[pskmail] Re: Need PSKMail for Disaster Relief Operations

  • From: karel fassotte <karel.fassotte@xxxxxxxxx>
  • To: pskmail@xxxxxxxxxxxxx
  • Date: Thu, 03 May 2007 07:01:57 -0500

Hi Per,
I cannot comment on your remarks about the auto baud support. I have been experimenting with the bandwidth of transceivers and the results are that the icom 706 will pass the signal of the 188-110a of the RFSM2400 software. Not the modified, but the milstd. I could pass 3Kbs on a 1 hop link, definitely very fast this mode. And as I noted the mode is persistent also under interference conditions. It will try to reduce baudrate and doe not give up easily. If jamming occurs on the center frequency at the moment of the pilot tone the communication is vulnerable.

I also tried ODFM modes like DRM and found it very efficient. Problem I found is that it did not synchronize quickly. It needs a second or 2 to do that. Bandwidth that can be transferred are even higher than 5Kbs. The DRM software is open source and it would be great to have this mode available too in PSKmail.

I would like to have faster modes present for the PSKmail because I would like to have the PSKmail as adaptive as possible. It would be great to have it pass the data at 2Kbs, would it not? This makes it much more useful also for non text elements of messages as are foto´s etc.

I know that for many of you text messages are sufficient, but it would be a marvel if we can make work faster modes.
73 Karel, hc1akp

At 02:07 a.m. 03/05/2007, you wrote:
Hi Karel,

Thanks very much for the attached file.
I discussed this with Charles a few years back and was ready to support
his efforts then. Unfortunately he was busy, understandably so, with his
commercial efforts and didn't have the time needed to continue improving
the software. STANAG 4285 is the NATO version of the mil-std and
naturally they couldn't use the standard but had to make changes, hi hi.
Its basically the same mode but the stanag lacks autobaud support
(receiver modem adjusts speed and interleaver to suit incoming traffic).
Speed can be set from 75 to 2400 bps and 2400 bps really does work.
Yes, there is 3600 bps as well but don't bother (perhaps for VHF ?).

A tiny problem with this mode is the bandwidth required, its made for
commercial rigs so it wants a rig that handles 300 - 3300 Hz.
They made STANAG 4529 go at half speed to reduce its bandwidth (1240 Hz)
so for ham use perhaps speed should be only slightly reduced (to keep
bandwith restricted as in RFSM).

I would very much like to have this mode available. One thing that
worries me a bit is the lack of license information in that archive.
Did Charles release this as GPL or how should this code be treated?

If he did release it as GPL then I would sure like to get it working.

Dave: I'll send the archive to you. Would you be interested in having
STANAG 4285 in fldigi ?

73 de Per, sm0rwo

ons 2007-05-02 klockan 17:19 -0500 skrev karel Fassotte:
> Hi Per, well, we will do some more work on it and will comment on it.
> You write shure it will do a great job for you.
> It shuold not anly do a great job or me, but I think we are not fixec
> to s certain protocol or standard is it?
> I have another linux modem that does the milst.188-110a
> I has been writen by Charles Brian. do you want te have it.
> I can send it by mail, see attachment. Its sourcecode and not completly ready.
> Maybe we can interest other people to look at it and do the job to
> integrate it in the PSKmail.
> Don´t you think it woudl be worth while look at the OFDM aproach lile
> DRM to see if it can be fixed into the PSKmail?
> Having several speed optiones, that might be selected on demand would
> be great I guess also for emergency communications.
> 73 karel hc1akp
> 2007/5/2, Per Crusefalk <per@xxxxxxxxxxxx>:
> > Hi,
> >
> > I didn't have much time to fiddle with rfsm. It worked at times under
> > wine but mostly I had sound out but not in. When I did get it to work it
> > would soon crash so I couldn't get it stable enough. You can probably
> > get it to work fine if you use two soundcards. Sure, MIL-STD-188-110A
> > should do a great job for you.
> >
> > 73 de per
> >
> >
> >
> >

Other related posts: