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Homepage Archive - September 2023 (page 1)

See Page 1 | 2 | 3 | 4 | of the September 2023 homepage archives.

Thursday the 7th

Channel Master Vacuum Tubes

Channel Master Vacuum Tubes, October 1960 Electronics World - RF CafeIn the 1950s and 1960s, S&H Green Stamps were the hot item for handing out to buyers of your goods and services. Housewives coveted them at grocery and department stores, and he who wore the pants in the family often opted for the gas station and hardware store that handed them out in proportion to money spent. That was also the era when banks gave out toasters, blenders, and clothes irons for opening a new savings account. Channel Master (the TV antenna company) decided it would one-up those enticements by offering Wm. Rogers Holloware Service silver-plated serving trays to distributors who agreed to purchase a certain volume of tubes. This promotion of course was not directed to Harry Homeowner who bought a few tubes per year to service a flaky television or radio. Depending on the condition, most of those silver-plated plates and trays are selling for between $10 and $40 ($1 to $4 in 1960 dollars).

Practical Applications of Simple Math

Practical Applications of Simple Math, July 1944 QST - RF CafeMany people were (and still are) reluctant to approach the theoretical aspect of electronics as it applied to circuit design and analysis. QST (the ARRL's monthly publication) often included equations and explanations in many of their project building articles. Occasionally, an article was published that dealt specifically with how to use simple mathematics. This "Practical Applications of Simple Math" piece in the July 1944 edition of QST is the third installation of at least a four-part tutorial covering resistance and reactance, amplifier biasing, oscillators, feedback circuits, etc. I do not have Part I from the May 1944 edition or Part IV from the August 1944 edition, but if you want to send me those editions, I'll be glad to scan and post them...

Werbel Microwave 2-Way Power Divider/Combiner for 0.5-6 GHz

Werbel Microwave Intros 2-Way Power Divider/Combiner for 0.5-6 GHz - RF CafeModel D-2065-N from Werbel Microwave is a 2-way power splitter / combiner covering the continuous bandwidth of 500 MHz to 6 GHz. The product features low insertion loss of 0.9 dB, high isolation of 22 dB and excellent return loss performance of 19 dB. Tight phase and amplitude matching between outputs. Aluminum body with stainless steel N(F) connectors. Ready for 5G and 6G deployment. The device is RoHS compliant. This part has versatile mounting options. Standard thru holes mount the part from the broad surface, while threaded holes allow for bulkhead rack-mountable mounting. Since 2014, Werbel Microwave has designed and produced high performance radio frequency components for military, commercial, test and measurement applications...

The Quest for Tx/Rx Compatibility

The Quest for Tx/Rx  Compatibility, May 18, 1964 Electronics Magazine - RF CafeThis story from a 1964 issue of Electronics magazine is close to home - literally. Well, it was close to home at the time, anyway. It reports on the work done by the Electromagnetic Compatibility Analysis Center (ECAC)* "...jutting out on a pier across the broad Severn River from the United States Naval Academy at Annapolis." I grew up in the 1960s and 70s just a few miles from there and distinctly recall seeing all the antennas in the area, including the now decommissioned and removed acres-big ELF (extremely low frequency, 30 to 300 Hz) submarine communications antenna farm. The Annapolis location, with its proximity to Washington, D.C., was the home to many government and military installations and defense contractors. It was an electromagnetic signal-rich environment, which made it the perfect setting for studying compatibility issues. Editor John Carroll wrote this rather extensive review of the state of the art for the era, although no doubt the true extent of the capability was known only to those possessing security clearances...

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 stencil symbol has been built to fit proportionally on the included A-, B-, and C-size drawing page templates (or use your own page if preferred). Components are provided for system block diagrams, conceptual drawings, schematics, test equipment, racks (EIA 19", ETSI 21"), and more. Test equipment and racks are built at a 1:1 scale so that measurements can be made directly using Visio built-in dimensioning objects. Page templates are provided with a preset scale (changeable) for a good presentation that can incorporate all provided symbols...

Thanks Again for RIGOL Technologies' Continued Support!

