[Elecraft] 8 pole vs 5 pole..I knew this would happen

[DOUGLAS ZWIEBEL]

Hi all:

The notation below (previously posted) is referring to the final
passband filter and NOT a roofing filter.  You are trying to compare
apples and oranges.

I think you would be hard pressed to discern (in real use) a
difference between the 200 and 250 hz ROOFING filter, except in LOSS
(which will be "compensated for" later).  Pesonally, for cw work, I
think both of those will be "too narrow" for my liking, especially if
I want to "tune around the band" and not have signals suddenly POP
into the final passband (which I like to keep fairly wide).  I want to
hear what's coming!

de Doug KR2Q


I had 2 CW filters in my TenTec OmniV and did a lot of A/B comparing
with them.  One was an 8 pole Inrad 400 Hz filter and the other was a 6
pole TenTec 500 Hz filter.  I had them both in the rig at the same time
specifically to decide which one to keep.  I was able to detect the
steeper skirts of the 8 pole filter as well as the narrower passband,
but the factor that eventually tipped the scales was ultimate rejection.
The TT filter, had better ultimate rejection.  Once I tuned past a
signal, it went away and didn't come back.  With the Inrad filter, the
signal would drop quicker, hit bottom and then come back up.  I could
hear strong signals 6-8 KHz away.