How did the development and production of radio equipment really get started in the U.S.?
Prior to the time when broadcasting as a movement took off, there were only a few commercial stations and the steadily growing number of amateurs who needed a receiver. (See the chapter on amateur radio enthusiasts in Radios von gestern). In 1920 Armstrong searches for license-takers for his regeneration (reaction) patent as annual fees and lawyer costs become a heavy burden. Up to that time amateurs more or less built their receiving devices themselves and thus avoided paying a license fee. In an advertisement Armstrong offers to the growing number of commercial manufacturers the legal use of his patent for a fee of 5% of the selling price. In approximately this sequence the following companies accept the offer: American Marconi (for 2 stations only), International Radio Telegraph Co., Inc; A.H. Grebe & Co., Chicago Radio Laboratory (Zenith from 15.02.1920); Clapp-Eastham Co. (on 18.04.1920); Cutting & Washington Inc. (on 07.07.1920, company later renamed Colonial); Adams-Morgan Co.;
