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Unable to get solid PSK-31 decodes

Michael Hatcher
edited April 2020 in SmartSDR for Windows

I am a fairly recent addition to the Flex 6000 community as I have only had my 6300 for about a month.  I am currently working mostly all digital modes as my location doesn’t allow too much else right now, and when I first received the Flex, I got GREAT copy of most PSK 31 signals with a  40M TAKTENNA up about 15 feet when conditions were good.  However about a week on and off of using it I noticed that the copy didn’t seem as good as it was before, but I didn’t always have a lot of time to play with settings, so I just chalked it up to conditions.  But the more I played with it, I have determined that there is something wrong, as I have just added a STEPPIR SmallIR vertical antenna and the copy is still less than 50% good when the signals look to be near perfect on the waterfall on the Smart SDR and HRD 780.  I have researched everything that I can about possibilities, and the one what seemed to be the biggest deal several months ago was people running older computers with Windows XP and having similar problems.  I have a very new, very fast system with AMD 6 Core 3.54 GHz, 16 Gig RAM, Radeon HD 6570 1 Gigabyte PCI-Express 2.1 Video Card, a 256 Gig SSD drive, 100 MHZ Cisco switch direct connection to the Flex running Windows 8.1.  So I don’t think the problems experienced by other because of slow computers or old operating systems, and the fact that it did work just fine before a much better antenna system leads me to think it is software or settings.  I am running the latest version of SmartSDR firmware, and when I upgraded to it from 1.4, I really didn’t use the Flex for a few days and can’t remember if I noticed the problem with the decoding before the upgrade or after. 

Here is what I have done to try to improve the decoding in DM780.  I uninstalled SmartSDR and all of the components, CAT, DAX, and Mini Deluxe.  Rebooted and reinstalled everything, still not change in decoding status.  

Some items that I am sure someone will ask about or comment about….

I have used the setup guide to getting my SmartSDR, DAX, CAT and DM780 setting correct, as decoding did work great in the beginning.

In the SmartSDR, I have the Digital profile selected, which give me DIGU, and 3K, AGC-T Off.  I have played with all the sliders and settings, and nothing seemed to help so if someone has a “Best Settings” idea, I am open to this.

In DM780, I have my squelch all the way to the left and the receive signals are full scale most times on the receive bar in DM780 on the PSK-31 signal that I am attempting to Decode.  My Dax receive settings are adjusted so that they are 90-95% scale and when I am transmitting my TX DAX setting are 90-95% scale as to produce a good signal.   When I transmit and call CQ time after time, I never get an answer, and if I respond to someone elses CQ, I always get a QRZ reply and even after replying multiple times with my Call sign they are not able to receive me successfully.  The CPU process at the bottom of the screen in DM780 reports about 2% use.

I have mostly conducted testing on 20 and 15 Meters.  On the SteppIR I have VSWR of 2.1 or lower on these two bands, and with the Flex ATU it goes down to around 1.2, and I transmit 40W out. 

The receive signals that I see on the SmartSDR and DM780 waterfall are strong signals, but there is only about 50% decode when I select these strong signals.

I have installed and tried FLDIGI and did not receive much better decode on PSK-31 signals using that software, so I am pretty confident it is in the Flex settings or something, even though there aren’t many.  I am sure it is something that I changed in playing with all the options that has made this change, I just need to know what it is to undo it.  I have tried everything that I can to get the great decode that I know the Flex is capable of, but am missing something.

In getting the station set up like I ultimately want, I have continued to add items and interconnectivity between other programs so let me give you the full setup of the station currently in case one of these other pieces might have something to do with this problem.

Currently running SmartSDR 1.4.3, DDUtil v3, (3) physical Serial ports in my computer (2) via a PCI card (Com 6 and COM 7), and (1) via a USB Serial port adapter (COM 3) that is connected to a GPS receiver that feeds GPS and time data into BktTimeSynch that keeps my computer time synched with GPS every 1 minute.  DDUtil v.3 is controlling HRD and is monitoring physical port COM 6 for the SteppIR SDA controller for band following when I change frequencies in DM 780.  I am running the latest version of HRD 6.29.355, Windows 8.1, dual monitors, dual Ethernet connections, 1 direct connection to internet provider (239.X.X.X address), and a separate direct connection to a Cisco Switch to the Flex 6300 (169.X.X.X) address.

Ok, today I formatted my SSD and reloaded Windows 8.1, SmartSDR 1.4.3, Ham Radio Deluxe and everything else and got everything somewhat talking to each other even though I cant get DDUtil to work with HRD. I can bring HRD up with Ham Radio Deluxe program to at least use it with DM780 to verify if I still am having problems.  And yes, even though the conditions are GREAT this evening and there are TONS of signals on 20M right now, I can’t get solid decodes on most signals.  Some will be pretty good, then next transmission, they will be unreadable with the decoding.  This is very frustrating.

I know this was long, but I wanted to cover everything so that maybe something sticks out to someone and I can get this resolved sooner rather than later.


