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Click here to read about RF CafeView the YouTube RF Cafe Intro VideoKirt Blattenberger ... single-handedly redefining what an engineering website should be.

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"The very term VCs sounded sinister. The only other VCs I'd ever known were the Viet Cong." - - Jerry D. Neal, RFMD

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3D Xpoint Memory: Faster-Than-Flash Storage Unveiled

Cellphones Can Steal Data from 'Air-Gapped Computers'

Satellite-Launching Drone Program Enters Next Phase

Amateur Radio Parity Act of 2015 Gains Momentum, Cosponsor List Tops 90

Demand for Radar Systems Boosts Infineon's Chip Production

'Seeing' Molecular Interactions Could Give Boost to Organic Electronics

What You Need to Know About Conflict Minerals

Short Wavelength Plasmons Observed in Nanotubes

Electron Spins Cross over in Femtoseconds

Destructive High-Energy Electrons Streaking into Earth's Atmosphere from Space

Researchers Predict Material with Record-Setting Melting Point

Apple HomeKit Requires Proprietary ID Chip

Major Flaw in Android Phones Would Let Hackers in with Just a Text

India Planning Fresh Radio Spectrum Auction

China Launches 2 Satellites as It Builds GPS Rival

Broadband 'Levy' for Super-Fast Net (aka 'Tax')

Join Now! The Official Radio
Service Men's Association, Inc.

Official Radio Service Men's Association, Inc., April 1932 Radio-Craft - RF CafeAs the advertisement for membership in the Official Radio Service Men's Association says, structured organizations for people of like mind and interests have long been the hallmark of an advanced society where there is a need for directed socialization and the 'strength in numbers' benefit. I suppose most people reading this piece belong to at least one such association like the Institute for Electrical and Electronics Engineers (IEEE), American Radio Relay League (ARRL), Armed Forces Communications and Electronics Association (AFCEA), Association of Old Crows (AOC), Electronics Technicians Association (ETA), etc. Having significant representation in government in the form of lobbyists is essential these days in order to obtain and retain fair treatment

Amateur Radio Specialty
License Plates - 2015

Amateur Radio Specialty License Plates: 2015 - RF CafeAccording to my research, in the year 2015, there are 29 states out of 50 that issue specialty license plates commemorating amateur radio. Those states that do not issue specialty plates offer a vanity plate with an FCC call sign. All require proof of call sign ownership. Some plates simply say "Amateur Radio," while others have a graphic symbol of some sort. I expected Connecticut, being the home base of the ARRL, might have a really nice design, but it is a simple lightning bolt type thing - better than nothing. Vermont is the only state that uses the schematic symbol portion of the ARRL logo. Ohio, host to the world's largest annual Hamfest, merely says "Amateur Radio." Sheesh, how about a tent with an antenna or something, guys? My own favorite is that of New York due to its simple but eye-catching design that includes the

50 MHz Dipole Antenna
Made from Crutches

50 MHz Dipole Antenna Made from Crutches - RF CafeI had to check the publication month printed on the cover of the latest Nuts & Volts magazine when I ran across this article last night. It is labeled "August 2015" and not "April 2015," but take a look at the photo below that accompanied an article titled "Build a 50 MHz Dipole out of Crutches" (p25). Author and amateur radio operator Bob Fischer (WB8BEL), aka "The Antenna Sculptor," actually fashioned a working 50 MHz dipole out of a pair of metal-framed crutches. The ones featured in the article were purchased new, but he advises suitable crutches can be bought second-hand for a couple bucks. Admittedly, he says, "I'm certain this novel antenna would never survive high winds or ice loads, but it was not built with permanent installation in mind. I think the best uses for these crutches are teaching antenna

Beware the Service Gyp!

Beware the Service Gyp!, September 1934 Radio-Craft - RF CafeRepair service businesses have always gotten a bad rap for deliberately inflating part and labor costs - often deservingly so - but it's a shame the honest brokers are dragged down by the scum ('or 'gyps' as this article calls them). Come to think of it, the word 'gyp' is likely short for 'gypsy,' which is sure to offend someone these days. Along with admonishing customers to beware of shyster servicemen, there is an example of an orchestrated 'sting' operation whereby a radio set was intentionally 'broken' in a certain way with witnesses as to the fault, and then a couple dozen repair services were called upon to troubleshoot and fix it, then present a bill for their work. The result is interesting, and even resulted in one guy being

