Monthly Archives: May 2019

OneTubeRadio.com Night at Feed My Starving Children!

Meals packed by our group in 2016, on their way to Haiti, Nicaragua, or the Phillipines.

Join us in volunteering to fight world hunger! Friday, June 7, 6:00 PM, Minnesota State Fairgrounds.

We previously posted about Feed My Starving Children (FMSC), a Christian relief organization which packages meals for distribution to malnourished children around the world. The meals are packaged by volunteers and then distributed by partner organizations around the world.

There is currently a large demand for meals, and on June 7-8, the organization is looking for 5000 volunteers to pack one million meals. You’ll be part of a small assembly line that assembles the ingredients, seals them in a plastic bag, and then packs them into cartons and pallets for shipment. You’ll probably be told which country will be receiving the meals you pack. You can read more about the event at this link. It’s a fun work environment. You’ll be working almost the full time, but the work is not strenuous. Children 5 and older are welcome with accompanying adult.

OneTubeRadio.com Night at FMSC!

On Friday and Saturday, June 7-8, FMSC will be running seven shifts. Each one is about 2-1/2 hours long. My family will be attending, and I signed up our group under the name OneTubeRadio.com. We will be working on Friday, June 7, at 6:00 – 8:30 PM at the Minnesota State Fairgrounds, 1265 Snelling Ave. N., St. Paul, 55108. Plenty of free parking is available. Also, free passes on Metro Transit are available.

We would love to have others join us! If you want to join us, you have three options. If you wish, you can contact me at clem.law@usa.net and I’ll add you to our reservation. You can also add yourself to the group with this link. If you sign up yourself, please let me know you’re coming, although if you’re an introvert and prefer to attend under the cloak of anonymity, that’s perfectly OK.

Our group will meet at about 5:30 near the Butterfly House, at the corner of Dan Patch and Underwood. (I’ll give you my cell phone number, and we’ll also have talk-in on 146.52 MHz.) The packing event itself starts at 6:00 in the Grandstand building. If you’re running late, you can simply meet us there.

If you can’t make it Friday evening but want to sign up for another shift, you can do so at this link. Many other businesses and organizations are also promoting the event. For example, see the links from KTIS radio and HandsOn Twin Cities.

Some of the shifts will fill, so please sign up or contact me as soon as possible to reserve your spot. You will make a real difference in ending hunger in the world. And, if you wish, you can have your picture appear on a world-famous blog (namely, this one). If you are not able to attend, please consider making a monetary donation.

FMSC is a Christian organization, and the evening concludes with a prayer over the packaged meals. However, they are truly welcoming to those of all faiths or of no faith.

1959 Underwater Speaker

Sixty years ago this month, the May 1959 issue of Popular Mechanics shows an idea that surprisingly never caught on: underwater music. You’re swimming at the pool and listening to music. But when you dive under the water, you can no longer hear the music. The problem is easily solved by installing a speaker inside the pool. Because sound travels five times as fast in water, “music from the submerged speaker is more true-toned than one mounted in the air.”

And the project is quite simple. All you need to do is purchase a “submergence-proof speaker.” The magazine recommended the University MM-2F (UW), a 25 watt speaker which sold for about $40.

And lo and behold, if you search Amazon for “submergence proof speaker,” one is still available today, although it appears to be marketed toward industrial applications. It is shown here, and the full details are available at this link. It appears quite similar to the model shown in the magazine. The price is higher today than it was in 1959, although most of the increase is attributable to inflation.

How to Cut Glass with Scissors

A hundred years ago this month, the May 1919 issue of Popular Science showed how to cut glass with a pair of scissors. Lo and behold, it is possible, as long as the glass is submerged under water.

The article noted that it is often necessary to cut an odd-shaped piece of glass, such as to replace the broken glass on an electrical instrument. According to the magazine, “ordinary window-glass may be cut to almost any desired shape by holding it beneath the surface of a pan of water and cutting with house shears.”

