[Elecraft] 8-pole vs. 5-pole roofing filters?

[Darwin, Keith]

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.

So, I went with the TT filter because for me, ultimate rejection was
more important than the slightly narrower passband.

Now, the question is whether or not the 5 vs 8 pole filters for the K3
have different levels of ultimate rejection.  If they do, then the
choice has become tougher.

- Keith N1AS -
- K2 5411.ssb.100 - 

-----Original Message-----
From: William Hein, NT1Y

What's the performance difference between the 8-pole and 5-pole K3
roofing filters?

For crowded-band CW performance am I better off with a 5-pole 200-Hz or
a 8-pole 250-Hz filter?