DIGU/DIGL offsets in 1.5 with Fldigi

  • 2
  • Question
  • Updated 3 years ago
  • (Edited)
I am really confused by these.

In the past, working digital modes, I would tune (point and click) a signal in FLDigi and that program would take care of the filtering and freq readout AIUI. I cannot understand that this new feature brings to the table. I thought that the digital program took care of all the filtering and IIRC I was once advised that narrowing the filter passband in SSDR for digital modes was not a good thing.

Do there need to be any changes made to FLDigi to work this way?

Be kind in the reply, I have not been on the air for months due to ill health. I'm just trying to keep up to speed with developments.
Photo of DrTeeth

DrTeeth

  • 1687 Posts
  • 387 Reply Likes
  • crock.

Posted 3 years ago

  • 2
Photo of DrTeeth

DrTeeth

  • 1687 Posts
  • 387 Reply Likes
A big, big thanks to Neal Campbell for answering this off the Yahoo SSDR/Flex group. He said "For fldigi-style rtty, you need to ignore the RTTY mode and stay with DIGI-U. Then everything stays the same. RTTY is using with programs that are written to look at small bandwidth of audio (I think you can operate MMTTY with a 150 hz bandpass if you desire, which fldigi uses a 3Khz window  to let you click your way around it".

I have further imposed on his goodwill by asking for a similar clarification about the digi mode offsets on p114 of the SSDR manual.
(Edited)
Photo of Alex - DH2ID

Alex - DH2ID, Elmer

  • 931 Posts
  • 172 Reply Likes
Guy, look at the postings concerning fldig and the modification you
should apply to the SmartSDR slice A/B xml files. With these mods
fldigi works fine in RTTY mode.
(Edited)
Photo of k3Tim

k3Tim

  • 849 Posts
  • 166 Reply Likes
Thanks to Bob (aka.N7ZO) for posting the updates.  I was able to add them into the XML files, figured out the "Sweet spot" (2205 ??) and worked the CQWW DX RTTY contest this weekend.  

It was wall to wall stations during certain times and bands.  With the RTTY filter set to 250, no problem.  I did have a bit of trouble with one station that was overlapped with another in their M/S frequencies.  Can't expect to copy when two stations are overlapped though.  

With the new RTTY setup it was easy to switch filter bandwidths as well as coarse tuning the frequency.  It's really interesting / amazing to watch FlDigi on the built in o'scope slowly fine tune a RTTY station and then one hits QSY and your dead on. I could mention the old days with LC filters and an Eico 753 but better forgotten.

_..--
k3Tim