Richard Harrison wrote:

At the time
of the magnetron gift to the U.S., British war production was already
bursting at the seams and the U.S. was well advanced in radar and had a
few tricks up its sleeve to improve the British gear.

All the major powers were well advanced in radar at the time. All the
ideas were already in place, and engineers everywhere were starting to
put them together. However, as Reg points out, freedom from bombing
raids is a wonderful aid to creativity.

The USA developed ways to mass-produce the magnetron, notably a method
of building up the cavity from laminations rather than needing to have a
skilled machinist mill it out from solid (and before Roy gets a word in,
they fixed the oil leaks too).

I`ve noticed early British airborne radar using yagi antennas. That
seemed quaint to me.

Those were the phased arrays for the earlier VHF radar, and consisted of
two or four two-element yagis clustered around the nose (of a
two-engined aircraft, obviously). This gave a fairly good
forward-looking capability. Both sides did much the same, and given the
relatively long wavelength, it's hard to think how better to do it.

The huge benefit of the magnetron was that it operated at much shorter
wavelengths, which frees up the antenna design and provides much better
spatial resolution - witness the downward-looking "H2S" radar which was
the magnetron's first major deployment.


--
73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek