Digital modes, it might have been asked before...

Discussion in 'Working Different Modes' started by VE3GZB, Jul 11, 2018.

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  1. VE3GZB

    VE3GZB Ham Member QRZ Page

    Thanks to the help I got here, now I'm starting to enjoy FT8 mode and I'm having a little bit of success with it, which is very nice considering I'm stuck in a condo area where not even clotheslines are permitted.

    So now, with the exact same setup on which FT8 runs, when I switch WSJTX to try to handle JT65+JT9, despite hearing the tones and seeing the waterfall there is nothing being decoded/displayed in the text screens of WSJTX.

    Why would it work on FT8 and not seem to decode anything on JT65+JT9? What could be so different?

    73s, VE3GZB
     
  2. ND6M

    ND6M Ham Member QRZ Page

    what do you have "JT65 nnnn JT9," set to on the Wide Graph?

    Also, you may have the filters on your rig "closed up" so tight that you are not "seeing" enough band width to Rx the signals. You need about 5 Kc width to Rx both JT65 and JT9 on the wide graph.

    copied from the manual:

    Bandwidth and Frequency Setting
    • If your transceiver offers more than one bandwidth setting in USB mode, you should normally choose the widest one possible, up to about 5 kHz. This choice has the desirable effect of allowing the Wide Graph(waterfall and 2D spectrum) to display the conventional JT65 and JT9 sub-bands simultaneously on most HF bands. Further details are provided in the Basic Operating Tutorial. A wider displayed bandwidth may also be helpful at VHF and above, where JT4, JT65, and QRA64 signals are found over much wider ranges of frequencies.

    • If you have only a standard SSB filter you won’t be able to display more than about 2.7 kHz bandwidth. Depending on the exact dial frequency setting, on HF bands you can display the full sub-band generally used for one mode (JT65 or JT9) and part of the sub-band for the other mode.

    • Of course, you might prefer to concentrate on one mode at a time, setting your dial frequency to (say) 14.076 for JT65 or 14.078 for JT9. Present conventions have the nominal JT9 dial frequency 2 kHz higher than the JT65 dial frequency on most bands.

    Also,.......... are you on the same FT8 freq,... or are you 2 Kc up?
     
    VE3GZB likes this.
  3. VE3GZB

    VE3GZB Ham Member QRZ Page

    Well, I don't fiddle with anything other than just choosing the mode. I'm back on FT8 just now and signals are decoding like there's no tomorrow, signals from half way around the world! Filter is set to upper side band-data and it is maxed out at 3.6kHz.

    If I switch over WSJTX from FT8 to JT65+JT9 and I change nothing else, despite hearing the tones and seeing activity on the waterfall there is precious little else happening.

    EDIT: I've poked around within WSJTX and the radio frequencies you've mentioned match what WSJTX possesses.

    Thanks and 73s, VE3GZB
     
    Last edited: Jul 11, 2018
  4. KK6RKY

    KK6RKY XML Subscriber QRZ Page

    Your setup may be working properly but there are just so many more FT8 stations compared to JT65 and JT9 stations. I just looked at PSK reporter and in the last hour there were 2806 FT8 stations reporting, 26 JT65 stations, and only 1 JT9 station. By the way, I enjoyed both JT65 and JT9 before FT8 was introduced but there are so few signals I haven't worked those modes in a long time.
     
    VE3GZB likes this.
  5. VE3GZB

    VE3GZB Ham Member QRZ Page

    Ok that makes sense. Thanks!

    73s de VE3GZB
     
  6. ND6M

    ND6M Ham Member QRZ Page

    Also,.......... are you on the same FT8 freq,... or are you 2 Kc up?
     
  7. VE3GZB

    VE3GZB Ham Member QRZ Page

    WSJTX changes the frequency automatically.
     
  8. KP4SX

    KP4SX Premium Subscriber QRZ Page

    There are so few JT signals these days you have to be lucky to see/hear one!
     
    VE3GZB likes this.
  9. KC9YGN

    KC9YGN Platinum Subscriber Platinum Subscriber QRZ Page

    KP4SX may be right and there may be nothing wrong with your setup, there just isn't anybody using the mode at the time you're listening. I haven't seen a JT 9 or 65 signal in days
     
    VE3GZB likes this.
  10. KB4QAA

    KB4QAA XML Subscriber QRZ Page

    With wide filters, the signal to noise ratio will be low. Try narrowing your filters, even as narrow as a single signal. The signal to noise ratio will maximize and increase your ability to decode.

    Check some other settings:
    -AGC: OFF or Fast
    -DSP: OFF or Minimum
    -NB: OFF if not required
    Use the minimum amount of processing which can modify the signal.

    -Don't overdrive the WSJT-X processor. Be sure your input signal is near the 30dB setting, as recommended. I have had this significantly decrease decoding when set too high.
     
    VE3GZB likes this.

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