[Boatanchors] F455FA21 and F455FB21 difference

[Rob Atkinson]

They are both 2.1 kc wide filters for a 455 kc IF.  The B type filter
I think is the old "bathtub" filter that went in the 75A-3.  that's
probably a rare filter.  Most B filters were 3.1 kc and 800 cycles.
There was a 6 kc AM filter that's almost unobtainium.  I don't know
anything about the A filer.

73

Rob
K5UJ

On Thu, Mar 5, 2015 at 8:22 AM, HL1FB <yonglee at yonsei.ac.kr> wrote:
> I have Collins mechanical filters marked F455FA21 and F455FB21.
>
> Anybody knows the difference between these two?
>
> I guess impedance difference but what are the exact values?
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