RIGOL Technologies (electronics test equipment)RIGOL Technologies is transforming the Test and Measurement Industry. Our premium line of products includes digital and mixed signal oscilloscopes, spectrum analyzers, function / arbitrary waveform generators, programmable power supplies and loads, digital multimeters, data acquisition systems, and application software. Our test solutions combine uncompromised product performance, quality, and advanced product features; all delivered at extremely attractive price points. This combination provides our customers with unprecedented value for their investment, reduces their overall cost of test, and helps speed time to completion of their designs or projects.

Wednesday the 6th

How Experts Thwart Lightning

How Experts Thwart Lightning, May 1952 Popular Science - RF CafeBenjamin Franklin is credited for coming up with the lightning arrestor scheme based on his famous experiments which ultimately determined that lightning was a form of electrical discharge*. He observed that during intense lightning storms around Philadelphia, the tallest buildings were usually the ones most likely to be struck - and often precipitating significant conflagrations upon itself and spreading to adjacent structures. Being certain that lightning was caused by a very large difference of voltage potential and the subsequent dielectric breakdown with an ensuing very large current flow, he theorized than providing a safe pathway for the current to flow could spare the structure. To test his theory, Ben installed pointed vertical rods at the highest point on the building and ran a conductor down to Earth ground. Amazingly, when a bolt of lightning struck the rod, the current was safely shunted to ground rather than igniting the building. People quickly adopted the scheme and set about installing similar lightning protection systems on tall buildings. After that, only the shortest buildings burned during lightning storms (not really - I made that up)...

Teledyne LeCroy 8650HD 65 GHz, 4-Channel O-scope

Teledyne LeCroy 8650HD 65 GHz, 4−Channel Oscilloscope - RF CafeThis is amazing - a 65 GHz oscilloscope! Their WaveMaster 8000HD series of o-scopes have bandwidths ranging from to 65 GHz, at 320 GS/s, and a 12-bit resolution at full bandwidth and sample rate. "Modern serial data technologies require an oscilloscope with class-leading performance in more ways than ever. Faster signals are driving higher bandwidth requirements. New trends towards higher-order modulations like PAM3 and PAM4 mean that oscilloscope resolution is now a critical consideration. Complex analysis methodologies demand more computing power. Long memory and high sample rates capture both millisecond-scale trends and picosecond-scale glitches. With up to 8 Gpts of acquisition memory, WaveMaster 8000HD captures events occurring over long periods of time, while maintaining high sample rate for visibility into the smallest details, and always at 12 bits of resolution..."

World Distance Charts

World Distance Chart No. 1 & No. 2, July & August 1934 Radio News & The Short-Wave - RF CafeBefore the Internet, cellphone apps, and personal computers, many calculations began with a lookup table, chart, or nomograph. In the case of long distance radio operators [Hams, Short Wave Listener (SWL), and professional types] seeking distance and direction information for pointing antennas, it took a map like this one published by Radio News & Short-Wave magazine in 1934 to estimate an optimal configuration. Such tools were essential in order to determine the best direction to point the antenna, which over a long distance is usually much different than what might be assumed by looking at a flattened projection map of the earth (see "Distance Lends Enchantment" below). Distances in Chart No. 1 are all relative to New York (NYers have always considered themselves the center of the universe ), so operators in other locales need to compensate. Here is one example of many online great circle calculators that allows you to enter two sets of longitude and latitude...

Fujitsu mm-Wave Chip for Multi-Beam 5G Radio

Fujitsu mm-Wave Chip for Multi-Beam 5G Radio - RF cafe"Fujitsu has developed a new millimeter-wave chip for 5G that supports multibeam multiplexing (excluding polarization multiplexing), enabling up to four beams to be multiplexed by a single millimeter-wave chip for the radio units (RU) of 5G base stations. The development was undertaken as part of the 'Research and Development Project of the Enhanced Infrastructures for Post-5G, Information and Communication Systems' commissioned by Japan's New Energy and Industrial Technology Development Organization (NEDO). With conventional technologies, a single millimeter-wave chip is used to generate a single beam, resulting in larger RUs and increased power consumption. When the newly developed technology is applied to actual base stations, Fujitsu demonstrated that it is possible to achieve high speed and high capacity communications of 10 Gbps or more with a device half the size of a conventional RU..."

How Many Microhenrys in That Coil?

