ShortwaveSchedule.com maintains this listen of reported High-Frequency (HF) radio broadcasts to Cuban agents in the field. Also known as “shortwave” or “ham radio,” HF broadcasts have proven themselves as a highly effective means of communications for decades. While such broadcasts can be intercepted, an abundance of low-cost encryption systems keep the sent message secure. For added security, Havana uses a standardized message format of 150 five-character groups. This technique prevents the listener from gaining insights based on the brevity or length of the broadcast.