5 Oct
2005
5 Oct
'05
12:34 p.m.
Fact Check...
Tubes typical of that era was the smaller
electrostatic types and 5up1/7
were of the era.
Electromagnetic (and combo) tubes were just as common starting in the
1940s. If a tube had a P7 phosphor, it was likely intented for PPI duty,
and nearly all PPI scopes of the era were rotating yoke types.
The aviation tubes used for that airborne radar were
surrounded by a mumetal shield to keep mag fields out and the graticule
was far thicker than the tube.
Graticle thickness not far thicker than the tube face in many
instances. Most actually were probably thinner. They varied from 3/16
inch to just a very thin sheet, maybe just a few thousandths thick.
Tubes larger than about 10"
didn't appear much till the mid 50s.
12 inch tubes were very common before 1950. Just about ever World War 2
Allied air search radar had one (or in the case of late war types, two).
William Donzelli
aw288 at osfn.org