Photo credit: Lietuvos centrinis valstyb?s archyvas.

Many thanks to SWLing Post contributor, Giedrius Blagnys, who notes:

The first national radio broadcast in Lithuania started on 1926-06-12 d. Photo above: the mic used for the first broadcast. 

Recording of the first transmission:

Many thanks for sharing this interesting bit of history with us, Giedrius!