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- Welcome to the RF Cafe Website Archives -

Established in February of 2014, RFCafe.net is set up as an archival resource for making certain that all information originally presented on RFCafe.com is readily available. With the exception of required index pages and some images, there is no intentional duplication of content between RFCafe.com and RFCafe.net.

If you can no longer reach a webpage that used to be on RFCafe.com, please change the beginning part of the URL from www.RFCafe.com to www.RFCafe.net and that should solve the issue for you. Example:

From: http://www.rfcafe.com/miscellany/homepage-archive/2014/smart-car-tipping.htm
    To: http://www.rfcafe.net/miscellany/homepage-archive/2014/smart-car-tipping.htm

I am working to restore as many web pages as possible as far back towards RF Cafe's creation date of July 1999. That's a lot of pages and a lot of images - so many, in fact, that their presence on the RFCafe.com web server was getting bogged down; hence the rfcafe.net website. Thanks, as always, for your loyal patronage of RF Cafe!

 

Sincerely,

Kirt Blattenberger,  Owner / Webmaster

 

June 10th RF Cafe Crossword Puzzle w/Weekly Headlines

RF Cafe Engineering Crossword Puzzle w/Weekly Headlines June 10, 2018At least 10 clues with an asterisk (*) in this technology-themed crossword puzzle are pulled from this past week's (6/4 - 6/8) "Tech Industry Headlines" column on the RF Cafe homepage. For the sake of all the avid cruciverbalists amongst us, each week I create a new technology-themed crossword puzzle using only words from my custom-created related to engineering, science, mathematics, chemistry, physics, astronomy, etc. You will never find among the words names of politicians, mountain ranges, exotic foods or plants, movie stars, or anything of the sort. You might, however, see someone or something in the exclusion list who or that is directly related to this puzzle's theme...


Too-Small Cubicles: 1932 "The Wireless World" Article 

Broadcast Brevities, March 9th, 1932 The Wireless World Article - RF CafeAs the old saying goes, "The more things change, the more things stay the same." Incredibly, back in 1931 people were complaining about shrinking office cubicle sizes. To wit: "At 'Broadcasting House' rooms measuring 8ft. x 6ft. are being coveted by the many people who will be condemned to labour in cubicles 7ft. x 5ft. The Civil Engineer himself, who helped to design and erect the building, works in a compartment in which, as the American said, 'You couldn't cuss a cat without getting hair on your teeth.'" ...and whoa!, dig this statement by the author regarding the demise of "local oscillators" in the UK (noisy regenerative Rx LO interference): "Steps might be taken to ensure the survival of a few specimens, perhaps by the founding of a national reservation similar to those which accommodate the Red Indians in America. The few remaining squealers and their..."


Light Modulation of Semiconductors

Letters from Our Readers, May 1969 Electronics World - RF CafeThis letter to the editor column from a 1969 issue of Electronics World got my attention because of the submission by reader Walter T. Stevenson. He mentions having discovered that semiconductors, in his case a transistor, could have their junction conductance modulated by ambient light sources, in his case a fluorescent light. Evidently some of the early transistors were shipped on a substrate where the die was potted with a translucent epoxy compound that permitted some light penetration. At least one manufacturer switched to an opaque compound as a result of Mr. Stevenson's report. I remember the first I experienced the phenomenon was as a technician working...


Meter-Reading Quiz

Meter-Reading Quiz, June 1966 Popular Electronics - RF CafeHere is the 46th quiz I have posted from 1960s and 1970s issues of Electronics World and Popular Electronics magazines. Most of were created by Robert P. Balin. I like to save these for Friday afternoons. Guys like me who cut our teeth on analog meters read these indications like a second language. Even novices usually do a good job on the meter needles, but reading a mechanical micrometer (#9) might be more of a challenge, especially if you have never used one before. The same goes for a dial caliper. Can you read the dials on a mechanical gas or electric meter, where some spin CW and others spin CCW?...


Antenna Orientation

Antenna Orientation, March 1965 Popular Electronics - RF CafeElectronics-themed comics are usually saved for Fridays, but what the hey; maybe you need some humor on Tuesday this week. At least three of these antenna-based comics required a harder look to determine what was happening and why it is humorous. One of those even requires a little technical insight to "get it." To see my take on the comics, highlight the text...


