An article in the February 1958 issue of Popular Electronics admonishes that “all of us should use a receiver that warns when the Conelrad alert begins,” and the magazine offered a simple circuit, shown here. The concept was about as simple as possible: The little self-contained receiver monitored continuously. If the carrier of the local station disappeared, then a buzzer would sound. Since all stations (other than designated stations on 640 and 1240) were required to leave the air during a CONELRAD alert, this would warn the owner of an impending attack.
It would seem that this particular design would be prone to false alarms. Obviously, it would work only with a 24-hour station. Otherwise, when the station signed off each night, the buzzer would sound until morning. And even most 24-hour stations signed off occasionally for transmitter maintenance. These periods often took place early Monday mornings, so someone relying on this receiver would probably get some rude awakenings if the receiver was left on.
And even though the receiver drew minimal current, it would probably go through the three penlight cells quite quickly.
But since hams were then required to monitor Conelrad, the receiver might have served a useful purpose, even though it probably wouldn’t work too well in continuous service.
As can be seen from the circuit here, the CK722 served as detector, and the 2N170 was hooked up to a relay, which would turn off the buzzer when the station left the air. The author, I.C. Chapel, notes that the relay is set to trip at 6 mA. At the conclusion of the article, there is an editor’s note stating that this figure “amazed” them, and concluded that the author must be very close to the broadcast station to get these results with his 10-foot antenna. One editor constructed the unit and tried it about 25 miles from New York City, and none of the stations there was strong enough to make the circuit work. With a more sensitive relay and a 150 foot antenna, though, they were able to get it to work with a 250-watt station 10 miles away.
In part 1 of this series, we looked at the ingenious technical details of the Japanese Fu-Go fire balloons of the Second World War. Part 2 remembered the only victims of these attacks, a pastor’s wife and five children who were killed in Oregon in 1945. While most of the balloons that made it to North America made it to the Western U.S., some of them made it far inland, although no damage appears to have been caused by the balloons making it further east. Today, we look at some of those remarkable distance flights.
For example, two of the balloons appear to have made it as far as Nebraska.
The night of April 18, 1945, there was an explosion in the sky over 50th and Underwood, in the Dundee neighborhood of Omaha. It flared brightly, but caused no damage. The spot is commemorated by a plaque inscribed “Dundee Bombed in World War II.”
The other “attack” on Nebraska involved a single piece of paper from one of the balloons that was located near Schuyler, Nebraska, on February 2, 1945. After the news embargo was lifted, the Colfax County Press reported this incident on May 27:
For some time Japan has been sending out balloons with high explosives over the western part of the United States, but all publicity was held down by the government and the FBI. These balloons drifted as far as Nebraska. They are about 32 feet in diameter and usually carry incendiary bombs or even gas bombs. One of these balloons landed on the Ludwig Vrba farm 9 miles southwest of Clarkson. The discovery of the balloon was kept secret while several FBI investigators were here and no publicity could be given at that time. Now the curtains of secrecy on these balloons was raised. The Press had known about the landing of the Jap balloon on the Vrba farm but said nothing about it, while we had been working on the case with the federal war authorities. Remnants of the balloon landed on the Vrba farm yard near the buildings but caused no damage as the greater portion of it as well as the mechanism carrying the high explosives had been destroyed before it had a chance to land. Report of any similar occurrences in this community will be greatly appreciated by us.
The piece of balloon found in Schuyler was very likely part of a balloon which made it as far as Iowa. According to a Navy report, the fragment found in Schuyler was a charred triangular piece of paper measuring about two yards by one yard. On the same day, more wreckage was found in Laurens, Iowa. No damage was reported, however, in the Hawkeye state.
None of the balloons made it to Minnesota, but according to the Navy report, five balloons made it to the neighboring Canadian province of Manitoba.
