I've been a ham for almost 50 years, but I never operated RTTY until about two weeks ago. It was an award offered by the Chinese for working their special event stations for the Beijing Olympics that was the catalyst.
I'm using a KAM connected to an FT-1000MP Mk.V and the WinWarbler program from the DX Lab Suite. I'm using 500Hz filters, and using the shift and width controls to narrow the passband from there. My 250Hz filters seem to be too narrow and I'm not sure why that is. The biggest problem I'm having is tuning in weak signals and copying through QRM. I have a couple of books on RTTY dating back to the 1960's. They talk about using TU's that can decode with only the mark or only the space signal. This seems pretty straightforward, since the mark and space together provide 100% redundancy. I haven't figured out how to do that with what I'm running, and on weaker signals I'm finding a tuning error of only 10Hz can make the difference between copy and no copy. What do I need to do better? Are there any good recent books on RTTY? I have the ARRL HF Digital Handbook, but it only covers the basics. Thanks! 73, John, K9MM