Transistor Transition (Editorial)

Transistor Transition (Editorial), February 1953 Radio-Electronics - RF CafeHugo Gernsback was well-known not just for his technical prowess, but for an uncanny ability to predict future developments in electronics, transportation, and production methods. Barely three years had passed since Messrs. Bardeen, Shockley, and Brattain, announced their invention of the transistor when this editorial titled, "Transistor Transition" appeared in Radio-Electronics magazine. Gernsback mentions the concept of "appliqued circuits" (i.e., printed circuits) and "roll-up display" transistor picture tubes (i.e., flexible displays), and "pocket radios" that can be held up to the ear. Production prices for transistors at the time were about $8 apiece, which is the inflation-adjusted equivalent of $76 in 2018. At that price point, who could blame the pro-tube, never-transistor crowd from denying the possibility of transistors ever replacing tubes...


Solid State Electronics - The Spacistor Et Al

Solid State, August 1967 Popular Electronics - RF CafeThe monthly "Solid State" column in Popular Electronics reported on all the wonderful new germanium- and silicon-based devices being prepared for the brave new world of electronics. It is a good resource for historical research. For instance, did you know that the unijunction transistor was originally going be called a "double-base diode?" How about a feeble attempt to integrate solid state and vacuum tubes by incorporating a "semiconductor cold cathode" to replace the standard 6.3 V or 12.6 V heated cathode for supplying an electron source? Have you ever heard of a "spacistor?" A 1957 edition of "Proceedings of the IRE" published a paper by Pucel and Statz titled, "The Spacistor, A New Class of High-Frequency Semiconductor Devices." The summary statement says..."


RF Cafe Engineering & src="https://www.rfcafe.com/miscellany/homepage-archive/2019 Puzzle April 8

RF Cafe Engineering & src=Each week, for the sake of all avid cruciverbalists amongst us, I create a new technology-themed crossword puzzle using only words from my custom-created lexicon related to engineering, science, mathematics, chemistry, physics, astronomy, etc. Words for clues having an asterisk (*) after them are part of this week's Easter theme. You will never find among the words names of politicians, mountain ranges, exotic foods or plants, movie stars, or anything of the sort. You might, however, see someone or something in the exclusion list who or that is directly related to this puzzle's theme...


Electronic Geometry Quiz

Electronic Geometry Quiz, January 1965 Popular Electronics - RF CafeUnless I find one I missed from my collection of vintage Popular Electronics magazines, this could be the last Friday electronics quiz for a while. All of the quizzes were created by Robert p. Balin, and range in difficulty from relatively easy to head scratchers (for typical test takers like myownself). Sometimes modern readers will be stumped by references to dated drawings and/or terms like vacuum tubes and CRTs (which are themselves vacuum tubes, of course). This Electronics Geometry Quiz might require a Millennial handicap on item "E" if you spaz out over the picture, but if you get the other nine correct, you'll get all ten by default. This is probably...


Are Modern Military Radars Infallible?

Are Modern Military Radars Infallible?, September 1971 Popular Electronics - RF CafePrior to the availability of high speed semiconductor circuitry, there was not enough computational power available - particularly in airborne platforms - to perform a significant amount of real-time signal processing in radar systems. Analog methods were available to do things like stationary target cancellation (moving target indication, MTI) and noise reduction to eliminate clutter on the plan position indicator (PPI, aka radar scope), range and azimuth blanking of selected regions of the scan, signal discriminators and integrators, and false target elimination via pulse repetition rate (PRR) and pulse repetition interval (PRI). There was nothing, really, in the older vacuum tube based systems to derive a target profile based on radar cross section (RCS) and signal vector (amplitude and phase) processing. This 1971 article reported on what was at the time information about very new technology that was just being...


Electronic Geography Quiz

Electronic Geography Quiz, April 1970, Popular Electronics - RFCafe1970 just doesn't seem all that long ago, but holy moly that is going on half a century! This quiz appeared in Popular Electronics to test the hobbyist's knowledge of the whereabouts of some of the major components and products companies. Many of the businesses have gone defunct, been bought and absorbed by other companies, or if they do still exist, are in new locations. It will take a real old-timer to score well on this quiz without resorting to lucky guesses. Still, there are a couple stalwart manufacturers today that even a newcomer can get right. Most of the Popular Electronics quizzes were created by Robert P. Balin, but this one was dreamed up by Thomas Haskett...


