Monthly Archives: January 2016

Color TV With the 1956 Colordaptor

1956ColorTV

Sixty years ago, the next big thing was color TV, and if you really wanted color, the January 1956 issue of Radio Electronics showed you the cheapest way to do it.  All you needed was your existing black and white set, and for about $85 ($50 if you had a well-stocked junk box), you could build yourself a Colordaptor.

The general idea is apparent from the picture above.  A color wheel in front of the screen would alternate red, green, and blue filters.  All that needed to be done was to synch them with the corresponding colors being transmitted.  This was accomplished with the six tube circuit shown in the article.  Some of the parts were available from the Colordaptor Company of Palo Alto, California, which also sold the device commercially.

Since the color wheel needed to cover the entire screen, it also extended above the screen, so it was hardly a compact design.  But if you didn’t mind the contraption on top of your set, and you didn’t mind it spinning while you watched, you would probably be the first on your block with a color TV.

The chasis of the Colordaptor could mount permanently on top of the set.  The color wheel could be removed for viewing black and white programs.

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1936 Crystal Sets

1936JanPM

80 years ago, this dad was helping his kids put together crystal sets from the pages of Popular Mechanics, January 1936.  That issue included plans for two sets that were particularly selective.  The magazine also pointed out that the audio quality of a crystal set was particularly good, despite the requirement for high-impedance headphones.

1936JanPM1The first set, shown here, was a fairly typical design employing a tapped coil and variable condenser.   The second set, shown below, was a simpler set but with an interesting design.  It was built in a hinged box with a honeycomb coil inside the box, with another in the lid.  To tune the set, it was placed on end, and the lid was opened and closed to tune the band.

1936JanPM2

The article noted that either set could be built for a few cents.  The most expensive component was the headphones, which started at 98 cents.

All of the parts, or suitable modern substitutions, for both of these sets are readily available.  For help on tracking them down, you can visit my crystal set parts page.

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Grain Belt “Talking Scoreboard” circa 1965

GrainBeltRadio

A few weeks ago, someone posted an interesting photo on the Old Minneapolis page on Facebook.   That page is one of the best on Facebook, as every day it includes more fascinating photos.  The most interesting photos are invariably of subjects that were mundane when the photo was taken.  But with the passage of years, these mundane scenes are the most fascinating. Sometimes, the story behind the photo is included. Other times, the viewer is left to wonder what was going on in the picture and why it was taken.

The photo was of the interior of a North Minneapolis bar, and was apparently taken in 1965. One eagle-eyed netizen noticed behind the bartender a most interesting radio, the Grain Belt Talking Scoreboard, like the one shown at the top of this page. The set measures about 18 inches wide, and consists of a scoreboard brightly backlit with two old style Christmas tree bulbs, on which the bartender could write in the score for each inning with a grease pencil. Inside the case is a radio for pulling in the game for the benefit of the patrons.

The radio itself is a typical “All American Five” (AA5) superhet, using a miniature tube complement consisting of a 50C5, 12AV6, 12BA6, 12BE6, and 35W4. The front panel controls consist of the volume control and tuning capacitor.

IMG_0023aA sticker on the back identifies the device as a Talking Scoreboard, and admonishes that “this electronic advertising sign is the property of the Minneapolis Brewing Co. and is loaned with the understanding that it will be prominently displayed.” There’s no indication of who manufactured the set, although from the tube lineup and other parts, it appears to have been manufactured in the late 1950’s or early 1960’s. At first I didn’t see them, but the set does have the triangular CONELRAD markings at 640 and 1240 on the tuning dial, as are visible on the closeup here, This places the date of the set’s manufacture at pre-1963 when CONELRAD ended.  A likely date for the set would be 1961, when the Twins came to town.  However, the set is generic in that it’s not marked with the name of any team.  Since Grain Belt was sold in other Midwestern states, it’s likely that it found use in taverns with loyalties to other teams.  And apparently another version of the set was available with a football scorecard.  You can find more discussion of the set at the antiqueradios.com forum.

The set shown at the top of this page is owned by Chris Manuel of Brookfield, Wisconsin, who graciously gave me permission to use the photo. He reports that the loopstick antenna makes the set more directional than is common for AA5’s, most of which used a larger loop mounted at the back of the set. But presumably, the radio only had to tune one station, namely the one broadcasting the game. So once it was set in a suitable spot, the directional antenna wouldn’t be much of a hindrance.  Perhaps the directional antenna even proved useful on occasion for nulling out a noisy neon sign.

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1976 Bicentennial Call Signs

BicentennialCalls

Today marks the 40th anniversary of the first use in the United States as the letter “A” for the first letter of Amateur Radio call signs. While the block AAA-ALZ had been assigned for decades to the United States, they had never been used for civilian call signs until January 1, 1976.

In honor of the U.S. Bicentennial, the FCC authorized U.S. amateurs to use special prefixes, starting at the stroke of midnight eastern time. At that point, since I was WB0MEB, I was authorized to use the call AB0MEB for the year. I used the special call a handful of times, but old habits die hard, and I signed my normal call most of the time. The chart shown above, from the January 1976 issue of QST, shows the complete assignments. Those of us with 2×3 call signs wound up with slightly shorter (on CW) calls. Those with older calls wound up with longer special calls, since W’s became AC’s, and K’s became AD’s. So the previous owner of my present call could have signed as AC0IS rather than W0IS.

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