How Many Microhenrys in That Coil?, December 1931/January 1932 Short Wave Craft - RF CafeThis is a nice short article covering the calculation of inductances for coils wound on cores and wire sizes. It appeared in a 1932 issue of Short Wave Craft magazine, but of course inductance has not changed since then so it is still relevant. The author recognized that standard formulas, although concise and accurate, are sometimes difficult to work with when calculations for a large number of values is needed for a particular circuit design. To address the situation, he presents a handy nomograph, chart, and a table of typical values. He also introduces a rarely seen term "Nagaoka's correction factor*" for skin effect. A smartphone app, a spreadsheet, or a desktop computer program would be used today to calculate inductance values, number of turns, winding spacing, etc., but back when mechanical slide rules were the order of the day, these visual methods were a real benefit...

RF Cascade Workbook

RF Cascade Workbook - RF Cafe RF Cascade Workbook is the next phase in the evolution of RF Cafe's long-running series, RF Cascade Workbook. Chances are you have never used a spreadsheet quite like this (click here for screen capture). It is a full-featured RF system cascade parameter and frequency planner that includes filters and mixers for a mere $45. Built in MS Excel, using RF Cascade Workbook 2018 is a cinch and the format is entirely customizable. It is significantly easier and faster than using a multi-thousand dollar simulator when a high level system analysis is all that is needed. An intro video takes you through the main features...

Thanks to Wireless Telecom Group for Their Support!

Wireless Telecom Group (RF power and noise measurement) - RF CafeThe Wireless Telecom Group, comprised of Boonton, Holzworth, and Noisecom, is a global designer and manufacturer of advanced RF and microwave components, modules, systems, and instruments. Serving the wireless, telecommunication, satellite, military, aerospace, semiconductor and medical industries, Wireless Telecom Group products enable innovation across a wide range of traditional and emerging wireless technologies. A unique set of high-performance products including peak power meters, signal generators, phase noise analyzers, signal processing modules, 5G and LTE PHY/stack software, noise sources, and programmable noise generators.

Tuesday the 5th

Octane: What It Is, What It Does

Product Feature: Octane, May 1968 Popular Mechanics - RF CafeThis "Product Feature: Octane" pamphlet was an insert in the May 1968 issue of Popular Mechanics magazine. As the subtitle claims, it summarizes "What it is, What it does, How to get your money's worth." Truth is it is really an infomercial from the Sun Oil Company (aka Sunoco), but there is some useful information about how octane levels affect engine performance. Back in the days before computers ran car engines, various factors like temperature rating of spark plugs, compressions ratio, condenser and ignition coil condition, timing (before top-dead-center, BTDC), ambient air temperature and humidity, altitude, and other factors made using the right blend of gasoline necessary to get top performance. Today's computers measure, monitor, and compensate for a lot of that, so most engines can run on just about any gasoline. An exception is high compression ration engines in expensive sports cars requiring high octane levels. As an aside, the current (2023) Sunoco logo is my favorite of the four historical logos. It looks very retro...

ConductRF RF Test Cables to 40 GHz

ConductRF High Performance RF Test Cables to 40 GHz - RF CafeConductRF's TSA89 series of TESTeLINK RF cables a provide microwave circuit and system designers with a versatile solution for most test scenarios and product applications. Here we offer customers a solution for 0.195" diameter coaxial cable with a double shielding effectiveness of ≥100 dB, and a minimum bend radius of 1.2" (30 mm). Power levels to 50 W with <0.68 db/ft at 40 GHz, with <1.35:1 VSWR. Stainless steel connector options include SMA, Type-N, 3.5 mm, 2.92 mm, and 2.4 mm, all of which provide excellent VSWR between DC and 40 GHz. Off-the-shelf TSA89 cables are available immediately from Digi-Key...

Carl & Jerry: Electronic Eraser

Carl & Jerry: Electronic Eraser, August 1962 Popular Electronics - RF CafeTeenage amateur sleuths, cum amateur radio operators, cum high-tech pranksters, cum serious electronics experimenters Carl Anderson and Jerry Bishop save the day once again with a cleverly devised device for erasing the contents of a tape recording. Their assignment, done at the behest of a secretive government agent, might have been made easier if they had had access to the super-strong rare earth neodymium magnets of today since a stereo speaker magnet would not do the job. Instead, the pair was forced to resort to a more challenging solution. As is author Frye's style, in this 1962 issue of Popular Electronics magazine he educates you on the workings of tape recorder erasing circuitry and functionality in the process of telling the story...

