Category Archives: Radio

75 Years of HCJB Shortwave

HCJB grounds.  Wikipedia photo. by Mschaa - Own work. Licensed under GFDL via Wikimedia Commons

HCJB grounds. Wikipedia photo. by Mschaa – Own work. Licensed under GFDL via Wikimedia Commons.

In the early 1940’s, the physics department of the University of Chicago was undoubtedly an exciting place. In late 1942, the world’s first self-sustaining nuclear reaction took place under the stands of the football stadium under the direction of Columbia Unviersity Professor Enrico Fermi.

On Easter Sunday 1940, the atomic pile had not yet been built, but the University was clearly about to be at the center of some of the greatest science of our time.  But one graduate student was about to hear a different call, and it came over the shortwave radio.

On Easter Sunday, 1940, a new radio station had just come on the air and was conducting its inaugural broadcast with a new 10 KW shortwave transmitter.  The station wasn’t entirely new, but it had just installed the new transmitter, and it now had a strong signal to North America.  That station was HCJB, the Voice of the Andes, in Quito, Ecuador.

The station had been founded in 1931 by American missionary Clarence W. Jones.  Jones had worked under Chicago evangelist Paul Rader, who had been one of the first radio evangelists, having a weekly program called “WJBT” (Where Jesus Blesses Thousands), which was carried by WBBM in Chicago.  Jones had been impressed by the radio’s ability to spread the Gospel, and felt called to establish a radio ministry in Latin America.  In 1928, he traveled to Venezuela, Colombia, Panama and Cuba, seeking a location for the station, but was unable to receive government permits in any of those countries.

Later, Christian and Missionary Alliance missionaries to Ecuador encouraged him to start the radio station there.  In 1930, Jones obtained the approval of the Ecuadorian government to begin a station,

HCJB came on the air on Christmas Day, 1931.  The initial 30-minute broadcast in English and Spanish was from a fairly respectable 200 watt transmitter.  But that transmitter was sitting on a table in Jones’ living room, with a simple wire antenna strung between two poles.  And there were only six receivers in the country at the time.

Notwithstanding its small start, the station continued to grow.  And by 1940, it was able to install the substantial 10 KW shortwave transmitter that would provide good coverage in both South and North America.  By 1941, broadcasts were expanded to include Russian, Swedish and Quichua.  Other languages soon followed.

The inauguration of the new shortwave transmitter was noted in North America.  The shortwave bands reflected the fact that Europe was now at war, and the message of peace transmitted from Ecuador was a breath of fresh air.  The shortwave editor of Radio Guide magazine made these observations in the April 20, 1940, issue:

            “The Voice of the Andes”

To those listeners tired of the eternal babble of Europe’s shortwave voices of hate and war: Turn your dials to HCJB (12.48), “The Voice of the Andes,” at Quito, Ecuador. Here, at an elevation of 10,000 feet, encircled by eleven snow-capped peaks of the mighty Andes, nestles the oldest city of the New World, one of the ancient capitals of the Incas steeped in fifteen hundred years of traditions; a city whose many white churches shelter staggering treasures in gold and precious stones; a city with winding cobbled streets, overhanging balconies, ancient archways, sunlit plazas and countless white-stone houses perched crazily on steep hillsides, their red-tile roofs, with green moss cropping out here and there in the cracks, forming vivid splotches of color against the snowy mantle of the guardian peaks.

Such a historic and picturesque setting seems indeed a fitting site for a missionary radio station whose messages are those of peace and good-will. This new 10,000-watt modern short-wave transmitter–the most powerful in South America and the only broadcast station to employ a fully rotatable antenna–stands as a tribute to the sacrificing labors of one many–Clarence Jones, a gospel missionary from Chicago, whose lifework is to minister to and teach the Andean Indians. Because of the rugged contours of Ecuador, making transportation exceedingly difficult, Reverend Jones recognized long ago the vital value of radio in carrying on his work and subsequently installed several small short-wave stations at Quito, including the former 1,000-watt transmitter of HCJB and a mobile broadcasting station which carries this active pastor’s voice to the most remote jungle and mountain tribes. The new station–a labor of love paid for by voluntary subscriptions from his loyal friends–was built by an American amateur, Clarence Moore, who is well known to hundreds of amateur friends under his call, HC1JB. The new “Voice of the Andes” was officially inaugurated on Sunday, March 24.

