07-22-2018, 01:05 PM
I'm not sure about the model 28, but American Bosch did make radios for Sonora and National Carbon Co. (Eveready):
https://books.google.com/books?id=uDk_5S...os&f=false
By-the-way, all three volumes of the Alan Douglas series Radio Manufacturers of the 1920's, is a great addition to any collector interested in early radio.
https://books.google.com/books?id=uDk_5S...os&f=false
By-the-way, all three volumes of the Alan Douglas series Radio Manufacturers of the 1920's, is a great addition to any collector interested in early radio.
John KK4ZLF
Lexington, KY
"illegitimis non carborundum"