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Homepage Archive June 2015


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Orbel Board Level Shielding

Meeting Automation Challenges

Orbel-Board-Level-Shielding-Meeting-Automation-Challenges-7-1-2015.htm" > Orbel Board Level Shielding Meeting Automation Challenges - RF CafeAs advanced automation continues to infiltrate industries around the world, Orbel Corporation has ensured that its board level shielding products keep pace with today's newest automation technologies. Designed as a starting point that leads to a fully custom EMI/RFI suppression solution, Orbel's extensive line of board level shields offers unlimited design flexibility for components needed for the parts and systems that contribute to automated technology. Based on an unwavering attention to detail and delivering exceptional customer service, Orbel board level shielding can also be custom-engineered Orbel-Board-Level-Shielding-Meeting-Automation-Challenges-7-1-2015.htm" ...

New Business Announced: Centric RF

Cable, Connectors & Components

New Business Announcement: Centric RF - RF CafeMr. Bob Hawkins would like to introduce Centric RF. "We're a start up company planning to offer from stock various RF and microwave coaxial components, including attenuators, adapters, cable assemblies, terminations, and more. Having started in June 2015, it will be a few months before we have a large selection and we're fully staffed. Currently we're in the design and procurement phase. When we finish parts for inventory we'll add them to [the website] in case they fit a customer's need; shipment will be within 24 hours until we're staffed, then it will be same day shipment. We're currently looking for vendors to partner with us." If interested please contact Bob at sales@centricrf.com


Lasers, August 1965 Electronics World - RF CafeNot so long ago the availability and usage of lasers was restricted to laboratory and military use, but today they are ubiquitous in our world. CD, DVD, and Blu-ray players are found in nearly every home and office. Laser pointers (including the green ones being illegally targeted on aircraft), laser distance measuring devices, laser leveling and alignment tools, laser light shows, laser cutting, even laser weapons can be found in many other venues, and a relatively low costs (except the weapons). Half a century ago, most lasers were fabricated from rare earth elements whose output powers were measured in a few milliwatts at most. The cost of even a low power laboratory experimental device was thousands of dollars. I can remember seeing something like a 0.5 mW helium-neon laser for hobbyists offered by Edmund Scientific back ...

Notable Tech Quote

Notable Tech Quote for June 30, 2015 - RF Cafe"There are two kinds of countries: Those that use the metric system and those that have sent men to the moon." - Anon

Electrifying Music: A Closer Look

at Engineering's Impact on Music

Electrifying Music: A Closer Look at Engineering's Impact on Music - RF CafeA lot of engineers, technicians, and even managers I have worked with over the years have been musicians that play in private, with small gatherings, or even as a part of for-hire bands. It is probably safe to say the opposite is not true - that many professional musicians are also accomplished technologists. Jared Cossaboom of Circa Interactive sent me a hyperlink of this infographic titled "Electrifying Music: A Closer Look at Engineering's Impact on Music" as created by the NJIT. I particularly like the introductory juxtapositioning of Nikola Tesla and Thomas Edison as representatives of AC and DC electricity, respectively ...

Please Welcome everythingRF

as a New Sponsor!

everythingRF bannereverything RF is a product discovery platform for RF & Microwave Products and Services. We list over 100,000 Products from more than 200 Companies across 200 Categories in our database and enable engineers to search for them using our customized parametric search tool. The parametric product search tool on everything RF has been designed to replace paper and PDF catalogs. It is fast, easy to use and very powerful – You can enter your specs and find products from multiple manufacturers that meet your requirement. You can then compare products, download datasheets ...

Linx HumDT™ Series Multi-Channel

Data Transceiver Module in 868 MHz

Linx-Technologies-HumDT-Multi-Channel-Transceiver-Module-868-MHz-6-29-2015.htm" > Linx Technologies Announces HumDT™ Series Multi-Channel Digital Data Transceiver Module in 868 MHz - RF CafeAt below $10 in volume, the Hummingbird platform is the lowest cost complete wideband transceiver with microcontroller module on the market today. The HumDT™ Series transceiver is built on this platform and is designed for data transfer. Linx is pleased to announce the addition of the HumDT™ multi-channel low cost RF modules in 868 MHz. Having a common footprint with the 900 MHz frequency agile model, designers can now serve the North American and European markets with common footprint modules, saving design time and material costs. Like its namesake, the low cost Hummingbird modules are tiny. At 11.5 mm by 14.0 mm, the HumDT™ uses advanced SOC Linx-Technologies-HumDT-Multi-Channel-Transceiver-Module-868-MHz-6-29-2015.htm" ...

