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 ...
All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.
My Hobby Website:
Try Using SEARCH
to Find What You Need.
There are 1,000s of Pages Indexed on RF Cafe !
The inventions and products featured on these pages were chosen either for their uniqueness in the RF engineering realm, or are simply awesome (or ridiculous) enough to warrant an appearance.
All Featured Product Archive Pages:
saw this DIP-format (dual-inline-package) miniature oscilloscope display in an article by
Brad Thompson, of Test &
Measurement World (he finds a lot of good stuff). It definitely qualifies as a Cool Product. Per the XMEGA website,
"The Xprotolab is the first mixed signal oscilloscope with an arbitrary waveform generator in a DIP module.
It measures only 1 x 1.6 inches, and can be mounted directly on a breadboard." The capabilities are amazing
for the $49 (yes, forty-nine) device. Amongst the features: dual 200 kHz (2 MSPS) input channels with
8-bit resolution on -14 V to +20 V signals, X-Y mode for Lissajous display, 8 digital inputs for logic
analyzer mode, single 1 MSPS arbitrary waveform generator output including frequency sweep. Application
potential is huge, especially as a real-time monitoring function for baseband (for up- and down-conversion).
In his article, Brad likens the Xprotolab to the tiny CRTs (Model 913) that RCA offered in the 1930s. In 2012
dollars, they cost about $87 apiece - nearly twice the Xprotolab price - and the CRTs were just dumb devices.
For most people, including me, the introduction to a transparent computer display that interacts with hand and head gesturing began in 2002 with the movie "Minority Report." Such a concept was not out of the realm of possibilities ten years ago, but even so, the scenes were not "real" in that the display would have to be superimposed over the actor's phantom motions in front of a green screen. Now we have this video of a for-real transparent display that is being developed by Microsoft. Sensors on the back track airborne hand and finger movement for manipulating objects on the screen. The advantages over a touch screen are many, including not blocking your view of the screen, keeping fingerprints off the screen, and adding a third dimension to the action. It is tempting to think that something like this would be difficult to adapt to using, but that's what was said of the mouse when it was first introduced. My biggest problem would be having the keyboard out of view behind the display, since my fumbling fingers would make even more mistakes than normal. It also breaks the accepted ergonomic model for healthy long-term computer usage. Of course this is just an R&D model, so...
"ParaScan™ is a family of proprietary, composite thin-film ceramic materials whose dielectric constant varies with the application of a DC voltage. Based on a proprietary doped version of Barium Strontium Titanate (BST), ParaScan represents a foundational technology for the ParaTune™ family of tunable ICs . Paratek can produce ParaTune tunable ICs in a virtually limitless number of configurations to meet specific customer needs. Paratek's business model is a flexible one, with customer collaboration representing the cornerstone of this model. The ParaScan material is also exceptionally flexible and can be used in numerous points within wireless components and products to make them better and more efficient! Voltage-tunable ParaScan has exceptional properties, including outstanding linearity and harmonic performance, very low power consumption, and high Q (100 at 1 Ghz and more than 80 at 2 GHz). ParaScan also provides high capacitance density, IP3 of greater than 70 dBm, and very fast switching speed.
you don't need the sophistication and bulk of a network analyzer when all you want to do is measure the return
loss (S11) of a component. Copper Mountain Technologies
offers this USB-connected vector reflectometer. Per their website, "PLANAR R54 is a Vector Reflectometer designed
for S11 parameter measurement. It provides high accuracy measurements for magnitude and phase in frequencies
between 85 MHz and 4.2 GHz. With a weight of only 8.8 oz, this device is portable so that you
can conveniently take it into any testing environment. PLANAR R54 is the ultimate compact workhorse analyzer,
providing a variety of analytical capabilities in the frequency and time domains." The last decade has seen
many such high quality USB-connected test equipment replace or supplement traditional boxes. Copper Mountain
Technologies also makes the full-featured, 2-port vector network analyzers as well for when you need bulk.
