Strange Decodes on 160 Meters FT8............

Discussion in 'Working Different Modes' started by K2WH, Dec 7, 2017 at 9:49 PM.

ad: L-HROutlet
ad: l-rl
ad: Subscribe
  1. K2WH

    K2WH Have a Happy and Merry Christmas Volunteer Moderator QRZ Page

    I have never seen this before, and it is only happening on 160 meters.

    Multiple decodes of the same signal. What do you think is causing this?

    Strange propagation maybe?

    Notice they are all stamped with the same time. The waterfall only shows one signal and it is not only on the call in the image, it is on most signals but not all. This is during grayline.

    upload_2017-12-7_16-47-15.png
     
  2. KD2NOM

    KD2NOM XML Subscriber QRZ Page

    That is strange - I have seen this before when the S/N is off the charts high - but your highest there is 6dB. I dunno mate.
     
  3. K3XR

    K3XR Ham Member QRZ Page

    Took a couple of times but we made it thanks Bill.
     
  4. K2WH

    K2WH Have a Happy and Merry Christmas Volunteer Moderator QRZ Page

    I am noticing something that indicates the signals are about 61hz apart.

    Not exactly, but if you add 61 to each one you start to see a little bit of a pattern although not exact.

    Hmmm.
     
  5. KD2NOM

    KD2NOM XML Subscriber QRZ Page

    so - I am seeing the same thing with a strong signal on 10 meter - could it be a backscatter echo?
     

    Attached Files:

    • ft8.PNG
      ft8.PNG
      File size:
      73.5 KB
      Views:
      7
  6. KD2NOM

    KD2NOM XML Subscriber QRZ Page

    Hmmm - and on 40 meter as well
     

    Attached Files:

    • ft8.PNG
      ft8.PNG
      File size:
      22.9 KB
      Views:
      9
  7. VA3VF

    VA3VF Ham Member QRZ Page

    I think it may be caused by the very strong signal. It happens on other bands as well.
     
    Last edited: Dec 8, 2017 at 1:46 AM
  8. K2WH

    K2WH Have a Happy and Merry Christmas Volunteer Moderator QRZ Page

    Backscatter, that's what I was thinking and the change in time the signal is getting to our receivers.

    Anyone know if there is an Aurora episode tonight ? Maybe that is it, but I'm glad it isn't just me.
     
  9. K2WH

    K2WH Have a Happy and Merry Christmas Volunteer Moderator QRZ Page

    I'm not so sure. The signals I was receiving were not strong and it has never happened before and to have other stations seeing the same thing - unlikely its caused by strong signals.

    To add evidence to that, the other signals are not showing as reflections on the other frequencies, just the "Center" frequency and, my receiving level is around 50 so it is not overloading the rig soundcard.

    See my initial posting. The signals are clean.
     
  10. VA3VF

    VA3VF Ham Member QRZ Page

    It's showing +6dB, that's very strong for FT8. Is he/she close to you?

    I don't think you receiver level is the problem. Mine is at 70. It can go as high as 85, before it turns red.
     
    Last edited: Dec 8, 2017 at 1:49 AM

Share This Page