns pizza chain had 40 employees in 1991 and today has 16,000. Their story is printed on the side of their pizza boxes (at least the last time I bought one it was). That pales in comparison to Domino's Pizza, who went from 500 in 1983 to 145,000 in 2011 - that beats Oracle. Qualcomm went from 436 employees in 1991 to 15,106 this year. Intuit, the TurboTax and QuickBooks people, grew from a staff of 110 in 1983 to 7,700 this year. You will probably recognize everyone on the list. These 2011 numbers are probably lower than they were a couple years ago due to a lot of layoffs, particularly for the tech companies. Many executives from top companies like these say massive, burdensome government regulation is killing their established businesses, while impeding and even preventing new start-ups from succeeding. While whining publically about lack of job creation, the politicians continue to pass laws guaranteeing things will never get better, and then send neo-hippies to Wall Street to protest.
probably immediately recognized this as a simple deterministic model illustrating the geomagnetic reversals. I know
I did (not). It's one of those strange attractor phenomena that goes by the title
Chaos and Geomagnetic Reversals. I have to admit, though ,that The Buddy System: Two Fish Swimming
Side-by-Side had me stumped. These and other images are part of Princeton University's annual "The Art of Science"
contest. The 2nd place entry from the Electrical Engineering department titled Tree, illustrates software
for a deconstruction algorithm that splits images into sub-images in a way that best captures important structures.
Per Mr. Xiang, "For each input image, our algorithm finds the dyadic tree that gives the most concise representation
of the image as measured by its Haar wavelet transform coefficients computed on this tree." Makes sense... why didn't
I think of that?
No, it's not an insect egg. This is a top view of the U.S. Air Force's latest monster airship, codenamed "Blue Devil Block 2." If you click on the thumbnail, you will see a tiny truck off to the left; that's an 18-wheeler tractor trailer! Sporting a 370-foot length and containing 1.4 million-cubic feet of helium, this blimp will be "parked" at an altitude of up to 20,000 feet near battle zones. Its massive suite of surveillance will include multiple types of radars, and optical, acoustic, and electromagnetic listening devices, covering as much as 36 squares miles. It can remain airborne for up to five days at a time. Though designed to operate remotely as an unmanned platform, it is capable of hosting a human crew. MAV6, a somewhat stealthy group, seems to be the architect and builder. According to their website, Blue Devil Block 2" is an "airship-based C4ISR aerial fusion node (and weapon system platform) integrating multiple distributed and local sensors with on-board processing ! into a common operating picture!." I sure hope the thousands of missing shoulder-launched missiles from Libya can't fly that high!
The U.S. government has published a series of National Broadband Maps that present various statistics on Internet service. The one shown in this thumbnail covers consumer broadband test speeds versus advertised speeds. Red indicates slower than advertised, green better than. Notice that at this scale you cannot even see any green. Even at full scale, green areas are tiny dots. The U.S. has long been way behind the curve on Internet speeds compared to places like South Korea (N. Korea doesn't even have a word for Internet yet). If you look at the advertised speeds map, most areas are advertising 6 MBPS or greater. To get those speeds in most places you have to pay for a premium service. I pay $52/mo. for 14 MBps (typically get about 13 MBps). That is the download speed. Upload is for some reason pathetically slow. Even with premium service, my upload is about 500 kBps. Since I do a lot more uploading than most people because of publishing RFCafe.com and AirplanesAndRockets.com (and a couple other smaller ones for family members), the slowness is very noticeable. According to a chart on Gizmodo, Japan has the highest speeds (61 MBps), France is #5 at 18, Canada is #8 at 7.6, the U.S. is #15 at 4.8. Mexico and Greece appear to still be on dialup.