Canada Halting Radio Applications and Complaints

Canada Halting Radio Applications and Complaints - RF CafeJust when you think government has committed the most outrageous act possible, along comes something else. Now, the Canadian Radio-television and Telecommunications Commission (CRTC), has announced a suspension of new radio applications and complaints for approximately two years. The CRTC says the decision came because of its desire to focus on implementing the Online Streaming Act, causing concern and surprise among radio broadcasters. "The CRTC justified the two-year deferral, arguing it would allow the public and potential stakeholders to focus efforts on participating in various proceedings aimed at modernizing the Canadian broadcasting system. The regulator emphasized that the implementation process will bring major changes to the system and will require considerable resources from both the Commission and the industry." Now that bureaucrats know they can get you to ruin society with mandatory mask wearing and social distancing, there are no limits to their power.

Hall Effect in Solid State

Hall Effect in Solid State, July 1968 Radio-Electronics - RF CafeAt this point in time, it's hard to imagine an article "introducing" the Hall effect to electronics enthusiasts, but that's the opening statement in this 1968 Radio-Electronics magazine piece. Although Mr. Edward Hall first discovered the eponymous phenomenon in the late nineteenth century, his work was with metals, which exhibit a rather small reaction to the application of a magnetic field on a conductor with current flow. The emphasis in this article is on semiconductor-based Hall effect sensors which produce a much larger change for a given amount of magnetic field. I found the printed title to be a bit strange: "Hall Effect in Solid," and wonder whether it was supposed to have had the word "State" added to it. Otherwise, it doesn't make sense to me. Maybe I'm missing something. Anyway, this is a good primer on Hall effect sensor theory, construction, and application. They are all around us today in the form of position indicators, current flow measurement, magnetic field strength measurement, rotational velocity measurement, and proximity sensor...

Promote Your Company on RF Cafe

Sponsor RF Cafe for as Little as $40 per Month - RF CafeBanner Ads are rotated in all locations on the page! RF Cafe typically receives 8,000-15,000 visits each weekdayRF Cafe is a favorite of engineers, technicians, hobbyists, and students all over the world. With more than 17,000 pages in the Google search index, RF Cafe returns in favorable positions on many types of key searches, both for text and images. Your 728x90-px and 160x600-px Banner Ads are displayed on average 225,000 times per year! 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. If you need your company news to be seen, RF Cafe is the place to be...

Many Thanks to LadyBug Technologies for Their Continued Support!

LadyBug Technologies RF Power Sensors - RF CafeLadyBug Technologies was founded in 2004 by two microwave engineers with a passion for quality microwave test instrumentation. Our employees offer many years experience in the design and manufacture of the worlds best vector network analyzers, spectrum analyzers, power meters and associated components. The management team has additional experience in optical power testing, military radar and a variety of programming environments including LabVIEW, VEE and other languages often used in programmatic systems. Extensive experience in a broad spectrum of demanding measurement applications. You can be assured that our Power Sensors are designed, built, tested and calibrated without compromise.

Monday the 4th

What's Right with the Service Business

Mac's Radio Service Shop: What's Right with the Service Business, May 1955 Radio & Television News - RF CafeAll types of sales and services get accused of ineptness of skill which requires more time than necessary, overcharging for parts and/or labor, underhandedness in faking problems and selling unnecessary replacement parts, improper customer interfacing, sloppiness in appearance and/or work environment, failure to arrive on time for appointments, etc. Some of the most often cited these days are auto mechanics, cellphone repairers, home improvement contractors, lawn care, and builders. Up until about a decade ago when cellphone repair began to dominate over computer repair, the latter was a big source of complaints. In the 1950s and 60s, it was TV and radio repairmen who took a lot of abuse not just from their customers, but from large, organized electronic service conglomerates and were abetted by mostly ignorant media outlets looking for a good story (even if they had to make one up - same as they do today). Many cases of media fraud have been documented in the bad-guy sales and service arenas, with one of the most well-known being NBC Dateline's staged blowing up of the GMC pickup truck using model rocket engines to ignite the fuel tank (c1992). That's not to say there were not legitimate cases of scandal...