The furthest traveled of the balloons could very well have traveled over Minnesota on its way to Michigan, where two were confirmed to have landed. One started a small fire in Farmington Hills in March 1945, but witnesses did not associate the fire with one of the balloons until the press embargo was lifted in May. Upon reading of the balloons in the newspaper, one of the witnesses investigated and found the remnants of one the balloon that had started the fire.
The other confirmed Michigan balloon was found on February 23, 1945, near Grand Rapids. Three young boys. Larry Bailey, and Ken and Robert Fein, were playing on a farm field when they saw something strange floating in the sky. They started dragging the trophy home after it landed when a neighbor drove by with a truck and offered to help them haul it home. They were planning what to do with the treasure trove when, unfortunately for the boys, the sheriff was called, and the balloon was confiscated by the FBI and ultimately taken by the Navy.
The Grand Rapids balloon was to make one more flight after the war was over, and we’ll learn about it in part 4 of this series. Click here to go to part 4.
A few months ago, I posted about a one-tube regenerative receiver from the September 1950 issue of Boys’ Life magazine. I was even sent some photos of a very similar receiver discovered by Jon, WS1K. That receiver covered short wave, I’m guessing about 3-6 MHz.
Interestingly, I overlooked this one-tube receiver appearing in the same magazine a few months earlier. In the January 1950 issue of Boys’ Life appeared this one-tube receiver. The article was written by one of the same authors as the September article, Glenn A. Wagner. The January receiver appears to cover the broadcast band, since it calls for a “standard replacement antenna coil” along with a 365 uF variable capacitor. It uses a single 1N5G tube with a 1.5 volt battery for the filament, along with a 45-90 volt B battery. It’s all mounted on a 5×7 pine board.
A hundred years ago, the Liberty Bell was sounded for the first time since 1835, and the sound transmitted by telephone to the Panama-Pacific Exposition in San Francisco. The photo here appeared in Popular Mechanics, May 1915. (More details are available in that month’s issue of Electrical Experimenter.) The article also notes that a phonographic recording was made. It was apparently recorded again in 1917, but it appears that neither recording has survived.
It was recorded again in 1944 as part of a D-Day broadcast, and there is also a computer-generated recreation of the bell’s original sound. Both of those recordings are available at the National Park Service.
The same issue of the magazine carries an interesting article summarizing how the warring powers of Europe are using wireless as part of the war.
In part 1 of this series, we looked at the ingenious control mechanism employed by the Japanese Fu-Go fire balloons of World War II. The balloons were launched from Japan and traveled to North America where they dropped incendairies. They were also equipped with a demolition charge set to destroy the weapon after it had served its purpose.
One of these balloons was responsible for the war’s only civilian deaths within the 48 United States caused by enemy action. The last balloon was launched in April 1945, but the deaths occurred seventy years ago this month, on May 5, 1945.
Southern Oregon was seemingly far removed from the war. Victory in Europe was only three days away, and the war raging in the Pacific seemed far away. The papers that Saturday morning were full of war news, but the news was all good, such as this photo of American POW’s being liberated in Germany.
Archie Mitchell was the 27-year-old pastor of the Christian and Missionary Alliance Church in Bly, Oregon. His wife, née Elsie Winters, 26, was five months pregnant.
On May 5, 1945, Rev. and Mrs. Mitchell took a group of five children from the church on a picnic and fishing trip at Gearhart Mountain, on land within the Fremont National Forest owned by the Weyerhaeuser Timber Company. The road near Leonard Creek was under construction. Mrs. Mitchell and the children got out of the car while Rev. Mitchell turned the car around and started getting out the picnic lunch.
While hiking around the area, Mrs. Mitchell and the children spotted one of the Japanese balloons. Due to the news blackout, they were oblivious as to its possible origin. One of the road workers nearby saw the six gathered around in a semicircle, but wasn’t able to see what they were looking at. Mrs. Mitchell called out to her husband to come look at it, and he responded that he would come and look.
