ADF (Automatic Direction Finder) radio waves are propagated as ground waves and/or sky waves. Problems associated with ADF are inherent in the frequency range that ...

IIIF provides researchers rich metadata and media viewing options for comparison of works across cultural heritage collections. Visit the IIIF page to learn more.

IIIF provides researchers rich metadata and media viewing options for comparison of works across cultural heritage collections. Visit the IIIF page to learn more. 3-D: 22 × 15.2 × 18.8cm (8 11/16 × 6 ...