A hundred years ago this month, the July 1920 issue of Popular Science reported that the United States Forest Service had found a valuable ally in the radiotelephone. 42 sets like the one shown above were in operation at remote points in Wyoming, Montana, and Oregon. Range varied from 10 to 300 miles, with about 50 miles being typical.

The article noted that two such stations bore a cost of about $3000. However, that particular circuit covered 60 miles, and a comparable telephone system would have cost over $5000. Even though rangers started with no radio experience, the Service reported that after a few months, they were able to expertly take and send messages.

The trees themselves were pressed into service as antenna supports. At each site, two suitable trees would be stripped of branches and the wires stretched between them. Initially, storage batteries were packed back to the closest town for charging, but gasoline generators had just been installed to save that labor.

Mules, such as the ones shown at right, transported the equipment to its station. But when the trails got too steep for the mules, the rangers themselves carried the equipment.

Seventy-five years ago this month, the July 1945 issue of Popular Science shared this self-explanatory helpful hint for mounting a radio on the wall. Many times, the radio wound up at the wrong end of the room, because that’s where the table was. With this idea, you can mount it wherever desired, and it had a sleek “built-in” look about it.

The magazine did caution that before following this scheme, you should make sure the radio’s cabinet is structurally sound.

Seventy-five years ago this month, the June 1945 issue of Radio Craft carried this schematic for a code oscillator sent in by one Gene Clardy of Fort Worth, Texas. According to Clardy, the circuit’s main feature was its safety, since no high voltages were present. With no possibiity of high voltages on the key or headphones, all possible shocks were avoided.

The set used a 6 volt doorbell transformer to light the filament. The secondary of the transformer was also rectified by half of the tube to supply the B+.

Fifty years ago this month, the June-July 1970 issue of Science and Electronics  carried this project, which itself dated back another fifty years. It’s a simple crystal set, but the most interesting feature is the tuning capacitor, which is a book-style condenser. It consists of two blocks of wood, each with a layer of aluminum foil carefully glued to one side. These are hinged together, and the set is tuned by turning a screw to open and close the book.

Astute readers might remember similar capacitors used in this 1944 crystal set and this 1942 tutorial on making parts at home.

I don’t know much about the provenance of this photograph, other than that it was taken in Atlanta about a hundred years ago. What is clear from their expressions, however, is that the two girls in the foreground obviously understand the magic of radio. Chances are, they had never heard a radio before, but when they heard music coming out of the headphones, they realized that the world had changed. I’m guessing their families were among the first on their block to get their own radio set.

Not everyone gets the magic, though. Many of the others seem a bit skeptical about this new contraption. All I know about this picture is that it appeared a hundred years ago this month on the cover of the June 1920 issue of Wireless Age, and that the caption reads, “members of an Atlanta club who danced to music received by wireless ‘phone.”

Shown here (at right) is the appropriately named Mr. R.F. Field, a radio engineer with General Radio Company. The photo appeared 75 years ago this month in the June 1945 issue of General Radio Experimenter, a monthly publication put out by the company.