[Collins] Filter Question
Dr.Gerald Johnson
geraldj at ispwest.com
Thu Jan 20 23:02:24 EST 2005
Collins part numbers for the last half of the 20th century had the constant
characteristic of a 3 digit family prefix, then a four digit part number. Then a
two or three digit suffix. Well before 1963 when I was there, the suffixes were
uniformly shown as 00 though a parts list in a bill of material the suffix would
be 001, 002, 003, 004, or 005 corresponding to the size off the drawing paper
it was drawn on. 001 being A size 8.5 x 11. This continued to be true of
engineering drawings. Sometime in the early 60s, before I started, it was
noticed that part numbers were being used up. So instead of using 100 part
numbers for 100 related parts (like a family of capacitors), one part number
was used along with 100 dash numbers (suffix). Maybe a 1000 dash numbers
for 1% precision resistors. So at that point it generally became important to
show all three suffix numbers.
So that filter should be 526 (an assembly drawing family) -9038-00 is a bit
earlier than the 75S3B. I don't know about the filters. The 9W2 nomenclature
is unusual. Might it be four digits of date code? In my 75S-3B manual, the
offered crystal filter is a F455Q200 for 200 Hz. bandwidth. The Q being for
quartz. By using the steady signal from the calibrator you should be able to
measure the filter bandwidth. That might help decode the filter number.
73, Jerry, K0CQ
--
Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
Reproduction by permission only.
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