Skyworks Intros webCRaFT™

Ceramic Bandpass Filter App

Skyworks-Ceramic-Bandpass-Filter-Application-6-26-2015.htm" > Skyworks Intros webCRaFT™ Ceramic Bandpass Filters - RF CafeSkyworks Solutions, through its subsidiary Trans-Tech, Inc., unveils Skyworks-Ceramic-Bandpass-Filter-Application-6-26-2015.htm" >webCRaFT, a new Web-based ceramic bandpass filter selection program. Customers can easily search for bandpass filter solutions by defining target performance criteria. Frequencies range from 300 to 5000 MHz and bandwidths from 2% to 25%. Filters outside of those boundaries are available upon request. To learn more, please visit Trans-Tech webCRaFT.

The Radio Month in Review

The Radio Month in Review, April 1936 Radio-Craft - RF CafeDid you know that some radio service equipment can be financed by the Federal Housing Administration (FHA)? That's right, if your business needs a new tube tester or maybe an oscilloscope, Uncle Sam is there to help. That was in 1936, anyway, per this Radio-Craft news blurb. Today, of course, the FHA no longer makes loans for business equipment - the Small Business Administration (SBA) takes care of that. Nowadays the FHA restricts itself to home loans - including to illegal residents and otherwise traditionally unqualified. Also reported, among lots of other interesting stuff, is some early instances of RFI (radio frequency interference) emanating from ...

Cobham Intros Dual-Polar Base Station

MIMO Sector Antenna Range

Cobham-Dual-Polar-Base-Station-MIMO-Sector-Antenna-Range-6-26-2015.htm" > New Dual-Polar Base Station MIMO Sector Antenna Range from Cobham - RF CafeCobham Antenna Systems, a market-leading supplier of antennas, has developed a range of dual-polar MIMO sector antennas covering the UHF, 2 GHz, 3 GHz, 4 GHz and 5 GHz bands. The range offers excellent coverage (azimuth beamwidths 60°, 90° and 120°) with peak gains of 14-17 dBi. All antennas in the product range include interleaved vertical and horizontal polarised antenna elements within a single aperture. This results in very compact, lightweight units with rugged and UV stable radomes. Performance across the range is excellent and Cobham-Dual-Polar-Base-Station-MIMO-Sector-Antenna-Range-6-26-2015.htm" ...

The Spook - Another Weird Effect

to Haunt TV

The Spook - Another Weird Effect to Haunt TV, March 1953 Radio & Television News - RF CafeHow often have we all mistaken 'spooks' for Barkhausen oscillations? Yeah, it's embarrassing, but we've all done it. I can't tell you how many times as a kid I saw the tell-tale effects on our old black and white TV and said, "Mom, can you remind Dad to do something about those dang Barkhausen oscillations when he gets home from the newspaper office?" If you believe that line of bull hockey, I've got some waterfront property in the Sahara Desert to sell you. The only thing close to 'Barkhausen' I might have known back then was the name of a German beer house on Hogan's Heroes. Anyway, this article, written in the days of over-the-air television broadcasts, presents a solution to ...

Werbel Microwave Intros 300-2700 MHz,

10 dB Directional Coupler

Werbel-Microwave-10-db-directional-coupler-6-26-2015.htm" > Werbel Microwave's Model WMDC10-0.3-2.7-S is a wideband 10-dB directional coupler that operates continuously over the frequency range of 300 to 2,700 MHz. Designed for wideband telecom applications. Covers all major commercial bands including Cellular, PCS, WiMax, LTE, Public Safety and UHF. Materials selected for low intermodulation Werbel-Microwave-10-db-directional-coupler-6-26-2015.htm" ...

Cardboard Slide Rule Calculators

The Original Mobile Apps™

Cardboard Engineering & Science Slide Rule Calculators - RF CafeLong before there were smartphones and software 'apps,' engineers and scientists carried around portable 'apps' of another kind. These apps were made from printed heavy cardboard stock and typically had either a sliding section sandwiched between two outer layers, or a rotating layer on a fixed base layer. They even sported rivets to hold them together - like the original Levis dungarees. I and guys much older than me [ ;-) ] routinely carried them in our shirt pockets, securely snugged behind out plastic pocket protectors. You definitely always wrote your name on them in indelible ink since there was a tendency for those cardboard slide rules to sprout legs and walk away while you were at lunch or in the can. RF Cafe visitor Neil Blaho just sent photos of some rare gems for your opportunity to wax nostalgic ...