  • Andrew O'Brien
    Andrew O'Brien Member ✭✭
    edited April 2015
    Just for the heck of it, can you try with Fldigi instead of DM780 ? Also, how about decoding of RTTY or other modes when you use DM780 ?
    Andy K3UK
  • Michael Hatcher
    edited April 2020
    Sorry, I didnt put that part in, but I did try Fldigi and Digipan, with the same result, no solid decode.  I didnt try any other modes with DM780 other than the PSK-31, PSK-63 and a couple PSK-128 ones.  It is harder to run across the other modes.
  • Andrew O'Brien
    Andrew O'Brien Member ✭✭
    edited April 2015
    Hmm, and I assume you tried different bands and ruled out weird things like aurora?  I have had similar "ppor decode" with my Flex 3000 and PowerSDR but it goes away after a PowerSDR reboot.  I think in my case VAC falls asleep.  I wonder if DAX has an issue.
  • Bill-W9OL
    Bill-W9OL Member
    edited October 2016
    last week was a disaster, that solar event knocked out signals for me
    only the absolute strongest locals got through, and I have a lot of antennas.

    Rarely does uninstalling-reinstalling work, And before tinkering, do a 'Restore Point' so if you tinker it worse, you can get back to where you were.

    BTW: it wasn't till last night and this am that I see signals strength back to normal.
  • Michael Hatcher
    edited April 2020
    Yes, signals today were great, but still no decode.  Well I didn't mention that I am in Afghanistan so I don't have the great signals all the time that most other people do, but I do know with the signals today not decoding, I know I have a real problem.  I just hope that someone has a solution that I haven't tried.
    Yes, I was really hoping that the reload would work, Then I was going to create a restore point.

  • George KF2T
    George KF2T Member ✭✭✭
    edited February 2019
    Hi Mike,

    I have noticed the same thing sometimes. Seems to run down to stability in the sound card - can you do the FL-Digi "WWV" calibration (using the "floating scope") and see how your clock is doing?

    When the system clock is tamed, the decodes get way better.

    Would be happy to listen for you sometime to see how things sound, but being a "little pistol" of a station (more like "squirt gun" it might be tricky.

    Welcome to the Community!

  • DH2ID
    DH2ID Dr.med. Member ✭✭✭
    edited March 2017
    Mike, my settings for PSK31 are a 3.9kHz wide DAX, TX gain 58, RX gain 55. AGC-T off, set to 50, increase if low noise.



    I have never had problems decoding PSK, only RTTY. If I set bandwidth to
    1kHz or less RTTY decodes fine...

    I hope you can fix your problems.

    73, Alex DH2ID
  • Michael Hatcher
    edited April 2020

    Thank you everyone for all of your great suggestions, I have figured it out.  It is sometimes the simplest things, but hardest to find when you are making many changes to or setting up a station.  I had read about the loud fan on the 6300 when it engaged to cool itself down and had also read how some people had installed the Laptop coolers under them to keep them cool.  So I installed one a couple weeks back when conditions were bad.  I guess that was the cause of all of my decode problems, as I unplugged it from the USB port on the Flex, and now I am getting GREAT decoding.  It makes sense to me now, but it sure didn't occur to me for all these days I have been troubleshooting.  I guess I will have to find another laptop cooler that doesn't interfere with it to keep it cool as I heard several people are using them and I guess are not having digital problems.

    I love my Flex and will be getting in my ACOM 1010 in the next week, so I look forward to trying some RTTY  with it.

    Thanks again and I will see you and hear you on the bands,



    T6MH in Afghanistan

    NC4MH in the states

  • Ross - K9COX
    Ross - K9COX Member ✭✭
    edited April 2015
    Curious if you would get the same results using the USB port on the PC for power.
  • Michael Hatcher
    edited April 2015


    That is a great point.  I will have to go out tomorrow and buy a USB extender cable, as the computer is not close to the radio.  I will try it and see if I get the same result or something different.  Good suggestion.  I will post my results.

  • Ken Davis
    Ken Davis Member ✭✭
    edited December 2016
    I am not the sharpest knife in the drawer so why does unplugging the laptop cooling pad improve decoding? 
  • Michael Hatcher
    edited April 2015


    That is a really good question.  I tried it again just a few mins ago, I clicked on a strong signal and was decoding it 100% and then plugged the USB Laptop Cooler back into the Top USB port on the 6300, and as soon as I did the decoding percentage went way down.  I unplugged the USB and the decoding resumed.  I am going to try a USB extender today to see if I can power it from the computer instead of the Flex and see if it makes a difference.  I guess it could be interference from the USB power, or maybe the two fans in the cooler spinning under the Flex.  I don't see anything obvious on the waterfall, but I didn't do a whole spectrum scan either.  I will watch that closer when I try my test later today. 

  • DH2ID
    DH2ID Dr.med. Member ✭✭✭
    edited December 2016
    Look up your USB devices and see how much current the cooler draws,
    and power it up with an external power supply, would be my solution.
    I haven't got a 6300, but my 6500 stays cool even when transmitting
    RTTY for long periods on full power.
  • KY6LA_Howard
    KY6LA_Howard La Jolla, CA. Paris and Sablet FranceMember ✭✭✭
    edited January 2017

    Tim - W4TME, Customer Experience Manager

    • 2658 Posts
    • 722 Reply Likes
    Official Response

    As per the SmartSDR Release Notes, we do not recommend plugging anything into the USB connectors on the radio. it may work, but if you experience strange behavior, please un-plug all USB devices from the radio.

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