On the dial, HCJB (12.46) comes in above the 25-meter band and approximately half-way between the 12 and 13 megacycles figures in frequency. You will have no trouble in hearing HCJB, since its unique location and rotatable aerial make it possible for it to project strong signals into North America.

HCJB is on the air for several hours daily with Spanish programs for the benefit of listeners in the Latin Americas, but English listeners will be primarily interested in “Ecuadorian Echoes,” on from 6:00 to 7:00 p.m., and the “Friendship Hour,” broadcast nightly except Mondays from 9:00 to 10:00 p.m. EST. These all-English programs are directed specifically to North America. “Ecuadorean Echoes,” one of the most interesting programs on the air, breathes the very soul of Latin America. During this period the native music, the literature and the very lives and habits of these romantic peoples come to life and parade before the microphone. “The Friendship Hour” is a strictly good-will program consisting of classical music, old-time hymns, simple gosple messages, the reading of letters from listeners and personal messages to friends everywhere.

Among the listeners to that first program on Easter Sunday 75 years ago was University of Chicago graduate student Clayton Howard. He had received his undergraduate degree in physics the previous year from nearby Wheaton College.  He had been born in China to missionary parents who returned to the United States when Clayton was 9, in order for Clayton’s father, Charles Howard, to organize the biology department at Wheaton.

By this time, Clayton was a licensed amateur radio operator.  In the 1938 call book, he is listed as holding call sign W9KJZ.  For whatever reason, he happened to be tuning above the 25 meter band that night and heard the new station.  He later recounted that he was aware of a missionary station in South America, but knew little about it before chancing upon its broadcast that night.  He was intrigued enough to seek out Reuben Larson, one of the missionaries to Ecuador who had a decade earlier encouraged Jones to start the station.

HCJB technical staff in 1945.  Head engineer Clayton Howard is in the center.   (Image by by SkagitRiverQueen, Licensed under CC BY-SA 3.0 via Wikipedia.)

HCJB technical staff in 1945. Head engineer Clayton Howard is in the center. (Image by by SkagitRiverQueen, Licensed under CC BY-SA 3.0 via Wikipedia.)

The name Clayton Howard is familiar to many hams and shortwave listeners.  1941 saw Howard be commissioned by his church as a missionary and accept a call to serve on the technical staff of HCJB.  Howard went on to become the station’s chief engineer, and is best known as being the on-air host of the “DX Partyline” program, which he produced and hosted for 22 years.  This program was very popular with SWL’s, as it included station reports and other listening tips.  The program always concluded with Howard offering a short segment entitled, “Tips for Real Living,” in which he shared with listeners a brief Gospel devotional message.

Clayton Howard and wife Helen hosting DX Party Line, 1970's.  Photo courtesy HCJB, used with permission.

Clayton Howard and wife Helen hosting DX Party Line, 1970’s. HCJB photo.

The Soviets didn’t normally provide recognition to Christian missionaries, but in Howard’s case, they made an exception.  When Howard retired in 1984 and made his last DX Partyline broadcast, Radio Moscow announced that “the living legend of the Andes has retired.”

If you grew up as I did listening to a shortwave radio in the 1960’s and 1970’s, the name Clayton Howard is certainly a familiar one.  And chances are, you heard one of those tips for real living.  If you did, it was probably because on Easter Sunday, 1940, a 12.48 megacycle radio signal traveled from the Andes to a receiver in Chicago.

As a result of that Radio Signal, Clayton Howard probably never met Enrico Fermi.  He probably had nothing to do with the construction of the atomic pile under the football stadium.  If he had, perhaps Howard would be remembered today as a nuclear physicist.  But God called him elsewhere, and it appears that He made that call on 12.48 megacycles.

References

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WBBM and KFAB Synchronize Their Signals With a Piece of Lead Pipe

In 1928, WBBM in Chicago and KFAB, then in Lincoln, Nebraska, both operated on 770 kHz with 5000 watts.  And they both carried the CBS network at night.  They generally coexisted well, but there was a problem for listeners, mostly in Iowa, who were equidistant from the two stations.  Both stations would come in equally strong, but interfere with one another.  These listeners complained to CBS, and the two stations worked at solving the problem.

Eliminating any heterodyne (the squeal caused by two signals on very close frequencies) was an easy enough problem to solve.  The two stations simply needed to make sure that the transmitters were exactly on the same frequency.  But there was another problem.  The signals from the network came by telephone lines, and those signals travel at approximately the speed of light.   Since Lincoln was 500 miles further away from New York than Chicago was, the program reached Lincoln about 23 milliseconds later than it reached Chicago.  Therefore, the two stations weren’t transmitting the exact same program.  KFAB was sending out the program with an additional 23 millisecond delay.  (When a different phone line was used later, the delay grew to 35 milliseconds.)

