Note
Radio News, Dec 1928, p. 594.
Radio News, Jan 1929, p. 689.
Radio News, Mar, 1929, p. 856
Radio News, Jun 1932, p. 1062. (not sure if this is the same unit or not)
The Thrill Box was National's first shortwave receiver (technically a tuner, since initially it has no audio stage). It covers a segment of the shortwave spectrum, but does not include the AM broadcast band. The set was first advertised in Radio News magazine in December, 1928, but had been on the market since some time before August of the same year, as evidenced by a satisfied customer's letter featured in one of the company's ads (see Figure 1). A photo of what appears to be the Thrill Box can be seen in National's ad in the June 1928 issue of QST, p. 77, but is not called out by name.
At first, National referred to the set as a "screen grid shortwave set." In a move almost certainly driven by the company's nascent understanding of marketing, this overly technical name was replaced with "Thrill Box" the following month, no doubt making the set more broadly appealing. In modern times, this version of the Thrill Box is often referred to as the SW-2 (a simple back-formation from the SW-3, 4, and 5), but that was never an official company designation.
By March 1929 National had added a third tube to permit operation with a speaker. Thereafter, the set was offered in two versions. One with two tubes for use with a headphones, and the other with three tubes for use with a speaker.
It is worth noting that the cost of the set ($36.00) adjusted for inflation is $640 in 2023. Moreover, the metal cabinet was optional and cost another $6.50 ($115.00 in 2023), so the Thrill Box was a very spendy radio.
In June, 1929, this original Thrill Box was replaced with a new version--the SW-4 Thrill Box. (The SW-3 would come later, in 1931.)
Tubes: (1) 201A, (1) 222 Note that the 201A is shown on the schematic incorrectly as a 112A.
Frequency coverage (in four separate coils) originally expressed in meters, stated here in megahertz for convenience, approximately: 2.6–19.3 MHz
Coil A: 11.3–19.3 MHz
Coil B: 7.3–12.7 MHz
Coil C: 4.6–8.0 MHz
Coil D: 2.6–4.7 MHz
Requires an external power source (typically batteries).
+135 VDC
+67 VDC
+45 VDC
and filament
