Monthly Archives: May 2018

Claire Trevor, CBS Radio 1938

1938MayRadioNewsCoverUndoubtedly, most of the hams who bought the May 1938 issue of Radio News did so for the articles, such as the one on page 37 showing how to build a portable six-tube transmitter for 28 MHz. But the issue’s cover shows actress Claire Trevor at the CBS microphone, performing her role of Lorelei opposite co-star Edward G. Robinson in the series Big Town.

Miss Trevor is most famous for her film roles, including an Oscar for best supporting actress in 1948’s Key Largo. According to the magazine, she made her stage debut in 1930 and appeared in numerous Broadway plays. She made a number of film shorts before going to Hollywood in 1933.

According to the magazine, it was hard to say whether her popularity was due to moving pictures or radio, but that she was a talented, versatile, and beautiful artist.

She died in California in 2000 at the age of 90. Her only son, Charles, was killed in 1978 in the crash of Pacific Southwest Airlines flight 182.



Memorial Day 1943

1943MemorialDayMemorial Day 75 years ago, 1943, was the second since America had entered the war.  This photo was taken at Arlington National Cemetery by Office of War Information photographer Esther Bubley.  The scout, who was serving as one of the color bearers, listens to the ceremony.



1958 One Tube Transmitter

Screen Shot 2018-05-08 at 11.00.50 AMSixty years ago this month, the May 1958 issue of Popular Science showed how to make this compact one-tube transmitter for local or standby use. The set used a 117P7 or 117L7 tube, which combined a rectifier and pentode, to put out about six watts on 80 or 40.  Band choice was accomplished with plug-in coils, and the rig ran directly off AC power.

Since the Altoid tin had apparently not been invented, a card file box was used for the enclosure.

Screen Shot 2018-05-08 at 11.07.08 AM

 



Hugo Gernsback’s Vision of the Telephot, 1918

1918MayElecExpCoverShown here on the cover of Electrical Experimenter a hundred years ago this month, May 1918, is Hugo Gernsback‘s vision of Skype, or what he called “telephot, an apparatus attachable to our present telephone system so that when we speak to our distant friend, we may see his likeness not only as an immovable picture, but we will see his image exactly as we see our own image when looking into a mirror. In other words, the apparatus must faithfully follow every movement of our distant friend whether he is only five blocks away or one thousand miles. That such an invention is urgently required is needless to say. Everybody would wish to have such an instrument, and it is safe to say that such a device would revolutionize our present mode of living, just as much as the telephone revolutionized our former standard of living.”

Gernsback reported that inventors were working on the problem, but the main catch was what we would today call the bandwidth, since it had to be “possible to attach it to the present-day telephone lines,” which to him was a single wire and a ground return wire. “In most of the schemes offered by inventors heretofore, a plurality of wires was necessary; in some cases several thousand pairs of wires. No matter how well such an instrument might work, this alone would doom it to certain failure.”



1978 Two-Transistor Shortwave Regen

1978MayEE The plans for this somewhat “retro” looking receiver appeared in Elementary Electronics magazine forty years ago, May-June 1978. The two-transistor regenerative set tuned 550 kHz to 14 MHz with the use of three plug-in coils.

Good performance was obtained through the use of “spiderweb” coils, which also added to the nostalgic appearance of the set. As the article noted, this type of coil was very popular in the early days of radio, since such coils exhibit a very high Q factor.

Another advantage of this type of coil is that it doesn’t require the use of now-unobtainium plug-in coil forms, since the article explains how to make the form. A template is included in the article, which is to be traced onto tissue paper, and then used as the template for cutting the forms from a sheet of plastic with a jigsaw or hacksaw. Brass eyelets (“available at notions counters in department stores”) were then used as the plug connections.



1943 Radio “Service Girl”

1943MayRadioRetailingTodaySeventy five years ago this month, the May 1943 issue of Radio Retailing Today detailed the experiences of Ben De Young, the owner of the De Young Radio & Television Shop, 126 S. Aurora St., Ithaca, NY. The magazine had earlier discussed the possibility of hiring “girls” to do radio repair work, and De Young had commented that the concept was hardly new, since he had been using girls since 1935. Wartime labor shortages were just then showing the wisdom of the veteran repairman’s foresight.

De Young noted that hiring experienced employees was always difficult, and that he often had to take his chances on an inexperienced man by training him. His experience, however, was that if the new man turned out good, then a manufacturer or jobber hired him away and he had to start the process all over again. And if the man turned out to be no good, the he wasn’t of any use to De Young either. Since girls were presumably less likely to be hired away in this manner, De Young found that hiring them was ideal. He noted that a girl had more agile fingers and in general did a neater job.

