> A very interesting story in this radar history is how the Dutch managed to > rescue the EF50 tube, essential for these early radar receivers, to England > just hours before the Germans invaded holland.
This is generally a good article, but has a major flaw or two. One, it describes acorn tubes as costly and difficult to build. This was certainly true in Britain and Europe - for some reason the overseas makers had a very difficult time getting acorns to work (and last) properly. This was not the case for RCA - there were large numbers in service by 1939. RCA must have kept the "secret" to making acorns tight to their chest. Two, it poorly describes (almost not at all, actually) the Sylvania loctal that came before the EF50. Most of what makes an EF50 can be found in the loctal series. US radars generally did not use loctals (some IFF transponders did - a related technology), but by 1940, the loctal was pretty obsolete and the 7 pin miniature banging on the door. -- Will
