[TenTec] Omni6+ mods: 125hz cw filter and 2 khz roofing filter

[K3BU at aol.com]

In a message dated 2/11/04 11:03:31 AM Eastern Standard Time, Rick at dj0ip.de 
writes:
>>Then in doing some research, I read somewhere that someone had
tried this and it did not bring the expected results and as I
recall, it was due to noise (but don't pin me down on that - it
was a while back when I read it). <<

Depends on band conditions and situation. I used 125 Hz filters in IC781 and 
Kenwood. There are times when it helps, there are times when wider BW gives 
better results. It has to do with one's "ear-brain DSP". Sometimes the way the 
signals sound, band noise, mushy signals, 125 Hz doesn't help. Sometimes when 
dense pileup and signals are "clear" it is like magic. Also as far as 
operating, sometimes it is better to use wider filter and catch off-frequenciers, 
sometimes when things get busy, narrow filter is big help in sorting out pileup.
You need, and never have enough flexibility/filters. DSP filtering with 
adjustable BW and steep skirts is great step forward in this direction.

The thing with "roofing" is, basically we want to get the first and best 
filter as close to the antenna as possible. OmniVI is probably the only rig that 
allows to cascade 3 socketed filters. I used 600Hz filter as the first 
(roofing) filter and then various combinations in 9 and 6 MHz IFs. I also keep 
combination of TT and INRAD filters. With QRN TT filters (simpler) have less ringing 
on static crashes. When sharper skirts are needed, INRAD filters rein.

I would prefer to have 600Hz first filter (roofing) and then arsenal of 
various filter TT and Inrad at 600, 250 and 125 in 2nd 9 and 3rd 6 MHz IFs. 
Otherwise for 125 at roofing position, switching arrangement might have to be 
implemented, it is too narrow for 100% use.

Yuri, K3BU