Monthly Archives: February 2015

Morse Code Secret Message in Colombian Song

FARC Guerillas. Wikipedia photo.

FARC Guerillas. Wikipedia photo.

Morse Code was used in 2010 to get a secret message to hostages being held in the Colombian jungle by FARC guerrillas.  Some of the hostages had been held for years, and the Colombian army wanted to deliver a message that they hadn’t been forgotten, that some hostages had already been rescued, and that they were next.

Since it was known that some of the prisoners knew Morse Code, and the captors probably didn’t, the Army decided to insert a Morse message into a popular song and get it broadcast on the air.  The result was the song heard on this YouTube video, Mejores Dias (Better Days), recorded by Colombian studio musicians Natalia Gutierrez Y Angelo.

I knew there was Morse Code coming, and I heard it the first time.  If I hadn’t been expecting it, I suspect it might have taken a couple of plays for me to notice.  And once I knew it was there, it took me several times to get the entire message, since it is well hidden in the music.  But if I had a lot of time on my hands, I would eventually decode the entire message.  It’s in the chorus, starting at about 1:30, 2:30, and 3:40 in the video, following the words, “escuchas esta mensaje, hermano” (listen to this message, brother).

To make sure that the song was heard, the Colombian army arranged to have it inserted into the play lists of the government-owned stations serving the jungle areas where the hostages were being held.  The guerrillas listened to the radio, and the hostages later reported that they even liked the song.  The message was heard, as rescued hostages later reported.

The message reads:   “19 LIBERADOS. SIGUEN USTEDES. ANIMO.”  (19 PEOPLE RESCUED. YOU’RE NEXT. DON’T LOSE HOPE.)  Even if you have only a passing knowledge of Morse Code, you will hear it, and you’ll eventually be able to decode it.

More information is available at, at the article linked below.



Heathkit GR-64, 1965

HeathGR64We recently looked at the Knight-Kit Star Roamer Receiver from 1964. It was a beginner’s general coverage receiver and was quite popular. The February 1965 issue of Popular Electronics announces another popular general coverage receiver for beginning SWL’s and hams, the Heathkit GR-64 shown here. It covered 550 kHz through 30 MHz in four bands, and made do with four tubes, a mixer-amplifier, IF amplifier, detector-audio amplifier, and audio output. The power rectifier consisted of two silicon diodes.

The kit retailed for $39.95.  The assembly manual is available for download at this link.


The Luxembourg Effect


An interesting ionospheric effect was first noticed about 80 years ago, and reported 80 years ago this month in Radio Craft magazine, February 1935.  Radio Luxembourg operated on 252 kHz, with a powerful 150 kw signal designed to provide coverage in England.

The phenomenon was discovered in 1933 by B.D.H. Tellegen, in Eindhoven, Netherlands, who was listening to a station in Beromunster, Switzerland, on 652 kHz. In the background of the Swiss signal, he could hear the audio of Radio Luxembourg. This same phenomenon was reported by other listeners. Due to the distance between the three points involved, it could not be explained by the receiver being overloaded. The Luxembourg signal could be heard only when the Swiss station was transmitting.

Tellegen noted that the three points were in a straight line: When the signal from the Swiss station made its way to the Netherlands, it passed directly over Luxembourg. He correctly theorized that the carrier of the Swiss station’s signal was being modulated in the ionosphere as it passed through the strong signal of Radio Luxembourg in the ionosphere.

The ionosphere had only recently been discovered, and was not totally understood. It was previously supposed that the ionosphere was a linear medium, through which radio waves passively reflected. But the existence of the Luxembourg Effect showed that the ionosphere could be artificially “heated,” to produce non-linear effects.

Interestingly, the carrier frequency of the signal didn’t seem to be critical.  The modulation of the interfering signal was superimposed on the other signal without regard to the carrier frequency.  Subsequent research showed that most of the effect took place in the lower range of the audio frequencies.

Much to the dismay of conspiracy theorists, this is the phenomenon that the High Frequency Active Auroral Research Program (HAARP) was working with. It’s relatively easy to generate a strong radio signal in the High Frequency (HF) region. HAARP had transmitters that could generate 3.6 MW signals from 2.8-10 MHz and radiate them toward the ionosphere. This strong signal was able to generate the same kind of “heating” effects caused by Radio Luxembourg.