Engineering Career and

Job Hunting Advice

Engineering Career and Job Hunting Advice for June 26, 2015 - RF CafeWow, six weeks have gone by since last posting a list of engineering career advice article links. May and June have been quite busy. The good thing about having waited so long is that there is a huge crop of such articles to choose from now. The first one has a slightly nonsensical title, until you realize Ms. Herman means 3 second per tip. She has also gone to the trouble of limiting each tip's length to 140 characters or less for facilitate your Tweeting one or more to a friend. Thoughtful of her, non?

- 101 Career Tips You Can Learn

    in 3 Seconds

- The Secrets to a Great Online

    Job Interview [Infographic]

- How to React When an Interview

    Doesn't Go as Planned <more>

RFMW Offers Family of

High Input TOI VVAs

RFMW-High-Input-TOI-VVAs-6-23-2015.htm" > RFMW Offers Family of High Input TOI VVAs - RF CafeRFMW announces design and sales support for a series of voltage-controlled variable attenuators (VVAs) from Skyworks Solutions. The SKY1223x series of attenuators is suitable for applications such as repeaters, wireless backhaul and wireless infrastructure. The four attenuators in the series, SKY12232-21, SKY12233-11, SKY12235-11 and SKY12236-11, are optimized for low distortion and centered at 1.95, 2.60, 3.15 and 3.8 GHz respectively. Together, the attenuators cover operation from 1.45 to 5.0 GHz and have control voltages ranging from RFMW-High-Input-TOI-VVAs-6-23-2015.htm" ...

Garod Model 5A4 Radio

Schematic & Parts List

Garod Model 5A4 Radio (RadioMuseum.com) - RF CafeGarod Radio Corporation, a shortened version of the original Gardner-Rodman Corporation, operated out of Brooklyn, New York, beginning in the early 1920s. Many of their models had a molded 'plastic' look long before plastic was used in commercial products. The material appears to be a painted or brightly stained type of phenolic substance. This schematic and parts list appeared in the July 1948 edition of Radio News magazine ...

Anatech Electronics Intros

Cavity & SAW Bandpass Filters

Anatech-Electronics-Cavity-SAW-BPF-6-25-2015.htm" > Anatech Electronics Intros Cavity & SAW Bandpass Filters, June 25, 2015 - RF CafeAnatech Electronics, offers the industry's largest portfolio of high-performance standard and customized RF and microwave filters and filter-related products for military, commercial, aerospace and defense, and industrial applications up to 40 GHz. Anatech has released three new designs: a connectorized 2260 MHz cavity bandpass filter, a surface mount 460 MHz RF SAW bandpass filter, and a connectorized 1650 MHz cavity bandpass filter. All can be ordered directly through their AMCrf web store.

Belmont Model 5240 Radio

Schematic & Parts List

Belmont Model 5240 Schematic & Parts List, July 1948 Radio News - RF CafeBelmont Radio Corporation was located in Chicago, Illinois. Founded independently sometime the 1920s, it became a subsidiary of Raytheon Manufacturing after World War II in an effort to quickly launch the Raytheon into nascent consumer FM radio and television markets. Belmont advertisements were prominent in electronics trade magazines throughout the 1940s to promote their war efforts. A schematic and parts list for this Belmont Model 5240 receiver appeared in the July 1948 edition of Radio News ...

Mantola Models 92505, 92506

Schematic & Parts List

Mantola Models 92505, 92506, July 1948 Radio News - RF CafeAccording to the RadioMuseum.com website, B.F. Goodrich manufactured the Mantola line of radio receivers. It was evidently a low quality, low price, short-lived run of models. The simplicity of the schematic shows the low parts count. A lack of multipole filter circuits likely means selectivity was fairly marginal. One good feature is that unlike many earlier radios and TVs, the AC line connection to the chassis is DC-isolated through a 150 kΩ resistor. Look at the schematics of older sets and it is not uncommon to see one line of the AC supply tied directly to the metal electronics chassis. An isolation transformer right at the input is the safest way to do it ...

