[TenTec] Inrad Roofing filter board in Omni VI

[Ken Brown]

Hi Jason,

Now that you have had the Inrad roofing filter modification in you Omni 
VI for a while, I wonder what are your impressions? I don't know what 
kind of operating you do, so you may not have noticed the improvement 
too much yet, if you have not operated any contests since you got it 
installed. Or maybe you operate on 40 meters amounst the SWBC carriers 
often, and have noticed a great improvement already. I am also curious 
whether you have noticed any difference in the way the noise blanker 
functions with the Inrad mod in line?

It appears that the location in the signal path of the Inrad roofing 
filter modification was chosen as much for ease of installation and 
deinstallation as much as for any other reason. There is only one gain 
stage (Q1 on the 9 MHz mixer/IF board) that the Inrad roofing filter is 
in front of, that the standard Ten-Tec 2.4 kHz filter (Y2) is not also 
in front of. And the Inrad mod is also in front of the NB detector and 
switch. This is based on my Omni VI schematic, and it is not a + or 
version 3. I don't have a schematic of those.

Can you discern any difference in the noise blanker function 
with/without the Inrad roofing filter? For instance when band conditions 
are such that your ability to copy a signal is not limited by close in 
strong signals, and is limited by QRN and you are using the noise 
blanker, what works best? Inrad roofing filter in or out?

Thanks,

Ken N6KB