> I previously mentioned in an email to the group that I was looking forward > to trying out the 200hz filter in my K3 for RTTY contesting. I had one > reply wondering if that filter was going to be too tight for RTTY. > > Any comments from the group on this. > > The other person that emailed was planning on using the 400hz filter.
I only operate RTTY with narrow filtering, all of the following simultaneously in the K3: - 250Hz crystal filter - 200Hz DSP filter - Dual-Tone Filter In the 756ProIII, I use the 250Hz RTTY DSP filter and the Twin-Peak Filter. The only roofing filter "choice" in the ProIII is the standard 15kHz, although the INRAD 4-5kHz can be added. I want the filtering as tight as I can get it so the RTTY decoders have the best chance to do their job. Stations need to be good at zero-beating, which is easy in RTTY because your decoder display is a perfect tuning indicator. Alternatively, on my side I have to ride the RIT a lot to pull in the off-frequency signals. This weekend there were a lot of stations calling off frequency, some as much as 200 Hz away. I suspect that those using AFSK with AFC were responsible for a lot of that. In other words, their receiver was zero beat with me but their "smart" encoder skewed their Mark tone away from where they were receiving. In a sense these off-frequency folks are helpful because they don't QRM the ones who are zero beat with me! Once I work the zero-beaters out of the pile-up, then I can grab the others with the RIT ... if they're still there. 73, Ed - P49X (W0YK) _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