Private Advertising Available

Once Again on RF Cafe!

Private Advertising Available Once Again on RF Cafe!At the request of some of my former advertisers and some new inquiries, I am now set up to once again host private advertising in the form of graphical banners in all page borders, and as textual Highlighted Ads on the Parts Vendor pages. I had stopped the advertising program at the end of 2014 in order to recover the rather large amount of time being required to manage all the advertisers. Everything was replaced with 3rd-party ads from Google, GlobalSpec, and Bing/Yahoo. However, a new plan is in place now that makes my job easier and allows time to host private advertisers' needs. If your company is interested in reaching RF Cafe's very diverse range of visitors, please review my Advertising Information page. Plans are available starting at $40 per month. Please pass this announcement on to your company communications / public relations department. Thanks for your support.

NI AWR Design Environment v12

First Major Release in 2015

NI-AWR-Design-Environment-V12-Release-2015-6-23-2015.htm" > NI (formerly AWR Corporation) announces the availability of the first major release in 2015 of NI AWR Design Environment™ for designers of monolithic microwave integrated circuits (MMICs), radio-frequency printed circuit boards (RF PCBs), modules and more. V12 was previewed for the first time at IMS 2015 in May 2015, creating significant interest, and feedback from early-access customers has been very positive. This latest release boasts new load-pull and antenna- and radar-specific features, as well as ease-of-use improvements, speed enhancements and third-party integration flows for improved stability analysis and design NI-AWR-Design-Environment-V12-Release-2015-6-23-2015.htm" ...

Radio Waves Heard

from Jupiter and Venus

Radio Waves Heard from Jupiter and Venus, September 1956 Popular Electronics - RF CafeAs a case in point about my claim with today's earlier post featuring Bob Berman's factoids on astronomy, this article from a 1956 edition of Popular Electronics illustrates how vital electronics are in the various fields of science. It has only been fairly recently that astronomers have been 'looking' at stars and planets outside of the visible wavelengths. Renditions of the sky in both shorter and longer wavelengths show in some regions a vastly different universe. Earlier this year, a comprehensive mapping of the entire known universe in the microwave realm revealed the largest contiguous feature ever detected - dubbed "The Cold Spot." Such ...

Astronomical Factoids

Astronomical Factoids - RF CafeMost people reading this article are engineers, technicians, academics, and hobbyists who appreciate the sciences and how they categorize, define, and explain the world around us. I think it not inappropriate, then, to present on occasion a few 'factoid' type pieces on topics not directly related to RF and microwave engineering. Many, if not most, nay, if not all modern discoveries are aided in part or in whole by the advent of electronics - even if that bit of electronics is a computer that crunches numbers for analysis, simulation or processing words in a technical paper. Accordingly, you will probably appreciate these few short tidbits of astronomical information which überprolithic astronomy author and practitioner Bob Berman wrote for the 2015 edition of The Old Farmer's Almanac (aka OFA) ...

Foundations of Antenna Engineering

Foundations of Antenna Engineering: A Unified Approach for Line-Of-Sight and Multipath - RF CafeFoundations of Antenna Engineering: A Unified Approach for Line-Of-Sight and Multipath, by Kildal Per-Simon. This is the first textbook that contains a holistic treatment of antennas both for traditional antennas mounted on masts (line-of-sight antenna systems) and for small antennas used on modern wireless devices such as smart phones being subject to signal variations (fading) due to multipath propagation. The focus is on characterization, as well as describing classical antennas by modern complex vector theory - thereby linking together many disciplines such as EM theory ...

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Practical Adjustment of the Gamma Match

Practical Adjustment of the Gamma Match, February 1953 QST - RF CafeThis is one of the earliest examples I have seen (and I've seen many) of an electronics article that was written in a conversational tone rather than in the heretothen[sic] stoic, all-business type prose. In fact, you would be hard pressed to discern it from a contemporary article in QST. Author Davis describes his process of interfacing 52 Ω coaxial cable to his multi-element beam antenna. The gamma match has the advantage in such an application of being usable when the center of a driven element is directly grounded to the antenna boom. Most other types of feed systems require that the driven element be isolated from the boom. BTW, SWR ratios are written here with slashes as the ratio ...

