Fifty years ago this month, QST carried an article entitled “Vacuum Tubes The Hard Way.” The author was Sam Diaz Pumara, ex-LU2DII. The Argentine ham’s address was listed as being in care of HRB-Singer, Inc., of State College, Pennsylvania, which is now part of Raytheon. Diaz details the meticulous process for building vacuum tubes in his basement. The end result is some of the samples shown here.

Making a vacuum tube at home is not a trivial proposition, but it is within the capabilities of an experienced craftsman. The first problem is creating a sufficient vacuum, which the author accomplished by using a variety of oil pumps, the last of which produced a vacuum of 10^-8 Millimeters (presumably meaning a column of mercury of that height). But the vacuum wouldn’t last, since the elements of the tube (and the glass itself) would occlude gasses. This problem was solved by heating the tube during the evacuation process to a temperature of 500 degrees centigrade.

The actual construction of the internal elements of the tube is a simpler proposition, but the painstaking detail needed in this work is also described in detail.

Another interesting article on the construction of homemade tubes can be found at the website of Dr. Rüdiger Walz. He mentions some of the other experimenters in this field, including Diaz.  One of the experimenters in this field had a call similar to my own, Marold Ross, W6IS, of Baldwin Park, California.

Finally, the video below shows Claude Paillard, F2FO making tubes:

You can view the 1965 article at this link.  (You need to be logged in to your ARRL account to download the QST article.)  For a much simpler method of making a diode vacuum tube, see my earlier post.

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We recently shared a 1940 picture of opera singer Lily Pons listening to her GE radio-phono combo. But it appears that Miss Pons had more than a passing interest in radio. Here, we see her in the April, 1938, issue of All Wave Radio magazine at the mike of amateur station W2JKQ. Shown in the picture are, from left to right, maestro Andre Kostelanetz, Miss Pons, and W2JKQ.

Miss Pons was probably first introduced to ham radio by her camera man, C. Roy Hunt, W6CNE. Mr. Hunt had allowed her to speak to her South American manager, who was at the mike of LU1DA in Buenos Aires. In this photo, she duplicated the contact from W2JKQ’s New York station. She also chatted with a fan in Greece, SV1KE.

Lily Pons in 1940.

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Film actress Hope Hampton starred in several silent movies. With the dawn of the sound era, she retired from the cinema and turned to opera, singing with the Philadelphia Opera. She returned to the screen in 1938, in The Road to Reno. She died in 1982 at the age of 84.

And in the 1920’s, she had an interest in radio. In the top photo, she is shown using one of the piano wires as an antenna. And the lower photo shows her confidently handling a soldering iron as she solders the tuning coil of her set. The pictures above appeared in the July 15, 1922, issue of Radio Digest.

Here, she appears with Lon Chaney in The Light of Faith (1922):

https://www.youtube.com/watch?v=U8zPmWFZn-Q

Hope Hapmpton, undated photo. (Wikipedia)

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This little one-tube short wave receiver appeared in Popular Science 75 years ago this month, April 1940.  It uses as 12B8GT tube, a combined triode-pentode. The pentode section is used as a regenerative detector, and the triode is pressed into service as a diode, serving as the rectifier. The set runs directly from 120 volts AC. A 360 ohm resistor in series with the filament drops the voltage to 12 volts, and a hefty choke and two capacitors filter the power supply. Even though it’s run directly from the AC mains, the schematic shows no connections directly to the chassis, so as AC-DC sets go, this one is relatively safe to operate.

According to the accompanying article, the set could pull in signals from South America and Europe most evenings.

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Here, in the April, 1920, issue of Radio Amateur News, we see the station of Miss Marianne C. Brown of of 206 W. 86th Street, New York City, which is the corner of 86th and Broadway.

Her receiver, designed by herself, was able to tune 300-1200 meters, which took in nearly all of the commercial stations. She also reported that it was very satisfactory for reception of wireless telephone stations and arc stations. It was usable either with an indoor loop or an outdoor antenna.

Still under construction was her transmitter, consisting of a 1/2 KW transformer and oil condenser. She expected to have the transmitter in working order in a short time.

She was listed in the 1920 call book as 2AOA.  Another short biography of this wireless pioneer can be found at this link.  She held a commercial license and trained as a marine operator, but theNavy had a policy forbidding women serving in this position.  She did get a position with the Marconi company testing equipment.

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