Just above the large tuning dial, the calibration in Kilohertz is projected onto the rectangular ground-glass screen, forming an excellent and accurate vernier sliding scale. When tested against WWV on 5 mHz and 10 mHz, the unit's accuracy was
less than 1 kHz.
Lautstarke = volume
Tonhohe = pitch/tone
Photo by Bruce Culp
Photo by permission of Stg.C.D.V.&T.