[MRCA] RE: PPI Scope Info

[Doran Platt]

OM,  I'll have a look a few older  AAF and AACS  books with ATC 
equipment.  If its a PPI it may well be part of a GCA or GCI system.  
The two wheels are probably for azimuth and elevation. I don't think 
that a GCA PPI had both elevation and azimuth controls as the beam is a 
vertical fan with good azimuth resolution.  What is puzzling also is the 
size of the tube.  Most late-WWII and later 40's ATC PPI scopes are 
something around 8" or more.  If you've seen the old Berlin Airlift 
movies you may have caught the system in operation.  The scope may also 
be part of a AAA gun laying/directing setup where the operator could 
switch to manually moving the radar to an area of concern after initial 
acquisition.  This is all conjecture on my part, of course.  There may 
be some radar collectors that will give you more info.  If you have a 
jpeg of the unit, many may be able ident it via a picture (you know, the 
1000 words....), as well as knob markings such as range or PRF.

Regards  K3HVG