National Radio's 50th Anniversary Album

A corner of National's Engineering laboratory in the early 20's. [The receiver on the bench in the lower right and being tested by the engineer in the middle left appears to be a National MB-29. This receiver was advertised in the November, 1929 issue of QST..]

One of the TRF SW series receivers in a appropriate period setting--circa 1923. [Pictured is the SW-4. This receiver is advertised in the Jan, 1929 issue of QST.]

The earliest attempt at band switching a communications receiver -- perhaps the reason why plug-in coils stayed popular for so many years!

The "innards" of the famous SW-5 Thrillbox -- which covered 9 to 2000 meters using two type 235, one 27, and two 45 tubes in a TRF -- regenerative detector -- push-pull audio set-up. [Pictured is either a SW-58 or SW-34. Both of these had the same basic circuit as the SW-5 but with a slightly updated/improved 1932 tube lineup. The earlier version of the SW-5 had a drum dial and two 27s in the final audio stage.]

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