Category Archives: Radio history

Syncom Satellite

Sixty years ago this month, the January 1964 issue of Electronics Illustrated noted that it had been just over six decades since Marconi bridged the Atlantic without wires or ships in 1901. In the intervening years, the job had been done with satellites such as Telstar I and II.

But on July 26, 1963, a new experimental satellite, Syncom, had been launched from Cape Canaveral. The satellite was new in that it was synchronous. Its orbital period was 24 hours, so it seeming hovered at the same longitude. Since it was launched from 33 degrees north, it actually did a figure 8, hovering between 33 north and 33 south. But that was good enough to be continuously visible from both America and Europe and 22,300 miles.

The magazine noted that if such a satellite were launched from the equator, then it would stay above a single point on the earth’s surface. The magazine didn’t use the word, but this is what we know today as a geosynchronous orbit, although most geosynchronous satellites are today launched from other locations, first into a geostationary transfer orbit before being maneuvered into geosynchronous orbit. According to the magazine, the satellite’s two transmitters put out about 2 watts on 1915 MHz.

1923 British Regen

A hundred years ago this month, the December 1923 issue of the British journal Wireless Weekly showed how to build this two-tube regenerative receiver. The exact frequency/wave length coverage is not stated (quite likely because the author didn’t really know for sure), but it was designed to receive long wave radiotelephone and radiotelegraph signals, as well as BBC broadcasts. So presumably, it covered the long waves and the medium waves.

It was said to pull in all of the BBC broadcasts with good volume.

The circuit isn’t all that different from similar receivers from subsequent decades. So it would be a good performer, even today. The picture above is somewhat deceptive, as it doesn’t show the components below the chassis. It is designed to be mounted in a a box about 3 inches deep, which is shown in the article.

1953 Model Train Voice Control

Seventy years ago, this young man was deriving new enjoyment from his train set, thanks to the voice control system his dad put together, from the plans in the December 1953 issue of Popular Electronics.

The system would cycle through forward, stop, and reverse commands. The actual words used didn’t matter, but with a bit of creativity, Junior could make it look like the device understood exactly what he said. For example, if the train was moving forward, then barking “stop” would have the desired effect. From a stop, the word “reverse” would do the trick. If the train was going backwards, then “now go forward” would give three syllables, making it cycle through to the forward mode.

The device was compatible with both Lionel and American Flyer train sets.

Mimi Benzell’s Hi Fi, 1953

Seventy years ago, it was a Hi Fi Christmas for soprano Mimi Benzell and her husband Walter Gould. They are shown here with what Santa delivered, namely, a Graarard turntable, a Pilot tuner, a Bogen amplifier, a University speaker enclosure, and a Wilcox Gay tape recorder.

They are probably shown at their home, which, according to Wikipedia, was at 45 Cardinal Road, Manhasset, New York. The picture appeared on the cover of the December 1953 issue of Radio News.

1943 Code Practice Oscillator

The December 1943 issue of Radio News carried the plans for this simple one-tube code oscillator. The 117N7 with a built-in rectifier meant that it could be done with a single tube.

The author of the article is one R.C. Zaun, an engineer with the Thorardson Electric Manufacturing Company. Not surprisingly, the most expensive part shown in the schematic is probably the audio output transformer, which just happens to have a Thorardson part number.

As shown here, the oscillator had a pitch of about 1600 Hz. This could be varied in one of two ways. First, R1 could be replaced with a variable resistor, although the article noted that this would also affect the volume. Another method would be to change the value of C4, switching in capacitors of different values to vary the pitch.

If wartime parts shortages meant that the 117N7 wasn’t available, it could be substituted with other versions of a different filament voltage. Of course, an appropriate dropping resistor would need to be used.

S.G. Brown Headphones

This ad appeared 75 years ago this month in the December 1948 issue of Practical Mechanics.

Your choice of headphones was important. For DX work, you needed good fidelity. But more importantly, you needed to uphold British prestige. And to do that, you needed the Type K headphone from S.G. Brown, Ltd.

1963 Radio Kit

Sixty years ago, if you were in the market for a transistor radio, and you had a little bit of mechanical aptitude, you couldn’t really go wrong getting this kit from General Electric. It was a kit, but the hard work, namely the construction of the individual circuit boards, had already been done at the factory. You just had to snip a few wires, and do a little bit of soldering, assembling, and gluing. In less than an hour, you would have a good five-transistor radio.

The kit was available from electronics suppliers, and this ad appeared in the December 1963 issue of Popular Mechanics.

Learning Code By Sleep Learning, 1923

A hundred years ago, these naval aviators look like they’re sleeping on duty, but sleeping was their duty. They are busy learning Morse code, and the Navy discovered that they could do so by sleep learning. While they were asleep, messages were sent to them at increasingly higher speeds. It was found that when they woke up, they were able to copy that speed. In fact, some of the trainees were able to recite the messages that had been sent to them while they slumbered.

The photo appeared in the December, 1923, issue of Popular Mechanics.

1963 Clock Projects

If you needed a bedside clock 60 years ago, the December 1963 issue of Popular Mechanics had a couple of good ideas. The gentleman shown here appears to be suffering some sort of night terror, but at least he knows what time it is, since the time is projected onto the ceiling. The projector is simplicity itself, consisting of a metal candy box (or some other enclosure that’s shiny on the inside). A 15-watt bulb illuminates a wristwatch strategically placed, and the image is reflected by a small mirror mounted at a 45 degree angle. The single lens makes sure that the image is not reversed.

The other idea was a $2.98 clock radio, which isn’t very different from similar ideas we’ve seen before. If you already own a perfectly good radio, you can turn it into a clock radio simply by attaching a switch to a wind-up clock.

1948 RCA Radios

If you were browsing the pages of Life Magazine75 years ago today, December 13, 1948, and you didn’t have your Christmas presents picked out, you couldn’t go wrong with one of these RCA radios.

If you wanted the “luxury look” in an inexpensive set, then the Model 75X16 was just the thing. The model 8B43 portable was just 6-1/4 inches high and came on the instant you opened it, thanks to the miniature but sturdy tubes and long lasting RCA battery.

The model 8X521 tabletop set was only six inches tall, and the model 8BX6 Globetrotter was a portable that could run on either batteries or AC.

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