[Boatanchors] F455FA21 and F455FB21 difference

[Rob Atkinson]

p.s.

I was once HL9UJ in Busan in the late 1970s.

On Thu, Mar 5, 2015 at 10:03 AM, Rob Atkinson <ranchorobbo at gmail.com> wrote:
> 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 filter.
>
> 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?