If It Sounds Too Good To Be True . . .

At first glance, this radio kit sounds like a great deal. For only $2.95, including postage, it looks like you get a kit to put together an “All American Five” radio, for considerably less than what it would cost to purchase one already assembled.

When I saw it, I was a little bit dubious, so I read more closely. Sure enough, it looks like it includes all of the components. I was still suspicious, so I looked even more closely, to make sure that it was a real five-tube superhet, and not some kind of stripped down crystal set. But sure enough, it includes a calibrated tuning knob and a volume control knob. Yep, it sounds like the real deal, and it sounds like, as the ad announces, a good way to get started in radio.

I bet there were a few who came to the same conclusion and sent in their $2.95. But first, let’s read it one more time, very carefully this time.

For $2.95, you don’t get started in radio. You get started on this radio, but you don’t finish for that price. They don’t furnish all of the components. They furnish all but the components! You get the cabinet, the chassis, name plate, the knobs (but apparently not the volume control or tuning capacitor), the back panel, and five tube sockets (but no tubes). In their generosity, they even include four screws and three grommets. But that’s it. For the actual components, you’re on your own.

The ad appeared 70 years ago this month in the April 1951 issue of Radio-Electronics. It was offered by the Lormel Products Co. of 10406 Superior Avenue, Cleveland, Ohio. They don’t seem to be in business any more.

1941 CW Transmitter

Eighty years ago this month, the April 1941 issue of Popular Mechanics showed how to put together this simple CW transmitter designed to cover five bands (160, 80, 40, 20, and 10 meters, since 15 meters wasn’t a ham band until after the war). Crystals for the transmit frequency could be used, or the crystals for 160, 80, and 40 would double easily. Plug-in coils were used to switch bands (and presumably, a 15 meter coil could be wound after the war).

The 20-watt transmitter was billed as suitable for the beginner. If the receiver in the photo above looks familiar, it appeared in the magazine’s January issue, and we previously wrote about it. The transmitter, like the receiver, had a built-in AC power supply, this one using a type 80 rectifier. The transmitter itself used a 6L6-G tube. The parts for the set were said to be available in kit form from a number of suppliers, and would set the builder back about $13, plus tubes, coils, and crystals.

The new ham putting together these sets would be able to work only other U.S. stations, since there were already restrictions on working foreign stations. And 8 months later, they would be off the air after Pearl Harbor, although the receiver would continue to pull in war news.

1961 British AM-FM Portable: The Roadfarer

Sixty years ago, the April, May, and June 1961 issues of the British journal Practical Wireless contained the blueprints and construction details for this ambitious project, dubbed the “Roadfarer.” The set was a completely self-contained portable that would tune the longwave, mediumwave, and FM broadcast bands. It would operate on batteries, but also included an AC power supply to give greater economy when close to the mains.

The magazine promised that the set would be found simple to build, thanks in large part to the use of printed circuit boards. A total of three boards were used, for the AM tuner, FM tuner, and audio amplifier.

The magazine announced prizes for the best constructional work carried out by readers. A panel of judges had been assembled from representatives of the firms whose parts were used in the receiver. Some of those firms kitted all of the parts needed to construct the set, and those were found in subsequent issues of the magazine.

Despite the announcement of the prizes, I wasn’t able to find any listing of winners in subsequent issues of the magazine.

US Post Office Airmail Radio System: 1921

A hundred years ago this month, the April 1921 issue of Popular Mechanics described the radio network of the U.S. Post Office Department. At a cost of $26,000, the post office had put together a string of 15 stations–10 owned by the post office, and 5 others shared with other government departments–to facilitate the carrying of airmail across the country.

65 airplanes were in use transporting 200,000 letters daily, and to manage the system and provide meteorological data, radio was necessary. The first one, shown here, was established at College Park, MD. Others were at Bellefonte, PA, St. Louis, MO, Omaha and North Platte, NE, Cheyenne and Rock Springs, WY, Salt Lake City, UT, and Elko and Reno, NV.

Work on the system had begun in 1920, and at press time, sixteen radio men were in the employ of the department. Plans were in the works to equip planes with radio direction finding equipment and radiotelephones.

TV Steeplejacks: 1951

This gentleman, shown on the cover of the April 1951 issue of Popular Mechanics, is a lot braver than I am, but he was a critical part of the radio-TV industry.

