The Battle of Britain Five Months That Changed History, May—October 1940 by James Holland (z-lib.org).epub

when minds were focused. Britain’s radar chain was rudimentary and
lacked finesse but it was the best that could be achieved within the time that
had been available. But it worked: approaching aircraft could be detected
up to 120 miles away. More than that, its rudimentary nature had worked in
Britain’s favour too.
In fact, the Germans had also developed radar, and earlier than Watson-
Watt. They called it Dezimator Telegraphie, or DeTe for short. Dr Rudolf
Kühnold, Chief of the Kriegsmarine Signals Research Department, had
been working on bouncing underwater sound waves – which became sonar
– when it occurred to him that the same principles could be applied to radio
waves above ground. This he developed into a radar that could be used for
ship detection and gun ranging, either from land or from a moving ship. A
prototype was developed which could change its range and accuracy by
altering the frequency it used. This became known as ‘Freya’, and its
shorter-range version, which was fitted to surface ships, was called
‘Seetakt’.
‘Freya’ and ‘Seetakt’ had been made by the Gema company, but in the
meantime Telefunken, a rival company, had developed a small, mobile
radar capable of plotting aircraft up to twenty-five miles away. The
‘Würzburg’, as it was called, was highly sophisticated, mechanically rotated
and elevated, and capable of guiding both anti-aircraft gunners and fighters
on to targets. And since it was rotational, it could operate on a 360-degree
setting and on land.
Thus when the Germans thought of other countries developing radar,
they assumed they would be small, rotational, sophisticated pieces of kit
like the ones they were developing, and not huge rows of iron lattice towers
staring out from the cliffs for all the world to see. And spot them they did.
German ‘tourists’ were packed off to Britain to go ‘sight-seeing’ around
Bawdsey, and then in May 1939 General Wolfgang Martini, head of the
Luftwaffe signal organization, persuaded Milch to allow him to fly over one
of the old Zeppelin airships to have a look. The airship, he believed, with its
ability to drift slowly and presenting a large object, would be perfect to try
and find out whether these masts were indeed some kind of primitive
British radar, or something quite different altogether. The Zeppelin duly
went over, approaching Bawdsey then turning north and heading along the
east coast. Expecting to hear some kind of response from their radio
receivers, the crew were surprised to hear nothing but a loud continuous