[pskmail] Re: integrating Winmor TNC
- From: John Douyere <vk2eta@xxxxxxxxx>
- To: pskmail@xxxxxxxxxxxxx
- Date: Fri, 28 Jan 2011 10:15:10 +1100
Hola Karel,
There are three key design objectives in the Pskmail project that
relate to your questions:
1. Open source
2. Narrow band (less than 500 Hz).
3. Solid link even in the presence of QRM/QRN
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.
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.
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.
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.
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.
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.
That is why Pskmail will TX and RX in different modes and adapt each
individually to the link quality.
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.
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.
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.
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.
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).
These are all factors that are important in your selection of the best solution.
Hope this helps.
Regards,
John (VK2ETA)
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
>
>
>
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