After Class: Understanding Decibels

After Class: Understanding Decibels, November 1958 Popular Electronics - RF CafeDecibels always have been and always will be a daunting subject to a lot of people. For electronics types, the issue of when to multiply the logarithm of the ratio by 10 or by 20 seems to be the biggest stumbling block. After many years of working with decibels, it becomes second nature. There are still instances, though, where I see seasoned engineers and technicians routinely confuse unreferenced decibel units (dB, the logarithm of a ratio) with logs of ratios referred to some base value (dBm, dBV, etc.). The bel unit was originally created to quantitatively assign changes in perceived levels of sound loudness...


Spot News - Electronic Industry News

Spot News - Electronic Industry News, April 1960 Electronics World - RF CafeTelevision broadcast stations were quickly growing in number in the post-Korean War era and the FCC needed to devise a scheme for accommodating more channels. There were only 13 channels (only 2-13 used) allocated in the VHF spectrum with 6 MHz-wide bands. Even though VHF propagates primarily in a line-of-sight mode, reflections and earth-bounce can extend the range fairly significantly, limiting density in closely spaced cities. The military refused to yield any spectrum so a decision was made to add new channels (14-83, also 6 MHz wide) in the UHF band. UHF presented its own problems with more difficult equipment manufacturing issues and higher atmospheric attenuation. It never really caught on because cable TV was being widely installed in metro areas...


Philco Refrigerator Ad from the November 6, 1948 Saturday Evening Post

Philco Refrigerator AdvertisementAs was the case for many of America's electronics manufacturing giants of the 20th century - General Electric, Westinghouse, Crosley, etc. - Philco also had extensive lines of household appliances (Crosley might have outdone them all by producing automobiles as well). Here is an advertisement for a Philco refrigerator-freezer which appeared in the November 6, 1948, edition of The Saturday Evening Post. Interestingly, the Alice in Wonderland theme occurred a few years before the 1951 Disney movie, so its popularity would have been based on the original Alice's Adventures in Wonderland, book published by Lewis Carroll in 1865. Note that the huge "freezer locker" is not claimed to be frost-free (aka frostless)...



Don't Bypass the Hobby Shop

Don't Bypass the Hobby Shop, October 1971 Popular Electronics - RF CafeIf - and that's a big "if" - you can find a hobby shop today, it is still a great source of tools and materials for building electronics projects. Just as the convenience, vast selection of products, and competitive prices of the Internet has been killing all sorts of brick and mortar stores since the early 21st century, local hobby shops (LHS's) have all but disappeared from most towns. There are still a handful of full-featured, well-stocked hobby shops to be found, but they are rare anymore. A lot of the small hobby-type hand tools (X-acto knives and saws, Dremel tools & bits) can be bought in home improvement stores, and the large craft stores often carry balsa, aircraft plywood, poplar wood, small gauge brass and aluminum tubing and sheets, plastic models and paint, and Estes rockets...


Phase Noise Reference Page Added

Phase Noise Explanation & Equations - RF CafePhase noise measurements quantify the short term stability of a frequency source. That is because phase and frequency are mathematically related by a differential function [ω(t) = dΦ(t)/dt] so they are directly connected. Phase noise also includes amplitude instability due to atomic scale effects like FM flicker noise (1/f3), white noise (1/f2), PM flicker noise (1/f), and possibly even voltage supply noise (typically discrete spurs). When the frequency source is used as a local oscillator in a frequency converter (up- or down-), the amount of instability (jitter) is modulated onto the transmitter or received signal. While not usually a major concern in analog systems, in high speed digital communication systems phase noise can degrade the ability of the receiver to correctly determine the difference between a "1" and a"0." That is because...


Fix Those Printed-Board Defects

Fix Those Printed-Board Defects, December 1959 Electronics World - RF CafeMy long-established collection of soldering aid and tuning wand tools still gets a fairly regular workout - but not necessarily for soldering tasks. Because of their purpose-designed ends, they come in handy for all sorts of model building activities. Most are non-metallic, meant for bending and poking, and are very strong and heat resistant. The metal types are still required for direct contact with molten solder. One of the best tips offered in this Electronics World article is for when replacing a leaded component on a printed circuit board (PCB). If possible, rather than heating the landing pad and plated through-via to remove the leads, just clip the leads far enough from the PCB surface to create a post or loop to solder the new component to...


