 WGU-20 was something of a mystery initially, with thousands of ham radio operators and radio hobbyists speculating about the nature of the station, until a small news article in "Popular Electronics" magazine outlined exactly what WGU-20 was.Afterwards, reception reports (some from as far away as Texas) were sent a special QSL card featuring Paul Revere on a horse, raising the alarm.WGU-20 was originally designed to be part of the Decision Information Distribution System (DIDS) that would be used to alert the public of an enemy attack (along the same lines as the then-current Emergency Broadcast System).