Dokonce se to zkoušelo na přehlídce u Westinghousů v roce 1933. By Unknown author - Retrieved March 21, 2015 from Short Wave Craft magazine, Popular Book Corp., New York, Vol. 4, No. 7, November 1933, p. 394 on http://www.americanradiohistory.com, Public Domain, https://commons.wikimedia.org/w/index.php?curid=39161881