Thomas Edison would be proud at the inventiveness of entrepreneur Larry Birnbaum. So am I. By now we all know about the ludicrous worldwide ban on the sale of incandescent light bulbs over a certain wattage. Here in the U.S., the ban was slated to begin in January of 2012* with prohibition against 100 watt bulbs, and over a couple years would eventually ban the sale of anything larger than 40 watts. Instead ,we are to buy mercury-filled, electronic waste-filled CFL bulbs or >$60 apiece LED bulbs. Within that 40-to-100 W range, several classes of specialty lights are exempt from the regulation including appliance lamps, rough service bulbs, 3-way bulbs, colored lamps, stage lighting, and plant lights. The rough-service class is where Mr. Birnbaum and his Newcandescent™ company comes in. Unlike the standard incandescent bulb that is typically rated for a 750-to-1,000-hour lifetime, Newcandescent bulbs are rated for a 10,000 hour lifetime (10x-to13x as long). They are advertised at 7 years. Anyone who has used CFL bulbs has probably already experienced a failure - long before their expected longevity of 5-7 years. Standard frosted incandescent bulbs from Newcandescent cost $2.88 each (less than about 30¢ per standard bulb service life equivalent). Floodlight versions are also available. "The inspiration to continue to manufacture...
Every once in a while an off-topic product is worth featuring just for the sake of novelty. This Gear Ring, by Kinekt, is just such a novelty. Electrical engineers and techs might not consider it an apt fashion accessory for displaying their chosen field of expertise, but mechanical engineers and techs certainly will, as will gear head hobbyists. A short video shows how the inner planetary gears rotate within the two outer ring gears. "The Gear Ring is fabricated using 316L, which is the highest quality surgical stainless steel in the jewelry market. Stainless steel has properties which make it highly durable and resistant to tarnishing, fading, scratching, and rusting. It will not bend or break and is hypoallergenic for those with metal allergies." At $165, it isn't cheap, but that does include worldwide free shipping. Maybe Kinekt should consider integrating tiny generators into the the gears to light up a couple LEDs when the outer rings are turned. That might increase the EE/EET customer level.
first I thought this was an April Fools gag, but evidently not. The AIRE mask is designed to allow charging
of mobile devices simply by wearing the device over your nose and mouth whether asleep or awake. Simply breathe
in and out, and the integrated wind-powered generators will provide power to your mobile phone, iPod, or pacemaker
(just kidding about the last one). My concerns are its durability in the warm, humid environment that is human
breath, and the ridicule that employing the AIRE mask in public might subject the user to. Will bullying levels
increase for users? Is there a medical warning included for asthmatics? If you try to make a call while wearing
the mask, do you sound like Darth Vader? Can an untrained person experience
pnigophobia (fear of smothering) or
even claustrophobia (fear of enclosed
spaces) as a result of wearing the mask? Should studies be conducted for such maladies? At least there is likely
no worry about suffering from technophobia
(fear of technology). AIRE mask is being offered at £60 in the UK and $70 in the U.S., although I cannot find
a purchasing venue anywhere yet.
TRICOR Systems makes some cool products for industry research and quality assurance programs like an electronics chocolate temper meter (who knew chocolate had a temper?), life cycle and fatigue testers (those machines that press keyboard keys a gazillion times or cycle hinges until they break), gloss and haze meters for measuring surface reflection properties, and photometric setups for measuring color content and brightness. TRICOR Systems also offers some assembly services that you might find useful, but I'll get back to that in a minute. Way back in the mid 1980s I worked for a company in Vermont that made, among other things, fuel measurement systems for aircraft. They consisted of capacitive sensors in the fuel tanks, a computer, and some used the first LCD displays ever deployed in military aircraft. Just like with the legendary $100 hammer for the Space Station, those displays required extensive testing both for initial qualification and for each unit during production (low volume). Part of my job as an associate test engineer (I was working on my BSEE at UVM at the time) was to write acceptance test procedures for the equipment that included HIPOT testing, an early form of ESD testing, and measurement of the LCD color, brightness, and contrast. The ESD tester was a custom unit that built up a charge with a scary-looking contraption that resembled something from a Frankenstein movie...