GTO - What Does It Stand For?

GTO - What Does It Stand For? - RF CafePontiac introduced their GTO muscle car in 1963 and produced it through 1974 - the year I turned 16 and got a driver's license. GTOs were hot items among those of us who could not (and still can't) dream of owning a Corvette or a foreign job. My first car was a 1969 Camaro SS, but a lot of my friends opted for Mustangs, Firebirds, Roadrunners, Chevelles, Novas, etc. I didn't hold it against them ;-) We had "alternate" meanings for the names of some cars. A few that come to mind are that Ford meant "Fix Or Repair Daily," Mopar was "MOre Parts And Repairs," GMC meant "Gay Man's Car" (hey, it was the 70s), and GTO was "Gas, Tires, Oil" (since they went through a lot of all three). It was not until recently, whilst perusing a 1965 issue Mechanix Illustrated magazine that I learned GTO actually comes from "Gran Turismo Omologato." Translated from Italian, it means "Grand Touring Homologated." No, that's not related to GMC; homologated means "approved." Never stop learning.

In-Situ Radiated Emissions Testing of Large Systems

In-Situ Radiated Emissions Testing Large Systems - RF Cafe"Combination of Near- and Far-Field Measurements for Radiated Emissions. As an EMC consultant, assessing the EMC performance of large systems and machines is a common task. Over the years, I have encountered a wide range of equipment, including high-power variable-speed drives (VSDs) in factories, specialized equipment installed on ships, food processing equipment, and many others. With technological advancements, there are now even more large systems that require in-situ EMC assessment, such as quantum computers, additive manufacturing machines, waste recycling equipment, renewable energy power generators, high-power electric vehicle chargers, and more. While testing equipment in an accredited EMC chamber is ideal, it may not be a realistic option for large machines for several reasons. First, a large chamber is required to accommodate these machines. Second, while the chamber is being charged for use, it can take days or even weeks to install the machine in a chamber and then disassemble it after the testing is complete. Finally, logistics and lead time for using the chamber can also add to the overall cost and time required for EMC testing of large machines...."

Practical Design of Mixer Converter Circuits

Practical Design of Mixer Converter Circuits, February 1941 QST - RF CafeIn the present era, designing a frequency converter circuit consists in most cases of picking from a catalog an IC or connectorized component that has the characteristics you need from a gain and mixer spurious product standpoint. Add a couple filters, a local oscillator (although in some cases the oscillator is part of the IC), and a power supply, and you're good to go. Of course there are special cases where you have to use a basic mixer and do everything yourself, but even that is simpler than designing a primary circuit using diodes or vacuum tubes as rectifiers. Obtaining match sets for good mixer spurious product cancellation is very difficult, especially in a large volume production environment. It really is amazing what engineers and hobbyists of yore were able to accomplish using point-to-point wiring and a slide rule. Here is a good article form the February 1941 QST magazine that discusses some of the considerations. Maybe you have an old radio to which this knowledge will apply...

Promote Your Company on RF Cafe

Sponsor RF Cafe for as Little as $40 per Month - RF CafeBanner Ads are rotated in all locations on the page! RF Cafe typically receives 8,000-15,000 visits each weekdayRF Cafe is a favorite of engineers, technicians, hobbyists, and students all over the world. With more than 17,000 pages in the Google search index, RF Cafe returns in favorable positions on many types of key searches, both for text and images. Your 728x90-px and 160x600-px Banner Ads are displayed on average 225,000 times per year! 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. If you need your company news to be seen, RF Cafe is the place to be...

Please Thank Lotus Communication Systems for Their Support!

Lotus Communication Systems Modular RF/Microwave Components - RF CafeLotus Communication Systems began in 2009, setting up CNC machine shop and RF/microwave assembling and testing lab in Middlesex Country, Massachusetts. Lotus is committed to highest quality and innovative products. Each RF/microwave module meets exceedingly high standards of quality, performance and excellent value, and are 100% Made in the USA. Lotus' RF/microwave products cover frequency band up to 67 GHz. Lotus also offers an COTS shield enclosures for RF/microwave prototyping and production. All products are custom designed. We will find a solution and save your time and cost. Lotus has multiple 4 axis CNC machines and LPKF circuit plotters. In stock, 1-day free shipping.

