[R-390] R-390A Pedigree

[Richard W. Solomon]

Whenever I see a message about the R-390A, I invariably see the name
of the manufacturer. That tends to let me believe that one manufacturer
is more prized than another. Is there a list anywhere showing the
hierarchy of worthiness ?

Also, I notice that in the one I got (Stewart Warner circa 1959) that
some of the modules are marked ..."Col. Ser. No."... . Does this mean
they were made by Collins ? Or does the Col. refer to something else ?

73, Dick, W1KSZ