The next major eclipse event is the Sunrise Eclipse, which will be visible in Hawaii on October 2. You can read more at our sister site, SunriseEclipse.com. Be there. Aloha.
The image here was taken on June 10, 2021. Wikimedia Commons photo by Anthony Quintano from Mount Laurel, United States – Statue of Liberty Annular Solar Eclipse,
CC BY 2.0.
Sixty years ago this month, the cover of the May 1964 issue of Electronics Illustrated shows Dad putting the finishing touches on this remote-control vehicle that he’ll be surprising Junior with. The transmitter puts out 100 mW on CB channel 23 for good range without the need for a license. One push of the button steers the truck to the right as long as the button is held down, and two pushes steers it to the left.
The editors couldn’t find any vehicles with steerable front wheels, so they bought the Tonka truck shown here and modified it by adding a steerable front axle.
Complete circuits for transmitter and receiver are included. The receiver employs five transistors, and the transmitter, three.
A hundred years ago this month, the May 1924 issue of Boys’ Life showed scouts how to put together this one tube broadcast receiver. The design was the winner of a contest put on by the magazine as the very best one-tube receiver. The winner was C.H. Brown of Edgewood, Maryland.
The magazine noted that the set was not regenerative. That was good, in that it wouldn’t break into a squeal to the consternation of listeners living nearby. It could be used for ‘phone signals, modulated CW, and spark transmissions. It was, however, no good for those newfangled CW signals that were showing up on the air.
A number of tubes could be used in the set, such as a UV-199, C-299, UV-201A, or C-301A. The set used a reflex design, meaning that the tube had two functions. It first amplified the incoming RF signal, which was then detected by a crystal detector. It was then fed back to the same tube which amplified the audio. This design accounted for the extraordinary distance and volume of which the set was capable.
Total cost was said to be about $18.00.
If you were in the market for a phonograph in Omaha, then the place to go would be the Schmoller & Mueller Piano Company, as shown in this ad from the Omaha Bee, May 6, 1924.
It wasn’t unusual for piano dealers to sell phonographs. This made sense, since they were hedging their bets–if phonographs meant people would stop buying pianos, they were covered either way. But this dealer took it a step further–just in case radio marked the end of phonographs, they had that covered, too. If you bought a phonograph from them, they would throw in a free crystal set.
The plans for this unusually designed one-tube regenerative receiver appeared a hundred years ago this month in the May 1924 issue of Popular Mechanics. Nothing about the circuit, using a UV199 tube, is particularly remarkable, other than the way it’s put into effect. The main coil is stationary, but the antenna coil and ticker coil are adjustable. They are all wound spiderweb style. To increase antenna coupling, you move the antenna coil closer to the main coil. To increase regeneration, you move the tickler coil closer.
According to the article, the set could be constructed of the odds and ends that can be found on any radio enthusiast’s worktable.
Eighty years ago, the May 1944 issue of Popular Mechanics showed how to put together this two-tube home telephone system. Both the master and remote units were built breadboard-style. It might have looked austere, but there was a war going on, and a metal cabinet would have been an unnecessary luxury. It ran off the AC line, and the filament voltage was obtained by dropping it through a 40 watt light bulb. Calling was accomplished by an independent bell or buzzer. Therefore, it could be switched off until needed.
This couple were using it to communicate from house to barn. But the magazine noted that it could be used to communicate with the photographic dark room, since the remote emitted no light.
All parts could be found in the proverbial junk box, or from the dime store. For example, the talk-listen switch is fashioned from the handle of a toothbrush.
We were sad to hear the news recently that MFJ Enterprises will be shutting down production on May 17, 2024. The company has long been a fixture in Amateur Radio, producing a wide variety of products, mostly station accessories, for the amateur market. Their products have the distinction of being functional and utilitarian, and usually reasonably priced. They are often dubbed “Mighty Fine Junk,” but it’s a term of endearment, with the emphasis on “mighty fine.” They are junk in the sense that they are usually not professional grade. But they usually serve their purpose well, and they will be missed.