But before he could get there, there was a huge explosion, throwing debris over 150 yards. Rev. Mitchell and the worker ran to the scene, only to find four of the children already dead. Mrs. Mitchell and the other child died within a few minutes, never regaining consciousness.
The victims of the attack were:
Elsie Mitchell, age 26
Jay Gifford, age 13
Edward Engen, age 13
Dick Patzke, age 14
Joan Patzke, age 13
Sherman Shoemaker, age 11
These were the only civilians killed by enemy action within the continental United States during the war.
Because of the deaths, the news embargo was lifted a few weeks later. By this time, however, the Japanese had abandoned the program.
One would think that this is the end of the story. But Rev. Mitchell had not seen the end of wartime tragedy. Within two years, he was remarried to Betty (née Patzke) and the couple was called as missionaries to Asia. Eventually, they were stationed in Vietnam and worked at the Ban Me Thuot Leprosarium, located about nine miles from the town of Ban Me Thuot. By 1962, the couple had four children, ages 4-13.
At dusk on May 30, 1962, the staff of the leprosarium were gathering for their weekly prayer meeting when twelve members of the Viet Cong entered the grounds. The missionaries convinced the Viet Cong that if they left Mrs. Mitchell and the children alone, that they would fully cooperate. They left the compound a couple of hours later with Rev. Mitchell and two other captives.
Military intelligence was able to track the hostages’ location for a number of years, but a military rescue mission was not possible. The Christian and Missionary Alliance engaged in negotiations to free the three, but the negotiations collapsed in 1969.
In the next part of this series, we’ll look at some of the extraordinary distances covered by some of the balloons, some of which were recovered in places like Nebraska, Iowa, and Michigan. Click here to continue to part 3. In the final installment, we’ll learn how one of these balloons found its way to Minnesota.
The January 1926 issue of Boys’ Life magazine contains the plans for this simple crystal set. According to the article, the parts would set the Scout back about 80 cents, not counting the headphones, which would cost about $3.00. The parts could be found at “any well-stocked five and ten cent store,” and the receiver was said to pull in stations up to twenty miles.
For those wishing to duplicate this or similar receivers, if your five and ten cent store isn’t sufficiently well stocked, you can get some ideas on locating the parts on my crystal set parts page.
Japanese Fu-Go Balloon Control System Schematic. U.S. Navy Image.
Many Americans are vaguely aware that the Japanese launched fire balloons at the continental United States during World War II. While relatively little damage was done, they were responsible for six fatalities seventy years ago this month, in Oregon in May, 1945. In the next part of this series, we’ll look at that attack, and the interesting connection that attack had with the Vietnam war a generation later. A few of these balloons drifted far inland, as far as Nebraska, Iowa, and Michigan. We’ll look at those cases in part 3. And in part 4 of this series, we’ll look at an interesting connection one of these balloons had with the State of Minnesota.
The balloons, known in Japan as fūsen bakudan or “Fu-Go,” were launched from Japan and designed to rise to a level of 30,000 feet. During the winter months, the prevailing winds at this level were about 100 miles per hour, allowing the balloons to make landfall in North America in about four days.
Those who are aware of these balloons generally think of them as primitive devices which the enemy simply released and hoped for the best. But this is far from the truth. They were actually quite ingenious and sophisticated. There was, of course, no way to steer the balloon after launch, but the direction and velocity of the prevailing winds were well known. As long as the balloon was maintained at the proper altitude, its ultimate destination was readily ascertainable. And the method of maintaining altitude was quite ingenious.
This is best seen from this 1945 Navy training film, which appears to be made for those who might be called upon to disarm the devices:
The balloon itself was made of rice paper or rubberized silk and was about 30 feet in diameter. It held about 19,000 cubic feet of hydrogen. The key to making the balloon reach America was maintaining its altitude, since the prevailing winds would inevitably deliver it to its destination, as long as the balloon was at a known altitude.