Engineering Crossword Puzzle

Engineering Crossword Puzzle, June 21, 2015 - RF CafeFor the sake of avid cruciverbalists amongst us, each week I create a new crossword puzzle that has a theme related to engineering, mathematics, chemistry, physics, and other technical words. You will never be asked the name of a movie star unless he/she was involved in a technical endeavor (e.g., Hedy Lamar). Enjoy!

A Few New Microwave & RF Articles

RF & Microwave Engineering Articles for June 23, 2015 - RF CafeI've been so busy making website changes that refreshing the list of RF & microwave industry magazine articles has been neglected. One of the many advantages of the Internet is that we no longer have to wait for a once-per-month publication to arrive in the mail in order to be able to read useful write-ups. Three weeks have passed since the last suggested reading list, so here is an update.

- Top Methods for Measuring 5

   Common Signal-Corrupting

   Distortions,  J-J DeLisle 

- Controlling EMI in the Microwave

   /RF Industry,  Ed Nakauchi

- Gauging IMD/PIM in Microwave

   Components,  Jack Browne <more>

Notable Tech Quoteh

Samuel F. B. Morse (Wikipedia) - RF Cafe"This mode of instantaneous communication must inevitably become an instrument of immense power, to be wielded for good or for evil, as it shall be properly or improperly directed." Samuel F. B. Morse, in an 1838 letter to Congressman and business partner Francis O.J. Smith, of Maine.

Mechanical Designer Sought by

COMET Technologies

Mechanical Designer Needed by COMET Technologies - RF CafeCOMET Technologies USA has an immediate opening in our Plasma Control Technologies (PCT) group for a qualified Mechanical Designer to work in our San Jose, CA office. This is an outstanding opportunity to learn from and work with experts in high power RF products in the semiconductor industry. Key responsibilities include designing and completing SolidWorks designs to ensure all BOM parts are included in the 3D models with correct material designations, generation of data records for piece parts and assemblies when is needed, and logging the data into the SAP system, work closely with COMET's R&D RF and mechanical engineers to complete new ...

Z-Comm Releases 2015 Selection Guide

Z-Comm-Releases-2015-Selection-Guide-6-22-2015.htm" > Z-Comm Releases 2015 Selection Guide - RF CafeZ-Communications is pleased to announce the release of a new Product Selection Guide. This short form catalog includes a wide variety of surface mount VCO (Voltage Controlled Oscillator) and PLL (Phase Locked Loop) synthesizer modules ranging from 40 MHz to 15 GHz. Users can download an electronic version of the product guide in PDF format or contact the company for a hard copy version. A complete listing of all available parts and specifications can be found on the Z-Comm's web site Z-Comm-Releases-2015-Selection-Guide-6-22-2015.htm" ...

The Real Helicopter Parents

The Real Helicopter Parents - Airplanes and RocketsThis article from the May 2015 edition of the Smithsonian Institution's Air & Space magazine reports on the latest trend amongst the überwealthy in California where their children are encouraged to earn helicopter pilots licenses. Doing so has become a major status symbol. Price, which can range from $100k to $½M depending on the age the kid begins, is no object for those folks. "Instead of sports after school, parents are putting their kids in helicopters. They think having a helicopter pilot's license on an application will help their kids get into college." "As soon as he gets his pilot's license, his dad wants to buy a helicopter so his son can chauffeur him around." It gives a new meaning to the term 'helicopter parent.' 

Decimeter Waves: The Future of Radio

Decimeter Waves - The Future of Radio, November 1935 Short Wave Craft - RF CafeCrowded frequency bands have been a problem since the beginning of radio because technology is constantly not only filling available bandwidth, but also pushing the frontiers higher. The advantage of going higher in frequency is that required bandwidths for existing modulation schemes represent a smaller percentage of the center frequency. For example, an 802.11b WiFi signal's 22 MHz bandwidth represents roughly 1% of its 2.4 MHz center frequency. 802.11a does 20 MHz at 5 GHz for 0.4%. Extend that center frequency up to 50 GHz and the channel occupancy is a mere 0.04%. That means for the same total band occupancy of 1% as with 802.11b, you can fit in 25 equivalent slots. The problem with going higher in frequency is that components ...

