Howard W. Sams Photofact Service

I and many people who visit RF Cafe tend to do our own repair and maintenance work whenever possible. Having had this obsession for as long as I can remember, there is no doubt that the ready availability of service information and how-to aids available on the Internet not only makes the job easier, but also makes things possible that could never have been achieved a couple decades ago. When I needed to put new rotors and brakes on my 2011 Jeep Patriot last month, a quick search turned up multiple videos of people demonstrating how to do it. Sure, I've done dozens of brake jobs and am fairly comfortable with what might be involved, but being able to watch a beginning-to-end video before diving into it is really nice. My trusty Hanes repair manual was on-hand, but a couple black and white photos and terse instructions usually do not describe the complete environment. A couple years ago when my gas-fired furnace would light and cut off after a few seconds, an Internet search turned up the likely cause...

Space Electronics

Success won in the realm of space-based communications has been fraught with many failures. As with most endeavors, it is thanks to the relative few who have sacrificed and endured against overwhelming odds to bring significant technological advances in communications to the many. Space presents a particularly difficult venue because of the harsh deployment and operational environment, and inaccessibility after deployment. Personal sacrifice has taken the form of depression, financial ruin, lost opportunity for other endeavors, broken families, sickness, substance abuse, and other maladies brought on by an obsession with success. Such sacrifice has built the modern world...

Radar Explores the Moon

NASA is currently collecting a phenomenal amount of data on the planet Mars. No small part of the effort is to determine whether sending humans to inhabit Mars would be feasible, or even at all possible. In order for it to be even possible for a long-term stay, it would be necessary for consumable resources to be accessible by Earth Martians. Discovering water ice would be the pièce de résistance since water is heavy and therefore very expensive to transport across vast reaches of space. Another key bit of data needed is frequency and size of meteor strikes on the surface since that figures directly into survivability. Long before we had the capability or even need to do that for Mars, NASA was doing the same sort of investigation on our moon (as opposed to one of Mars' two moons, Phobos and Deimos). The resolution of telescopes, all ground-based in the day, was good enough to perform site selection surveys in the x-y plane, but altitude data could only be inferred via estimations based on shadow lengths along the terminator (night/day line of demarcation) and sideways glances of peaks and valleys. That was not good enough for planning a human expedition to the surface, so engineers and scientists came up with a radar mapping technique to obtain z-axis data. That effort is reported here in this May 1961 edition of Popular Electronics...

RF Cafe: How to Remove Clutter from Online Document Displays

If you are annoyed by pop-ups and extraneous framework elements and/or SEO (search engine optimization) tracking code accompanying application notes, white papers, and images, and videos, many times you can get rid of them by editing the URL displayed in your browser address bar. Compare the displays in this set of screen captures based on the original URL provided in an e-mail (top) to the one where all the extraneous terms have been removed from the URL (bottom). Note that the yellow highlighted components have been eliminated. Often, I remove that stuff from hyperlink URLs before sending my visitors to websites. Companies don't particularly like me doing that, but doing so helps maintain your privacy. URLs in e-mails are particularly likely to contain appended code that contains one or more "&utm_" parts. UTM is the Urchin Tracking Module introduced by Google Analytics' predecessor Urchin and are now supported by Google Analytics. They typically...

Electronics-Themed Comics

There are few better ways to wind down a work week than with some good old-fashioned (literally) technology-themed comics. This three fifths of a handful of comics appeared in a 1944 issue of Radio News magazine. You need to know when looking at these scenarios that people in the 1940s cherished and revered their radio sets like people today do with their cellphones. Magical and supernatural attributes were assigned to them by some, especially the non-technically inclined. Entire families gathered around the radio in eager anticipation of the latest episode of "The Shadow," The Lone Ranger," "Little Orphan Annie," "Jack Benny," and "Inner Sanctum Mystery." BTW, if you want to experience the aura of old time radio shows, many of them are available for listening online on the Old Time Radio Catalog website and others...

Engineering & Science Crossword Puzzle for December 1

For two decades, I have been creating custom engineering- and science-themed crossword puzzles for the brain-exercising benefit and pleasure of RF Cafe visitors who are fellow cruciverbalists. This December 1st puzzle uses as part of its grid the common schematic symbol for a MOSFET dual gate, n-channel, depletion mode transistor. A database of thousands of words is used which I have built up over the years and contains only clues and terms associated with engineering, science, physical, astronomy, mathematics, chemistry, etc. You will never find a word taxing your knowledge of a numbnut soap opera star or the name of some obscure village in the Andes mountains. You might, however, encounter the name of a movie star like Hedy Lamarr or a geographical location like Tunguska, Russia, for reasons which, if you don't already know, might surprise you...

Getting Feedback Straight

Feedback has been widely misunderstood by many electronics enthusiasts, even those who have a fairly extensive background in circuit design (that which does not involve feedback). In fact, there have been instances of articles being printed in magazines like Popular Electronics, Radio-Electronics, etc., where the authors got relatively simple feedback equations wrong due to improper summing of nodes, necessitating a correction in a later issue based on reader feedback (a convenient and appropriate word for this comment). This article discusses feedback in audio circuits to avoid distortion, but the concepts apply to any frequency of operation. It is possible in many cases to implement seat-of-the-pants feedback schemes successfully, but if you need a specific response and guaranteed stability...

