RF Cafe Software
About RF Cafe
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 ...
All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.
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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
mount electronic components were around long before the 1980s miniaturization craze began. The surface used for
mounting this 70 kW FM constant impedance high power 3 dB combiner / bandpass filter from Jampro is made of concrete
- about 6 inches of it... with rebar. In the realm where most of us work, we pressure vendors to trim fractions
of an inch off packages in order to reclaim a few pitiful fractions of a square inch on a PCB; these babies need
square yards of space. Insertion loss is a mere 0.08 dB in WB operation. Something like that would make a nice addition
to your drawer of lab test components. Now, who sells a between-series 6-1/8" EIA - to - SMA connector adapter for
that? BTW, 0.08 dB at 70 kW represents a 1.3 kW heating loss.
Here is a new approach at recycling e-waste - turn it into functional furniture. This coffee table was hand fashioned from black walnut, glass, and a bunch of old computer motherboards - most from an Intergraph 6000 machine - that designer / builder GuyInMilwaukee had in his junk box. The website with his original posting is out of service, but a great series of photos was put on another site that shows details. All of the PCBs are attached to an inner structure that sits inside the other. Here is a PCB-based chair from a different craftsman that might go well with it. If I had the parts, I would try building a similar glass table with a maze of waveguide inside.
Here is one of the many advantages of serving on the International Space Station (ISS). This photo of the Aurora Australis (Southern Lights) was taken over the Southern Indian Ocean at an altitude of 350 km. The story did not mention the length of the exposure. The curve of the Earth and the blue light of the atmosphere can also be seen. There is also an earth-based photo of the Aurora Australis as seen from the South Pole. Ham radio guys hear warble on the HF bands during trans-polar communications that is caused by the rapidly changing conduction properties.
is an impressive collection of radio superstars made during a visit to RCA's experimental Transoceanic Communications
Station in New Brunswick, NJ, in 1921.The usual suspects are in attendance: David Sarnoff
(radio/TV pioneer), Dr. C. P. Steinmetz (mathematician
/ engineer), Dr. Irving Langmuir (physicist), Dr. Albert W. Hull (photoelectricity),
Dr. Saul Dushman (thermionic emission), and R.H. Ranger
(RCA engineer). But, who's that dude left of center with the black cowboy hat,
looking like the villain in an old silent movie? It is none other than Albert Einstein. This photo is in the front
of Cornell Drentea's new book, "Modern
Communications Receiver Design and Technology."
You have seen the human evolution chart showing man's progression from lungfish crawling out of the primordial ooze all the way to homo sapiens. You have probably also seen the humorous chart of similar style where the knuckle-dragging, hunched-over primate transitions to erect man, only to end up hunched over again - this time in front of a computer. Well, I found another evolutionary rendering that appears to be a fairly accurate representation of recent, short-term evolution. It singles out software engineers, but the harsh reality tends to apply to a majority of folks in the technical fields where long days (and nights) are spent in cubicles and labs. Look around you.
"Art is in the eye of the beholder," as the saying goes (oft borrowed from the original saying about beauty). Not normally one to be impressed with impressionistic and neo-anything art, I am, however, stricken with awe by many of the subjects with origins in the fields of science. Shown here is a plastic transistor. I'm not sure whether the conductors are really green, or if false color is being used to subliminally imply the eco "greenness" of the product. Princeton University's fourth annual "Art of Science" exhibition also includes images of magnetic reconnection, an optical trap, and the winning Xenon Plasma Accelerator.
NASA recently released this map of airborne particulate matter concentrations, as detected from satellites. It shows areas of the earth where the population is exposed to potentially dangerous levels of pollution. Red areas bad, blue areas good. I suggest that it is also a map of something else - where manufacturing is occurring across the globe. Note the nearly total blue of North America - even with all the evil SUVs and pickups roaming the roads. So, as you open your 99th unemployment check this week and despair over the lack of a future in America, take solace in knowing that your air is not as dirty as those who are actually working. Red areas good, blue areas bad.
The July/August edition of Discover magazine has a story about the SETI Institute's history of placing calls to and hoping to answer calls from extrasolar inhabitants. This is SETI's 50-year anniversary. In April 1960, astronomer Frank Drake first began listening for intelligent radio signals from the star Tau Ceti, in the constellation of Cetus, the whale. Drake and Carl Sagan famously sent a message from Arecibo in 1974, pointed at the Messier 13 globular cluster. The above photo is a shot of a control room patchboard at SETI for selecting Butterworth or Gaussian filters of various center frequencies and bandwidths. It appears from the amount of wear on the Gaussian channels that they get the most use. Seeing as how no discernable message has been received to date, maybe it's time to install a panel of Chebyshev or raised cosine filters.
A couple years have passed since I posted my first collection of science and engineering themed tattoos. It does not take long these days for many more examples to appear on the Internet. One of the biggest challenges is verifying that the tattoos are real, and not Photoshopped or penned on. One guy liked the Moog synthesizer active ladder filter so much that he had it permanently emblazoned on his arm. Another has a binary ASCII code on his side (I decoded it for you).
sent me a link to this web page titled "Soul-Crushing Cubicles." A few look staged, but unfortunately for the occupants,
many appear to be as advertised - genuinely soul crushing. Being easily distracted while trying to concentrate,
I would never survive in such an environment. Most cubicles I have been assigned to have been about 8x12 feet, which
was good enough for me. I've had two offices with doors in my career - one at Comsat and the other at Harris. While
cubicles might seem inhumane in some ways, it is better than the pre-cube days when huge open rooms full of desks
were the norm. I remember an old engineer who worked at Boeing in Seattle describing expansive engineering offices
with desks butted together where you faced the other person, and the lines of desks stretched as far as the eye
could see. So, it could be worse.
A while back I posted information about the big money that is paid to marketing firms for creating effective, memorable, and if appropriate, clever logos for companies. That goes for both design and color selection. Someone sent me an e-mail recently with examples of some really slick logos that have secondary messages integrated into the design. The Sony Vaio logo is a good example where it combine an analog shaped "VA" and a digital 1 and 0 for "IO." An Internet search for more turned up the same group of logos everywhere, so I looked through my collection of company logos on RF Cafe and discovered many by electronics companies worthy of note.
Google Earth continues to amaze... as well as frustrate. Since its launch in 2005, casual observers have been mesmerized by the incredibly high resolution images garnered from the spaceborne cameras, while industrial and military entities have been horrified to see their facilities' secrets laid bare. Nowadays, there are people exploiting the technology to their own advantage by creating earthscapes in hopes of being imaged. This roof shot is of the Ford plant in Detroit. The link goes to a slideshow with lots of examples of natural and manmade subjects. Of course the really amazing thing is that if this level of detail is available for the public eye, just imagine what the capabilities of military imaging exists.