[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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