Hello John, I will comment below. 2011/1/27 John Douyere <vk2eta@xxxxxxxxx> > Hola Karel, > > There are three key design objectives in the Pskmail project that > relate to your questions: > > 1. Open source (right its no open source9 > > 2. Narrow band (less than 500 Hz). (why ?) > > 3. Solid link even in the presence of QRM/QRN (NVIS links are very stroung > little interference) > > The Winmor protocol is available as a software TNC (like Fldigi) but > unfortunately only under Windows. So that excludes for the moment > having it linked to Pskmail. (right) > > On the speed aspect there would be some work required to increase the > speed further with say 2PSK or 4 PSK (e.g. 2 or 4 PSK500 or PSK500R > modulations in parallel). That would not be that hard to do in Fldigi, > but the timing will become more critical in Pskmail as it was more > designed to accommodate very different (and some slow) digital mode > timings rather than a fixed and precise timing between client and > server. (that could be a solution. However I liked the very ffast and > efficient turn arround of Winmor) > > So probably the issue at present is more to understand the need for > faster speed as the design objectives has served us well until now I > believe. (yes that might be the case but link build up and conecting speed, > addaptive is of great advantage for a quick handling of mail. Speed is also > an issue) A mail of 1KB should be transfered and handled in a minute. > > Please note that Pskmail (at least in recent versions) will > automatically adapt it's speed depending on the conditions, from THOR8 > to PSK500 and in my personal experience has been able to establish > links several times when I could not with Winmor from my same portable > setup. (I dont have the same experience. I have no problem linking Winmor > on my links) > > Of course it could be a difference in the server's setup since they > are separated by several kilometers and don't run the same antennas, > but that is my experience.(My conexions are NVIS links up to about 1000km) > > What happens often is that the link is not symmetric, either because > the portable station is running low power and/or has compromise > antennas, or the server (which normally runs high power - say 50 watts > - and has good antennas) has local QRM. (maybe an item) > > That is why Pskmail will TX and RX in different modes and adapt each > individually to the link quality.(I understands but that takes time and > time is critical for emergency communications) > > I have several time run QRP power (FT-817) with a dipole in NVIS > conditions (which I believe represents the most common situation for > disaster conditions) and had very good downlink from the server and > poor uplink to it, but Pskmail did it's job nicely almost every time. (I > hope it can be faster and better) > > When the link is good the PSK500 modulation will provide an 800 words > per minute raw speed, and taking into account the compression of text > messages (about 2 x for text) and the overhead of the Pskmail protocol > we should see net exchanges of about 200 to 400 words per minute or > above 70Kb of data per hour. That is a lot of data exchanged I feel. (for > bigger files I would use another protocol 188-110, this is slower bulding up > the link but has much faster data troughput uo to 2Kb/s) > > In my experience also, the psk modulations (as used in Fldigi and > Wiinmor) are not the most robust due to phase shifting and selective > fading that is characteristic of that propagation mode. In that case > the fsk modes (MFSK and THOR for example) provide much lower error > rates. (Winmore is fast adaptive and uses 5Khz. bandwith or 1,6Khz. > Bandwith using multi carriers OFDM PSK) > > I have seen many times a slower but more reliable link (in MFSK for > example) providing a higher net data rate than a fast, lest reliable > link with many repeats. (Looking for a solution for a good NVIS link, not > for links wit a lot of QRM, QSB, speed should be maximum 1300b/s) > > What format do you expect your emergency network to take: NVIS or long > distance, what type of stations (fixed, high power, good antennas OR > portable low power, compromise antennas), how many stations, how many > messages, of what size, what type of message content (text or binary > data). (NVIS uo to 1500 km, 50 watts of power 100% duty cycle, a good NVIS > dipole on several frequencies. About 20 stations, 1K, max. 2KB messages. > Messages usualy are text based but could contain binary attachments (small) > > These are all factors that are important in your selection of the best > solution. > > Hope this helps. > > Regards, > > John (VK2ETA) > Please go on suggesting, I might not the only one thats looking for this solution. Greetings and thanks Karel (HC1AKP) > > > On Fri, Jan 28, 2011 at 3:03 AM, karel Fassotte > <karel.fassotte@xxxxxxxxx> wrote: > > Hello all, > > I have been investigating for some time now solutions for a emergency > > network in Ecuador I also have been testing pskmail. I think it is > allright > > but I would like to have more and faster modem waveforms included. FLDIGI > is > > a nice multiwave form software modem, but for mespeed could be faster. I > > have been testing the WINMOR TNC of Winlink. > > My results are that the WINMOR TNC is very adecuate and hast handling > > maximizing overall troughput. This is of big interest for an emergency > > network. Many small (1KB) messages should be handled. > > The RMS message terminal is also very easy to use. > > This is all closed software, only windows untill now. I am not interested > in > > windows, but I am interested in solutions for open code with maximum > > funcionality and easy use. > > Can this WINMOR TNC be integrated in pskmail? This would realy be a great > > improvement over the existing FLDIGI modem. > > Do exists other soundcard modems that have the same specs as the WINMOR > TNC? > > Please let me know. > > greetings, 73 > > Karel Fassotte > > HC1AKP > > > > > > > >