Since TV and FM signals require line of sight propagation, antennas need to be up high, and steeplejacks were the men who made sure they were up there. According to the magazine, some of the employees were old timers used to working jobs up high, but some were young men. There were few accidents, because the one thing all workers had in common was that they could have only one accident.

In New York, the 1250 foot Empire State Building had just grown 222 feet with the installation of the antennas for five New York TV stations. The idea was to eliminate ghosts and extend the range 50 miles.

The magazine pointed out that the building came with a “spike” originally designed as a mooring spot for Transatlantic dirigibles. It came in handy providing a solid base for the antennas.

1961 Speed Mail

Sixty years ago, the U.S. Post Office tried something that Popular Electronics, in its April 1961 issue, called “Electronic Speed Mail.” The official name for the service was just “Speed Mail,” but it was an early hybrid of electronic mail (or more accurately, facsimile) and snail mail.

The Post Office Department envisioned having centers in 71 cities strategically located across the country. To write a letter that would be delivered the same day, a sender would write the letter on a special form provided by the post office, taking care to write only within the lines. The form was likened to the special “V-Mail” form of World War II, with which letters were microfilmed stateside and delivered to Army Post Offices where they were printed and delivered, or vice versa. In this case, the message form was sealed and deposited into the mails. At the local post office, it was fed in, still sealed, to a facsimile machine. The machine opened the mail, scanned it, and placed it into a sealed container. After the operator was sure that the message had been properly sent, the batch of message forms was destroyed.

The scanned message was then sent via the Echo 1 satellite to the closest post office to the recipient. There, the message was printed and sealed into a window envelope with only the recipient’s address and return address showing. Again, the entire process took place without human eyes seeing the message.

An example of the message blank is shown below. This one bears a message sent from Postmaster General Arthur Summerfield to Vice President Nixon, late in 1960. (Even though the message was sent crosstown in Washington, it was relayed via Chicago to demonstrate the service’s capabilities.)

When the Kennedy Administration took office, newly appointed Postmaster General J. Edward Day (best known for the creation of the ZIP code) was less enamored with the system, and no further efforts were made to promote it. The Western Union Mailgram service (“the impact of a telegram at a fraction of the cost”) was introduced nine years later in 1970, and allowed rapid mail service. Messages were sent by Western Union to the nearest post office, where they were printed and delivered the same day received.

National Postal Museum image.

1941 Portable Transmitter-Receiver

In the April 1941 issue of Radio News, William D. Hayes, W6MNU, of Oakland, California, recounts that since he liked to build his own equipment and constantly improve as the state of the art progressed, he had amassed a large collection of perfectly good spare parts. To put them to use, he put together this transmitter-receiver. It was intended for portable use while vacationing, but could also be put to use as a backup rig from the home station.

The receiver employed a 27 tube as regenerative detector, with a 47 used for audio output to drive a speaker, mounted on the wooden front panel with a piece of window screen for protection. The receiver covered 70 through 550 meters in two bands. The author noted that tuning the broadcast band was a useful feature, since the set would be used on vacation. He reported that the simple receiver provided very good reception on the broadcast band.

A bandspread capacitor covered the 80 meter ham band perfectly.

The 80 meter transmitter was a crystal oscillator also using a 47 tube. The use of the same tube as used in the receiver was intentional, to minimize the number of spare tubes that had to be carried. With the type 80 rectifier tube, only three spare tubes had to be brought along.

The author reported that from his cabin in the Santa Cruz mountains of California, and with a 130 foot antenna only 10 feet off the ground, he made numerous contacts with California, Washington, Oregon, Idaho and Nevada.

Aleutian Islands Earthquake and Tsunami: 1946

Hilo residents fleeing tsunami. Wikipedia photo.

Today marks the 75th anniversary of the April 1, 1946, Aleutian Islands earthquake and tsunami. The quake had a magnitude of 8.6 and resulted in hundreds of casualties, including all five lighthouse keepers at the Scotch Cap Lighthouse on Unimak Island. 55 foot waves raced across the Pacific at 500 miles per hour and hit Hawaii 4.9 hours later. In Hilo, 173 were killed, including some who were swept out to sea by the receding waters. The destruction prompted the creation of the Seismic Sea Wave Warning System, the forerunner of the Pacific Tsunami Warning Center.

