Vintage Radio Shack TV Commercials

There are still plenty of us around who remember seeing Radio Shack commercials on TV back in the days when all television sets had at least one vacuum tube in them - the CRT (cathode ray tube). As evidenced by the huge number of vintage Radio Shack commercials posted on YouTube, and the amount of views for them, there is still a desire by people to take a nostalgic trip back in time to see the content they remember. Of course at the time we usually considered all commercials an imposition on our TV program watching. One of the annoyances of modern TV programming is that even though you have to pay for the service, you still have to sit through even more commercial time per show than was imposed when reception was free (over the air). I have to be honest and admit that I don't recall ever seeing any of the Radio Shack commercials in this collection of videos, but they definitely have the "look" of the ones I do remember from the days of yore. I used to visit...

General Electric Radio Advertisement

When metal-encased vacuum tubes came on the electronics scene in the 1930s, they were billed as the innovation that was going to radically change the radio world. The built-in Faraday shield properties of the tubes did in fact stop the effects of cross-coupling between adjacent tubes and permit more densely packed circuits, but they also caused some other problems as well. Capacitance between tube elements and the shield caused electron flow control issues and affected operational frequency. Packing tubes closer together also meant the rat's nest of resistors, capacitors, inductors, and wires on the underside of the chassis that were installed in a point-to-point manner rather than neatly on printed circuit boards (which largely did not exist at the time) were closer together and therefore created new problems due to proximity. Still, metal tubes served a very useful purpose when employed wisely and continued in use along with unshielded tubes...

CapaciQuiz - 1961 Popular Electronics

Robert Balin, Popular Electronics magazine's quizmeister, created this CapaciQuiz for the February 1961 issue. Most of these are elementary, but think carefully about the exact wording of Q4 before you answer. With Q8, believe the better explanation is that for a purely capacitive circuit, current and voltage are 90° out of phase, so when the sinewave voltage is at zero, the current is at a maximum. Note that Q6 and Q10 are opposites (parallel vs. series capacitor combinations), so if you have trouble reasoning one of the configurations, work on the other and then you'll know both. Bon chance!...

Exit Heterodyne QRM

"QRM" is the Q-code in Ham-speak for unwelcomed manmade inband electrical interference. Interference is not just random signals like noise from motor brush arcing, intermittent electric distribution system connections or inter-conductor arcing, etc. An improperly tuned or ineffectively filtered radio transmission, or EM energy leaking from a poorly shielded electronic device is also QRM. I distinguish such noise as unwelcomed because what might be considered as noise by one person could be a desired signal by another. "QRN" stands for electrical noise generated in nature such as lightning bolts, solar storms, or even, as discovered by Drs. Arno Penzias and Robert Wilson, the 160 GHz Cosmic Microwave Background (CMB) radiation that emanates from all regions of the sky. A mnemonic for remembering which Q-code is which is the trailing "M" for manmade and "N" for natural...

The Yagi Antenna

The Yagi–Uda antenna (usually referred to as a Yagi), is a relatively simple to construct multielement structure consisting of a combination of driven (director) and reflective (reflector) diploes. Careful phasing of the configuration results in a directional radiation pattern that is used often for long distance (DX) and direction finding work. It is also useful in a dense signal environment where there is a need to exclude received signals not emanating from a preferred source. Common (or what used to be) rooftop television antennas were of the Yagi type and served not just to pull in distant stations, but to help reject multipath signals that would cause ghost images on the screen. The concept is the 1926 brainchild of Messrs. Shintaro Uda and Hidetsugu Yagi, both of the Tohoku Imperial University, in Japan. The Yagi antenna described in this 1952 issue of Radio & Television News magazine is for VHF channels 2-13...

Recent Developments in Electronics

The items reported in the September 1967 issue of Electronics World magazine represent the beginning stages of many technologies that are still in used today. The monolithic ferrite memory was a major producibility improvement in what was formally hand-wired toroidal matrices of cores. They were the first step in integrated memory (although we don't use magnets anymore in ICs (just on hard drives). The Electronically Controlled Robot looks like something from a modern Japanese university - without the skin, hair, and eyeballs. Note that as today, supplying power is one of the biggest hurdles in making a human-looking robot (umbilical required). The Solid State Camera "Tube" is one of the very first solid state camera imaging chips. It had a whopping 2,500 pixels. The Computer-Directed Drawing Machine converted a 2-dimensional drawing into a 3-dimensional perspective. Shipboard Satellite Communications was at the time one of the first uses of satellites for global communications, it being a big deal because...

Electronics Themed Comics

Are you having a rough week? If so - and even if not - take a few minutes to get a laugh from these electronics-themed comics from the pages of vintage Radio News magazines. Beginning sometime in the late 1930s and early 1940s, single-panel topical comics began appearing frequently in many hobby and even professional magazines. Sure, comics showed up in magazines before that time, but they generally did not necessarily have to do with the main subject of the publication. The Saturday Evening Post, for example, had many single-panel comics, but they were on any random theme. I can't go without commenting on the April 1946 comic since it reminds me of a situation while in tech school at Keesler AFB in Biloxi, Mississippi, in 1979. I can't recall exactly what the circuit was that the instructor was covering, but it involved tuning to achieve a waveform with a null in the center of two bandpass regions similar to this:  ∩∩ . He and everyone I worked with in the field after tech school referred to it as the "Dolly Parton waveform." Such a scenario would never pass muster with the overly sensitive...

