Monthly Archives: October 2018

1948 Periscope

1948OctBLFor anyone desiring to see around corners, the periscope is the ideal solution to the problem. 70 years ago this month, the October 1948 issue of Boys’ Life showed how to make this simple but effective model.

In addition to a small wood block, only two parts were necessary.  And if you can’t find them locally, you can order them on Amazon:  Two two-inch mirrors and an 18 inch, 2 inch diameter mailing tube.  For making the precise 45 degree cuts, a miter saw was recommended.  Rounding out the bill of materials was some glue, and black shoe polish to paint the interior angles to reduce glare.

For older scouts, the completed periscope could be a useful tool for any number of purposes.  And for younger students, the project could serve as the basis for an interesting science fair project.

And for the more impatient modern youth, another option is to simply buy the genuine plastic periscope shown here.

 



1968 Police Dash Cam

1968OctPMFifty years ago this month, the October 1968 issue of Popular Mechanics shows this early rendition of a police dash cam.  According to the magazine, the Connecticut State Police had just started using the system shown here. The Sony camera was mounted on the dash, with a small microphone hanging around the officer’s neck. The back seat was taken up by the video recorder and monitor. The system ran entirely on 12 volts, at a cost of “less than $2000.”

The article quoted Sgt. Nelson Hurlburt, who reported that he simply let the tape keep running while on patrol. The tape had 30 minutes of recording time, so if he didn’t catch anything at the end of that time, he rewound the tape and started over. The lens was adjusted three times, at the beginning of his shift, again at 10:00 AM, and then again at dusk. The camera could automatically adjust to changing light levels during the day.

The magazine noted that the videotape evidence made a compelling case to the driver who was pulled over or, if necessary, in court.



Hurricane Michael Links

Hurricane Michael. NOAA image.

Hurricane Michael. NOAA image.

With Hurricane Michael bearing down on the Gulf coast, here are links to earlier posts on hurricane preparedness:



KIRO 1968 CB Traffic Reports

1968OctRadioElecThis photo from the October 1968 issue of Radio Electronics shows KIRO Seattle disc jockey Jim French taking a traffic report via CB radio. The article noted that instead of depending on helicopter reports, the station had a network of 40 CB-equipped motorists sending in live reports. The studio and CB antenna were located atop the 600 foot Space Needle. The location ensured a coverage radius of 20 miles, but the QRM was described as unbelievable at times.



1928: Buy or Build?

1928OctPSNinety years ago this month, the October 1928 issue of Popular Science tackled the vexing question of whether you should buy or build your radio receiver. The magazine noted that as between building and buying, the magazine championed neither option. It viewed its function as assisting with a wise purchase for those who so desired, or to help solve home construction problems for those who decided to build.

The gentleman shown in the illustration opted to build, and the magazine noted that if you enjoyed working with tools, then assembling your own set would yield good results.

It noted, however, that building a radio was really a misnomer. It was really a matter of assembling factory-built parts.

Either way, the magazine stressed that it was important to identify your needs. Was bringing in distant stations the main appeal, or did you put tone quality first?  By first answering these kinds of questions, the radio consumer would wind up with a suitable set, whether they decided to buy or build.



Canadian Red Cross Packing Plant, 1943

1943OctManitobaCallingThe Canadian women shown here are volunteers packing prisoner of war Red Cross food parcels on their way to Canadian POWs, primarily in Germany and Italy.

The photo appeared in the October 1943 issue of Manitoba Calling, the magazine and program guide of CKY Winnipeg.  It shows the Red Cross packing plant in Winnipeg, the largest of five in Canada. The plant was staffed five days a week by volunteers and turned out food parcels at a rate of 4400 per day. The plant was described as businesslike, with two long conveyor belts. As the parcels moved down the line, a woman placed a food product in the same spot in each box. Items were picked for their nutritive values, and included chocolate, raisins, tinned butter, and corned beef. An acknowledgement card was included in each parcel, which were signed by prisoners and returned by mail to the Canadian Red Cross as proof of delivery.

From Canada, the parcels went by sea to Lisbon. From there, they were taken by Red Cross ships to Marseilles and then by train to Geneva to the warehouses of the International Red Cross. From there, they were distributed within the enemy countries.

The magazine noted that many of the volunteers were related to prisoners, 900 of whom were Manitoba boys.



1943 Toothbrush Twins

1943OctPM2

1943OctPM3If you look closely at this picture from the October 1943 issue of Popular Mechanics, you’ll see a 1H5 tube lying on the table. This means that the trio shown here decided to build the one-tube version of the receiver described in the issue. Included were the plans for two almost identical receivers, the difference being that the one shown at left used a crystal detector, while this group decided to tackle the only slightly more complicated,tube version, shown below.

1943OctPMTubeFor either set, as long as the builder had a good set of headphones, a quick look at the junk box, or a trip to the dime store, would produce the necessary parts.

Either set was mounted on a 10 x 13-1/2 inch breadboard, with the coil wound on a toilet paper tube. The coils were tapped and hooked to the switch that gave the sets, the Toothbrush Twins, their name. The switch was made with the handle of a toothbrush from which the bristles were removed with a pair of pliers. This was used as the slider, which contacted thumb tacks layed out on the board with the help of a compass.

If a shorter antenna was used, this was fed to the coil. A longer antenna had its own Fahnestock clip, and bypassed the coil.  Either set was said to provide excellent results with local stations, with the tube version showing a bit more selectivity.

1943OctPMSchematics



1943 One Tube AC-DC Shortwave Regen

1943OctRadioCraftThe October 1943 issue of Radio Craft carried this schematic for a one-tube AC-DC shortwave receiver. The circuit had been sent in by Leo Silber of Springfield, Mass., who reported that in 25 nights, he had pulled in over 200 stations from as far away as Little America, Antarctica.

The set used a 6C8G, with half the tube serving as rectifier and the other half as regenerative detector. Plug-in coils were used along with a variable capacitor for tuning. Silber reported that the set could drive either headphones or a small speaker.

For those wishing to duplicate the circuit, it appears that a 6SC7 can be substituted.  Those tubes are still rolling off the Russian assembly lines of Sovtek, and are available on Amazon.  For information on winding the plug-in coils, see our plug-in coils page, and for sourcing other parts, you can get ideas at our crystal set parts page.

If the circuit looks familiar, it’s because the magazine’s March 1943 issue had carried a slight variation on the same circuit, also sent in by Mr. Silber.  Silber, then a high school senior, was apparently not licensed before the War, but the 1949 call book shows him as holding W1NRP.  He went on to receive his Ph.D. in Physics from Purdue University, and later served as Professor of Electrophysics at the Polytechnic Institute of New York, Brooklyn.  A 1981 biography is available at this link.



1943 Cable Reel

1943OctPM

In 1943, teen girls went for the boys on the Audio-Visual crew, as shown by this illustration from the October 1943 issue of Popular Mechanics.  (Note the book bag at her feet, ready to be carried home by one or both of the helpful lads.)

The two shown here are running wire to an extension speaker using the large diameter reel shown in the magazine. Not only are they impressing the girl with their knowledge and skill, but they’re being patriotic by being careful with wartime strategic materials, since storing the cable on such a reel made it last longer than if simply hung on a nail or small diameter peg.

1943OctPM1The boys probably made the reel in wood shop where they showed their skill, since the magazine noted that the unusual design, shown here, “provides an interesting sawing problem for students.”