Monthly Archives: April 2021

1961 British AM-FM Portable: The Roadfarer

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

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

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

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



US Post Office Airmail Radio System: 1921

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

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

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



TV Steeplejacks: 1951

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

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

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

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



1961 Speed Mail

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

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

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

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

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



1941 Portable Transmitter-Receiver

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

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

A bandspread capacitor covered the 80 meter ham band perfectly.

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

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

1941AprRadioNews2



Aleutian Islands Earthquake and Tsunami: 1946

 

Hilo residents fleeing tsunami. Wikipedia photo.

Hilo residents fleeing tsunami. Wikipedia photo.

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

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

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

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