Light Conversations in Future

For the majority of the last century, Bell Telephone Laboratories (Bell Labs) led the telecommunications industry, both for wired and microwave links. Whenever you learned of a breakthrough in telephony, you could assume it was another Bell Labs innovation and probably be right. Of course there were discoveries in other venues like university research facilities, but often those were at least partially funded by Bell. The company grew to be so large and influential that the government decided breaking them into smaller pieces would reduce their influence over the nature of communications systems. It is similar to how Google dominates Internet search engines and advertising, and how Facebook dominates social media, except nowadays those venues are considered vital to political futures so they are permitted to continue to grow unabated. This item about how fiber optic communications will provide a vital link to high capacity, high bandwidth transmission lines...

Mac's Radio Service Shop: Barney is Promoted

Certain things about John T. Frye are very apparent to the many of you familiar with techno-dramas - "Carl & Jerry" and "Mac's Service Shop" - and his many magazine articles on topics related to electronics and amateur radio: Mr. Frye has a good imagination, he is a good story teller, and he has a very deep knowledge of electronics theory, troubleshooting, repair, and practical operation. One particular aspect about him you might not know is that he spent most of his life in a wheelchair, as the result of polio. Born in 1910, John could not benefit from the polio vaccine invented by Dr. Jonas Salk in 1955. That was a mere three years before I was born. We are fortunate to live in these times when so much amazing medical research is happening to prevent, treat, and cure diseases, and while great advances have been made...

Dots and Dashes, July 1934 Radio News and the Short-Wave

If you read through this "Dots and Dashes" column from the July 1934 issue of Radio News, you will find many familiar topics -- and a couple weird ones. Among the familiar are transmitting electrical power via RF waves, an electronics industry convention and exposition being held in Chicago, elevator control with electric sensors to assure the cars stop at floor level, global communications, the closing of a historic radio station (how 'historic' can a radio station be in 1934?), earth-moon-earth (EME) experimentation, and remote control of beacon stations with radio signals. The weird ones? How about an "electric woman" with glowing breasts and a "queer-acting" radio microphone, do they qualify?...

Theory and Application of UHF

This is part 8 of a series authored by Milton Kiver entitled, "Theory and Applications of UHF," that appeared in Radio News magazine in the mid 1940s. As you might expect it is a very extensive delve into the relatively new realm of UHF generation, transmission, propagation, and reception. You might not know that up through the 1930s, UHF circuit and practice had been relegated to the amateur radio operators because those frequencies from 300 MHz to 3 GHz were considered too unexploitable for professional use. It was not until Hams did the hard work of figuring out practical methods of building circuits and antennas and characterizing geographical and atmospheric conditions that affected propagation that suddenly industry and government decided UHF might be useful after all...

A Guide to Home Study Education in Electronics

When I ran across this "A Guide to Home Study Education in Electronics" article in a 1972 issue of Popular Electronics, I did a double-take upon seeing the author's name. This author wrote pieces for National Radio Institute (NRI) home study courses like the one appearing in a 1971 issue of NRI Journal, which supports his qualification for penning this particular article. He has appeared in '73 and Ham Radio magazines since the 1970s. His name still regularly shows up in the bylines of articles in Electronic Design, Microwaves & RF, and Nuts and Volts. Many books have been published in his name including Principles of Electronic Communication Systems, Handbook of Serial Communications Interfaces, and even one entitled How to Become a VP. At this point in time, there are not a whole lot of people who could claim the accomplishments in terms of having been so widely read over so many years by laymen, hobbyists, students, and professionals...

Carl & Jerry: TV Antennas

In this episode of Carl & Jerry, the teens ponder a question posed by Jerry's mother upon looking down their hillside home: "[L]ook at all those TV antennas down there. Hardly two of them are alike; yet they're all intended to receive the same stations. How come there are so many different kinds?" That was all the pair needed to set them off in an investigation to determine the answer. Being avid electronics and RF hobbyists and experimenters, they discuss the principles of how antennas work, various types of transmission lines, impedance matching, antenna types, bandwidth, and other topics relevant to the challenge. As with most Carl & Jerry stories, the intent is to educate the reader. As a bonus, I posted two of the electronics-related comic panels that were in this edition of Popular Electronics...

Block that Ghost!

It is probably safe to say that the vast majority of cellphone users never consider that their cherished devices are fundamentally radios, and with that capability they would be merely powerful PDAs. Even less likely to be thought about is that as wireless devices, an antenna is needed to establish communications. Up until the early 2000s, most cellphones had some form of obvious antenna protruding from the case - either an extendable type or a molded stub around an internal antenna. Operational frequencies at the time were primarily in the 850 MHz, 900 MHz, 1800 MHz, and 1900 MHz bands ,with 1/4 wavelengths of about 3.5 inches, 3.3 inches, 1.6 inches, and 1.5 inches, which was convenient given the physical size of phones. Always seeking to develop new features to outclass the competition, manufacturers decided...

Engineering & Science Crossword Puzzle for December 8

As with my hundreds of previous engineering and science-themed crossword puzzles, this one for December 8, 2019, contains only clues and terms associated with engineering, science, physical, astronomy, mathematics, chemistry, etc., which I have built up over nearly two decades. Many new words and company names have been added that had not even been created when I started in the year 2002. You will never find a word taxing your knowledge of a numbnut soap opera star or the name of some obscure village in the Andes mountains. You might, however, encounter the name of a movie star like Hedy Lamarr or a geographical location like Tunguska, Russia, for reasons which, if you don't already know, might surprise you...