If you’re looking for a science fair project that can be put together with parts you’ll find around the house, you can’t go wrong with this motor from the July 1940 issue of Popular Science.
The main components used are paper clips. You’ll also need some insulated copper wire and a few other odds and ends. The old-fashioned dry cell batteries look cool, but it will work just as well with a couple of alkaline D cells.
We’ve previously written about (here and here) Elementary Electronics CB editor Kathi Martin, KGK3916. She got her big break fifty years ago this month, July 1970, when her column, Kathi’s CB Carousel, first appeared in the magazine.
We read her column every month, but we always wondered what a nice girl like Kathi was doing in a place like 11 meters. In any event, we congratulate Kathi on this important anniversary and wish her all the best.
One of our readers made a strong circumstantial case that Kathi, along with her husband, is the author of this interesting looking book on how live a retirement lifestyle yet keep money rolling in with continuing education seminars. It’s not a bad idea, as I also try to make a living with such seminars (although mine tend to be in places like Iowa, and she seems to recommend more popular tourist destinations).
Sixty years ago this month, the July 1960 issue of Electronics World carried the plans for this CB converter. The magazine noted that inexpensive transceivers were available with superregenerative receivers, and that those worked well at first to get people on the air at a low price. But as the band became more and more popular, the lack of selectivity posed a problem, and a superheterodyne was becoming necessary.
This circuit used a single 6EZ8 triple triode, and would use a standard AM radio tuned to 1500 kHz as the IF stage. It circuit could also be tuned to cover any 400 KHz segment of the 10 meter band.
We’ve previously featured ads from Young McCombs department store in Rock Island, Illinois and its well-stocked radio department. This ad appeared a hundred years ago today in the July 15, 1920, issue of the Rock Island Argus and Daily Union.
Sixty years ago this month, the July 1960 issue of Popular Mechanics showed this car radio from Motorola, which, according to the magazine, was the first mass-produced transitorized FM car radio. The set installed under the dash, and despite its compact size, it was completely self-contained, with its own speaker.
The radio was in response to the demands of discriminating motorists who enjoyed a more specialized programming, and the set was capable of reproducing the full range of FM audio.
The gentleman shown here is listening to one of the first pocket-sized radios, the plans for which were shown in the July 1950 issue of Popular Science.
The magazine notes that you don’t have to carry your portable radio–you can wear it. The receiver is so small that it will slip into your pocket, and you’ll hardly know you have it with you. The set was a four-tube superheterodyne that would pick up everything on the dial, thanks to four subminiature tubes.
The article did state that one needed to have “a little practice in radio building” in order to put it together. Indeed, the mechanical construction looks very challenging, trying to squeeze all of the parts into a small makeup box.
Unfortunately, the project is challenging partly because it’s unclear which tube is which. The set calls for four tubes: 2G22, 2E32, 2E42, and 2E36. Unfortunately, they’re not labeled on the schematic, and the text gives only a few hints. The 2E36 is the audio output, the tube on the far right. I think the other three, from left to right, are 2G22, 2E32, and 2E42, but I’m not positive. In any event, the tubes are taped to the sides of the IF transformers to squeeze everything into place. Of course, it probably doesn’t matter, since these tubes are probably all unobtainium.
Update: A reader sent us a copy of the page below, which shows the missing tube numbers. Apparently, the top of the page was cut off, but is visible in the scan below. Thank you!!
Yesterday, we posted this quiz from the July 1940 issue of Radio Craft magazine. Based upon the symptoms shown, what was wrong with the radio? As promised, here’s the answer: R1 is open. Here’s a more complete explanation:
We’ll give you 24 hours to think about it, and then post the correct answer tomorrow.
Would you have made the grade as a radio technician 80 years ago? You can find out from this quiz in an ad in the July 1940 issue of Radio Craft magazine. Based upon these symptoms, can you figure out what’s wrong? If you graduated from National Radio Institute’s home study course, you would undoubtedly identify the problem right away.
For a larger version of the image, click on it. Then, in most browsers, click on it again to enlarge.
We’ll give you 24 hours to think about it, and then post the correct answer tomorrow.
In this day’s issue of Broadcast magazine 75 years ago, the Broadcasting industry was alerted to something that hams would soon figure out as they got back on the air in the following years: There was going to be a lot of surplus equipment hitting the market soon. There were already rumors of a warehouse full of transmitters, and some 250 watt transmitters were already hitting the market.
A broadcast engineer with time on his hands could probably even track down most of the parts necessary for a 50 kW transmitter. With the war still going on in the Pacific, there was already an estimated $30 million in surplus available. And when hostilities ended, this was estimated to hit $5 billion.
An interesting look at Herbert Hoover’s 1928 campaign can be found at the National Archives Hoover Heads Blog.