Each balloon’s payload consisted of about four incendiary bombs, designed to set fires after the craft reached the United States. But the bulk of the payload consisted of ballast sandbags which were part of the altitude control mechanism. The payload also contained a number of barometers used for measuring altitude.
The balloon contained a relief valve which vented excess gas when it reached its cruising altitude. This was a simple spring-loaded valve at the base of the balloon set to 9/10 ounce per square inch pressure. This valve would vent due to the reduced pressure at the higher altitude.
When the balloon began to lose altitude, it would begin dropping ballast. With modern electronics, it would be quite easy to build the necessary circuits. Indeed, even in the 1940’s, it would have been relatively easy to build the electronics, but it would have been impossible to power the necessary vacuum tubes for the long flight. Therefore, another method was required.
When the balloon descended to about 27,000 feet, one of the barometers would trip a switch which would blow an explosive charge in two blast plugs that were holding the first sandbag in place. The sandbag would drop, and the balloon would begin rising. It would then be necessary to arm the plugs holding the second sandbag. But a delay would be necessary. If the second sandbag were armed immediately, while the balloon was still at the lower altitude, it would drop immediately, followed quickly by all of the remaining sandbags. It was necessary to build in a delay before the second sandbag was armed. This delay was accomplished by means of a fuse. The charge used to drop the first sandbag also ignited a fuse that was sufficiently long (2-1/4 minutes) to allow the balloon to rise to its cruising altitude. Only after this time had elapsed was the next sandbag armed. The balloon would continue cruising at 30,000 feet. When it again dropped to 27,000 feet, the second sandbag would be dropped and the fuse for arming the third sandbag would be lit.
This process would continue until the 36th and final sandbag had been dropped, at which point the balloon would be over the United States. The final drops would then consists of the incendiary bombs, controlled in the same way. After the final one was dropped, a fuse was lit to a demolition charge to self-destruct.
The electrical power was provided by a two-volt lead-acid battery, which was housed inside of a box containing a solution of calcium chloride to serve as a thermal ballast to keep the temperature of the battery as constant as possible. This was housed in another box with an air chamber to provide some insulation.
The first balloon was launched in November, 1944, and examples were found in Alaska, Washington, Oregon, California, Arizona, Idaho, Montana, Utah, Wyoming, Colorado, Texas, Kansas, Nebraska, South Dakota, North Dakota, Michigan and Iowa, as well as Mexico and Canada. An unexploded bomb was found as late as 2014 in British Columbia, and was detonated by the Canadian Navy. The single fatal attack took place on May 5, 1945, when Elsie Mitchell and five children, ages 11-14, were killed near Bly, Oregon during a Sunday school picnic. This was the war’s only lethal attack to take place in the 48 United States, and we’ll look at it in more detail in our next installment.
Newsweek carried an article on January 1, 1945, about a “balloon mystery,” and a similar story appeared in newspapers. However, the Office of Censorship asked papers not to mention balloon bomb incidents. After the deaths, however, the total press blackout was lifted. One of the first accounts can be seen in the Milwaukee Journal, May 23, 1945. The AP story notes that “some may be buried in melting snow. With the coming of warm weather and the end of the school session it is desirable that people and especially children, living west of the Mississippi river, be warned of this possible hazard and cautioned under no circumstances to touch or approach any unfamiliar object.” The article does not, however, mention the May 5 fatalities.
The blackout was largely successful, however, since the Japanese believed that the attacks had been unsuccessful, even though they had some measure of success. In addition, attacks had destroyed most of Japan’s hydrogen production, and the project was abandoned.
Part 2 will remember the victims of the May 1945 attack and the curious connection to the Vietnam War. Click here to go to part 2. Part 3 will look at some of the balloons that reached far inland to the Midwest. And Part 4 will show the flight of one of these balloons to Minnesota.
The June 1911 issue of Modern Electrics magazine carries an interesting article written by one Norman Barden, detailing experiments being carried on at East High School in Minneapolis. Among other things, the reason why the article caught my eye was that this school was the predecessor of my alma mater, Minneapolis Edison.
