Though I have come to beleive it's probably an early electric hearing aid device, dont' let the seeming lack of cellphone towers in that era dismay you regarding the hypothesis that it's a cellphone type comms device---there was no shortage of radio towers back in those days, none whatsoever. Also, such things as the Eiffel Tower in Paris. What would prevent this time-travelling or alien tech from piggy-backing those existing radio towers?

There's also the matter of the satellite known as "The Black Knight" which was discovered in 1960 (somewhere I read it was like 1958, but cannot find the ref) This sat was larger than anything the US or USSR was capable of launching, and it was REPEATING RADIO PROGRAMS OF THE 1920'S-'30's. Google it, you'll find info pro/con regarding it.

If the Black Knight was real, there's no telling how long it was in orbit, and might have been serving as a comm-link for "explorers" mapping earth in the 1920's-'30's.