My experience indicates that Olivia 16-500 and MFSK are very solid modes for the conditions that we presently are experiencing during the current phase of the sunspot cycle.
I, like Bill, am amazed at Olivia's ability to copy signals that you can barely see on the waterfal and not even hear via audio. 30 meter propagation is sometimes not very good and Olivia really shines on this band. I have had a dozen or so QSOs with MT63 and that mode seems to give a binary result. There is a lot of FEC going on in this mode so it should work very well under poor conditions. If you can copy, the copy is excellent -- near 100%; otherwise, no copy whatsover. Not too many people seem to use this mode so I believe I need more experience before having a good appreciation of this mode under various conditions. 73, Bernie ----- Original Message ----- From: Bill McLaughlin To: digitalradio@yahoogroups.com Sent: Tuesday, February 13, 2007 11:44 PM Subject: [digitalradio] Re: Domnio, PAX etc Well can only relate my impressions; hope others chime in.... I think even though DominoEX halves the speed when FEC in engaged, it is well worth the speed trade-off. 160/80 seems to vary night to night in this regard; probably due to qrn and multipath. It also depends on one's ability/willingness to read between the lines as there are a few hits at the higher speeds and one needs to brain- error correct as there is no ARQ. As for Throb; I find it very sensitive, but at times it does not seem to decode signals that are audible....never figured out why. As for MFSK modes, yes they are very frequency sensitive although I have had little trouble tuning most, aside from a few that took a long time to sync. Multipsk's AFC seems to lock quite well on MFSK signals, not sure how other software does....certainly DominoEX is superior in that sense. I have not worked enought MT63 to comment. I have had better luck with CHIP64 although both seem to not be qrp modes and require a high signal to noise ratio... It is odd (but probably not so if studied correctly), on some nights (condx) certain modes just seem to work better under various conditions....at times I am amazed that Olivia can decode signals in the mud....other times I swear at it...one night on a VHF path only PSKAM10 or JT65B would get through; guess that what makes it all fun. 73 Bill N9DSJ --- In digitalradio@yahoogroups.com, KV9U <[EMAIL PROTECTED]> wrote: > > Hi Bill, > > Yes, busy night tonight on 160:) > > The question I wanted to ask the group was whether they have found on > the lower bands (especially 80 and 160) that DominoEX (DEX) is better > when operating at a given speed such as DEX11/without FEC or is it > better at twice the speed, but with FEC, e.g., DEX 22 with FEC? > > Tentatively, I almost want to say that it may be better at the higher > speed with FEC. If true, and I am not sure it is, it could be because > the higher speed still has a fairly low baud rate, even for some serious > multipath on the lower bands. The 77 wpm speed with DEX22/FEC is faster > than is comfortable for keyboarding so a slower speed is not bad. The > DEX11/FEC does seem quite robust, even with static crashes and who knows > how much multipath. Of course you can never get 100% copy under certain > conditions when too much of the data is damaged and the Viterbi decoder > can not reconstruct the character. Then an ARQ mode would be needed. > > I wonder how well this type of mode would work with a PSKmail type of > program? I know that I had a very difficult time reading a PSK31 signal > that was up the band from me. The earlier station that I was talking > with for our weekly sked for experimenting with these modes at a "short" > distance of about 35 miles or so indicated that he had good luck with > MT-63 in the past but the faster (wider) mode seemed to work better due > to having the data spread out so far. Has anyone else found this on the > lower bands with MT-63? > > The ability to only approximately tune in DEX signals is extremely > helpful for me as I find that I have a difficult time locking in on > MFSK16. Earlier tonight WA9HCZ and I started our experiments with ThrobX > and although he could copy me solid, I could never decode his signal. So > I must have been doing something wrong. Ideally, these modes that need > extremely accurate tuning, should have some kind of display to help you > determine if you are far from locking in to the signal or not. Something > like we had with the early PSK programs. > > 73, > > Rick, KV9U