East Highwas opened in 1900 and operated under that name until 1927, at which time it was used as a vocational school for a number of years. It was located between University Avenue and Southeast Fourth Street on what was then First Avenue Southeast, which was later renamed Central Avenue. Edison opened in 1922 and Marshall High (in whose old building I had my office for a number of years) opened in 1924, eliminating the need for East High. So in a sense, I went to the same school.
Barden starts his article by pointing out that the “public has been startled” to learn that a high-frequency current can pass through the human body with no ill effects. He explains that “there are several different theories put forth to explain why high frequency current does not produce fatal results upon animals and the human body,” even though the same current and voltage at a lower frequency or at DC, “fatal results occur.”
Undaunted by the possibility of fatal results, and apparently oblivious as to the reason why they were non-fatal, Barden went ahead and sent the potentially fatal currents through humans, including himself, as shown in the picture here.
(It turns out that the explanation for the non-lethality is somewhat mundane. The equipment appears to be an ordinary Tesla coil, meaning that while the voltages are very high and will generate a most impressive spark, the current passing through the human subject is extremely small.)
It turns out that this wasn’t the only dangerous science going on at East High. Mr. Barden was apparently shooting guns in the photography lab, as detailed in other published articles. In articles in the May 1911 issue of Popular Electricity and the 1914 Journal of the U.S. Artillery, he publishes photos of bullets photographed in flight after being shot from a .22 caliber rifle and a .32 caliber revolver. Not surprisingly, he points out that when you fire guns at school, “a back-stop must be provided to keep the bullets from penetrating the wall.” He used a piece of boiler plate behind a 2-1/2 inch piece of wood. He also points out that you need to be careful, since you’re doing the experiment (including firing the gun) in a totally darkened room. If you are going to replicate his experiment, it’s probably not a good idea to walk around after turning out the lights. Barden is shown below with his co-experimenter, Loyle Dobbs. The 1914 article also appeared in Scientific American.
As you can see, the rifle is plainly visible in this photo. Apparently, East High didn’t have a “no guns” sign on the front door.
In addition to these publications, Barden also had published in a 1910 issue of Popular Atronomy a photograph of a comet he had taken through a telescope he had constructed himself.
When I saw the original article, I assumed that Mr. Barden was a teacher at the school. But it turns out that he was actually one of the students. A hundred years ago, high school students could get their articles published in Scientific American. Today, they’re not allowed to touch the experiments.
The first record of young Mr. Barden is an article in the the June 14, 1906 Minneapolis Journal, where he is listed as a seventh grade student at Holmes School. He’s shown here in his East High yearbook photo, which shows that he graduated in January, 1912. In 1913, he is listed as a sophomore at the University of Minnesota College of Science, Literature, and the Arts. And in 1919, he graduated from medical school in Ohio.
He returned to Minneapolis in time for the 1920 census, and went into practice. In this 1921 directory, he is shown as having an office in the Donaldson Building and a home address of 1209 7th St. SE. According to the 1921 Journal-Lancet of the Minnesota State Medical Association, He was the assistant to Dr. C.D. Harrington, a “pioneer in the therapeutic use of radium and the x-ray,” and the rongenologist of Northwestern, Asbury, Abbott, and St. Mary’s Hospitals.
Unfortunately, Dr. Barden’s promising scientific career came to a tragic end with his mysterious death in 1926.
The newspapers of August 18, 1926 reported that one Mrs. J.D. McDermott, the wife of a Chicago millionaire contractor, was being held by Minneapolis police following Dr. Barden’s death. His body was found by police in a room occupied by the couple in a downtown hotel. According to news accounts, the doctor was found “fashionably dressed and wearing several diamond rings said to be worth more than $10,000.” Two days later, the papers reported that Mrs. McDermott had been released, the post mortem having determined that the doctor had actually died from “acute alcoholism.”
