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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 typing up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

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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Windfreak Technologies Frequency Synthesizers - RF Cafe

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Remember when … schematics were drawn with pencil and paper and required layout planning in advance?

Today in Science History

Tech Industry Headlines

Tech Industry Headlines - RF Cafe- Archive -

• 3.45 GHz Auction Surges Past $14.8B Reserve Price

• Technician License Training Course on ARRL YouTube Channel

• Lack of Power Grids Doomed Early Electric Cars

• When Will 6G Start to Emerge?

• Huawei Makes Push for Greener 5G Networks

• Global MilSatCom Confex to Focus on Disruptive Space Technology

• ARDC Grants to Fund Amateur Radio Project Expansions

• Microsoft Says Transport Latency Can Nullify Benefits of 5G

• ETSI Global Standard for Reconfigurable Intelligent Surfaces 

Morse Code vs. Texting on Jay Leno Show

Morse Code vs. Texting Contest on the Jay Leno's "The Tonight Show" - RF Cafe Video for EngineersOn the May 13, 2005 episode of The Tonight Show, Jay Leno held a Morse code vs. SMS speed contest between two Ham Radio operators using Morse code and two Millennials using their smartphones for texting (SMS). At least one member of the audience thought texting would win. Watch the video to see if she was right. Mr. Chip Margelli (K7JA) did the sending. He declares, "Let me assure you that we never saw that message before I flipped the blue card over. Each message, in rehearsal, was different. The character count was the same as the one during dress rehearsal, though, to account for the time slot. And they put the card on the table "upside down" creative to how I flipped it, as you can see on the video." Mr. Ken Miller (K6CTW) did the receiving...

Station Design for DX (Part IV)

Station Design for DX (Part IV), December 1966 QST - RF CafeIn 1966, Paul Rockwell wrote a 4-part series for the ARRL's QST magazine on station design for long distance communications (DX) that covered antenna selection and siting (Part I), economics and construction (Part II), Station Configuration and Receiver Topics (Part III), and Propagation Quirks and Operating Tips (Part IV). This the the forth and final installment. One of the handy-dandy items shown is a Geochron Map-Clock which had a template of the familiar day-night analemma-based curve superimposed on the projection map of the earth. It was quite a deal in its day, and believe it or not, the company is still in business offering software-based Map-Clocks and restoring models all the way back to when they first came out in 1965 (only a year before it appeared here)...

Anisotropic Film Packs Transistors More Densly

Anisotropic Film Packs Transistors Closer Together - RF Cafe"Stacks of atomically thin sheets of molybdenum disulfide both move and block heat. Packing transistors close together raises the problem of heat frying the devices. Now scientists have developed an artificial material that is one of the best ever at conducting heat in one direction while keeping that heat insulated from its surroundings in other directions. The research might one day help microchips grow more powerful without breaking from overheating. As electronics continue to miniaturize, greater amounts of heat are getting produced in a given space, which makes heat control a key challenge in electronic design..."

Carl & Jerry: Succoring a Soroban

Carl & Jerry: Succoring a Soroban, March 1963 Popular Electronics - RF CafeDo you know what a soroban is? I have to admit ignorance prior to reading this 1963 "Carl and Jerry" adventure in Popular Electronics. As with many of these stories, real equipment, people, and companies were referenced; this time it was the Pastoriza Personal Analog Computer, a modular electronics system for calculating differential equations. The cost was around $300 (~$2,700 in c2021 money per BLS Inflation Calculator). Analog Devices bought the company from James Pastoriza in 1969. What does the Pastoriza computer have to do with the story, you might ask? Nothing, really; it was mentioned in a discussion Carl and Jerry had when accepting a calculating speed challenge from obnoxious dormitory mate, Bruce. Jerry would add a series of numbers on his soroban while Bruce would add them with a pencil and paper. The winner got bragging rights...

RF & Electronics Stencils for Visio

RF & Electronics stencils for Visio r4 - RF CafeWith more than 1000 custom-built stencils, this has got to be the most comprehensive set of Visio Stencils available for RF, analog, and digital system and schematic drawings! Every object has been built to fit proportionally on the provided A-, B- and C-size drawing page templates (or can use your own). Stencils are provided for equipment racks and test equipment, system block diagrams, conceptual drawings, and schematics. Unlike previous versions, these are NOT Stencils, but instead are all contained on tabbed pages within a single Visio document. That puts everything in front of you in its full glory. Just copy and paste what you need on your drawing. The file format is XML so everything plays nicely with Visio 2013 and later...

Thanks to TotalTemp Technologies for Continued Support!

TotalTemp Technologies - RF CafeTotalTemp Technologies has more than 40 years of combined experience providing thermal platforms. Thermal Platforms are available to provide temperatures between −100°C and +200°C for cryogenic cooling, recirculating circulating coolers, temperature chambers and temperature controllers, thermal range safety controllers, space simulation chambers, hybrid benchtop chambers, custom systems and platforms. Manual and automated configurations for laboratory and production environments. Please contact TotalTemp Technologies today to learn how they can help your project.

