Glass-Dielectric Capacitors

Continuing with the series on capacitor types, particularly dielectric material, this July 1965 Electronics World magazine article reports on glass materials used by Corning Glass Works. Glass dielectrics are popular for aerospace and space applications because of their tolerance for high radiation levels found in regions not protected by the Earth's atmosphere. Glass compound consistency provides for mass producing values with tight tolerances and exceptional parameter tracking over temperature. High "Q" values and low loss at extreme temperature and high frequency (at the time) made them the component of choice by missile and satellite designers. 0.5 pF through about 0.01 μF is the typical value range for glass dielectric capacitors. Author Archer Martin mentions radiation exposures of 1018 NVTth, which appears to be a measure of neutron flux exposure, but I could not find a good definition of the term ("NVT," without the "th" is used here)...

Frenzied Radio

"And there is nothing new under the sun." - Ecclesiastes 1:9, NKJV (did you know that is the origin of the saying?). This 1930 editorial by Radio-Craft editor Hugo Gernsback describes a coordinated scam perpetrated by radio manufacturers to compel consumers to buy new sets rather than have their existing sets repaired; such schemes persist today. In short, retail prices were inflated to accommodate a built-in "trade-in" allowance that far exceeded the repair cost or used radio cost. Radio service shops were getting the short shrift because many people who might have otherwise elected to have repairs made would instead trade in the old set for a new one. That a conspiracy was underfoot was evidenced both by the practice of destroying traded-in sets so they cannot be used again (similar to the Cash for Clunkers program where engines were destroyed after trade-in), and by making it difficult or even impossible for repair shops to obtain adequate technical documentation...

An Unusual TV Antenna

This being an April issue of Popular Electronics magazine, I am not sure whether this is an April Fools gag article of the real McCoy. The Iron Curtain was in full force, the Cuban Missile Crisis was a mere five years earlier and the Gary Powers U-2 incident just seven years hence, so anything related to the USSR (aka Soviet Union) was considered mysterious and possibly nefarious. Seeing Ruskie text was a real attention-getter. The article entitled "НЕОБЫЧНАЯ ТЕЛЕВИДЕНИЕ АНТЕННА" reportedly appeared in the April 1966 issue of the Soviet Union's "Radio" magazine (still in print). I did a search for it and could find the March and June 1966 issues, but not April. BTW, if you plug the Russian text into the Duck Duck Go translator, it does indeed come back with "Unusual TV Antenna," just as author Joseph Zelle claimed in 1966. Now, as to whether the article's claim is legit or not, I can't say...

World Peace and Amateur Radio

It hasn't been just Miss America contestants that have wished for world peace over the years. In April 1967, this article entitled "World Peace and Amateur Radio" was published in Popular Electronics magazine extolling the efforts of Ham radio operators in attempting to break through communications barriers erected by governments. Amateur signals could reach into the USSR, Cuba, China, North Korea, and all the other hopelessly oppressed regions of the world - even Chicago ;-) - to let people know that there is hope beyond the Iron Curtain of Communism. This particular story reports on one Ham's outreach to the people of Japan which, fortunately for them, was not a member of the "Red club." When this article was first posted in 2013, Yemen and North Korea prohibited amateur radio communications with the United States. According to the FCC website, there are currently no countries on the banned list...

Amplifier Gain Nomogram

Even with the ready availability of programmable calculators and smartphone apps, there are still times when having a handy-dandy nomograph printed out and hanging on the wall for quick reference can be a great asset. This nomograph which appeared in a 1965 issue of Electronics World magazine provided ready conversion between two different (input and output) voltage and power values to equivalent decibel values. It seems strange that the watts and voltage scale is on the left and the milliwatts and millivolts scale is on the right. That might be more intuitive for a nomograph of attenuation, but not - at least to me - for positive gain as through an amplifier...

Wireless Engineering Themed Crossword for September 11th

This custom Wireless Engineering themed Crossword Puzzle for September 11th, 2022, is brought to you by RF Cafe. 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 or the Tunguska event in Siberia). The technically inclined cruciverbalists amongst us will appreciate the effort. Enjoy!

How Dependable Are Your Meter Readings?

Not many people are still using analog meters for making voltage, current, resistance, and power measurements these days; however, for those who are and even for those using digital readout meters, there are valuable lessons to be learned from this article on factors that can affect the accuracy of your measurements. Whenever you make a measurement with any kind of instrument, the first step to take in minimizing the chances of inaccurate readings is to be certain the instrument is in good working order and is known to be reasonably accurate. If it is battery powered, know that low battery voltage can cause erroneous readings in both analog and digital meters, so beware. If you are making a measurement to verify a known entity and the reading is correct, then there is little reason to suspect that anything is wrong with your meter. If a reading is way off from what you expect to see, then verify the accuracy of your instrument before going any further lest...

Doppler Radar Charts the Airlanes

Doppler radar is familiar to most people these days mainly because of the weather reports available online and on television reports. Not many actually understand the principle behind it, though. A handful can tell you that in sound form it is the frequency shift phenomenon that occurs when a train goes by while blowing its horn. Almost none could say why or how it is useful in detecting storm systems or for tracking aircraft. This 1959 Popular Electronics magazine article attempts to explain Doppler radar to the uninitiated. Having worked as an air traffic control radar technician in the USAF, and then having done the RF and analog system circuit design for a prototype Doppler weather radar as an engineer, I have had a lot of exposure, but I am by no means an expert...

