[pskmail] Re: R: Re: Modes, comparison and usage

  • From: John Douyere <vk2eta@xxxxxxxxx>
  • To: pskmail@xxxxxxxxxxxxx
  • Date: Thu, 28 Jan 2010 00:31:13 +1100

Hi Per,

Replies below for context:

On Wed, Jan 27, 2010 at 7:32 PM, Pär Crusefalk <per@xxxxxxxxxxxx> wrote:
> Thanks John,
> Yes, I noted it but just as you mention it contradicts my experience of
> the mode. When map and reality do not match I was taught to not trust
> the map. It could be correct but I think we need more work done to be
> sure about this.
> I am somewhat preparing for this winters skiing excursions and I intend
> to compare modes then. I'll be somewhat further north and I was thinking
> abt adding a way to just note beacon success rate in the client. That
> way it could be "sounding" the channel all day and I could change modes
> every day to compare and create nice & shiny graphs.
> Perhaps we can find a way to merge all our test results too?
I will also do some more formal NVIS tests when I go away which is not
before a few weeks unfortunately.

> I will add THOR 8. I just figured it was too slow so didn't. Regarding
> the upper and lower case I tried to find some data on that but could not
> find any. The best page I could find about the mode is here:
> http://www.w1hkj.com/FldigiHelp/Modes/THORdesc.htm
> Perhaps you know where I can find out more?

Thanks. I don't know of a previous analysis of the speed comparison
but I can use the same logic as on Dave's web site for speed
calculations: count the number of bits including stop markers for the
word "paris+space" in lower case and upper case. I will do that
tomorrow and send you the comparison.

> Yes, MFSK should be there too. Is MFSK16 and 32 all I need to add?
> I have little experience there, I think I have only abt 10 QSO's and
> then only using MFSK16. MFSK64 should perhaps be left out due to the
> bandwidth needed, then again it could be useful on higher frequencies?

Yes MFSK16 and 32 are IMHO the main ones. I haven't tried others apart
from MFSK64 but unfortunately it does not have an RSID allocated as
far as I know and therefore is not usable right now. Otherwise a very
good and fast mode when bandwidth and s/n is not an issue.

> Another mode that "everyone", including K2MO, seems to get good results
> with is Olivia. Of course there are some obvious problems with it but
> perhaps we could overcome them?
> - 7-bit alphabet (should be ok)
> - Excessive latency (we already adjust that for modes used now)
> - At least a million different submodes, perhaps we could use 16-500?
> Unfortunately I have very little user experience...

Me too. I can't really comment there. I remember giving up on this
mode early in the piece for PSKmail application but I can't remember
the exact reason.

> Perhaps we should have a mode comparison table on the wiki so that we
> can all update it and link to our test results?

Not a bad idea at all as mode selection is very much dependant on the
situation and not only the propagation (number and distance of
servers, QRN/QRM etc...).

> 73 de Per, sm0rwo


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