Sunday the 3rd

Electronics Theme Crossword for September 3rd

Electronics Theme Crossword Puzzle for September 3rd, 2023 - RF CafeThis week's crossword puzzle for September 3rd sports an electronics theme. This being the 3rd day of the month, many of the words begin and/or end and/or contain with the letter "C." Clues for words containing "C" are marked with an asterisk (*). All RF Cafe crossword puzzles are custom made by me, Kirt Blattenberger, and have only words and clues related to RF, microwave, and mm-wave engineering, optics, mathematics, chemistry, physics, and other technical subjects. 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, Hedy Lamarr, or the Tunguska event in Siberia). The technically inclined cruciverbalists amongst us will appreciate the effort. Enjoy!

Get Your Custom-Designed RF Cafe Gear!

Custom-Designed RF-Themed Cups, T-Shirts, Mouse Pads, Clocks (Cafe Press) - RF CafeThis assortment of custom-designed themes by RF Cafe includes T-Shirts, Mouse Pads, Clocks, Tote Bags, Coffee Mugs and Steins, Purses, Sweatshirts, and Baseball Caps. Choose from amazingly clever "We Are the World's Matchmakers" Smith chart design or the "Engineer's Troubleshooting Flow Chart." My "Matchmaker's" design has been ripped off by other people and used on their products, so please be sure to purchase only official RF Cafe gear. My markup is only a paltry 50¢ per item - Cafe Press gets the rest of your purchase price. These would make excellent gifts for husbands, wives, kids, significant others, and for handing out at company events or as rewards for excellent service. It's a great way to help support RF Cafe. Thanks...

Please Thank IPP for Their Long-Time Support!

Innovative Power ProductsInnovative Power Products has been designing and manufacturing RF and Microwave passive components since 2005. We use the latest design tools available to build our baluns, 90-degree couplers, directional couplers, combiners/dividers, single-ended transformers, resistors, terminations, and custom products. Applications in military, medical, industrial, and commercial markets are serviced around the world. Products listed on the website link to detailed mechanical drawings, electrical specifications, and performance data. If you cannot find a product that meets your requirements on our website, contact us to speak with one of our experienced design engineers about your project.

Friday the 1st

An Introduction to Analog Computers

 An Introduction to Analog Computers, December 1961 Popular Electronics - RF CafeAnalog computers are said to be the oldest form of computer, but I maintain digital computers predated analog computers by millennia. That's right, our ancient forebears certainly counted using their fingers and toes (aka digits) for addition and subtraction long before anyone assembled a mechanism for performing mathematical operations. Astronomers were some of the most prolific inventors of analog computers for determining the positions of planets, moons, comets, and even longitude and latitude upon the face of the Earth. Charles Babbage made one of the most famous mechanical computers - the Babbage Difference Engine. Probably the most widely used analog computer is one form or another of a slide rule. I say one form or another because many of the cardboard type calculators are forms of slide rules. One type of analog computer we use in the RF business everyday is a frequency mixer, which takes two numbers (frequencies) and produces the sum and difference. This 1961 issue of Popular Electronics magazine reports on a couple low cost analog computers available at the time, including the three-dial Edmonds Analog Computer...

BT Selling off Red Dr. Who-Style Phone Boxes

BT Selling off Red Dr. Who-Style Phone Boxes - RF Cafe"As the UK's famous red phone box turns 100 next year, UK telco group BT is encouraging communities to repurpose another 1000 of them for things such as defibrillator stations and micro-art galleries. BT began the Adopt a Kiosk programme in 2008, in which communities, parish councils and registered charities can repurpose redundant phone boxes for the modest fee of £1. Since then more than 7,200 phone boxes have been snapped up and turned into things ranging from the practical, such as defibrillator units, and the twee, such as and pint-sized libraries, art galleries and local museums. It's now announced there are 1000 more waiting to be snapped up, and is encouraging local people to claim them. BT will continue to provide electricity to power the light for adopted phone boxes for free, which is nice of them. At their peak in the 1990s there were around 100,000 phone boxes in the UK. Since mobile phone ownership and signal coverage became more and more widespread, BT has gradually decommissioned..."