Lafayette Radio Electronics Advertisement

Lafayette Radio Electronics Advertisement, January 1965 Popular Electronics - RF CafeA lot of nostalgia gets waxed here on RF Cafe, to which frequent visitors can readily attest. Old timers (if you're not one now, you some day will be) often like to see remembrances of days of yore, the halcyon days of past hobbies, family, long naps, school (yuk), vacations, and other pleasurable times. Hopefully, you already have or will soon have a few of your own. This 3-page Lafayette Radio Electronics spread from a 1965 issue of Popular Electronics magazine is typical of what what avid electronics hobbyists would have read and drooled over with so many great items in the offering. If you were like me, the cost of most of the things I wanted were well outside my budgetary reach. Prices for electronics gizmos were quite high...


Electronic Magic at the World's Fair

Electronic Magic at the World's Fair, July 1965 Popular Electronics - RF CafeMaybe it's just because black and white photos don't offer the visual stimulus of vivid color that we're used to seeing nowadays, but these images used to evoke a sense of awe and wonder at displays featured at the 1964 New York World's Fair don't quite hit the mark. Disney played a large role in the building of the displays. Audiovisual and robotic technology were the main themes of the event, and no doubt they were impressive at the time, although the recently posted video of Boston Dynamics' "Atlas" robot / humanoid running through a field puts General Electric's Progressland's "Grandpa" to shame. Each will give you a different kind of nightmare. Note Elon Musk's comment on "Atlas." Melanie and I went to Disney World / Epcot Center on our honeymoon in May of 1983 (it first opened in Fall of 1982), and saw what was billed as first walking, talking humanoids where Mark Twain...


RF Cafe Engineering & src="https://www.rfcafe.com/miscellany/homepage-archive/2019 Puzzle December 16

RF Cafe Engineering & src=Each week, for the sake of all avid cruciverbalists amongst us, I create a new technology-themed crossword puzzle using only words from my custom-created lexicon related to engineering, science, mathematics, chemistry, physics, astronomy, etc. You will never find among the words names of politicians, mountain ranges, exotic foods or plants, movie stars, or anything of the sort. You might, however, see someone or something in the exclusion list who or that is directly related to this puzzle's theme, such as Hedy Lamarr or the Bikini Atoll, respectively. This week's crossword contains a shameless plug for my custom software products - they're inexpensive and will save you a lot of time... 

 

Your Friendly, Fading Technician

Your Friendly, Fading Technician, July 1969 Electronics World - RF CafeWould you work a 44-hour week for $127? That's $6,600/yr, or $2.89/hr for a highly skilled electronics technician in 1969. According to the U.S. Bureau of Labor Statistics' Inflation Calculator, the equivalent pay in 2017 would be $45,703.89/yr, or $19.98/hr. A quick look at the current pay rate for an E4 pay grade in the USAF is $2,139/mo ($25,668/yr). That does not factor in free housing, meals, and medical care (including for all dependents) - which has significant value. GlassDoor reports the average salary for an electronics technician in 2017 was $42,390. That amount is actually a bit lower than the 1969 average. Assuming the present...


Corner Press QSL Card Printing Services

Corner Press QSL Card Printing Services - RF CafeBarry Rimer (WA2WAO), proprietor of Corner Press, has been printing QSL cards since 1961. QSL cards are cards Amateur Radio Operators (HAMS) send to each other to confirm a QSO (talking to each other on the air). QSL's were our first product; it's how we started in 1961. In 1971 we changed the company name to Corner Press to reflect a more diverse product line, not just HAM radio specific. There are more than 70 standard designs to choose from, or submit your own custom design. We produce QSL's in many styles: Flat printed in one or two spot colors, Raised printed in one or two spot colors, Full bleed full color. Please contact Barry for your QSO printing needs...


Channel Master Antenna Advertisement

Channel Master Antenna Advertisement, October 1959 Electronics World - RF CafeA few months ago I posted a write-up on the vintage Alliance Model U-100 Tenna-Rotor that I installed in the garage attic with a Channel Master CM5020 VHF / UHF / FM antenna atop it. There are not many television antenna manufacturers around anymore; their numbers have been decreasing continually due first to the advent of cable-delivered TV and now with Internet-delivered TV. The "cord-cutter" movement is helping to give over-the-air television broadcasting a rebirth due to the outrageous cost of subscription programming. Anyone contemplating installing a television antenna today has the same concerns as those back in 1959 when this Channel Master advertisement appeared in Electronics World magazine - gain, directivity, bandwidth, ruggedness...


