Adrian, Thank you for the information. It is a good reference and is my source of information when I experiment with digital modes in Fldigi. Are you active in PSKmail? Best regards, John (VK2ETA) On Fri, Aug 28, 2009 at 8:10 AM, Adrian Engele <aa5uk@xxxxxxxxx> wrote: > Hi John, > > Just reading all the PSKMail BB messages and just saw yours. Interesting > analysis for sure. > > I was wondering if you had seen the following analysis of the various modes > on the flidigi site: http://www.w1hkj.com/FldigiHelp/Modes/index.htm > > Just thought I would pass it along in case you haven't. > > 73, > > Adrian > AA5UK > Chicago, IL > > > > ------------------------------ > *From:* John Douyere <vk2eta@xxxxxxxxx> > *To:* pskmail@xxxxxxxxxxxxx > *Sent:* Thursday, August 27, 2009 4:57:57 PM > *Subject:* [pskmail] Re: pskmail on other mode > > Hi Greg, > > Here in VK we have long distances and not many people in between, so mobile > coverage is quickly fading off when we get away from the cities. > > So I have done a number of experiments in HF NVIS and VHF and although it > is not "PSKmail" per say it works quite well with other modes (some better > than others). > > Here is a summary of my experience: > > - in VHF and UHF I did some comparisons between SSB and FM. Although FM > needs a higher signal to noise ratio than SSB to work for voice, some > digital modes give almost the same performance in SSB and FM: I have tried > successfully THOR, MFSK but not DominoEX for a strange reason. > > One issue with SSB on VHF and worse in UHF is that for staying within the > acquisition range of the server (typically 20 to 40Hz), the accuracy of the > VFO would need to be much higher than what is available currently. My FT857 > and 817 give at best +/-1PPM but at 145MHZ I would need 0.27PPM of > stability. > > So most modes like PSK, and the slow MFSK ones are difficult to tune using > SSB at VHF as it is easy to be 100 or 150Hz out despite having the right > dial frequency. > > This is where FM wins, because tuning is not so important. So what you > loose in sensitivity (a little only with the right modes), you gain in ease > of tuning. The only modes I had success with on VHF/SSB was THOR because of > it's tolerance to mis-tuning. > > Using FM, I could barely hear the signal in the noise (no squelch), but the > decoding was good. In only one case did THOR perform better on SSB than on > FM. > > - In HF, as Rein (or Per I am not sure) has confirmed by tests, some other > modes are much more sensitive than PSK250 or 125. They also survive much > better the multipath distorsion of NVIS and lightning strikes noise in the > low frequencies (typically 80 and 40M). > > My best experiences have been using MFSK and THOR. I had poor results with > DominoEX which is strange since it is a close cousin of THOR. I also had > poor results with the MT modes because I believe of the interaction between > fldigi and PSKMail (the control characters are not consistently passed > through in my experience). > > I haven't tried Olivia much but it should work also. > > So my best vote so far based on my experience: THOR8 for robustness (but it > is slow), otherwise THOR22 is a good compromise. For speed MFSK64 is really > good but 1K bandwidth, and MFSK16 or 22 a good compromise between robustness > and bandwidth. > > In my experience in marginal conditions THOR22 and MFSK32 will beat PSK > hands down. You can try one of these two with the current settings in the > servers. > > Note that if you want to use the slower modes like THOR8 or MFSK16 some > adjustments to the timings of the server are necessary. In fact I have > compiled a series of small changes that are required for the server to > accept these slow modes. > > I can now successfully have a position report or a connected session with > THOR8. I get a very very robust link. I can send you the code if you want to > experiment. > > Sorry for the long response, but I find that subject interesting. > > Hope this helps, > > Regards, > > John (VK2ETA) > > > On Fri, Aug 28, 2009 at 5:11 AM, Greg <kb1ncj@xxxxxxxxx> wrote: > >> Would pskmail function on MT63 2k on vhf, uhf? It wouldn't be "psk"mail, >> but was wanting to experiment... -Greg >> >> > > start: 0000-00-00 end: 0000-00-00 >