Bell Telephone Labs - Type-O Open Site Systems

Always creating and pushing the leading edge of communications technology, Bell Telephone Systems and their research group, Bell Telephone Laboratories, frequently ran full-page promotions in many types of magazines, from electronics industry publications like the 1952 issue of Radio-Electronics, to domestic rags like Woman's Day and Better Homes and Gardens. In this instance, Bell Labs was justifying its continued use of the original open-wire telephone line distribution systems using poles with individual pairs rather than the newer multi-pair cables that carried sometimes hundreds of circuits in the space of a few square inches of cross-section, and in a protective sheath that guarded against signal interference and weather degradation. An entire volume of the Bell System Technical Journal (BSTJ) was published on the Type-O (open wire) Carrier System in the same year this ad appeared. It basically came down to economics based on the fact that so many thousands of miles of the old lines in existence performed adequately well, and new technology allowed two or more circuits to co-exist on the same twisted pair...

QSL from Sputnik

Securing confirmation of having made a contact (QSL in ham-speak) with a radio operator behind the communist Iron Curtain was a real achievement during most of the 20th century. Russian and Chinese citizens were routinely imprisoned for such activity, and if you did manage to elicit a response to your CQ (request for contact), there was a good chance it was with a government propagandist posing as a civilian. When Sputnik 1 was put in orbit on October 4, 1957, a whole new realm of DXing (long distance communication) opened up by providing satellite relay paths. Sputnik 1, the world's first artificial satellite, broadcast a series of pulses at 20.005 and 40.002 MHz that were tracked and reported by both professional and amateur radio operators. Vital data was learned based on the time and strength of signals that allowed scientists to ascertain the physics of upper atmosphere characteristics...

Crosley Model 555 Schematic

This is another Radio Service Data Sheet that appeared in the March 1936 edition of Radio-Craft magazine. I post this schematic and functional description of the Crosley Model 555 (A.F.M.) 5-Tube 2-Band Superhet radio manufacturers' publications for the benefit of hobbyists and archivists who might be searching for such information either in a effort to restore a radio to working condition, or to collect archival information. As mentioned previously, manufacturers usually did not provide this data to anyone other than an authorized service shop, so making it available via the magazine was a huge benefit to repair shops and do-it-yourselfers. Unfortunately, not very much textual content was included with the schematic. It was part of a group of seven different models (see table of contents), and not much more than the schematic was provided for each...

Transistor Topics

"Transistor Topics" was a monthly column in Popular Electronics magazine that helped introduce and educate readers to/on the relatively new topic of transistor design and troubleshooting. Transistors were first invented in December of 1948, but it took about a decade before they were reliable and inexpensive enough to be integrated into a large variety of products - and affordable to the hobbyist. Editor Lou Garner often presented questions from readers and answered in layman's terms. This month's question came from a reader in Bogota, Columbia, which in 1960, was a big deal. Nowadays we take for granted how small the world is due to the Internet. Aldens department store is mentioned, which I remember moving into a shopping plaza next to Hechinger lumberyard and home center in Annapolis, Maryland, sometime around 1970...

The Art of Xerography

I am always amazed when reading articles like this one on "The Art of Xerography" at how the engineers and scientists who develop these system manage to think up the processes and materials required to make everything work so well, and then to make it manufacturable on a mass basis. How did Chester Carlson discover that dyed lycopodium powder, made from creeping cedars, sprinkled over a waxed paper plate would create the likeness of an original image - after, of course, rubbing a sulfur-coated metal plate with a handkerchief and quickly exposing the plate to light transmitted through the glass with a pattern on it? Electrostatics eventually came to play a big role in high volume printing, as described here. I saw a video one time (can't find it now) of a high voltage and chemical processed used on thin aluminum sheets used in newspaper printing up through the 1970's for making masters. My father worked at The Evening Capital newspaper in Annapolis, Maryland, and I remember back in the 1960's walking through the printing press area and seeing operators pounding away on typesetting machines that assembled the lead die into lines of text, and from there the entire process up through actual printing and folding of the newspapers. From around 1970 through 1974, I delivered those papers in my neighborhood on my bicycle. The subscription cost was a whopping $2.10 per month...

Electronics in Medicine

Every time I see one of these articles on "modern" medial electronics it makes me think of the Star Trek IV movie titled, "The Voyage Home," wherein Dr. McCoy (aka "Bones") intervenes as a 20th century brain surgeon is about to operate on Chekov - "My God man, drilling holes in his head is not the answer!" The 1948-vintage electrocardiograph featured in this Radio-Craft magazine article looks like it was built from parts salvaged from World War II field gear. Having a doctor attach wires to you is scary enough, but back when the probes were powered by instruments using circuits with 200-300 volts of plate bias in them would add an extra level of anxiety. BTW, have you ever wondered how "star dates" in Star Trek were determined? As it turns out, the system has not been consistent throughout the series from television and the movies then back to television. It began as a random number to avoid needing to specify a particular century...

E, I, R, and P Chart

Maybe given the nature of the newly introduced Popular Electronics magazine (this was only the third issue), the editors decided using a big word like "nomograph" might be a little too out of the realm for use in a magazine seeking to appeal to newcomers to the electronics field. It is a little surprising since students of the day were quite accustomed to using this type of a graph since computers still filled entire rooms and hand-held calculators went by a different name - slide rules. In fact, because of a familiarity with using a slide rule, people were more accustomed to having to shift decimal points to the left or right first to do the calculation on a device that only displayed values in a single decade range, and then to arrive at the final answer after the calculation. That is exactly the skill needed to use the nomograph. I guess that people today - even engineers - would have a harder time keeping track of powers of 10 than...