[TenTec] [OT] re: 50hz PSK filter?

[Ken Hopper - Amateur Radio N-9-V-V]

Dear Mark and the group,
I am confused about this. Can you help me out? I thought the strength of
PSK (and MFSK) was in the DSP filtering done at 31.5hz by the SOUND CARD
and the front end RX didn't really matter. For example the PSK-20
(PSK-80 Warbler, PSK-10) is purposely a BROAD BAND receiver and works
like gangbusters on PSK. I certainly agree that some receivers exhibit
very bad desensitization when in the presence of a S9+ PSK signal nearby
(make that PACTOR signal nearby :-) but programs like HamScope 1.5 have
a NOTCH filter and BANDWIDTH filter that knock out the offending sigs. 
PSK-Deluxe shows more than 40 signals at once on my display (outstanding
freeware) and it _relies_ on broad banded RX. 

So does the bandwidth of the RX matter on PSK? or is it something
mysterious like Dynamic Range and AGC?

TU,
de ken n9vv
http://www.n9vv.com/psk31resources.html