A straight cut was not possible, but it was possible to “chew out” the piece. Of course, my first reaction was that if this was indeed possible, then there would be YouTube videos, and indeed there were, such as this one, which inexplicably tells you not to try it at home. I encourage you to try it at home, but the recommendation to use eye protection is a good one.

According to this website, an unnamed issue of Scientific American explains the phenomenon by saying that water causes glass to crack more easily when water enters the crack. The “silicon-oxygen bond at the crack and an oxygen-hydrogen bond in the water are cleaved, creating two hydroxyl groups attached to silicon. As a result, the length of the crack grows by the size of one bond rupture. The water reaction reduces the energy necessary to break the silicon-oxygen bonds, thus the crack grows faster.”

How well does it work? That question would be suitable for some young scientist to explore as part of a winning science fair project.

Einstein and the Eclipse of 1919

Eclipse as seen on Principe. Wikipedia photo.

Today marks the 100th anniversary of the eclipse of May 29, 1919. The total solar eclipse, which darkened the skies over a band from South America to Africa, had the distinction of having the longest totality (6 minutes 51 seconds) of any since 1416.

Einstein in 1921. Wikipedia image.

But the eclipse was most notable as making possible an experiment that demonstrated one of the predictions of Albert Einstein‘s General Theory of Relativity published in 1915. The gravitational pull of a large object (such as the sun) would bend light waves passing close by, and Einstein predicted how large the effect would be. He noted that a solar eclipse would be the perfect opportunity to prove or disprove the theory, since stars close to the sun would be visible. Their “correct” location in the sky was known. If they could be observed in the “wrong” location, then the measured location would confirm his theoretical findings.

The first attempt was done in conjunction with the eclipse of August 21, 1914. An expedition made up of German and U.S. astronomers traveled to Crimea to observe the eclipse. Unfortunately, Germany declared war on Russia on August 1. The German scientists were either sent home or taken prisoner. The U.S. astronomers were not detained, but clouds prevented the necessary observations.

Dyson (left) and Eddington (right). (Photo credit.)

The 1919 eclipse was the next opportunity, and an experiment was organized by British astronomers Frank Watson Dyson and Arthur Stanley Eddington. This came to be known as the Eddington experiment. Rather than place all eggs in the same basket, as happened in Crimea, the 1919 experiment would have observations taken at two sites: Sobral, Brazil, and the island of Principe off the west coast of Africa.

In Principe, even though clouds obscured the sun until shortly before the eclipse, the team was able to make several photographic plates, one of which showed the background stars clearly enough. The positions did confirm Einstein’s predictions.

While the scientific community was slow to fully accept the findings, the popular press jumped on board, and Einstein’s name became a household word as a result of the experiment. The news clipping below, for example, calling the experiment “the greatest discovery in history” appeared in the Washington Times on November 9, 1919.

1939 Two-Tube Shortwave Set & Three-Tube Marie Antoinette Radio

Eighty years ago this month, the May 1939 issue of Popular Science carried the plans for this two-tube set, which was said to “bring in London, Rome, and Berlin as easily as local broadcasts.” The circuit was very efficient, since the two 6C6 tubes ran on a B+ voltage of only 3 volts for shortwave, or 1.5 volts for standard broadcasts. The tubes, although nominally 6-volt filaments, used 3.4 to 3.8 volts, as adjusted by the 10 ohm rheostat.

For those desiring a slightly different radio experience, the same magazine also showed how to put together this three-tube “dressing table radio” concealed within a Marie Antoinette doll. The radio itself is concealed under Marie Antoinette’s dress. Atop is affixed a ceramic figurine. While the exact replacement is apparently no longer available, this Marie Antoinette salt shaker would undoubtedly work perfectly:

HCJB Transmitter Site, 1959

This picture of the HCJB transmitter site at Pifo, Ecuador, appeared in the May 1959 issue of Popular Electronics. The magazine noted that the station was currently capable of transmitting on a single shortwave frequency with 50,000 watts, but would soon have the capability of transmitting on two frequencies simultaneously at 30,000 watts each.