Many hams and others will instantly recognize the picture above as being the tape from a teletypewriter machine. The machines were capable of sending faster than operators could type, so to reduce transmission time, the message could be punched onto the paper tape shown here and fed into the machine for later transmission. I remember such devices still in use into the 1980’s by hams using radioteletype (RTTY), and the machines invariably originated from landline telegraph systems.
And most hams who look at the image closely will immediately notice that it’s a 5-bit code, and they will probably proclaim pretty quickly that it’s Baudot, since the Baudot 5-bit code was in use for many years.
They might be surprised to learn the age of this particular tape, and they will also be surprised to learn that it’s not Baudot. This tape is a hundred years old, shown here from the May 1915 issue of Electrical Experimenter. The technology was relatively new at the time, and the accompanying article describes it in some detail. The particular tape shown here came from the Associated Press, and is the beginning of a news item. The AP New York office sent out 32,000 words a day over the wire, and this type of automation was necessary to handle the volume of news. During the office’s busiest hours of the day (11:00 AM – 1:00 PM), three or four operators were perforating tape simultaneously so that these tapes could be fed into the machine that sent them out. One of those operators is shown here.
And despite the similarities, the code being used in this tape is not Baudot. It turns out that standardization didn’t take place for a few more years. The code shown here is “Morkrum Code.” If you look closely, you’ll see that the code for the letter A appears to be the same. And like Baudot, it required the operator to shift from letters to characters and back again. But the encoding is different. If you’re interested in the history of the various codes in use, you’ll find them in an article entitled The Evolution of Character Codes, 1874-1968 by Eric Fisher.
The code that’s undoubtedly bringing these words to your screen are the ASCII code, an 8-bit code which came into use in the early 1960’s. But the basic idea has been around for over a century.
The tape at the top of the page, read from right to left, reads as follows:
MER PAWNEE. PHILADELPHIA. TO THE CLYDE
S S CO. WITH MDSE PASSED IN QUA
This scrap of tape appears to have originated five years earlier, since this snippet appeared in the shipping news of the New York Tribune on August 25, 1910, in the clipping shown below.
Ninety years ago this month, May 1925, Radio in the Home Magazine featured a number of portable sets then available on the market. The young woman shown here is listening to the Kodel P11 one-tube model, which measured only 5-3/4 x 4-1/4 x 3 inches, and which would operate either with or without an aerial. It appears that this is the portable version of the model C11, some pictures of which are available at this link.
The Kodel listener is anonymous, but that is not the case of the young woman shown here in her fur coat getting ready to listen to her Crosley portable. She is Miss Phyllis Sacia of Galesville, Wisconsin, who was the winner of the 1925 Crosley-Dolly Varden Annual Beauty Contest. According to her 1953 obituary, she married the year after this picture was taken and taught home economics in Menomonie, Wisconsin.
Finally, the young woman shown in the final photograph below appears to be listening to an ordinary home set. But this set, the Operadio convertible, had a special cabinet which allowed the radio to be removed and used as a portable. A surviving example of this six-tube TRF set can be found on this website. The article warned that “there is a saying in the radio industry that you can put a strap and a handle on a grand piano and call it a portable instrument if you want to.” That advice might have applied to this set, which weighed in at about 40 pounds.
As can be seen from the circuit here, the CK722 served as detector, and the 2N170 was hooked up to a relay, which would turn off the buzzer when the station left the air. The author, I.C. Chapel, notes that the relay is set to trip at 6 mA. At the conclusion of the article, there is an editor’s note stating that this figure “amazed” them, and concluded that the author must be very close to the broadcast station to get these results with his 10-foot antenna. One editor constructed the unit and tried it about 25 miles from New York City, and none of the stations there was strong enough to make the circuit work. With a more sensitive relay and a 150 foot antenna, though, they were able to get it to work with a 250-watt station 10 miles away.