Bell Telephone Laboratories

Bell Telephone Laboratories Advertisement, October 1949 Radio & Television News - RF CafeBell Telephone Laboratories used to run some pretty interesting advertisements in magazines back in the 1940s through 1960s that touted the many communications innovations coming from their scientists and engineers. They built what was indisputably the worlds best, most reliable telephone network. It, along with the Interstate Highway System, is credited for a large part of what fueled America's growth so significantly after World War II. This ad from a 1949 issue of Radio & Television News magazine tells how repairmen used a specially designed sensor to trace out faulty phone lines by listening for a test signal sent out by the central office. What caught my attention about this ad was the uncanny resemblance the man in the photo has to Melanie's father - especially with the ball cap and glasses. She was amazed when I showed her the picture...

How to Target RFCafe.com for Your Google Ads

Google AdSense - it makes good sense - RF CafeOne aspect of advertising on the RF Cafe website I have not covered is using Google AdSense. The reason is that I never took the time to explore how - or even whether it is possible - to target a specific website for displaying your banner ads. A couple display opportunities have always been provided for Google Ads to display, but the vast majority of advertising on RF Cafe is done via private advertisers. That is, companies deal with me directly and I handle inserting their banner ads into the html page code that randomly selects and displays them. My advertising scheme is what the industry refers to as a "Tenancy Campaign," whereby a flat price per month is paid regardless of number of impressions or clicks. It is the simplest format and has seemed to work well for many companies. With nearly 4 million pageviews per year for RFCafe.com, the average impression rate per banner ad is about 220,000 per year (in six locations on each page, with >17,000 pages). That's pretty good exposure for $300 per month. Some companies have expressed an interest in being able to manage their advertising accounts themselves a la the Google AdSense program...

Anatech Electronics Intros 3 Filter Models for August

Anatech Electronics Intros 3 Filter Models for August 31st, 2023 - 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. Three new filters have been announced: a 2195-2210 MHz bandpass cavity filter with a high side rejection of 40 dB minimum at 2125 MHz and low side rejection of 10 dB minimum at 2179.5 MHz, a 2198.5-2204.5 MHz cavity bandpass filter with high side rejection of 25 dB minimum at 2214.5 MHz and low side rejection of 25 dB minimum at 2188.5 MHz, and a 2245 MHz cavity bandpass filter with high side rejection of 50 dB maximum at 2340 MHz and low side rejection of 50 dB maximum at 2150 MHz. Custom RF power filter and directional couplers designs can be designed and produced with required connector types when a standard cannot be found...

Electronics Newsletter - Mars Reentry Vehicle

Electronics Newsletter (Mars Reentry Vehicle), January 24, 1964 Electronics Magazine - RF CafeRemember when the first manned spacecraft transported astronauts to Mars and then back to Earth in the 1970s - a 13-month round trip? Yeah, me neither. In the mid-1960s, Electronics magazine reported on the preparations being made by NASA for Mars travel at the same time they were busy preparing the Apollo mission to the moon. The world's first manned orbit (Apollo 8) of the moon didn't happen until in December 1968, a mere seven months before the historic July 1969 Apollo 11 moon landing, but NASA was wasting no time planning for the next big thing. Of course you know to date we never have made it to Mars with a manned spacecraft, but the headlines are still filled with "any day now" projections by SpaceX's Elon Musk (whom I like) and his contemporaries. Sure, I would love to be alive to witness a manned mission to Mars, but I'd settle for another manned mission to the moon for establishing a lunar way station for future trips to Mars. Moon base objectionists [sic] say its lack of atmosphere to burn up meteorites is an insurmountable hazard - just look at all the craters there! However, the International Space Station (ISS), Apollo-Soyuz, Skylab, Mir, and Salyut existed for decades (not at the same time) without a protective atmosphere and without a major incident. Atmospheric winds have erased nearly all evidence of the meteorites that have reached the Earth's and Mars' surface; many have impacted over the millennia.

These archive pages are provided in order to make it easier for you to find items that you remember seeing on the RF Cafe homepage. Of course probably the easiest way to find anything on the website is to use the "Search RF Cafe" box at the top of every page. About RF Cafe.

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