[Drake] Filter for R4C - what's this for a filter

[Rolf G. Schroeder]

Hi,
I have recently bought a Drake 4C line which came with an addtional Filte=
r=20
from Network Sciences inc. With numbers like SL 4006 (last three digits=20
unsure) 7904 and 5.645-4.0/8 on it. It was produced on May 15 1979 (that =
at=20
least is the stamp on the bottom. Should I replace the original filter in=
 the=20
first IF by this one?
--=20
Best Regards
Mit freundlichen Gr=FC=DFen
Rolf Schr=F6der, DL8BAG

They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety.=20
- Benjamin Franklin, 1759 -=20