Radio Amateur Course

Resistance, Inductance, and Capacity

Radio Amateur Course, November 1935 Short Wave Craft - RF CafeAs mentioned many times in the past, some things never change regarding the basics of electricity and electronics. Resistance, inductance, and capacitance are examples. When first starting out in this science, an effective introduction to the fundamentals can often determine whether a person sticks with it or finds another area of interest to pursue as a hobby and/or vocation. Analogous examples of voltage and water pressure, resistance and the diameter of a water hose, inertia in a spinning mass opposing a change in rate and an inductor opposing a change in current, etc., are presented along with some good sketches of ...

Sherlock Ohms: Can You Solve

This Engineering Mystery?

Can You Solve this Engineering Mystery? - RF CafeYea! Finally, another good Sherlock Ohms story, and this one concludes without having solved the mystery. Author Chuck Bagg describes an experience he encountered four decades as an electronics test technician shortly after leaving the U.S. Air Force. It has all the makings of a great techie head scratcher: a meter movement, a battery, a length of RG-178 coaxial cable, and an unexplained voltage spike. A few people have offered possible explanations, but nothing definite has yet been posted. Give it your best shot and help Mr. Bagg end his career in peace ;-)

RF Test Engineer Sought by

COMET Technologies

COMET Technologies USA has an immediate opening in our Plasma Control Technologies (PCT) group for a qualified RF Test Engineer to work in our San Jose, CA office. We are seeking a team player who will bring their extensive RF product development knowledge and experience to our product development team. This is an outstanding opportunity to learn from and work with experts in high power RF products in the semiconductor industry. Required skills include final test of RF matching network assemblies, test of components and assemblies, develop automated test routines for accelerated life testing , design validation testing and production final testing of RF ...

The Convair Analogue Computer

The Convair Analogue Computer, January 1954 Radio & Television News - RF CafeAs quoted in this article about analog[ue] computers as compared to digital computers, "Add two and two. Coming from an analogue computer, the answer would most likely be, 3.999 or 4.001." While that is a true statement, there is one important feature that an analog computer had over digital computers of the era: once initially set up with a transfer function, outputs were nearly instantaneous as the input was varied over a range of values, whereas a digital computer could take quite a bit of time to crank through involved mathematical equations. Performing tasks such as computing aircraft flight paths and other sequential operations was the analog computer's forte. If you ...

Please Welcome Ken Lemke to the

USAF Radar Shop Hall of Fame

USAF Radar Tech Ken Lemke Added to the Hall of Fame - RF CafeKen Lemke completed his career in the USAF just as mine began. He worked on the vacuum tube based MPN-13 mobile radar system after tech school at Keesler AFB, Mississippi, switched over to the transistorized TPN-19 mobile radar system, and eventually ended up as an instructor back at Keesler AFB. Ken didn't say whether he volunteered for instructor duty at Keesler or whether he was randomly issued orders. Even if it was an unplanned assignment, it was better then having been sent back to Lackland AFB as a TI (training instructor, as opposed to DI, drill instructor, in the Army) ...

Carl & Jerry: Abetting or Not?

Carl & Jerry: Abetting or Not?, October 1956 Popular Electronics - RF CafeCarl and Jerry found the appearance and construction of 2400 megacycle transmitters and receivers to be quite odd compared to the equipment they were used to dealing with. It's sometimes hard to believe such an attitude of wonder when our world today is utterly filled with wireless devices operating in the 2.4 GHz ISM band. Author John T. Frye could never have imagined that such a reality would would exist half a century after his story of the pair of teenage electronics sleuths. Unlike our postage stamp size integrated assemblies that cost a few dollars, they speak of "special ultra-high-frequency 'light-house' tubes with ...

Skyworks Intros Variable Attenuators

for Wireless Applications

Skyworks-Variable-Attenuators-Broad-Wireless-6-18-2015.htm" > Skyworks Introduces Variable Attenuators for Broad Market Wireless Applications - RF CafeSkyworks introduces a series of Skyworks-Variable-Attenuators-Broad-Wireless-6-18-2015.htm" >voltage-controlled variable attenuators (VVAs) which are designed to have excellent third order input intercept point and superb dynamic range. The devices cover operation from 1.45 to 5.0 GHz, and have control voltages ranging from 0 to 5.0 V. The SKY12232-21, SKY12233-11, SKY12235-11 and SKY12236-11 are optimized for use as low distortion, analog attenuators – centered at 1.95, 2.60, 3.15, and 3.8 GHz. These VVAs are ideal for automatic power Skyworks-Variable-Attenuators-Broad-Wireless-6-18-2015.htm" ...

