During the Interwar period many nations developed massive listening machines to detect aircraft acoustically.
I took some toy musical instruments from the dollar store to use as the horns.
The base is probably at least 50 years old, it's a base from a Tootsietoy searchlight.
Shown here with a few 1/72nd scale troops for size.
After painting it looks a lot less goofy.
For a junk toy coupled with a few dollar store bits, I think it turned out okay.
It will work as an air defense for my 1938 US Army.
The finished device with painted wheels.