Science Theme Crossword Puzzle for October 24th

Science Theme Crossword Puzzle for October 24th, 2021 - RF CafeThis Science Theme Crossword Puzzle for October 24 has many words and clues related to RF, microwave, and mm-wave engineering, optics, mathematics, chemistry, physics, and other technical subjects. The letter "P" figures Prominently in this crossword. As always, this crossword contains no names of politicians, mountain ranges, exotic foods or plants, movie stars, or anything of the sort unless it/he/she is related to this puzzle's technology theme (e.g., Reginald Denny or the Tunguska event in Siberia). The technically inclined cruciverbalists amongst us will appreciate the effort. Enjoy!

Please Thank IPP for Their Long-Time Support!

Innovative Power ProductsInnovative Power Products (IPP) has over 30 years of experience designing & manufacturing RF & microwave passive components. Their high power, broadband couplers, combiners, resistors, baluns, terminations and attenuators are fabricated using the latest materials and design tools available, resulting in unrivaled product performance. Applications in military, medical, industrial and commercial markets are serviced around the world. Please take a couple minutes to visit their website and see how IPP can help you today.

Radio in the Atom Tests

Radio in the Atom Tests, July 1946 Radio-Craft - RF CafeA year after the two atom bombs were dropped to end World War II, the newly formed Atomic Energy Commission conducted detailed detonation tests at the Bikini Atoll, in the South Pacific. Most people more than 40 years old are very familiar with the images of the giant mushroom cloud that formed over the site. This "Radio in the Atom Tests" article from the July 1946 issue of Radio−Craft magazine reports on plans being made to measure and record sound pressure, nuclear radiation, radio and radar signatures, temperature, light spectrum and intensity, and other parameters. The information would be used for improved bomb making, nuclear power generation, medical imaging and treatment, and general research on nuclear fission and fusion (a fission implosion is to initiate a fusion reaction)...

Drones for Safer & Better Cellular Connectivity

Drones for Safer & Better Cellular Connectivity - RF Cafe"Researchers from King Abdullah University of Science & Technology have proposed a solution to address the widespread public concern about electromagnetic fields (EMF) exposure from mobile networks. Masters' student Zhengying Lou, postdoctoral student Ahmed Elzanaty and distinguished professor Mohamed-Slim Alouini of KAUST proposed that mobile tethered drones might offer a speedy and environmentally friendly alternative for receiving terrestrial base stations while alleviating public concerns about exposure to EMF. Ahmed Elzanaty stated that it is mainly a problem of perception, but this concern has led to attempts to destroy signaling towers, especially those associated with the 5G network. He does point out, however, that recent experiments on animals link some adverse health impacts with long-term exposure to EMF..."

Radar Network for Air Traffic Control

Radar Network for Air Traffic Control, February 1957 Radio & Television News - RF CafeThe Civil Aeronautics Administration (CAA), born in 1940 and now known as the Federal Aviation Administration (FAA, since 1958), was established originally to regulate the burgeoning commercial airline and cargo transport air traffic as well as the private aviation activity. According to an FAA document, on April 3, 1947, CAA controllers began in-service evaluations of the ground approach control (GCA) radar system at Washington National and Chicago Municipal airports. It was commissioned for official use by the CAA on January 7, 1952, at Washington National Airport. This story from a 1957 edition of Radio & Television News magazine reports on the system upgrade to long-range radars that would permit, eventually, continuous coverage across the entire USA...

Thanks to PCB Directory for Continued Support!

PCB  Directory - RF CafePCB Directory is the largest directory of Printed Circuit Board (PCB) Manufacturers, Assembly houses, and Design Services on the Internet. We have listed the leading printed circuit board manufacturers around the world and made them searchable by their capabilities - Number of laminates used, Board thicknesses supported, Number of layers supported, Types of substrates (FR-4, Rogers, flexible, rigid), Geographical location (U.S., China), kinds of services (manufacturing, fabrication, assembly, prototype), and more. Fast turn-around on quotations for PCB fabrication and assembly.

Crosley Radio Advertisement

Crosley Radio Advertisement, February 1932 Radio-Craft - RF CafeCommercially available radio receivers for the home had only been around for a couple decades when this advertisement from Crosley appeared in a 1932 issue of Radio-Craft magazine. I keep looking in old electronics magazines for an ad featuring my 1941 Crosley model 03CB console radio, but thus far with no luck. There is a chance, although I have not seen any direct evidence of it, that the 03CB chassis was sold as a special upgrade to the less ornate 02CA model. What makes it special is that it was probably one of the last new radios sold prior to the shift of material usage to military equipment in World War II...

