here is one very old and well made radio. a real piece of history. A lot of radios this old were made by the owners.
correct me or if I am wrong , I think it has 3 tubes? and the screen is to look through to admire the glowing tubes. I assume this gave the operator an idea how bright the filaments were glowing in order to adjust for battery strength.
Download federal.jpg. (Caution: This file may not be virus scanned.)