This caused a problem for listeners in Iowa.  The signals from Lincoln and Chicago traversed the airwaves to Iowa in the same amount of time.  But since the Lincoln signals started with a built-in delay, the effect in Iowa was that the there was an echo effect when listening to CBS on 770.

The stations solved the problem in a number of ways.  First of all, WBBM paid KFAB to sign off at 10:00 PM, after the end of network programs.   After 10:00, WBBM had a clear channel as far west as its signal would go.  The two stations also coordinated their station ID’s so that one announcer was not talking over the other.  But the biggest problem to solve was the delay.  To solve the problem, WBBM had to delay the network feed.  With digital processing today, this would be a trivial problem to solve.  But in 1928, it was a major engineering challenge.

The WBBM engineers eventually came up with an electronic solution involving 19 stages of filtering, equalization, and amplification.  A series of filters, consisting of a capacitor and inductor, were carefully chosen.  Each filter attenuated one frequency range, but also introduced a delay.  Since they didn’t want the attenuation, the equalization was needed to restore the audio to its final form, and the amplification was needed to make up for the loss in the filters and equalizers.

But until that system was designed, WBBM engineers came up with a Rube Goldberg solution that worked amazingly well.  The speed of light is about 300 million meters per second.  But the speed of sound is about 1080 feet per second.  To generate the necessary 23 millisecond delay, sound would need to travel about 23 feet.  So the WBBM engineers procured a 23-foot section of lead sewer pipe, mounted a speaker at one end and a microphone at the other end.  The sound was simply fed through the pipe before going on the air.

The system wasn’t perfect, since echos from the microphone reflected back, adding a new echo effect, what they were trying to get rid of in the first place.  But this echo was solved by wadding fabric into the pipe.  Close to the microphone, this consisted of gauze.  Closer to the speaker, thicker material was needed.  Fabric from a pair of overalls belonging to one of the staff turned out to fit the bill, and they were stuffed into the pipe.

The result was a very high quality audio signal, with a dynamic range of 100-5000 cycles.  Eventually, broadcast standards called for slightly better audio, and the electronic system using filters was used.  But for a time, WBBM’s programming passed through 23 feet of sewer pipe before hitting the airwaves.

References

 

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OSCAR III: 50th Anniversary

OSCAR3Satellite

Fifty years ago, from March 9-27, 1965, the first two-way amateur satellite, OSCAR III, was in operation. The 16.3 kg spacecraft was launched on March 9 from Vandenberg Air Force Base, piggybacking with seven Air Force satellites. Over 1000 amateurs in 22 countries made contact through the satellite’s linear transponder, with both the uplink and downlink taking place on the 2 meter amateur band. Signals were received by the satellite on 144.1 MHz, and were retransmitted on 145.9 MHz. The downlink had a power of one watt, which was divided over the whatever stations were in the passband of the uplink frequency.

A beacon transmitter sending voltage and temperature readings was audible for several months. The orbit was nearly circular, with an altitude of 570 statute miles and an orbital period of 103.5 minutes.

OSCAR3The photo here shows Ed Hilton, W6VKP, and Don Norgaard, W6VMH, working on the satellite’s electronic package in Hilton’s garage. This photo is taken from the March, 1965, issue of Popular Electronics.  A summary of the mission and complete list of contacts made and calls heard during the spacecraft’s 250 orbits is also available online.



One Dollar, One Tube Radio, 1935

Mar35RadioCraft

Eighty years ago this month, March 1935, Radio Craft magazine featured this one-tube broadcast radio that could be built for a dollar. The only manufactured radio part was the type 30 tube, which ate up 75 cents of the budget. Everything else was scrounged from household goods. The author reported receiving a station in Dallas, 1500 miles away from his location, the first night.

The two fixed condensers were made of tinfoil and waxed paper. The filament condenser consisted of 36 feet of 36 gauge wire wound on a spool. The grid leak condenser, which would probably be about 1 megohm, consisted of a pencil mark on a piece of wood. The tuning condenser consisted of two metal plates separated by celophane. The tuning coil was home wound on a cardboard form, and the tube socket was four paper clips.

The diagram of the completed receiver is shown below.