As detailed in the August 1946 issue of QST, at Ikatan, Alaska, the quake was felt by amateur radio operator Henry W. Peterson, K7FFG, who reported four earthquakes followed by a tidal wave cresting at 60 feet. His home was washed into the bay and many other buildings were damaged. He reported families having to head for the hills until daybreak when they could see what was going on.

At 6:00 AM, he put out a call of QRR, but was unable to make contact until 10:00 AM, when he got in touch with government station KNLL. He also raised Signal Corps station WXFP, which requested that he keep a constant radio watch and report every 15 minutes for 24 hours. He then reported all shocks twice a day. There were a total of about 70 shocks up through April 7.

Local residents were very relieved to know that he was in contact with the Signal Corps and could get help at any time if needed.

1961 British “Ranger 3” 3-Transistor Regen

Shown here from the March 1961 issue of the British magazine Radio Constructor is a set dubbed the “Ranger 3,” a pocket sized three-transistor receiver for the medium waves, including the 160 meter ham band and marine frequencies. The set employed a regenerative detector and had a built-in ferrite antenna. The basic set used an earphone, but as shown in the schematic, it could drive a speaker with a few additional parts.

As was often the case with this magazine, there was a construction article, and the ad for a parts supplier conveniently appeared in the same issue with all of the parts. In this case, Henry’s Radio Ltd. of London could supply all the required parts for just over 79 shillings.

The ad points out that the set should be able to pull in Radio Luxembourg in most areas, and the ad turns this into “Luxembourg Guaranteed (where normally receivable).” The BBC had a monopoly on broadcasting in Britain, and the English commercial program from Luxembourg was a popular alternative.

This simple set did a good job of pulling in the distant station because it was optimized for the station’s wavelength of 208 meters (1439 kHz). Since this was close to the top of the dial on most sets, the reception might be marginal, since they were probably optimized for the middle of the broadcast band. The Ranger 3, however, covered 600 kHz to 2.5 MHz, meaning that the Luxembourg station was right in the middle of the dial. In fact, the article suggested waiting until late at night to tweak the receiver, using Radio Luxembourg as the test signal.

According to the article, the set was a very good performer, pulling in numerous continental stations, especially at night.

Vinegar and Baking Soda Experiments: Beyond the Volcano

Every self-respecting young mad scientist probably discovered as a toddler that many hours of fun could be had by mixing vinegar and baking soda. When the time comes for their first science fair in elementary school, many of them harken back to this early experiment and decide to make a vinegar and baking soda volcano. In fact, if you Google the words “science fair vinegar and baking soda volcano“, you will get over a million results, many of which we are sure are fine educational projects. But we also know that our readers, even the youngest ones, strive for a bit more. So if your young mad scientist is thinking of a science fair project involving these venerable home chemicals, here are a couple of more advanced projects, which appeared in Boys’ Life magazine 70 years ago this month, March 1951. They are just as easy (or even easier) than the stereotypical volcano that other kids will be bringing, but they demonstrate some additional scientific principles.

To do the experiment shown above, you start with a tall glass of water and add a tablespoon of vinegar. You then slowly stir in a half teaspoon of baking soda. Finally, you put four or five mothballs in the glass. They’re heavier than water and will sink to the bottom, but after about a minute, they will rise to the surface. They’ll sink again and continue rising and falling for hours.

What’s happening is that the mothballs are only slightly heavier than water. Little carbon dioxide bubbles affix themselves to the surface, which gives just enough buoyancy for them to rise. At the surface, the bubbles pop, and the mothball sinks again. If you don’t have any mothballs around the house, I’m told that raisins will work just as well.

If Junior likes playing with fire (and what kid doesn’t?), they will enjoy the experiment shown at the left. You start with a teaspoon of baking soda at the bottom of an empty glass. To this, you add a tablespoon of vinegar diluted with a tablespoon of water. When the mixture begins to fizz, you lower a lighted candle into the glass. Since carbon dioxide is heavier than air, it fills the glass. And since carbon dioxide doesn’t support a flame (which is why fire extinguishers use it), the flame extinguishes itself.

But there’s more! If you act quickly enough, you can lift the candle back out as soon as it goes out, and the flame will miraculously come back to life. This is because there is still vaporized wax, and the wick is still hot enough to ignite as soon as it gets back into sufficient oxygen.

The kid who made the volcano will undoubtedly go home with a nice participation ribbon. But armed with these simple experiments proving scientific principles, Junior will undoubtedly take home the blue ribbon.

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