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HF DStar reception skills ?

Andrew O'Brien
Andrew O'Brien Member ✭✭
edited October 2018 in Third-Party Software
Anyone worked out settings for maximizing the likelihood of successful reception of an HF D-star signal using the ThumbDV with a Flex signature series radio? As with FreeDV, D-Star seems to take quite a signal to actually decode.  S3 to S5 signals don't seem to make it.  I'm wondering if there are tweaks I can implement to improve my chances.
Andy K3UK


  • Michael Coslo
    Michael Coslo Member ✭✭
    edited November 2016
    A digital signal must be very good to decode it. And an S3 signal probably has too much noise in it. That's an educated guess based on the cliff effect.
  • KF4HR
    KF4HR Member ✭✭
    edited February 2017
    Has anyone compared the decode sensitivity between the Flex and ThumbDV, to a standard DStar radio, using the same antenna?  Just curious.
  • Michael Coslo
    Michael Coslo Member ✭✭
    edited November 2016
    They don't have any HF stock  D-Star radios that I know of. Anyone?
  • Andrew O'Brien
    Andrew O'Brien Member ✭✭
    edited November 2016
    Not using the same antenna but today myself and another ham about 100 miles away tried on 80,and 40. He was using an icom 7100.  On standard LSB his signal received by me was about 1 S unit stronger than he received me (we also had telephone contact to hear signals). His signal was clear on one Dstar brief transmission , the rest I had no decode on him.  He never heard any digital signal from me.  I saw fairly good signals in the waterfall and played with squelch settings but it made no reak difference.

    Andy K3UK
  • pa0bie
    pa0bie Member
    edited November 2016
    I have a lot of noise ( S7 ) on 80 meters. But with FreeDV 1.1 , not FLEX waveforms , I only need 1 S-point to hear the signal and 2 S-points for a perfect decode.
  • Andrew O'Brien
    Andrew O'Brien Member ✭✭
    edited November 2016
    PA0PLE, Can you explain a little more?

  • KM6CQ - Dan
    KM6CQ - Dan Member ✭✭
    edited October 2018
    Free DV works okay. D-Star does not work very well on HF, the S/N has to be very good to be able to decode. 
    The ThumbDV works just fine without the Flex on reflectors. But that's boring. 

  • pa0bie
    pa0bie Member
    edited November 2016
    I mean 1 or 2 S-points above my normal noise level , which is S7.
    KENT HUFFORD Member ✭✭
    edited November 2016
    ICOM came out with the 9100 years ago. When you put the DSTAR card in it, it does DSTAR on all bands, including HF. The ICOM 7100, which has been out for a few years comes from the factory able to do DSTAR on all bands including HF. The ThumbDV stick gives the FLEX 6000 the capability to do DSTAR on all the HF bands.

    I have been doing DSTAR HF for about 5 years. There are scheduled nets for DSTAR HF. When the bands are open, you can talk to Australia, New Zealand, Japan, and all over Europe. The way the conditions are right now on HF. You can during any net make it across the USA and Canada. About 15-20 stations participate during each net. About 5 or 6 are FLEX radios.

    When FLEX added the DSTAR wave form, it had some real issues. Most all have been addressed. They are still working on a couple of minor nits.

    The DSTAR signal is about 6.2khz wide, about like AM. So, it has the same propagation issues as AM.  I have all three radios. IMOHO, the 7100 decodes DSTAR HF better than the other two. The FLEX with a ThumbDV decodes OK, but not as good as the 9100 or 7100. I think FLEX is working on this. HOWEVER, the FLEX on DSTAR allows one to find about 6.5khz opening on the bands. It cannot compete with other signals, so it needs a clear band path. It will never replace CW or SSB, but it is a lot of fun.

    International DSTAR HF Testing NetWINTER Schedule –  

    Use your ICOM 7100/9100, or STAR Boarded non ICOM DSTAR HF, or the FLEX 6000 series radios with software 1.5 or better and the ThumbDV.

    Here is some video of DSTAR HF Voice simplex on a 7100


    We are on each band only for 5 min. or so as to spend less time, if the band is dead we move on earlier. You can go back to a good freq after the net. MONITOR REF030C to coordinate. WE may need to move early or if the freq is busy. We do not want to step on any AM or SSB activity.

    We also use a web page to keep track of who and where we are at -     http://hf.dstar-relay.net/

    You also can check-in to this web site anytime 24/7 to find a DSTAR HF Ham to talk to.

    We have a PRENET for 30 min. before the start of the scheduled time. This PRENET is for ‘FREE FORM” contacts. One should check the web site  http://hf.dstar-relay.net/  sign in and find a working freq to work on. When the net starts at the scheduled time, please join the net and follow the freqs.


    Sat PM 7:00 E (2400Z)

    Sunday AM 10:00 E (1500Z Sunday)(Spend more time on each open band, and start on 80m)

    Sunday PM 7:00 E (2400Z)

    Check USB/LSB on freq to make sure the freq is clear.
    SUNDAY AM, we start with 80m and work towards 6 meters.

    6 mtrs 50.210 DV for 2 mins

    10 mtrs 28.570 DV for 5 mins

    12 mtrs 24.938 DV for 5 mins

    15 mtrs 21.380 DV for 5 mins

    17 mtrs 18.148 DV for 5 mins

    20 mtrs 14.335 DV for 5 mins

    40 mtrs 7.285(or another open freq) DV for 5 mins

    75 mtrs 3.880 DV for 5 mins.

    NCS will check the freq ahead of time to make sure we don’t step on anyone 3KC up and DOWN.

     "Digital voice is defined in the Commission’s rules based on content as voice (i.e. phone), not data, per Section 97.3(c)(5) of the Rules." Check out the most recent comments by the ARRL:  http://apps.fcc.gov/ecfs/document/view?id=7521063715



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