Japan: An Industrious Competitor

Japan: An Industrous Competitor, October 4, 1965 Electronics Magazine - RF Cafe"Japanese electronics firms' real strength is their engineers, characterized by creativity, ingenuity and an awesome willingness to work long and hard." That statement by editor Lewis Young is the key point in this article that appeared in a 1965 issue of Electronics magazine. That Japanese technology companies were deemed to be only about five years behind the U.S. was a real wake-up call to America and the European countries. Both Europe and Japan had been very diligent about rebuilding and modernizing techniques and infrastructure since the destruction caused by World War II. A few stories about Japan's post-war efforts report on how the government left most of the responsibility (aka financing) up to universities and private companies. Industry in some of the more...


June 3 Engineering Crossword Puzzle w/Weekly Headlines

RF Cafe Engineering Crossword Puzzle w/Weekly Headlines June 3, 2018At least 10 clues with an asterisk (*) in this technology-themed crossword puzzle are pulled from this past week's (5/28 - 6/1) "Tech Industry Headlines" column on the RF Cafe homepage. For the sake of all the avid cruciverbalists amongst us, each week I create a new technology-themed crossword puzzle using only words from my custom-created related to engineering, science, mathematics, chemistry, physics, astronomy, etc. You will never find among the words names of politicians, mountain ranges, exotic foods or plants, movie stars, or anything of the sort. You might, however, see someone or something in the exclusion list who or that is directly related to this puzzle's theme...


RF Cafe Engineering & Science Crossword Puzzle May 13

RF Cafe Engineering & Science Crossword Puzzle May 13, 2018Each week, for the sake of all avid cruciverbalists amongst us, I create a new technology-themed crossword puzzle using only words from my custom-created lexicon related to engineering, science, mathematics, chemistry, physics, astronomy, etc. You will never find among the words names of politicians, mountain ranges, exotic foods or plants, movie stars, or anything of the sort. You might, however, see someone or something in the exclusion list who or that is directly related to this puzzle's theme, such as Hedy Lamar or the Bikini Atoll, respectively. Enjoy!...


Natural Code Non-Ambiguous Optical Encoder

Wayne-George Corporation Advertisement, February 28, 1964 Electronics Magazine - RF CafeAdmittedly, the only thing I remember about Gray Code (aka reflected binary) from college courses is that successive count values change only one bit per increment, saving power in some digital circuits. The power savings comes from the fact that, especially for CMOS circuits, current only flows during the transition of a state change from "0" to "1" or from "1" to "0." Shaft position encoders were and still are a primary application of Gray Code switching. If the encoder output digital code is going to be used in a binary computation system, then there is an advantage in generating a direct binary ("natural") count that does not require a Gray-Code-to-Binary conversion circuit (or software routine). When the Wayne-George Corporation introduced its paradigm-changing "Natural Code Non-Ambiguous Optical Encoder" in 1964, those conversion circuits were probably not simple, compact, inexpensive semiconductor IC's...


Fairchild Instrumentation Scope Camera

Fairchild Instrumentation Scope Camera, October 18, 1965 Electronics Magazine - RF CafeAre you old enough to remember when in order to make a measurement on a circuit board it was necessary to physically connect an oscilloscope probe to a trace or component lead? "Wait," you say, "What are you talking about? You still do have to physically connect a probe." Right you are, but 50 years from now your progeny will be asking that question, just as today I ask you do you remember when in order to get a "screen shot" of an o-scope or spectrum analyzer display it was necessary to connect a camera to the front of the CRT? Some instruments had an(a) output port(s) for driving a pen plotter, but getting a plotter set up and calibrated was often more work and frustration than hanging a camera on the front. Most of the cameras used Polaroid film packs to enable "instant" pictures...


B&K Manufacturing Co. Advertisement

B & K Manufacturing Co. Advertisement, April 1960 Electronics World - RF CafeUntil solid state electronics had supplanted the majority of vacuum tube type televisions and radios, portable tube testers were essential equipment to successful, efficient troubleshooting and repair in businesses and people's homes. Yep, believe it or not the stories told about doctors and electronics repairmen visiting homes are not just fables. I remember as recently as the 1960s having our family doctor make house calls when I or one of my fours sisters got sick. Both doctors and TV servicemen ceased the practice at about the same time - probably the result of a Brotherhood of Electronics Technicians and General Practitioners collective bargaining agreement ;-) Many column inches of editorials, articles, comics, and letters to the editor were devoted to the trials and tribulations of in-home servicemen and the experiences...


