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[WD4SIX]

Although I have been a ham for many years I am just now getting interested in digital Ham radio.  I am running Linux Mint as my OS.  I have a SDRPlay that I have been using with CubicSDR.  I have gotten familiar enough with it to copy CW and SSB signals.  I also have FLDigi installed and have been successful in getting the audio from CubicSDR to the waterfall on FLDigi.  I can clearly see the signals.  I spent quite a while yesterday trying to get FLDigi to decode the signals.  I thought it would be easiest to decode CW since I can copy it in my head and compare to what FLDigi shows.  I found a couple of strong clear CW signals that were fairly high speed.  Like about 20 WPM or higher.  But I was not able to get any of them to give me a good copy on FLDigi.  I then found a slow speed CW signal that was pretty weak.  I could barely copy it by ear.  But it copied almost error free on FLDigi.  It was probably about 10 to 13 WPM.

So I think I probably have some settings I need to change on FLDigi but I have no idea what they might be.  I have looked at the FLDigi manual but really didn't find any info there I thought would help.  Obviously I am getting signals to FLDigi but  don't know if I need to change some volume settings or what.  I did try changing the dynamic range on FLDigi but that didn't seem to make any difference. Does anyone have any suggestions?

Thanks for any help you can give,
Carroll (WDSIX)

[W1VT]

Hi Carroll,
I think the issue is that a lot of old timers, the ones with better signals, send by hand using a keyer and paddle. This is usually OK for decoding by ear, but not by computer.  I know that my conversational sending isn't as good as before I had a stroke, but I haven't switched to a keyboard for rag chews.  Instead, I operate contests using a keyboard and work DX sending by hand.  I've worked over 300 countries sending by hand.  I was able to work JX2US on 80 CW with one call!

Zak W1VT

[KE6SLS]

Hi Carroll,

I too am an old timer and cw fan.  FLDigi doesn't really sport the best in CW decoding.  But I will share some basics all users need to know to use FLDigi, or any software for that matter.

Your radio, the SDR in this case, should be put into upper side band for all digimodes on all bands.

Don't swamp the receive with audio.  Black is silent, then as you increase the audio level, you will start to see specks appear.  Keep adding audio until you can see the signals of interest turn a white/yellow color on the waterfall screen.  You don't want to see yellow everywhere on the waterfall. 

That will help you a little in decoding the cw.  Now if you want to try testing some of the cw decoder options, simply take your mouse down to the bottom left of the fldigi screen, hover mouse over mode (cw in this case) and right click.  That brings up the MODEM config for CW.  Note the current settings (so you can return to default settings) then test the options and see if it helps decode the higher speed cw.

Other poster already made it clear, lots of ops muddle their fists pretty badly, even on low speed code and it does make it tougher for machines to understand it.

Now, if you want to enjoy some of the many modes FLDigi offers, go to the very top right of the screen and turn on the RxID.  Neet little trick there since it will decode and change into the mode automatically if the sending station sends a TxID.

Fun modes are PSK31.  If you enjoy cw and regchewing, this is a great, super narrow mode that does really good even in fair/poor conditions.  It's one of the first of the digimodes to use the sound card of modern computers without need of expensive hardware (like old time phone modems etc).  I've enjoyed it since I learned of the modes introduction in QST.  I enjoy the chatting, not really into collecting numbers of qso etc.

I'm assuming you will, at some point, connect the computer to your transceiver and start making some QSO's.  Great.   

Make SURE you turn on your radio's ALC meter.  When transmitting on digital, we just want to see the meter just twitch and NO MORE.  Adding more gain will increase the likelyhood of major splatter and a signal that is hard or impossible to copy.  You will not make friends like this.  This is critical for all digital modes and digital software.

MFSK32 is the goto mode for ops enjoying digital nets and building digital skills.  It has great FORWARD ERROR CORRECTION so perfect for 100% copy of messages and traffic handling.

Olivia 4-250, 8-250, 4-500 & 8-500 are also very popular for DX ragchews when conditions are very tough.  It is S L O W but usually provides 100% copy and easy for folks who won't learn to type to use.  Hopefully operators are sending the Txid since it is very hard to hear the difference in this modes.  Sending the Txid and the listener using the RxID, the mode is transmitted and the receiving stations mode will auto change into the sending stations mode. 

FLDigi by the way, is the main component in the FLSuite of tools.  There is FLMsg, FLAmp that our nets use extensively for moving/relaying messages and traffic.  It IS the Swiss Army Knife of digital message handling and runs on every operating system (Linux where it was created, M$ Windows, Apple, BSD's, etc)

I love the digital modes as much as CW.  It's led me to Qsstv for copying the cool images on 14.230 Slow Scan TV. 

FLDigi and other digital software simply add more ways to enjoy our amazing radio service.

Hope you enjoy the experiences!

73
Jaye

[K6SDW]

KE0OG, the ARRL/QST's new technical editor, just put out an excellent YouTube video on this very subject and, IMO, answers why computers are not good or will ever be perfect at decoding CW....this is a place where the human brain is superior to the machine.

I'll add that I too use FLdigi to decode CW and it does a decent job of that.....

GL/73

[WD4SIX]

Thanks to everyone for your suggestions.  Following some of the advice I have been able to decode several CW signals now.  I have been looking at the suggested site for how to identify the other digital signals.  I think that is going to take some practice.  I do have one question.  Can FLdigi be used to decode FT-4 and FT-8 signals?   I didn't see that as one of the choices in the operating mode menu.  Am I looking in the wrong place?  Or does that take a different program?

Thanks again for the help.
Carroll   WD4SIX

[W1VT]

I use WSJT-X to decode FT8 and FT4 signals.  I've not heard that FLdigi can do that.

[K0UA]

I use WSJT-X to decode FT8 and FT4 signals.  I've not heard that FLdigi can do that.

FLdigi cannot.

[WD4SIX]

Thanks again for the suggestions.  I installed WSJT-X and had no trouble at all decoding a bunch of signals on 20 meters.  Now I just need to get busy and learn how to connect my rig and make proper calls. I have some other things I need to do first so that may be a little while.  But just seeing how many countries all around the world are on FT8 is amazing.

Thanks again,
Carroll  WD4SIX