>"Commercial transmitters and receivers for 160 meters have long been >available."
To Frank¹s point, here are some additional early commercial 160m receiver examples: National SW-3 (ca. 1931 regenerative with dedicated 160m band spread coils) National HRO (ca. 1935 with sliding 160m coil drawer and bandspread taps) National NC-101X (ca. 1938 with 160m sliding catacomb assembly). Produced in 1931, the National SW-3 may be the first commercial receiver with dedicated 160m operation. For Hallicrafters and Hammarlund, I¹m not sure how early these sets were produced with a 160m band-spread position. For Hammarlund, possibly the first Comet in 1934 with plug-in coils. For commercial transmitters, Collins had 160m coil sets going as far back as 1935 with the 30FX and 30FXB and similar variants on these models. I own a ca. 1935 Collins 30FX with three 160m coils (Osc., Buffer, and 211 Final). Paul, W9AC _________________ Topband Reflector Archives - http://www.contesting.com/_topband