DollarRadioDiagram



1957 CONELRAD The Easy Way

1957ConelradStarting in 1957, U.S. Amateur Radio operators were required to participate in CONELRAD. (If you’re unfamiliar with CONELRAD, I explain it in other posts, including this one.) Under the regulations that took effect that year, hams were required to monitor an AM broadcast station whenever transmitting. If that station went off the air, the ham was required to check to see if the absence from the air was due to a CONELRAD alert. If so, he was required to leave the air.

The regulations could be satisfied by keeping an AM radio on low volume in the background, but the preferred method was to have an automated alarm that would sound if an AM station left the air. One popular receiver for that purpose was the Heathkit CA-1 CONELRAD alarm, which was an external monitor that would be hooked to a receiver. Other dedicated receivers wwere available, such as the Kaar Engineering Conalert II, although a unit such as that would be out of the price range of most hams, and probably used mostly by broadcast stations.

The April, 1957, issue of Radio News carries an article entitled “Conelrad the Easy Way,” with a simple method of converting a five-tube broadcast receiver into a CONELRAD monitor. As shown in the schematic above, it required only three parts, and allowed the radio to be used for normal listening. The additions to the circuit are the three parts inside the dotted lines.

This circuit ties in to the AVC voltage of the first audio amplifier. As long as there is an AVC voltage present, the added resistor biases the first tube to silence the radio. But if the AVC voltage disappears (because there is no signal present), then the output of the final audio amplifier gets fed back to the first audio amplifier, causing the two stages to break into oscillation to emit a loud squeal.

It’s a pretty ingenious and easy modification, and the author reports that many hams were using it and that he thought “it is the answer to the Conelrad needs of most hams.” He even notes that the circuit “is so simple that many broadcast listeners may want to install it on their receivers, just in case.”

The author, by the way, is John T. Frye, W9EGV. If that name rings a bell, it is because Frye was a prolific writer in many electronics and radio magazines. He was most famous as the author of the “Carl and Jerry” stories that appeared in Popular Electronics from 1954-1964.



Integrated Circuits Fifty Years Ago

EI1965IC

Fifty years ago this month, the cover of the March 1965 issue of Electronics Illustrated showed this integrated circuit, the Motorola MC556G. The case of this IC measured 5/16 inch in diameter, and the chip itself measured about 1/10 inch square. It contained six transistors and eight resistors. The accompanying article noted that it was now on the market at a price that hobbyists could afford to use for experimental projects,  $3.35.

To put the new device in perspective, the article compared it to the still ubiquitous 5-tube radio, which consisted of about six basic circuits using about 20-30 components. The article noted that the day would soon arrive when one or two IC’s would constitute a “complete radio that is equivalent in performance to that five-tube AC/DC job.”  That prediction came true only seven years later, in 1972 with the ZN414 AM radio IC from GEC-Plessey. The modern functional equivalent of that IC is the MK484/TA7642 am-Radio IC, which is a complete radio in a chip, requiring as its only external components a battery, coil, tuning capacitor, and earphone.

While the eight transistors in a 1/10 inch package was revolutionary at the time, transistors in current IC’s are in the range of tens of nanometers in size, allowing several billion transistors per chip. But building something with an IC was revolutionary fifty years ago, and Electronics Illustrated featured two projects making use of the MC356G. The first was a square-wave signal generator, and the second was the AM radio shown below. In this diagram, the portion shown in black is internal to the IC, and the components shown in red are external. As you can see, the circuit makes use of four of the chip’s eight transistors, and four of its resistors.

1965ICradioschematic

The IC was designed for use as a logic gate, but transistors are transistors, and they could be used for their amplification function. For the radio in particular, getting the circuit to work took several experimental designs, but the author finally “hit upon one that has a decent amount of sensitivity, selectivity, and audio output.” The author noted that most of the headaches in designing the radio were caused by the close proximity of the components on the chip. Having only 1/10 of an inch to work1965ICradio with presented leakage paths between the circuits that would be out of the ordinary for a radio designer.  The finished project is shown here.

In the design, two of the transistors are used as RF amplifiers, with the signal being fed back through a regeneration control. The second of those transistors also amplifies the audio, and there are two more audio amplifier stages. The actual detector consists of two external diodes.

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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 TheVerge.com, at the article linked below.

References

 



The Luxembourg Effect

LuxembourgEffect

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.

References

 



One-Tube Wartime Receiver, 1945

RadioCraftFeb45

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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Heathkit CB-1 “Benton Harbor Lunchbox”

HeathCB1

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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