Bombshell: The Hedy Lamarr Story

Bombshell: The Hedy Lamarr Story - RF Cafe Video for EngineersBy now, most people involved with spread spectrum communications are (or should be) aware that Hollywood starlet Hedy Lamarr is credited for being the first to suggest a frequency hopping scheme for secure communications. If you do a Google search on Hedy Lamarr and spread spectrum, you see that except for a few mentions on tech websites, it has only been in the news since the end of the last decade. Scientific American magazine ran an article titled, "Hedy Lamarr: Not Just a Pretty Face," in 2008. Google honored her in 2015 with a Doodle on their homepage. "The most beautiful woman in the world," with the assistance of her co-inventor-composer George Antheil...


Mac's Service Shop: Servicing Amateur Equipment

Mac's Service Shop: Servicing Amateur Equipment, July 1959 Electronics World - RF CafeAccording to sources I can find, it wasn't until the early 1970s that most (>50%) of homes in America had air conditioning. Many homes on my boyhood street, including ours, didn't get their first window unit until the late 1960s. We suffered through some pretty miserable hot, humid summers just a few blocks from the Chesapeake Bay in Annapolis, Maryland. Going into stores - especially grocery stores, was a great relief from the oppressive heat. The A&P frozen foods aisle, with the open freezers, was my favorite spot. It's kind of gross, in retrospect, to imagine all the sweat that dripped off people and onto the icy packages lying in the freezers. Electronics service shops of the era definitely required air conditioning to keep all the vacuum tube TVs and radios cool while troubleshooting and aligning them...


Electronics Review: Gemini Rendezvous & Space Electronics

Electronics Review: Gemini Rendezvous & Space Electronics, December 27, 1965 Electronics Magazine - RF CafeWhen I originally tagged this Electronics magazine article for posting, it was before Golden State Warriors guard Stephen Curry tapped into his immense cerebral power to inform us all that NASA has been faking its accomplishments in space - notably all the moon landings. Now, based on such unimpeachable authority, I'm not so sure this story should even be posted, lest it potentially perpetuate a long-running ruse. In the manner of contemporary news pieces reporting on criminal activity while avoiding legal claims of libel or character assassination, please mentally preface all of the claims here with "alleged" or "allegedly." The world's first successful spacecraft rendezvous, accomplished by Gemini 6 and Gemini 7, happened on December 15, 1965. Both astronaut crews participated in many communications experiments that included radio, visual, and laser media...


Color TV - The Field Sequential System

Color TV, October 1953 Radio & Television News - RF CafeIf the technology futurists of the 1970s had been correct, by now we would be reading historical articles on the early days of holographic television. I have read, though, that any day now a battery-powered flying car with a holographic dashboard / instrument panel display is going on sale. Not. The Sadly, the Ercoupe (pronounced "air coupe") is still the closest thing to "an airplane in every garage." But, I digress. This story from a 1953 issue of Radio & Television News magazine reports on the roll-out of the country's first color television system: The field sequential system (aka the CBS system). It was a fine system, but unfortunately the modulated signal format was not backward compatible with the existing B&W system. That meant separate receivers for B&W and color televisions. Even as CBS TV sets were being produced, the NTSC was working on a replacement system that permits co-existence of B&W and color signals. Note the mention of how the DPA, in 1951...


Anxiety Amid Affluence: Why Color-TV Makers Worry

Anxiety Amid Affluence: Why Color-TV Makers Worry, December 27, 1965 Electronics Magazine - RF CafeDecisions, decisions, decisions. As the title states, color television manufacturers were, in 1965, finding themselves between a rock and a hard place, as the saying goes, regarding a change from vacuum tubes to transistors. The buying public (aka consumers) had mixed emotions about the newfangled semiconductors based at least partly on bad information about transistors. Transistors had been designed in various circuits for a decade and a half and were gaining rapidly in performance and reliability. The price was coming down, but as reported here, still cost $5 to $10 apiece compared to a $1 vacuum tube. Company management needed to decide whether to delay implementing the new engineering and production methods required to deal with transistors for a couple more years until the market had more time to make up its mind whether to begin. A couple firms enthusiastically...


