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Windows bug causes decoding performance with certain Soundcard Interfaces.

Discussion in 'Amateur Radio News' started by NT1K, Jul 29, 2015.

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  1. NT1K

    NT1K Ham Member QRZ Page

    Anyone using a Soundcard Interface using the TI PCM2900 (Rev-C or prior) series chipset might not be aware that the windows driver is adding 60db+. This bug is known and it's seen on Windows Vista and later.

    Devices like the Signalink and radios like the Icom 7100/7200 and TS-590S use this chipset. Modes like JT65 would be more difficult to decode because of the added distortion. There is a fix thanks to KD9DAL, he posted his fix to reddit and made a video showing exactly what is going on

    Source:
    https://www.reddit.com/r/amateurrad...windows_bug_ruining_your_receive_performance/

     
    NT1K, Jul 29, 2015
    #1
    AC9ZL, KC7ES, AI6AS and 3 others like this.
  2. W0EA

    W0EA Ham Member QRZ Page

    I tested this with my 590 and windows 8.1 and 10 and noticed the problem on both. This video fixed it and helped me get a lot more decodes on JT. This is a really bad bug and I sure hope we can get Microsoft to offer us a solution.

    However it is not a problem on linux or Mac operating systems.
     
    Last edited: Jul 30, 2015
    W0EA, Jul 30, 2015
    #2
  3. WA6MHZ

    WA6MHZ Ham Member QRZ Page

    What is the link to the level meter as shown in the vid?
    Thanks
     
    WA6MHZ, Jul 30, 2015
    #3
  4. KA0CZW

    KA0CZW Ham Member QRZ Page

    I just spent 2 days trying to get Signal Link to decode JT-65 HF from my Kenwood TS-2000. Gave up and went to my Flex 3000 and VAC. Everything worked like magic!

    Now I know what I was fighting and I confirmed it after watching this video. Thanks a million for the information.
     
    KA0CZW, Jul 30, 2015
    #4
  5. W6IR

    W6IR XML Subscriber QRZ Page

    W6IR, Jul 30, 2015
    #5
  6. KD6BZN

    KD6BZN XML Subscriber QRZ Page

    My levels are now normal on my IC-7600 and Windows 7 machine. I was running the volume at 2 before, but now 100 and working much better than before. Thanks!
     
    KD6BZN, Jul 30, 2015
    #6
  7. K5SRG

    K5SRG Ham Member QRZ Page

    Confirmed this issue & fix on my B43-00 serial # TS-590S in 'doze 7 x64 Ultimate box.
    USB\VID_08BB&PID_29B3&REV_0100&MI_00
    USB\VID_08BB&PID_29B3&MI_00

    Will I notice any improvement to my PSKxx and RTTY mode decoding?

    Skip - K5SRG
     
    K5SRG, Jul 30, 2015
    #7
  8. N7AMD

    N7AMD Ham Member QRZ Page

    Skip,

    Yes you should see better performance on PSK and RTTY. We did some basic initial testing to verify this. As time permits, we will do more testing to fully understand how much of an improvement will be realized.

    Cheers
    Ben
    KE7II
    FBOM International
     
    N7AMD, Jul 30, 2015
    #8
  9. W5LMM

    W5LMM Platinum Subscriber Platinum Subscriber QRZ Page

    Why don't they fix the driver?
     
    W5LMM, Jul 30, 2015
    #9
  10. K5SRG

    K5SRG Ham Member QRZ Page

    Seemed better working Germany on PSK63 immediately after the fix applied but sure appreciate the confirmation.

    Thanx Much - K5SRG
     
    K5SRG, Jul 30, 2015
    #10
  11. NT1K

    NT1K Ham Member QRZ Page

    Because TI has since came out with revisions of the chip (Now at Rev E).
    With vista or later, Windows recognize that the chip doesn't have an input volume so windows automatically assign a value that happens to treat the input as a microphone instead of a "Line In" device giving an extra 60db of "gain".
    Makes for a distorted signal. Simply turning down the volume in the sound settings will not help since you are just attenuating an already distorted signal.

    Will M$ fix it? Most likely not. There are new revisions of chips that do work with vista and up. The new Elecraft K3S uses a new rev PCM2XXX
     
    NT1K, Jul 30, 2015
    #11
  12. W5LMM

    W5LMM Platinum Subscriber Platinum Subscriber QRZ Page

    Is there a newer solder-in chip for Signalinks?
     
    W5LMM, Jul 30, 2015
    #12
  13. W0EA

    W0EA Ham Member QRZ Page

    No, unfortunately the newer chips are not drop in replacements
     
    W0EA, Jul 30, 2015
    #13
  14. K7JGM

    K7JGM Ham Member QRZ Page

    Thank you!!!
     
    K7JGM, Jul 30, 2015
    #14
  15. KK4SUH

    KK4SUH Ham Member QRZ Page

    Never knew about this, thanks for sharing.
     
    KK4SUH, Jul 30, 2015
    #15
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