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ThumbDV still doesn't seem "ready for prime time"???

Roy LauferRoy Laufer Member ✭✭
edited June 2020 in SmartSDR for Windows
I have been toying with a pair of UHF/VHF antennas newly installed - one connected to my Flex 6700, the other connected to my Icom IC-7100. I happened upon a local D-Star Repeater and tuned both radios into it.

The ThumbDV installed Flex has a lot of drop out, while the IC-7100 does not. If anything the Flex has the better UHF/VHF antenna and I turned the Flex off, unplugged the power and removed the ThumbDV dongle and then started it all up again, with no change in the tendency to drop out audio.

Either Flex or the ThumbDV dongle does not appear as "robust" in decoding the D-Star voice stream as my IC-7100???

Has anyone noticed this?

Are there any plans to tighten up this weak spot at some time down the road???

Open for Comments · Last Updated


  • Lee MaiselLee Maisel Member
    edited March 2016
    Yeah, tell me about it.   I was very disappointed with the performance of the ThumbDV , it's been rare that I could decode anything with it.   I thought it was just me.
    As for the FLEX itself, I am extremely impressed, and really enjoy the radio!   but they need to either work on the "waveform" or the thumbdv, my bets are on the D-star "waveform" plugin, especially since I have no problems with FreeDV on the same radio.

  • Lee MaiselLee Maisel Member
    edited March 2016
    JUst to clarify:   I believe it is not the radio, nor the ThumbDV, but the D-star "waveform" plugin that needs some work.

  • Roy LauferRoy Laufer Member ✭✭
    edited May 2017
    Fine! I was unsure "who dropped the ball", but I would just really like to know if anyone in charge is aware that there is a problem and plan to address it in the future.

    Don't get me wrong. I love my Flex 6700 and I will possibly need to have it pried away from my dead hands when I shuffle off this mortal coil. I proselytize the virtues of SDR's in general and the Flex 6000 series in particular (and wear my Flex baseball cap proudly). I could never go back to "legacy radios" and find nostalgic QSOs from guys wedded to their 1950's radios (apparently when they went through puberty) more and more tedious.

    I just want my 6700 to be the best that it possibly can be!
  • Cal  N3CALCal N3CAL Member ✭✭
    edited March 2017

    +1 for the DSTAR Waveform Plug-in!  I have used the ThumbDV with my Flex 6500/XV-144 transverter on VHF(Also my Flex 6300 before trade-up) Besides our local DSTAR repeater, I also have a DSTAR GMSK node.  It has been a waist of time and money for me.  I'm not happy with the Flex's current performance at all.   I'd much rater use a IC-7100, 5100, or 51A, they decode fine but the Flex is very poor with too many lost/dropped packets to make it enjoyable to use. 



  • Lee MaiselLee Maisel Member
    edited May 2020
    Yeah, can we get someone to look into the D-star Waveform plugin?  Possibly add in some user-selectable optimization settings?   I'm convinced the Radio and dongle are not the problem, but the plugin needs some work.
  • Tim - W4TMETim - W4TME Administrator, FlexRadio Employee admin
    edited December 2016
    The DStart applet is an open source application, so anyone can take it and make improvements.
  • Lee MaiselLee Maisel Member
    edited March 2016
    That would be great if I was a developer, but I purchased the hardware expecting it to work, but as I said, I'm certain it's a software issue.

    I'm VERY happy with my Flex-6500 and SmartSDR, but the D-star plugin definitely needs work.
  • KF4HRKF4HR Member ✭✭
    edited February 2017
    I question the need for the ThumbDV.   In many cases VoIP connection works thru DStar linked repeaters considerably better than a DStar RF signal.  Since odds are you're using your ThumbDV in your shack environment, why not just use DV Dongle, or DVAP and DStar HT instead?  Or am I missing something?
  • Tim - W4TMETim - W4TME Administrator, FlexRadio Employee admin
    edited June 2020
    I have entered this report into our bug tracker as defect #3339 for further investigation.  Please report any additional information related to this specific issue in this community topic.  Thank you for the defect report.
  • Roy LauferRoy Laufer Member ✭✭
    edited March 2016
    Thanks Tim! I appreciate it.

    I was concerned that the 'Waveform Plugins" might become the proverbial 'red headed step child' of FRS. It is a very powerful feature that could be implemented much more productively than as it presently has been demonstrated.
  • k3Timk3Tim Member ✭✭
    edited December 2016
    Hey Tim Okay - I'll take the bait.... The D-Star API is described in this document: https://www.flexradio.com/downloads/smartsdr-waveform-api-pdf/ but there seems no way to download said document. I 've checked around for the open source code but do not see it . Can you kindly provide a link? One installs D-Star and the file: ThumbDV.cfg is interesting (from a hacking standpoint). It appears one could make simple adjustments to: waveform set ThumbDV rx_filter high_cut=3500 waveform set ThumbDV rx_filter depth=2 waveform set ThumbDV tx_filter high_cut=4800 waveform set ThumbDV tx_filter depth=2 and change the performance. Is this assumption correct? Is there any doc on writing a custom waveform? For example can one write a 64-QAM modem strictly from the Waveform interface or is the radio internals also requiring updates, such as the FOGA VHDL code? Thanks and Regards, Tim
  • Tim - W4TMETim - W4TME Administrator, FlexRadio Employee admin
    edited December 2016
    You just click the green download button to download the docs.  It is isn't working, I presume it is a client (bowser) side issue, as it just worked for me using Firefox and Chrome.

    The info on waveforms is located on the FlexADP web page:

  • Phil M0VSEPhil M0VSE Member ✭✭
    edited September 2016
    If it was just about being 'better' then wouldn't we all give-up this radio stuff and use Skype instead? ;)
  • Lee MaiselLee Maisel Member
    edited April 2016
    I don't know..   I think the plugins are a fine way of doing it, rather than having more complexity and options that most people will not use built into the program.

    However, it seems this particular plugin needs some work yet...

  • Lee MaiselLee Maisel Member
    edited March 2016
    Yeah there is no green button for the API document.  It's not a browser issue in my case. as I can download everything else on flex's site.   Something is wrong with the code on THAT page.

    OK   so the GREEN Button is MISSING, but if you click where it SHOULD be, you get the download.
  • Michael CosloMichael Coslo Member
    edited May 2016
    As a question, what is the D-Star bandwidth?  I've heard both that it is narrower than SSB (which I doubt) and that it is 6.25 KHz  between upper and lower -26 db points.
  • Ken - NM9PKen - NM9P Member ✭✭
    edited December 2016
    You might be confusing D-Star with FreeDV. FDV runs about 1.4 - 1.6 kHz wide. D-Star is much wider.

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