EF50 was Re: radar history

:> The high frequency power tubes were required for better spacial resolution. My understanding was that major difference between the German radar and allied was that the Germans had a single trace, like a time domain reflectometer. The allies had a rotating image that is similar to what we see on current radars, today. Both sides had the displays you describe. The first is called A-scope, and the latter PPI (Plan Position Indication). Consider that early radar, well into the 1950s, was actually pretty horrible. PPI back then often resulted in a screen full of indistinct smudges, so nearly every search radar had the "old" A-scope, where the operator would use a cursor* and get a very accurate range and azimuth reading. Basically, the PPI scope was good for "the big picture" "show me all the information", and the A-scope was good for getting the information that was actually useful. Significant, but only sometimes significant. Higher frequencies produced by magnetrons were useful for bombing and gun laying (anti aircraft and naval guns) as it improved range accuracy greatly, but it did nothing for air search radars. VHF radars (with triodes) were still in front line service until the 1950s, simply because they did a much better job at illuminating aircraft. Germany often gets the short end of the stick when it come to radar tech in World War 2, but towards the end, their (non-magnetron) air search radars were some of the best. Why? Because that is what they needed with their skies full of Allied bombers. The graphical real-time cursor and joystick, in one or two dimensions, has its origin in World War 2 radar systems. It is astonishing how many historical accounts of early computer graphics do not mention this. -- Will