Here’s another more or less self-explanatory homemade telegraph set, from the pages of Popular Mechanics 90 years ago this month, June 1926. Unlike the one we featured a few weeks ago from 1916, this one relies on manufactured doorbell buzzers, and is intended to allow practice for aspiring radio operators, since the buzz of the doorbell more closely simulates the sound of a radio telegraph signal, as opposed to the clacking of the sounder of the landline telegraph shown in the earlier example. The article noted that the sound of the buzzer might be a lower pitch than desired, but explained how to increase the pitch by strategically placing a piece of paper in the buzzer.

This one can be set up either for practice at a single station, or two units can be interconnected as shown here. To receive, the other station needs to short out the key with the shorting bar shown.

The set is powered by two dry cell batteries. The article notes that if the two stations are some distance apart, such as in different houses, then a set of batteries might be necessary at each station.

In case you’re wondering, you can still find old-fashioned door bells, although they are getting harder to find.

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