New Online Opamp Circuit Calculators

everything RF calculators - RF CafeThe good folks at everything RF have just added a few new online calculators for opamp circuits. Included are:

- Current to voltage converter

- Voltage to current converter

- Differential voltage amplifier and common mode rejection ratio (CMRR)

- LLog amplifier

- Non-inverting gain for ideal and non-ideal opamp

- Output of a summing opamp

The Vanishing Circuit Designer

The Vanishing Circuit Designer - RF CafeHow is this for a prescient prediction from the early 1960s? "As a result of modular and integrated circuitry techniques, all future circuit design work, regardless of degree, will become the responsibility of the component manufacturer instead of the equipment producer." Texas Instruments' (TI) Jack Kilby is credited with designing the first integrated circuit in 1958. The first commercial IC, Ti's Type 502 flip-flop, had just hit the market in early 1960, and already pundits were prognosticating and ruing the disappearance of circuit designers. Maybe it was concerns over job security that they seem to favor forever building every circuit ...

RF Engineering MANAGER

Needed by COMET Technologies

COMET Technologies USA has an immediate opening in our Plasma Control Technologies (PCT) group for a qualified RF Engineering Manager to work in our San Jose, CA office. The successful candidate will manage a team of engineers and technicians to develop custom RF matching network products for plasma process tool, develop a product portfolio and technical solutions for a specific market segment, participate in the factory release of products developed by your team, identify and allocate resources to staff projects for internal and external customers, assist ...

NI AWR Project Files for Antenna Design

Application Examples Available

NI-AWR-Design-Environment-Software-Antenna-Examples-6-17-2015.htm" > NI AWR Design Environment Software Project Files for Antenna Design Application Examples Now Available to Download - RF CafeNI (formerly AWR Corporation) announces that the accompanying example project files for two recently released application examples - Design and Simulation of a 2.4 GHz/5.6 GHz WLAN Antenna on PCB Technology and Design and Simulation of an ISM Band Antenna on PCB Technology are now available for customers and evaluators to download (registration required) NI-AWR-Design-Environment-Software-Antenna-Examples-6-17-2015.htm" ...

Radio Service Data Sheets

Zenith Farm Model 6V 27, 6-Tube Superhet. Receiver Radio Service Data Sheet, April 1936 Radio-Craft - RF CafeFor the benefit of hobbyists who restore and service vintage electronics equipment, I occasionally scan and post Radio Service Data Sheets that appeared in electronics magazines. Most - if not all - electronics servicemen had subscriptions to these magazines because they were a ready source of not just data sheets, but also extensive articles offering advice on servicing radios and TVs. Many electronics manufacturers had a policy of supplying service data only to bona fide shops. Of particular interest for the Zenith Farm Model receiver is an included wind-powered electricity generator meant to supply power in a rural location ...

- Philco Model 59, 4-Tube A.C. Midget Superheterodyne

- Zenith Farm Model 6V 27, 6-Tube Superhet

- Ward 10-Tube All-Wave High-Fidelity Superhet, Series ODM

The Art and Science of

Ultrawideband Antennas

The Art and Science of Ultrawideband Antennas - RF CafeThe Art and Science of Ultrawideband Antennas, by Hans Schantz, is a new publication released by Artech House. Along with theoretical formulations behind the engineering, this book is chock full of examples of actual antennas with very unusual shapes, and there is a nice chart of the evolutionary timeline of UWB antenna development that dates back to Maxwell in the 1800s (a nice wall chart candidate for the lab if the publishers would enlarge and colorize it). "This comprehensive treatment of ultrawideband (UWB) antennas and time-domain microwave engineering serves as an invaluable practical reference for anyone involved in antenna and RF design work. This authoritative volume enables ...

RF Engineer Needed

by COMET Technologies

COMET Technologies USA has an immediate opening in our Plasma Control Technologies (PCT) group for a qualified RF Engineer to work in our San Jose, CA office. We are seeking a team player who will bring their extensive RF product development knowledge and experience to our product development team. This is an outstanding opportunity to learn from and work with experts in high power RF products in the semiconductor industry. Our San Jose PCT engineering team works in a technical, entrepreneurial, ...

