[TenTec] Effect of roofing filter selection on Orion II NB

[HENRY PFIZENMAYER]

Grant -- I feel I see the same on NR -- because of my terrible noises , I 
run 100 cycles BW virtually all the time and especially on 80 and 40 
meters - I am pretty convinced I hear better with NR cranked in HARD (8 or 
9) - I have no measurements but fer instance last night on 40 TZ6DEL was 
extremely weak and fading in and out with occasional good peaks to 
maybeS3!!!!! It took me maybe ten minutes to be sure of his call and that he 
was listening up 2. Fired up the trusty Centurion on one peak , called , and 
when he came back I had to use ESP to get my call - so I listened for 
another 10 minutes playing with all the bells and whistles- threshold versus 
RF gain  vs NB on or off vs roofing filter BW but always came back to NR in 
hard (even though it gets pretty harsh) -  anyhow he sneaked up out of the 
noise real good one more time , I called , and this time was 100 percent 
copy , my call and the usual hilarious 599 report . (Of course I played the 
game with a 599 AZ even if he was only copiable 5 percent of the time !!!!)

 Re the noise generator/small signal -- I was thinking of a 3 db hybrid 
combiner to combine my noise generator and the Elecraft XG1 with a pulser - 
and with variable attenuation between both sources and the hybrid -Then I 
was just going to watch on a scope as I played with things to get the most 
signal above the noise . Also gonna look back thru some old papers - kinda 
seems like back years ago when I was playing 2 meter VHF stuff with a KW big 
array and all the latest converter front ends (417a , 416B etc) somebody had 
a slick pulsed weak signal source.

 Even back then I still think I could hear more weak stuff with my HQ129x as 
an IF instead of my 75A2A as an IF rx!!!!!

 73 de Hank K7HP

>>          Which illustrates my previous point that there is
>> nothing NR does that turning BW down manually will not do
>> (and much faster).
>
> To your point, I've come to the conclusion that while you're generally
> correct, NR does add to SNR even at very narrow bandwidths.