Editing Naxos radar detector (section)

==Background==
Prior to the introduction of the [[cavity magnetron]], [[radar]] systems used traditional vacuum tube electronics and were limited to about 1.5&nbsp;m wavelength in UK use, and as low as 50&nbsp;cm in German systems. Both could receive the transmissions of their opposing radar systems and radar warning receivers were widely used by both sides in a number of roles.

By 1942, the UK had made enough progress on the magnetron to begin introducing new radars using it, including the [[AI Mk. VIII radar]] for night fighters, [[ASV Mk. III radar]] for sea-surface search (anti-submarine) and the [[H2S radar]] for bomber guidance. None of the existing German receivers could operate at the magnetron's 10&nbsp;cm wavelength, and the introduction of the ASV Mk. III, in particular, led to significant losses among the U-boat fleet during the summer of 1943.

Before the magnetron had been deployed operationally, there was a great debate in the UK over whether or not Bomber Command should be allowed to use it. Unlike other types of tube electronics of the era, which are quite fragile, the main component of the magnetron is a large block of copper. If an aircraft carrying one were shot down and recovered, there was a very good chance the block would survive, at which point the secret would be revealed to anyone familiar with microwave techniques. This is precisely what occurred on the night of 2/3 February 1943, when the second mission to attempt to use H2S led to one of the [[Short Stirling]] bombers carrying it being shot down near [[Rotterdam]]. The magnetron was recovered and this ''Rotterdam Gerät'' (gadget, or device) led to the rapid formation of a study group to exploit it.

The group first met at the [[Telefunken]] offices in Berlin on 22 February. Although the possibility of developing radars using it was considered, the much more pressing need was the development of countermeasures to this now-undetectable radar. This effect was hampered by the industry's recent decision to give up on microwave research, considering it to be a dead-end, as had British engineers before the introduction of the magnetron. Adding to their problems was the lack of a suitable rugged [[crystal detector]], which was the only system able to reliably detect these high frequency signals. Enormous effort was expended to address these problems, and prototype units were available by the summer.