[1000mp] INrad Collins vs Yaesu Collins 500 Hz Filter for 1000MPs

[Joe Subich, K4IK]

N4ZR writes: 

> I disagree slightly with Ian and Earl, at least if you are using 
> your sub-receiver for contesting and DXing, and not trying to have 
> it perform like the main receiver.  The wider skirts can be quite 
> useful for trying quickly to locate a split pileup and look for a 
> crack in it, where the Inrad 400 may be so steep-sided as to cause 
> you to miss stuff that is much off frequency.

I come down in the middle of this ... for me the Collins filter is 
useless in the subreceiver due to it's very sloppy skirts.  With 
a shape factor more than 2.5:1 and a 6 dB bandwidth of nearly 
600 Hz, it's not much better than the SSB filter in a pile-up.  

I ended up putting the Collins filter in the main receiver (since 
I had it) and using an old Yaesu 500 Hz crystal filter (equivalent 
to the INRAD 721C 500 Hz crystal filter) in the subreceiver.  It's 
a bit wider than the 400 Hz filter but the skirts are sharp enough 
that I'm not listening to the entire pile-up when I'm looking for 
the (typically weak, backscatter) station the DX is working.  
Similarly, during a contest, I can find that weak multiplier right 
along side W3LPL or K1TTT that would be impossible with the much 
wider Collins filter. 

73, 

   ... Joe, K4IK