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Applications and Characteristics
of Copper-Oxide Rectifiers

Applications and Characteristics of Copper-Oxide Rectifiers, July 1933 Radio-Craft - RF CafeWhile reading through this article on copper-oxide rectifiers, I am once again reminded of how much we take for granted the conveniences of electrical test equipment on today's shop benches. The advent of FET-input multimeters was a huge step forward because the meter input impedance is so high that it has practically no impact on the circuit being measured. Prior to that, most simple meters drew their power from the circuit under test, thereby altering the true value of current or voltage being measured. Of course there were vacuum tube voltmeters (VTVM) with high input impedances, but few hobbyists or laymen could afford them. This piece reports on how the advent of a non-tube-based rectifier permitted AC measurements to be made by DC-driven d'Arsonval meter movements so as to not excessively

Notable Quote: Henri Poincaré

Henri Poincaré, mathematician, in "Science and Hypothesis" - RF Cafe"Science is built up of facts, as a house is built of stones; but an accumulation of facts is no more a science than a heap of stones is a house." - Henri Poincaré, mathematician, in Science and Hypothesis

Not Quite Getting It...

A mathematics professor explained to students through various lectures and examples:

Not Quite Getting It (math limit problem) - RF Cafe

It became obvious not everyone understood after one student submitted the following on a pop quiz:

Not Quite Getting It (math limit answer) - RF Cafe

 - originator unknown. 

Radio Service Data Sheets for
RCA Victor and Philco Radios

Philco Model 15 Series, 11-Tube Superheterodyne Chassis Radio Service Data Sheet, August 1932 Radio-Craft - RF CafeAt least for now, I am going to only scan and post Radio Service Data Sheets in graphical format, and run OCR on them to separate the textual content and make it searchable. These featuring Philco Model 15 Series, 11-Tube Superheterodyne (PhilcoRadio.com photo) - RF Cafethe RCA Victor Model R-78 B1-Acoustic 12-Tube Superheterodyne floor console radio and the Philco Model 15 Series, 11-Tube Superheterodyne Chassis, are among what has been added already, with lots more to come. There are still many people who restore and service these vintage radios, and often it can be difficult or impossible to find schematics and/or tuning information. I will keep a running list of all data

Microelectronics circa 1963

Microelectronics, January 1963 Electronics World - RF CafeIt seemed weird to read of microelectronics device density expressed in parts per cubic foot of semiconductor substrate. Describing density that way makes some sense when considering 3-dimensional devices with vertically stacked elements, but this was in a 1963 article in Electronics World, so that could not have been the case. The motivation, evidently was to be able to compare microcircuit density with that of the human brain in terms of neuron density. In fact, there is an interesting chart presented that shows the evolution in circuit density beginning with vacuum tube circuits, progressing through the state of the art in 1963, projecting for future years, and finally peaking with the brain's density. Interestingly, the brain density shows as about 5x1011/ft3, while the "nonredundant semiconductor device" limit is

Famous Scientists' (FI+LN)
Crossword Puzzle

Famous Scientists' First Initial & Last Name Crossword Puzzle for July 26, 2015 - RF CafeThis Famous Scientists crossword puzzle took a long time to make because of all the names that I managed to squeeze into the matrix. The way this one works is the person's first initial and completely spelled-out last name, indicated by (FI+LN) in the clue, is used as the answer. For instance, filter transfer function developer Stephen Butterworth would be written as SBUTTERWORTH. There are at least sixteen names here with which you should be familiar. Good luck

Neil Blaho - "EMI Guy"
Bio & Vintage Test Equipment Ads

Neil Blaho - "EMI Guy" - Bio & Vintage Test Equipment Ads - RF CafeThis could prove to be a popular feature if other RF Cafe visitors care to get involved. Yesterday, Neil Blaho (aka "EMI Guy" - see his helmet for proof), having seen all the vintage magazine articles and advertisements posted here over the years, sent me an e-mail with the ads pages below attached. Wrote Neil, simply, "I'll never admit to using these items years ago…." His statement alludes to what many of us veteran communications electronics industry types recognize as the uncomfortable number of years that have slipped by while we were busy making a living and raising families. I wrote back asking him for permission to post the images and requested a short biography that could be posted along with them. To wit: "Greetings Neil: That's quite an interesting lineup of stuff. I'm sure there are lots of guys like you out there who wax

Fairview Debuts Complete Family of High
Rel RF & Microwave Power Amplifiers

Fairview Microwave Debuts a Complete Family of High Reliability RF & Microwave Power Amplifiers - RF CafeFairview Microwave Inc., a supplier of on-demand microwave and RF components, has released a complete portfolio of coaxial high reliability power amplifiers with broadband frequencies ranging from 0.5 MHz to 20 GHz that can operate over extreme temperatures across -55°C to +85°C. These high-rel amplifiers are commonly used in demanding environments for applications involved with electronic warfare, instrumentation, military communications, radar, point-to-point radio, telecom, test & measurement, medical, and SATCOM industries. The new families of hi-rel power amplifiers from Fairview are designed to overcome the electrical and ...

Keysight Technologies Supports PAM-4
M8000 Series BER Test Solutions

Keysight Technologies Introduces PAM-4 Support on M8000 Series BER Test Solutions - RF CafeKeysight Technologies today expanded its PAM-4 measurement solutions with support for PAM-4 data formats and built-in error counters on the M8000 Series BER test solutions. PAM-4 support and the ability to integrate a device’s built-in error counter helps R&D and test engineers characterize and test high-speed digital receivers for the data-center networking, storage and computer industries. R&D and validation teams characterizing next-generation digital designs face several test challenges. With data rates continuously increasing, emerging data center standards like OIF CEI and IEEE 802.3 Ethernet are moving to PAM-4 multilevel signaling formats. In addition, many ASIC

NI AWR Software on Display
at European Microwave Week

NI AWR Software on Display at European Microwave Week - RF CafeNI (formerly AWR Corporation) announces that NI AWR Design Environment™ V12 will be featured in a host of activities at European Microwave Week 2015 (EuMW2015), being held September 8 to 10 in Paris. New load-pull and antenna features, ease-of-use and speed enhancements and third-party integrated flows will be on display in Booth #E112. In addition, key new features will be showcased in several MicroApps presentations and at the combined European venue of AWR Design Forum 2015 (ADF)/European User Group Meeting

Werbel Microwave Intros 500-6000 MHz
6-Way Power Divider

Werbel Microwave Intros 500-6000 MHz, 6-Way Power Divider - RF CafeThe 6-way power divider model WMPD06-0.5-6-S is the newest edition to the 500 - 6,000 MHz family of power dividers from Werbel Microwave LLC. This unit comes with SMA connectors; type N is also available. Measures 9.0 x 6.0 x 0.9 inches. Input and output return loss is -11 and -15 dB typ. respectively, isolation is -20 dB typ. and insertion loss is 2.2° max. Phase and amplitude balance are typically 3°/0.4 dB. Rated ta 50 watts input power as a splitter only. Part of Werbel Microwave's growing series

Triad RF Systems Intros 4.4-5.0 GHz
Bi-Directional Power Amplifier

Triad RF Systems Intros 4.4-5.0 GHz Bi-Directional Power Amplifier - RF CafeThe TTRM1008 is a high linearity GaAs FET bi-directional SSPA suitable for use with any modulation and signal type. It is currently utilized in UAV data links and long range point-point COFDM video links. High speed T/R switching and sequencing of the PA, LNA, and switch driver circuitry is performed by an on-board CPLD, where switching timing can be adjusted in firmware based on system requirements. The transmit section produces over 25 watts of BPSK power, and over 5 watts of 64 QAM. The unit also features a manual digital gain setting and a three color status LED on the front panel that shows if the SSPA is in transmit or receive mode, or if an alarm condition exists. The amplifier

Saelig Intros TDDS100-48 DDS
1 Hz-100 MHz Signal Generator

Saelig Introduces Tiny TDDS100-48 Direct Digital Synthesized 1 Hz-100 MHz Signal Generator - RF CafeFairport, NY, USA: Saelig Company, Inc., announces the availability of the USB-stick-sized TDDS100-48 - a laboratory quality Direct Digital Synthesized RF signal source with a frequency range of 1 Hz to 100 MHz and a minimum of 0dBm output power that is available from its SMA female socket. The TDDS100-48 is the smallest USB-controlled DDS synthesized source available and is priced significantly below other offerings. The high purity source can be swept in steps as low as 1Hz between any two frequencies in its specified range. Frequency changes are phase-continuous, so there are no glitches and phase noise is better than -140 dBc @ 100 kHz