Promote Your Company on RF Cafe

Sponsor RF Cafe for as Little as $40 per Month - RF CafeNew Scheme rotates all Banners in all locations on the page! RF Cafe typically receives 8,000-15,000 website visits each weekday. RF Cafe is a favorite of engineers, technicians, hobbyists, and students all over the world. With more than 16,000 pages in the Google search index, RF Cafe returns in favorable positions on many types of key searches, both for text and images. New content is added on a daily basis, which keeps the major search engines interested enough to spider it multiple times each day. Items added on the homepage often can be found in a Google search within a few hours of being posted. I also re-broadcast homepage items on LinkedIn. If you need your company news to be seen, RF Cafe is the place to be.

Many Thanks to Bittele Electronics for Continued Support!

Bittele Electronics PCB Fabrication - RF CafeSince 2003, Bittele Electronics has consistently provided low-volume, electronic contract manufacturing (ECM) and turnkey PCB assembly services. It specializes in board level turnkey PCB assembly for design engineers needing low volume or prototype multi-layer printed circuit boards. Free Passive Components: Bittele Electronics is taking one further step in its commitment of offering the best service to clients of its PCB assembly business. Bittele is now offering common passive components to its clients FREE of Charge.

Mac's Radio Service Shop: Salesmen and Service Technicians

Mac's Radio Service Shop: Salesmen and Service Technicians, June 1952 Radio & Television News - RF CafeDealing with on-site traveling salesmen has always been a sort of love-hate (or maybe a necessary evil, to put it less extremely) relationship - for both the salesman and the engineer/technician. Not having been in the engineering design environment for nearly two decades, I don't know how much face-to-face contact is made anymore. Up through the early 2000s, I was still occasionally meeting with components salesmen. In this June 1952 issue of Radio & Television News magazine's Mac's Radio Service Shop technodrama, proprietor Mac McGregor takes the occasion of an afternoon rain torrent to discuss the situation with two of his regular sales representatives. The open trading of pet peeves and appreciated behavior on both sides is common sense stuff, but are courtesies often forgotten while in the throes of the daily work grind. Mac references a book...

19 Smaller Carriers Urge FCC to Auction 2.5 GHz

19 Smaller Carriers Urge FCC to Auction 2.5 GHz - RF Cafe"A coalition of 19 smaller U.S. carriers are calling on the Federal Communications Commission to move on scheduling a spectrum auction for licenses in the 2.5 GHz band, saying it’s a critical opportunity for rural and underserved areas. The service providers, all members of the Competitive Carriers Association (CCA), sent an October 11 letter (PDF) to Acting Chairwoman Jessica Rosenworel that urges the regulator to immediately set an auction date for the more than 8,000 mid-band licenses in its inventory. C Spire, GCI Communications, Union Wireless, Carolina West, Viaero Wireless, and Nex-Tech Wireless are among some of the signatories..."

Many Thanks to Anatech Electronics for Long-Time Support!

Anatech Electronics logo - RF CafeAnatech Electronics (AEI) manufactures and supplies RF and microwave filters for military and commercial communication systems, providing standard LP, HP, BP, BS, notch, diplexer, and custom RF filters, and RF products. Standard RF filter and cable assembly products are published in our website database for ease of procurement. Custom RF filters designs are used when a standard cannot be found, or the requirements dictate a custom approach for your military and commercial communications needs. Sam Benzacar's monthly newsletters address contemporary wireless subjects. Please visit Anatech today to see how they can help your project succeed. 

Electrical Conductors, Wiring Techniques, & Schematic Reading

Introduction to Electrical Conductors, Wiring Techniques, and Schematic Reading - RF CafeNavy Electricity and Electronics Training Series (NEETS) Module 4 - Introduction to Electrical Conductors, Wiring Techniques, and Schematic Reading. Upon completing this chapter, you should be able to: 1. Recall the definitions of unit size, mil-foot, square mil, and circular mil and the mathematical equations and calculations for each. 2. Define specific resistance and recall the three factors used to calculate it in ohms. 3. Describe the proper use of the American Wire Gauge when making wire measurements. 4. Recall the factors required in selecting proper size wire. 5. State the advantages and disadvantages of copper or aluminum as conductors. 6. Define insulation resistance and dielectric strength including how the dielectric strength of an insulator is determined. 7. Identify the safety precautions to be taken when working with insulating materials...

Build This Novice CW Transmitter

Build This Novice CW Transmitter, February 1955 Popular Electronics - RF CafeEven though this CW (continuous wave, for sending Morse code) transmitter circuit was published in 1955 in Popular Electronics magazine, it is still legal for today's Amateur radio operator. Portions of the 40-meter and 80-meter bands are still reserved exclusively for CW operation. As of 2021, the 40−meter band (7.025-7.125 MHz) and the 80−meter band (3.525-3.600 MHz) are both reserved for CW for Hams holding either Novice (no longer issued) or Technician licenses. Additionally, the 15−meter band (21.025-21.200 MHz) and the 2−meter band (144.0-144.1 MHz) have CW-only areas. That is different than the frequencies given in the article, so beware if you are tempted to throw one together for old time's sake. The value for XTAL will need...

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