[RTTY] RTTY spectrum analysis article

[pcooper]

Hi all,

I must have missed the original posting about this subject, but just wanted to the thoughts from Bill W6WRT with respect to the new Icom rigs.

Bill wrote:
"Interesting. For years I used 250 Hz filtering in my IC-765Pro3, so
when I got my new IC-7600 I set it the same way. The reception seemed
pretty poor, so on a hunch I widened it out to 300 Hz and things
returned to normal. Not sure whether the actual bandwidth was
different or if the skirts on the '7600 were too steep. Anyway, 300
works fine."

I purchased a new IC7800 in 2011 to replace the trusty old IC756Pro.
On getting it, I set everything in the 7800 as I had it in the Pro. 
The tight filter (for contesting) was set to 250Hz, which worked very well for me. I also had a 450Hz filter for when I was in S&P mode.

However, my first session with the 7800 on RTTY turned out to be less than I expected.
I was having problems decoding even strong RTTY signals, so I played around with the filter settings, and found that I had to use a 400Hz filter as the tightest setting, with the next one being 600Hz for S&P.

I also had to set the roofing filter to 15kHz, as the 6kHz and 3kHz filters were just too limiting.

Maybe the DSP side of things has changed more than I expected in the Icom rigs of late!

73 de Phil GU0SUP