It’s more difficult to generate signals in the Extremely Low Frequency (ELF) region. Among other things, ELF signals are used to communicate with submarines. The main idea of HAARP was to generate these signals not in a transmitter, but in the ionosphere itself, by mixing two strong HF signals. For example, it would be practically impossible to generate a radio wave of 0.1 Hz with a transmitter. But by beaming two signals into the ionosphere, one at 4.000000 MHz, and one at 4.0000001 MHz, the result would be a radio wave, generated in the ionosphere, with a frequency of the difference, 0.0000001 MHz, or 0.1 Hz.

The phenomenon is sometimes called the Luxembourg-Gorky effect, since the powerful longwave transmitter at Gorky, USSR, produced similar effects.



One-Tube Wartime Receiver, 1945


Radio parts were in short supply during the War, and radio enthusiasts had to make do with what they had. “H.T.,” a resident of Bothell, Washington, apparently had in his junk box a 1D8GT tube, and a low-impedance earphone, and wanted to know what he could do with them. So he wrote to the editors of Radio Craft magazine asking for a diagram of a receiver covering the broadcast band making use of the parts he had. He wanted to mount the earphone in the cabinet for use as a small speaker.

The editors indulged him and provided this diagram in the February 1945 issue. It was reprinted from the July 1940 issue, and showed how the combination diode-triode-pentode tube could be used in this circuit. The triode section of the tube was an RF amplifier, followed by the diode detector, with the pentode serving as an audio amplifier. Unfortunately for H.T., the low impedance earphone would need to be used in conjunction with an audio transformer. This set would drive a pair of high-impedance headphones, but to use it with his low-impedance earphone, it would need to be wired as shown for the speaker. So H.T. had to find himself either a set of hi-z headphones, or the output transformer, in addition to what he already owned.

The other hard-to-obtain part would be the variable capacitor. The circuit here shows a ganged condenser, but the response pointed out that two separate condensers would provide better results.

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1940 Two-Tube Two-Band Receiver

1940FebPM75 years ago, Popular Mechanics, February 1940, carried the plans for this simple two-tube, two-band receiver, which could be run off flashlight batteries, 8 for the B+, and one for the filaments. It used two Type 49 tubes, and tuned both the broadcast band and short wave. The short wave band covered the then-police freuencies, as well as the 160 and 80 meter ham bands. It was mounted on a wooden chassis and had a wooden front panel.  It was a very simple design, with one tube serving as the regenerative detector, and the second as audio amplifier.

This particular receiver would be difficult to duplicate, since the coils are unobtanium. The article notes that the coil is a “three-circuit tuner” which did away with “tedious coil winding, often a stumbling block for beginners.” The coil came with a pre-marked terminal strip which made wiring errors next to impossible. The rotating tickler coil was included. It even had a built-in switch wired to the taps on the coil for easy switching from broadcast to short wave.

As was often the case, the Popular Mechanics project was available in kit form from Allied Radio. The 1941 catalog shows this kit as selling for $4.70, plus $1.39 for the tubes and batteries.

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Battle of Iwo Jima, Feb. 23, 1945


The iconic photo of U.S. Marines hoisting Old Glory on Iwo Jima was taken 70 years ago today, February 23, 1945. It appeared on the front page of the Chicago Tribune, February 28, 1945, as the drawing shown here. As the artist wrote, “Not with a rope, but with Blood and Toil is the flag raised, and Devotion only can keep it aloft.”

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The Real Reason Scouting Is Important

MeasureDistancePeople sometimes ask what is the most important thing that youth learn from Scouting. They usually expect to hear something along the lines of that it “builds character.” In some cases, it is probably true that Scouting builds character, but I honestly can’t point to too many people who would have wound up being bad characters if they hadn’t been in Scouting.

A better reason why Scouting is important is summed up in this diagram, which appeared in Boys’ Life magazine 70 years ago, February 1945.  That’s not to say that measuring the width of a river is a particularly important skill in the scheme of things. In fact, I don’t recall ever being taught this particular method. But it’s illustrative of something I did learn, without knowing that it was being taught. What I really learned was that when I’m faced with some obstacle, it is usually possible to achieve the desired result, by applying a little bit of thought. But the first step is to know that there is a solution to the problem. Once a person realizes that, then finding the actual solution (or more often, one possible solution out of many) is usually pretty simple.

In this illustration, the Scout needs to know the distance across the river. The article, written by William “Green Bar Bill” Hillcourt, explains the method being used here. He starts at point A, which is directly across the river from a given point with a convenient object, in this case, a tree. He then walks along the river a set distance, such as 100 paces, and places a stick at that point. He then keeps walking that same distance. When he reaches the point marked C, he walks at a right angle, and keeps going until he’s along the same line containing the tree and the stick. At that point, the distance he’s walked away from the river is equal to the width of the river.

