|Company||Federal Signal Corporation|
|Sound output||128 dBc at 100 feet|
The RSH-10, also known as the Thunderbeam, was a rotating electromechanical siren produced by Federal Signal Corporation. RSH stands for Rotating Single-Tone High. Its unusual design consists of a hornless STH-10 mounted at the top with a slanted disc in a cage below. The housing directs sound downward from the rotor and stator, onto the disc. The disc is rotated using a gear reduction off of the rotor shaft, directing the sound in different directions.
The trademark for the Thunderbeam was filed on January 7, 1983 (No. 73408887). The Thunderbeam was invented and patented by the late Earl Gosswiller (1912-2009), who was a chief designer for Federal Signal. Most of all, he is known as the father of the Beacon Ray light, which is believed to be the inspiration for the Thunderbeam. The siren was submitted to the US Patent Registry on December 3, 1982, and published on July 16, 1985 (Patent No. US 4529969 A). The Thunderbeam proved to be his last patent however, as Mr. Gosswiller retired from Federal in 1982 according to his obituary. The Thunderbeam was discontinued in the 90s at some point, as the last mention of the Thunderbeam is in a Federal Signal publication from 1995.