My first encounter with MFJ was probably the product shown at left, which is typical of their offerings: It met a very specific need at a reasonable price. It looked kind of clunky, but it worked well. When the MFJ-313 VHF converter came out in 1982, inexpensive handheld radios for 2 meters were just hitting the market. For example, my first HT was an Icom IC-2AT, which was priced at about $225. Unlike most ham rigs these days, the radios of that era generally tuned only the ham bands. So receiving was limited to 144-148 MHz.
The ability to tune other frequencies, particularly NOAA Weather on 162 MHz, was a useful addition, and the MFJ-313 solved that problem. It was a receive converter, powered by a single AAA battery, that attached to the radio and antenna. You could transmit right through it, “and it won’t burn out.” But at a flip of a switch, the local oscillator inside the converter would come to life at 16 MHz, and you would be able to tune the weather on 162.55 by tuning the receiver to 146.55.
Most of MFJ’s products filled similar niche needs. They weren’t glamorous, but they got their job done.
Another MFJ product I own is the MFJ-9040 CW transceiver for 40 meters. There was a time when I had been off the air for a few years, and didn’t really have a station set up. I wanted to get on the air fast, and this rig did the trick. I’ve traveled to multiple countries with it, and it’s always performed well. It’s not a perfect rig–it’s notorious for having a lot of frequency drift when first turned on. But that’s part of the charm, and the drift isn’t too bad once it’s been turned on for a while.
You wouldn’t build your whole station using MFJ gear (although with rigs like the 9040, you certainly could). But they took care of all kinds of needs.
If you’re still interested in getting in on the fun, the company isn’t going out of business just yet, and they undoubtedly have a lot of New Old Stock on hand in their warehouse, and at their many dealers. If you want to build something, I would recommend their MFJ-8100K regenerative receiver. It covers shortwave broadcast and amateur bands from 80 to 15 meters, and should be a relatively easy kit for the beginner. It’s also available assembled.
I suspect that some of MFJ’s brands will be sold to other manufacturers, and it’s not all doom and gloom. Those other little accessories they make, even if MFJ stops making them, will still be available. For example, I really like my MFJ-9040, but QRP Labs has a superior product in the QCX Mini, which I previously reviewed. We will miss MFJ, but amateur radio will continue.
MFJ got its start in 1972, and as far as we can tell, it’s first products were the two audio filters shown in this ad in 73 Magazine, December 1972. They made an innovative product, and kept adding more innovative products. We’re confident that someone will do it again.
We thank MFJ’s founder and owner, Martin F. Jue, K5FLU, for over a half century of service to the Amateur Radio Community, and wish him the best in his retirement.
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The solar eclipse of June 8, 1937, was the longest in over 1200 years, and this fact was verified by an expedition to Peru headed up by Clyde Fisher of the Hayden Planetarium. The expedition used precise timekeeping instruments from Longines, as pointed out in this ad in Life Magazine, 80 years ago today, May 1, 1944.
According to the ad, Longines chronometers were also used by the planetarium’s expedition to view the April 7,1940 annular eclipse, headed by William H. Barton, Jr.
This artist’s conception of telehealth appeared a hundred years ago this month, on the cover of the April 1924 issue of Radio News.
According to the magazine, a prototype of the unit shown here had already been constructed, and a block diagram was included in the accompanying article. We note, however, that it was the April issue of the magazine.
The plans for this crystal set from Down Under appeared 80 years ago this month in the April 1944 issue of Australasian Wireless Review. It’s dubbed a “mystery” crystal set, and the entire circuit is built in to one side of an ordinary pair of headphones. The coil is as many turns as possible of wire wound spider-web style.
Before installing it into the headphone, it was a good idea to test it on a board, and ascertain the best spot to tap the coil. Then, it would be soldered into place and inserted. A small hole was drilled through which a shaft to the trimmer condenser was inserted for tuning. Two wires, with spring clips at the end, were used to connect to a convenient antenna and ground.
The magazine recommended a fixed crystal of the “small round flat type,” although we’re guessing a 1N34 diode would work even better. It noted that the detector might be hard to obtain, with a war going on and all, “but all good Radiomen should be able to rig something up.”
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