There are certainly other methods to figure out the distance, another one of which is also shown. But one method, which seems to be the most commonly used these days, is to consult outside information. It’s usually possible to ask someone who knows the answer. And it’s even possible to go to Google Maps, look at the image, and get the exact width. Those are very valid methods, and in many cases, they are more convenient and better methods. But the Scout learns that they are not the only methods. Even if outside assistance is not available, it is possible to figure things like this out on your own, without outside help.

I never really realized this until a few years back, when I started hearing from RV’ers that they couldn’t possibly camp in a non-electric site. I happen to enjoy the convenience of electric power, and if it’s available, I gladly take advantage of it. But I don’t view it as a necessity. When pressed, these people invariably come up with the same rationale for needing electricity: They need it in order to plug in their electric coffee maker.

Now, I drink a lot of coffee, and I probably drink more coffee than most of those people. So I understand their need for coffee. But I also realize one thing that they don’t know: I know that there are many methods of making coffee that don’t involve the friendly local electric utility. In response to their concerns, I even created a website entitled “How To Make Coffee Without Electricity.”  That website is written in a somewhat tongue-in-cheek style. But it’s also full of information that people don’t know, even though I always assumed that it was just common sense. It’s probably common sense to me because I was in Boy Scouts. I know that I can figure out the width of a river even if Google Maps is unavailable. So it stands to reason that I can figure out how to make coffee even if the power happens to be out.

There must be a lot of people who weren’t Scouts. Whenever a hurricane is bearing down on some part of the English-speaking world, my coffee page starts to get hundreds of hits. A day or two before the storm, these are from desktop computers. The day after the storm makes landfall, the number of hits increases, but most of them are from mobile devices. In other words, the power goes out, and only then they realize that they don’t know how to make a cup of coffee. I’m glad their mobile device is still working, and I’m glad that Google is still working, and I’m happy to impart my lifesaving knowledge that it is, indeed, still possible for them to make a cup of coffee.

But I worry about these people if Google ever becomes unavailable for some reason. Maybe they should have been Boy Scouts. I’m sure these people are of fine character, and they didn’t need Scouting to build it. But learning the lesson that self-reliance is usually possible probably would have served them well.

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Heathkit CB-1 “Benton Harbor Lunchbox”


Most hams who have been around a while have encountered the “Benton Harbor Lunchbox.”  This was a series of transceivers from Heathkit, and the most common were the HW-30 “Twoer,” which covered two meters, and the HW-29 “Sixer” for six meters.  Less common was the HW-19 “Tener” for, you guessed it, ten meters.

These were very popular in their day.  They were a single-band transceiver.  The transmitter put out about 5 watts of AM, and the receiver was superregenerative.  The tuning was very broad, but once they locked on to a signal, they were surprisingly sensitive.

By the time I became a ham in the 1970’s, VHF AM was virtually gone.  There was one six-meter AM net in the Twin Cities that hung on, and I was a regular check-in with my Sixer and later a Gonset Communicator.  But FM had taken over two meters by then, and Twoers were basically given away for practically nothing, even though they were often in pristine condition.  I owned many of these little rigs, and at one time I owned a complete collection.

My collection included the lesser-known cousin, the Model CB-1 CB transceiver shown here.  The CB model came out in about 1960, and is shown here in this ad in the February 1960 issue of Popular Electronics.

It sold in kit form for $42.95, and was also available wired for $60.95.  It featured one crystal-controlled channel (the crystal was included).  The receiver was the same superregenerative receiver used in the other Lunch Boxes, and was calibrated for channels 1-23.  It had a built-in power supply for 120 volts.  For mobile use, it used an external power supply, which consisted of a vibrator and transformer.  The power was supplied to an octal plug on the back (the same as the bottom of a tube).  The 120 volt power cord and the DC power supply had  octal sockets on them, along with appropriate jumpers.

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WW2 Shortwave Broadcasting

CBS Short Wave Listening Station, Long Island. Wikipedia photo.

CBS Short Wave Listening Station, Long Island, 1941. Wikipedia photo.