For more information about the station, see our earlier post about the station’s history.

Line Voltage Booster

This was by no means a new idea at the time, but the May 1979 issue of Popular Electronics shows a simple way to boost your line voltage. It employs a six-volt filament transformer wired so that it becomes an autotransformer, and the voltages on both coils add. So if you start with 120 volts, you wind up with 126. As the accompanying text explains, you might need to use some trial and error. If you wire it up and the voltage goes down by six volts, then you need to reverse the secondary windings.

While they are not common, 6 volt filament transformers are certainly not unobtainium, and you can get them from Amazon at this link:

If you need a slightly heavier duty version already assembled, then you can’t go wrong with an adjustable autotransformer (commonly known as a variac) like this one:

1934 Try-Mo Scout Shortwave Receiver

The May 1934 issue of Short Wave Craft magazine included this ad for the “Scout,” a one tube shortwave set from the Try-Mo Radio Co., Inc., of 85 Cortlandt Street, New York. The set sold in kit form for only $3.95, but the type 230 tube, batteries, and headphones would run an additional $4.25. The set came with plug-in coils for shortwave, but a coil for the standard broadcast band would cost an additional 39 cents, probably a good investment in case the short waves were quiet.

1944 WERS Transceiver

Seventy five years ago this month, the May 1944 issue of QST carried a construction article for this 112 MHz transceiver for the War Emergency Radio Service (WERS). The article was unique in that it showed how to “mass produce” the set in a high school shop class.

The Altoona, PA, WERS organization operating under call sign WKYU, had little appropriate equipment. Compounding the problem was the fact that few skilled amateurs remained at home to do the building. The problem was solved by setting up construction of standardized transceivers by radio and electronics students in the vocational department of Altoona High School. The school benefitted by having interesting and worthwhile lab work, and WERS benefitted by having a source of the needed equipment. In addition, the students who were involved in WERS also had particular pride in using equipment they themselves had built.

The circuit is a familiar one for VHF transceivers of the era. A 6J5 served as oscillator and self-quenched superregenerative detector, although other tubes could be substituted. A 6G6 pentode served as modulator and audio amplifier. Since wartime shortages meant that some tubes were not available, the article suggested substitutions for each.

175th Anniversary of Electric Telegraph

Morse sending message from Capitol. Wikipedia image.

Today marks the 175th anniversary of the first use of the electric telegraph on May 24, 1844, a message sent between Washington and Baltimore by Samuel F.B. Morse.

As shown by the newspaper clipping to the left, the device was in immediate commercial use. The article appeared in the Whig Standard on May 28, 1844.

The 38-mile line was authorized by Congress in 1843, and $30,000 was appropriated. It was completed by May 1, 1944, and a demonstration took place that day. This is the demonstration apparently being discussed in this article, since the May 1 demonstration included sending the news of the Whig Party’s nomination of Henry Clay for President. The author of that article announces in astonishment that “those attending at the Capitol may almost be said to have been in attendance at all the Conventions in Baltimore!”

Morse in 1857. Wikipedia photo.

The line officially opened on May 24, 1844, with Morse in the Capitol building sending the words “what hath God wrought” to Baltimore. Within the next six years, 12,000 miles of line were placed.

Interestingly, the word “telegraph” was already firmly ingrained in the English language. Morse’s invention might have been the first electric telegraph, but other devices for sending signals over a long distance already existed. For example, I have transcribed the 1797 Encylopaedia Britannica article on the telegraph, which describes some of the pre-electric telegraphs.

Most readers are undoubtedly aware of the current uses of Morse Code, even 175 years after its first use. An interesting article at Smithsonian.com explains some of them.

The International Morse Code is standardized by the International Telecommunications Union. The most recent addition to the code is the addition of the @ sign ( .– – .– .) in 2002.

Historical marker along path of Washington-Baltimore line. Wikipedia photo.