Transistor Topics - Heathkit TCR-1, MOBIDIC

For many years, Popular Electronics magazine had a monthly column titled "Transistor Topics" that reported on news in the world of those newfangled semiconductors. To wit, this article from the April 1960 edition begins, "Each month, more and more transistorized consumer products are developed as replacements for vacuum-tube designs." The Heathkit TCR-1 clock radio is featured for its six-transistor superheterodyne AM receiver circuit. A mechanical clock is still used since other than using Nixie tubes, digital displays were not commercially available. The MOBIDIC "super" computer is also covered for its total transistorization. At about 4 feet wide and 6 feet tall, it is hard to believe that the "MOB" portion of the acronym stands for "mobile"...

Designing an All-Channel TV Antenna

Yes, the old days of over-the-air broadcasts and analog television could be a pain. Perfect adjustment of the antenna and TV controls one day could be totally useless the next day or even later the same day. Atmospheric and physical variations can change suddenly and significantly, affecting both radio and television. Proper separation and processing of horizontal and vertical synchronization of the video, color and intensity, and audio by the TV's electronic circuits depended on the right combination of antenna, and lead-in cable. The advent of semiconductors in place of vacuum tubes helped stabilize the television's role in viewing quality and lessened the overall irritation level, and the introduction of cable-based and then satellite-based programming distribution to reduce irritations to the point where most people never had a problem. That said, I would happily return to the days of yore and suffer the aforementioned inconveniences, to enjoy a time when the content was significantly less rude and crude, and patriotic and traditional family-based shows were by far the rule rather than the exception...

Burgess Battery Advertisement

This could be a modern day photo of an American DHS (Department of Homeland Security) or an Israeli IDF (Israel Defense Forces) agent displaying a body bomb found on an attempted suicide bomber after thwarting an attack, but it's not. In actuality, it is a 1934 Burgess battery advertisement that appeared in QST magazine with the intent of demonstrating to Hams the kinds of research the company was doing. This design was called a "ribbon battery," and it could conveniently be wired in a flexible manner with almost any number of series and parallel connections to accommodate required voltage and current combinations, including taps for multiple voltages needed for vacuum tube radios. The packs could be "wrapped about one's body for portable receiver use." Hmmmm, maybe that's what made me think of the body bomb...

FITSAT-1 CubeSat Flight over Erie, PA

I stayed up late on the night of of December 11, 2012 (early in the morning, actually) to watch the FITSAT-1 CubeSat satellite flash its Morse code "HI DE NIWAKA JAPAN" message via super-bright LEDs over eastern North America. It was scheduled to pass just south of my location in Erie, Pennsylvania, at 1:14 AM, with a lights-on intensity great enough to be easily seen with binoculars. FITSAT-1 is a project conceived of and built by professors and students at the Fukuoka Institute of Technology (FIT) in Japan. In addition to the LED visual display, the satellite also carries several Amateur Radio payloads including a CW beacon on 437.250 MHz, a telemetry beacon on 437.445 MHz and a high-speed data downlink on 5,840.0 MHz. The CubeSat Project was developed by California Polytechnic State University and Stanford University's Space Systems Development Lab. It creates launch opportunities for universities previously unable to access space. A CubeSat is 10 cm on a side and may have a mass of up to 1.33 kg. Launch vehicles sell space to CubeSats for around $40,000, which makes them very affordable to place in orbit...

Wireless Technology Theme Crossword Puzzle for August 28th

This custom made Wireless Technology theme crossword puzzle from RF Cafe is for August 28th, 2022. "Across" words consisting of five or more letters begin with the first letter of this puzzle's theme. 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 puzzle 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!

Atwater Kent 305Z Radio Service Data Sheet

For many years I have been scanning and posting schematics & parts lists like this one featuring the Atwater Kent Model 305Z 5-Tube 32 V. D.C. Superhet radio. It appeared in a 1936 issue of Radio-Craft magazine. OCR (optical character recognition) software is run on them to separate the textual content, which allows search engines to capture words that helps people find information. There are still many people who restore and service these vintage radios, and often it can be difficult or impossible to find schematics and/or tuning information. I keep a running list of all data sheets at the bottom of the page...

Carl and Jerry: Too Lucky

As is the normal modus operandi (MO) of John T. Frye with his "Carl & Jerry" series of techno-dramas, this "Too Lucky" episode combines adventure with electronics to teach a lesson in the process of entertaining with a great story. If you're a fisherman, you'll particularly enjoy this one. I have to admit to not knowing about this method of "electrofishing" (although not called by that name here) for drawing fish to a high voltage alternating electrical field and then capturing them with a net once close enough to be paralyzed (stunned). A process called "galvanotaxis" which causes uncontrolled muscular convulsion in the fish causes them to swim towards the source...

Television Set Shipments by Areas

According to a tally crafted by Radio & Television News magazine in 1949, the total number of television sets sold in the United States in 1947 and 1948 was 964,206. There were approximately 146 million people at the time per the U.S. Census. If there was an average of 4 people per household, that works out to around one television set for every 36 houses. Some households already had TV sets during that time, but far fewer than half owned a television. Nobody owned a color TV then because no commercial broadcaster used a color camera. Color was still a future feature being hyped in Mechanix Illustrated and Scientific American, like flying cars and personal computers. Today, of course, everybody that wants a television has a television... or two... or three. Effectively, every smartphone and computer is a TV (via Internet, not direct OTA transmissions) as well. In 1949, almost all TVs were owned by people who paid for them themselves. Today, many sets are bought by people who have been subsidized by fellow citizens forced to help pay for them via tax policies...