In earlier posts, I’ve looked at the shortwave broadcast bands, and short wave listening during World War 2.   75 years ago, the Saturday Evening Post carried an interesting look at the war of words that was then filling the short wave bands. It gives a fascinating and detailed look at what the bands must have sounded like for short wave listeners as Europe was at war. The original article is now available at the Saturday Evening Post website.  There is a link to the original 1940 article, “The War of Lies and Laughs: The Story of Radio’s 24-Hour A Day Word Battle,” which was written by freelance writer J.C. Furnas, and appeared in the February 3, 1940, issue of the magazine, at page 16.

In addition to the informative text, it contains a couple of photos of the CBS shortwave listening station on Long Island, New York, complete with at least three National HRO receivers. From the look of the listening station in 1940, it appears that the station was thrown together hastily by CBS. The tables are unfinished wood, and the staff are making use of folding chairs.

Shown operating the receiver at the CBS listening post was one Carl Schutzman, and CBS newsman Elmer Davis is shown combing through the news picked up from the short waves.

Furnas begins his account of the propaganda war with the reaction of a loyal German-American Iowa farmer, who is outraged to hear an old acquaintance, one Fred Kaltenbach–or someone claiming to be him–persoanlly addressing the Iowa farmer on the Berlin radio. The speaker, ostensibly a German immigrant who returned to the old country, mentions the Iowan by name and even mentions the name of his old schoolteacher in an effort to establish his bona fides. He tells the Americans that they shouldn’t fall for the British propaganda cooked up by that liar Winston Churchill, and stay out of Europe’s war. (Kaltenbach was indicted in absentia,  for treason, but died in Soviet custody after the end of the war.)

The scuttling of the Graf Spree in Montevideo harbor was still fresh on the American mind, and Furnas’ article points out the contradictions of the various short wave accounts coming from Europe. The article discusses both broadcasts directed to America, as well as broadcasts directed by the beligerents to the other warring nations. It notes that in neither case is it possible to determine exact numbers of listeners. It points out that listening to foreign radio is a criminal offense in Germany, and notes that a four-year sentence was reportedly handed down recently for that offense.

Furnas does point out that prior to the war, NBC received about 600 letters a month from German listeners, which dropped to six per month after the war began. But he’s quick to concede that the drop in mail volume was probably because the Germans didn’t want to get caught listening–not because they actually stopped listening. And according to Furnas, very few Americans actually listened to German broadcasts, despite the fact that 40% of American receivers tuned the short wave bands. “When crack receivers with expert staffs, working for broadcasting companies, have trouble getting clear reception for days on end, what can the man in the average living room expect?” He answers this question by saying that their likely to revert to Charlie McCarthy.

Lord Hawhaw, 1943 artists' conception. Wikipedia image.

Lord Hawhaw, 1943 artists’ conception. Wikipedia image.

The most interesting part of Furnas’ article, except possibly for the photos, is the accounts of the English-language programs coming from each side. At that time, the identity of Lord Hawhaw was not known, and Furnas speculates that it was Norman Baillie-Stewart.  Baillie-Stewart had actually been connected with the broadcast until 1939, but had been replaced by the time the article was published by William Joyce,
who was executed for treason in 1946.

Despite the fact that few Americans were listening to foreign broadcasts, Furnas points out that the situation was better for the Germans in South America. Many South American newspapers, unable to afford wire services, were said to collect most of their news from foreign broadcasts, and the Germans capitalized. But even before the U.S. entered the war, the Americans made a concerted effort to target South America, with much success, probably for the same reasons that the Germans were successful–it was an easy source of news for small papers. And the American stations came in a lot stronger.

The article details the propaganda styles in use between Germany and Britain. British broadcast contained quite a few recordings of Hitler, in the hopes of pointing him out as a liar with his own words. German broadcasts to England, on the other hand, were heavy with insults such as “England will fight to the last Frenchman,” and various insults against “the old liar” Churchill, whose initials, the German announcers were quick to point out, were the same as those of a Water Closet.

Germans also concentrated on the empire. “Berlin loves to put eminent Hindus on the air,” and broadcasts to South Africa did their best to incite the Boers.

Britain broadcast the names of German prisoners of war, and the Germans followed suit. (For more information on prisoner broadcasts, see my earlier post.)

Of course, in 1940, American SWL’s had no means of making recordings of broadcasts, but Furnas’ descriptions to some extent make up for the paucity of recordings. In the 2015 update to the article on the magazine’s website, there are, however, a handful of recordings, both before and after America entered the war.  But Furnas’ article itself is one of the best I’ve seen to depict what an American SWL might have been able to hear during the war years.

For a look at Japanese shortwave propaganda later in the war, please see my recent post on Japanese propaganda directed toward African Americans.

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