A Winding Machine for Spaced-Turn Chokes

A Winding Machine for Spaced-Turn Chokes, December 1931 QST - RF CafeThere are still a lot of people who wind their own coils, whether it be for an amateur radio rig or for work in the lab. I know I've wound many a coil around a drill bit or wooden dowel - a somewhat awkward task. This simple coil winding machine that appeared in a 1931 edition of the ARRL's QST magazine would be a handy addition to anyone's bag of tricks, especially if you find yourself winding single-layer coils that have a precise, fixed space between the windings. The home stores like Lowes and Home Depot sell small pieces of oak and maple that would be perfect for this kind of project. Soft woods like pine and poplar would not hold up as well under the strain of winding wire. Use your soldering iron to burn your name onto the base. A little stain and a coat of varnish would give it a real vintage look...


How to Stack TV Antennas to Increase Signal Strength and to Reduce Ghosts

How to Stack TV Antennas to Increase Signal Strength and to Reduce Ghosts, November 1965 Popular Electronics - RF CafeYou probably won't find too many people stacking television antennas these days, but many Hams still do it. Vertical stacking is used primarily to increase overall gain without appreciably altering the azimuth beam, while horizontal stacking forms a tighter azimuth beam without appreciably affecting the overall gain. When it comes to optimizing antenna designs installations for operations below about a gigahertz, Amateur Radio practitioners have pretty much written the book on the subject - actually, they have written hundreds of books on the subject. Antenna stacking is often used...


Understanding Ungrounded Oscilloscope Measurements

Understanding Ungrounded Oscilloscope Measurements, May 1973 Popular Electronics - RF CafeThose of us who have been making measurements on electrical and electronics equipment for a long time are well aware of the need to be certain that the ground (common) lead of a piece of test equipment - oscilloscope, multimeter, or other instrument - is never connected to a point in the circuit that is above ground potential. Doing so can be dangerous and/or destructive. If the test point is above ground potential, connecting the ground lead to it creates a direct short to ground, which can destroy the device under test (DUT) or at least cause the measured signal to be altered...


Cable TV - Where It Is & Where It's Going

Cable TV - Where It Is & Where It's Going, January 1972 Popular Electronics - RF CafeAccording to this 1972 article in Popular Electronics magazine, cable television began around 1950. The system was very different that what we have nearly 70 years later. The familiar acronym CATV does not stand for CAble TeleVision, but rather Community Access TeleVision. CATV, as originally implemented, was a means of bringing broadcast TV to areas either too remote or too shielded from over-the-air (OTA) RF signals to provide good signal reception. Depending on the need, CATV could range from re-broadcasting of signals into targeted areas or sending signals through cable (originally unshielded) to individual homes. As you might expect, opponents of the new system predicted that such a scheme would eventually be the kiss of death for local broadcasters since large, well-funded conglomerates would be able to dominate programming selection and dry up...


Look Out! It's Hot!

Look Out! It's Hot!, June 1966 Popular Electronics - RF CafeElectrocution has always been - and always should be - a hot topic (pun intended) in the realm of electrical and electronics servicing and usage. Trade and hobby magazines have dedicated many column inches to it over the years. A lot of people are deathly (there I go with the puns again) afraid of being anywhere in the proximity of an exposed electrical connection. My father, a newspaper classified advertising manager, was one of those people. He would cringe when I took the cover off the fuse panel in the house to work on it. He could barely bring himself to replace a blown fuse, which was not a completely unjustified fear given the low standards of older electrical wiring. Those screw-in fuses had a threaded metal perimeter around the bottom portion with a button connection at the bottom center. Theoretically, that threaded metal perimeter is at ground potential...


Why Not a Ham License Just for Ladies?

Why Not a Ham License Just for Ladies?, December 1967 Popular Electronics - RF CafeIn this saga of YL (young lady) and OM (old man) Ham radio operators, General license holder Carole H. Allen elucidates, with a touch of humor, the woes beset upon women pertaining to repairing radio equipment. Mrs. Allen's lament is in fact not the treatment of women participating in the communication aspect of Ham radio, but the reluctance of men to allow them to engage in the technical aspects of the electronic equipment. From an operator standpoint, guessing the gender of the Ham on the other end of the signal can be nearly impossible, particularly with CW (Morse code). Poor transmission quality can make phone (voice) determination of YL or OM difficult sometimes as well. Back in the 1960s it was not possible to simply surf to the FCC's Universal License System website...

Copper Mountain Technologies (VNA) - RF Cafe
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Crane Aerospace Electronics Microwave Solutions: Space Qualified Passive Products

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