[pskmail] Re: new fldigi with jpskmail

  • From: Pär Crusefalk <per@xxxxxxxxxxxx>
  • To: pskmail@xxxxxxxxxxxxx
  • Date: Mon, 25 Jan 2010 06:38:16 +0100

sön 2010-01-24 klockan 19:57 -0500 skrev Greg:
> I have installed newest jpskmail and fldigi on win xp also on ubuntu. I 
> notice waterfall set at 1500 mark. Not hearing any beacons after a few 
> days trying, maybe wrong time of day but today noticed activity at the 
> 1000 mark. I forced it down and it was a position report on psk250. I 
> wonder if that station was tuned to something besides 10.147 dial or if 
> the new fldigi is locked in the wrong position. Thanks for the help in 
> advance... -Greg

Hi Greg,

Great that you managed to hear something!
I will paste a part from the manual I am working on, its regarding
frequency management/assigned frequency. I hope it explains what is
going on.

73 de Per, sm0rwo

Assigned frequency

PSKmail is based upon the use of narrow band modes, at the start PSK63.
Finding a server is not like finding someone when working PSK31. Servers
use very narrow filters and clients have to transmit just where the
server is listening, if they dont match the servers assigned frequency
then it will not work.

We cannot assume that all radios will want to use the same base
frequency in fldigi. For instamce my ICOM IC-706MK2G is used with a 900
Hz tone, that way I can crank the BFO to 900 Hz and listen in cw. That
makes it possible to use the 500 Hz cw filter in the rig and that makes
a huge difference with regards to signal/noise ratio. I like to use 1500
or 1000 Hz with my Yaesus (passband middle). Others like to use a higher
tone as they can do other tricks to employ filters.

It then follows that we cannot say that you should set 10147 on your
dial, if I'm using 900 Hz on my server and I use USB then I will
actually listen at 10147,9. My Yaesu 817&897 with 10147 on the dial will
actually listen at 10147 kHz + 1500 Hz = 10148,5 kHz. That setup will
never work.

This is why all frequency listings use the actual frequency being used,
the assigned frequency.

For instance, my server is listed at 10147 kHz on 30 meters. When
transmitting I have 10146,1 and USB on the dial, this is due to that 900
Hz tone I mentioned earlier. So, 10146,1 + 0,9 = 10147 kHz.

Using a commercial rig I sometimes use I set the dial to 10145,5 and
USB, fldigi is then centered around 1500 Hz. 10145,5 + 1,5 = 10147. 

So, assigned frequency (the acual frequency) is dial frequency + fldigi
tone (using USB). I'm not mentioning LSB as we should not use that here,
some digital modes, such as THOR, do not work when we mix modes (as that
reverses it).

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