I Married a Hobby

I Married a Hobby, August 1948 QST - RF CafeMrs. Helen McKee knew exactly what she was signing up for when she agreed to marry Mr. McKee. After all, she met and got familiar with the guy over the air during some rag chewing sessions. This story is a humorous (and true) account of what life can be like for the spouses of enthusiastic Ham radio operators. We all hope for such an understanding 'significant other.' Melanie has certainly endured and supported a lot of my pastime endeavors over the past 32 years. It's a short read, so take a break and put a smile on your face ...

Cold War Era "Duck & Cover" Drills

Duck & Cover School Drill Cold War - RF CafeI saw this photo with some news story the other day. It is from the Cold War era "Duck and Cover" drills that kids used to do in school in the 1950s and 1960s. The idea was upon hearing the civil defense siren, you needed to crawl under your school desk and cover your head, and remain there until the 'all clear' was given. When I saw this picture, my first thought was how stupid the one kid must have been to have his head and back not even under the desk. He might as well be standing in the middle of the room. Then it occurred to me --- that's probably exactly what I did during our duck and cover drills. Maybe ...

Antenna Electrocution

West Virginia Section Manager Charles Hardy, WV8CH - RF CafeWest Virginia ARRL Section Manager Charles Hardy, WV8CH, of Fayetteville, died June 14, apparently as the result of an accidental electrocution while he was working on an antenna at his home. He was 50 and had been a radio amateur since 2008. Hardy became West Virginia SM in October 2013. Hardy was the President of the Plateau Amateur Radio Association (PARA) and of the Summit Repeater Association. Survivors include his wife, Jane, WV8JH.  RIP ...

Federal Telephone and Radio Company


Federal Telephone and Radio Company Advertisement, January 1954 Radio & Television News - RF CafeCoaxial cable is the most familiar form of RF transmission line for most people these days. Up until 2009 when the U.S. switched to digital television (DTV), there were still a fairly large number of people who had the old 300 Ω twin lead cable running from roof-top antennas to TV sets. Over-the-air reception has petered off precipitously since then. Coaxial cable is undoubtedly more convenient and forgiving regarding routing since proximity to structures - particularly metallic components - than twin lead. Good quality 300 Ω twin lead cable (~30¢/foot today) ...

Notable Tech Quote

Eric Ryan, Method and Olly founder (Inc photo) - RF Cafe"Mediocre hires are like empty calories: They make you bigger but less healthy." - Eric Ryan, Method and Olly founder, in June 2015 Inc magazine article titled "Playbook: The Fine Art of People."

Winged Insects from Electronics Components

Winged Insects from Electronics Components - RF CafeUK-based artist Julie Alice Chappell has given a whole new meaning to electronic component bugs with her array of hand-made bugs and butterflies fabricated from recycled electronics parts. Resistors, capacitors, inductors, integrated circuits, connectors, pins, circuit boards, connectors, switches, adaptors, wire, batteries, terminals, insulation, mounting hardware, oscillators, and other types of components are fair game for inclusion in her handiwork. Some items like the transparent wings are made from "reclaimed acetate," but the majority appear to come from discarded electronic appliances. Those amazingly detailed wings are hand-painted based on examples ...

Sherlock Ohms:

Used Buick Has a Short Fuse

Sherlock Ohms: Used Buick Has a Short Fuse - RF CafeIt's been quite a while since I linked to a Sherlock Ohms; they subjects just haven't been piquing my interest like in the past. This one, however, touches on the subject if proper fuse design, which includes proper placement for servicing. I just posted an article titled "Selecting the Proper Fuse," from Electronics World so this is a timely coupling of pieces on fuses.

Prize Winners for Best "YL" Photos

Prize Winners for Best "YL" Photos, August 1935 Short Wave Craft - RF CafeIn an effort to promote entry of women and girls into the amateur radio hobby, Short Wave Craft magazine ran a few contests for Best "YL" Photos. Amazingly - and maybe there are still instances of it today - many (if not most) of the YLs featured had built their own equipment. In 1935, most people built their own equipment, so that is not too surprising. The winner for this month was a 16-year-old young lady (i.e., "YL") who in fact built her rig. Another winner was an 83-year-old grandma who was born before Marconi, Maxwell, and Hertz did their best work! The third winner was a girl who earned her Ham license at age 6, which back in the day required sending and receiving 5 words per minute (WPM) in Morse code ...

About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024


    Kirt Blattenberger,


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 World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

Copyright  1996 - 2026

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.

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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