1943MayRadioRetailingToday3The secret to De Young’s success was having his shop equipped with the best test equipment. He was able to quickly diagnose the problem, and then letting the girl actually replace the components. He had a large bench so that she could get to work while he started diagnosing the next set. In the picture above, his assistant, identified only as a Miss Gould, is soldering in an IF coil that he had previously identified as the culprit.

She was also able to read schematics, and often saved him time by taking1943MayRadioRetailingToday2 care of details such as looking up values of components.  When she wasn’t wielding the soldering iron back in the shop, she worked in the front of the store, as shown here taking in a set for service.



1968 Marine Receiver

1968MayEEThe plans for this ambitious looking receiver appeared fifty years ago in the May-June 1968 issue of Elementary Electronics.  The transistorized set is written up as being for the SWL, but as the design suggests, the article points out that it’s also a suitable receiver for the “yachtsman.”

Construction is simplified by the inclusion of two pre-wired circuit boards available from Lafayette, the IF amplifier and audio amplifier stages. An additional four transistors make up the portions of the circuit that needed to be built. The completed receiver tuned longwave (150-420 kHz), standard broadcast (550 to 1700 kHz), and shortwave (1.6 to 4.3 MHz). In addition, a separate detector tuned VHF (144-162 MHz). A BFO was included for tuning in CW signals.

The actual construction consisted of building four separate modules, and then assembling them into the completed unit. There were actually two bandswitches, one for the preselector stage, and another for the main receiver. Switching bands meant flipping both switches.

While not explained in the article, the purpose of the rotating loopstick antenna was for use in radio direction finding, as explained in an earlier post.



1943: Dealing With Wartime Parts Shortages

1943MayServiceSeventy-five years ago, the radio serviceman had to deal with wartime parts shortages, and this often called for creativity. As with many such magazines of the era, the May 1943 issue of Service magazine gave some pointers.

In most areas, the common tubes for “All American Five” receivers had become unobtainium. If a tube went bad, something had to be substituted. The diagram here shows how the serviceman could deal with a shortage of 12SA7 tubes. A 6SA7 might be available, and was identical in all respects other than filament voltage. In these AC-DC sets, the filaments were wired in series, and the filament voltages had to add up to 120 volts. If the 6-volt tube was simply plugged in, the filament would quickly burn out.

The solution is shown above. A resistor (such as a “curtain burner” cord) is placed in series with the filaments, dropping the total voltage in half. The problem, of course, is that the other tubes still required their original voltage. This was solved by pairing up the other tubes, wiring two tubes in parallel, and then putting all of the pairs in series.

Other pointers addressed in the article included making delicate repair of speaker windings and IF coils. In most cases, the break was close to one end, so the patient serviceman could locate it and solder in a new lead. Volume controls were also hard to come by, and the article discussed how to clean and repair them.

The article noted that these kinds of procedures were necessary not just to keep revenue flowing in, but as a public service to keep America’s radios in service to bring in war news and entertainment.



Electronics Illustrated, 1958-1972

1958MayEISixty years ago this month, the first issue of Electronics Illustrated, May-June 1958, rolled off the presses of Fawcett Publications, the publisher of Mechanix Illustrated. Construction articles in the first issue included the 40 meter novice transmitter shown here, as well as a code practice 1958MayEI2oscillator featuring a 2N107 transistor. For the more ambitious, the magazine also included plans for a garage door opener system, using tube type transmitter and receiver. (The B+ for the transmitter came from the rectified output of a small inverter designed to operate an electric shaver in the car.)

For those starting out in electronics, the issue also included a tutorial on how to solder.

My own introduction to electronics came largely from discovering this magazine amongst the offerings of the Publishers Clearing House (sent to me personally by Robert H. Treller, who added a number of personal notes to the mailing).  It looks like the first issue I received was the one for May 1970, and I even managed to get my name in the March 1972 issue as a finalist (but alas, not a winner) in their “Win The World” SWL contest by sending in a batch of QSL cards.

Emboldened by seeing my name in print, I was strategizing as to how I could win the next year’s contest. Unfortunately, the magazine ceased publication with the November 1972 issue, so that second chance was not to be.

The remainder of my subscription was satisfied with a subscription to Mechanix Illustrated, which for a time included something to the effect of “including Electronics Illustrated” on its cover.



1948 Heathkit Ad

1948MayPSHeathThis early ad for Heathkit appeared in Popular Science 70 years ago this month, May 1948.  These were among the Heath Company’s first offerings in electronic kits, which they offered from 1947 to 1992.

Their offerings included a regenerative receiver for $5.95, which covered the standard broadcast band and shortwave. It was available as either a two-tube battery set, or for AC operation, a three-tube set including rectifier tube.

Also included was a compact one watt 80 meter transmitter, complete with tube and crystal for only $3.95.