For some reason I am strangely attracted to this early magnetic sound recording device - the Blattnerphone. At the dawn of the motion picture industry, producers were desperate for an economical and reliable means for including sound with their movies. The many silent movies is evidence of it not being a trivial matter. Early methods attempted to use wire and optical disk recordings, but none panned out. German engineer Kurt Stille had developed a successful steel wire sound recording machine for office dictation, motivating film producer Louise Blattner to engage him to work on a means of creating something that could produce sound that was synchronized with film action. The Blattner Company was contracted in 1930 to install the prototype in Avenue House, home of the BBC's research department. The Blattnerphone recorded onto 6mm wide steel tape running at 5 ft/sec. Operation required a technician to manually adjust a rheostat for maintaining synchronization. Marconi machines eventually replaced the Blattnerphones, but dedicated work by KURT Stille and Louis BLATTNER paved the way to our modern movies. Read the entire story on the Blattnerphone here, and be sure to read the addendum by Butterworth.
R601S Tube Radio Teardown Report. Earlier this year I really started pining for a vacuum tube radio. After
a little poking around on eBay, it became clear that buying something like that sight-unseen was too risky for
the money people were asking for anything in halfway decent shape. So, I began looking to determine whether
anyone offered a newly manufactured line of vacuum tube radios. There is a surprising selection available, but
most are very expensive. The one I finally settled on was the Model R601S from Tesslor. It has the advantage
of employing a fully solid state front end and tuner, with vacuum tubes being used in the audio output amplifier
stages. A single 6N2 tube provides preamplification, and each of the left and right speaker driver channels
uses a 6P1 tube. Many serious audiophiles claim that there has never been a solid state audio circuit designed
that can faithfully replicate the "warmth" of a tube circuit. Supposedly the mechanical vibrations within the
tube elements are responsible for the quality. My hearing is pretty darn acute (unlike my eyesight), but I cannot
claim to be able to tell the difference. My motivation is purely from a nostalgic craving for a tube set. Oh,
the R601S does have a fourth vacuum tube that is mounted in the front of the radio case beneath the tuning dial.
It is roughly the equivalent of the old "cat's eye" light used for fine tuning. In this case, it indicates when
an FM station's signal is being properly resolved into separate right and left channels for stereo...
You cannot really call yourself a leading-edge technophile if you are not a haptic communicator. You might already be doing the haptic comms thing and not even know it if you ever put your cellphone on the vibrate setting. "Haptic" refers to the sense of touch, and derives from the Greek "haptesthai," meaning to grasp or touch. If plans work out as Nokia hopes, you might someday be alerted to calls by feeling that vibrating sensation via a tattoo printed on your skin rather than relying on the phone vibrating in your pocket or vibrating across a table like the old electric football games. Their goal is to eliminate missed calls due to not hearing or feeling the phone. Nokia plans to use magnetic ink to embed a pattern into a person's arm or other chosen location; one can only image where some might end up. Similar to ringtones that can be variously assigned to alert the owner as to whether the call is from a particular friend, spouse, significant other, workmate, or an unknown, a series of Morse-like pulses will differentiate and can even include intensity for helping to signal the phone user. I'm guessing that Nokia has either already contracted with a pharmaceutical company to develop the ink or plans to. Amateur artistry at a beer party from cigarette ashes just won't do the job here...
Antenna-in-a-Can. ...a spray can, that is. Chamtech Operations has introduced a spray-on emergency antenna kit that can be used for creating ad hoc antennas in just about any environment - even under water. According to a short video done by Chamtech CEO Anthony Sutera, "The material relies on a proprietary formula that uses thousands upon thousands of nano-capacitors that automatically align themselves properly when sprayed onto a surface. They charge and discharge quickly, and notably don’t generate much heat--a major selling point for a product that might be sprayed onto anything from wood structures to cell phone cases to vehicle exteriors." Oddly, there is almost no information on Chamtech's website. I'm a bit dubious about the improvements claimed for the famously antenna-challenged iPhone 3 since it was measured sitting in an Faraday cage (likely a TEM) that probably did not model the human hand near the antenna). Mr. Sutera report a "20 dBm" increase. That's an increase of 10 mW, so he probably meant to say 20 dB, which is a 100x power increase. I believe it makes a suitable antenna for emergency conditions, the need for large, concealed antennas, or for creating a Faraday shield, but common metallic paint has been used for years for those purposes. Maybe the nano-particle content of this stuff is more durable. Will urban drug-dealing taggers adopt it for improving ad hoc law-evading cellphone nets?