The Super Cool Nerdy Bits

Recently our family went on a trip exploring the channel coast in the United Kingdom.  Besides a number of the classic sites (e.g. Stonehenge, Salisbury Cathedral, Battle of Hastings, Dover Castle and the White Ciffs of Dover, Bletchley Park, and Canterbury Cathedral), one of the most fascinating pieces of history I saw where the sound mirrors along the English Coast.

As many know, I joined the Army in 1982 as a 98J SIGINT Non-communications Interceptor.  Some of my training dealt with RADAR, it’s uses, and other bits of knowledge.   I’ve been doing that type of stuff now for over 40 years.  It’s not often I hear / see some other type of detection system – but the sound mirrors were a new one for me.

Initially build during World War 1 and still being built up to the mid 1930’s, these systems were used during World War II.   These structures of various size, shape, and orientation were designed to give the British early warning of approaching aircraft.   Various readings over the last weeks indicate that the mirrors provided a 5 to 10 minute warning of approaching aircraft – enough time to scramble gun crews and even possibly aircraft.  Unfortunately, unlike radar, things like altitude and direction of flight where extremely limited and based on a “tuned ear”.  Although early RADAR wasn’t perfect, it could see further and give more information than the sound mirrors – hence the stopping of the program.  The sound mirrors were still monitored in the early days for WWII, however they eventually were abandoned as RADAR improved during the war.

Nowadays, RADAR plays a key part in keeping the skies and waterways safe.  Not more than a ½ mile from a sound mirror location, HMCG runs a maritime radar site that monitors shipping in the channel.  These radars spin day and night, keeping track of all the shipping.