Loading ...
Sorry, an error occurred while loading the content.

Multiple Signals on JT9

Expand Messages
  • d8066ebf5d969b327cde122f4b6dd03a
    I am noticing a lot of duplicate signals on JT9 form the same person and have had this happen on my signal. Will see the same call sign , say at , 1190 and
    Message 1 of 3 , Nov 13, 2013
    • 0 Attachment
      I am noticing a lot of duplicate signals on JT9 form the same person and have had this happen on my signal. Will see the same call sign , say at , 1190 and 1210 . Is this perhaps a band condition causing this? I usually operate at 5 watts and no ALC or Processing.
    • Jim - N4ST
      This usually happens when a signal is very strong, +15dB or more. Usually one of the signals is strong and the others are down by 20-30 dB. It can be caused by
      Message 2 of 3 , Nov 13, 2013
      • 0 Attachment

        This usually happens when a signal is very strong, +15dB or more.

        Usually one of the signals is strong and the others are down by 20-30 dB.

        It can be caused by the transmitted signal being overdriven or by your receiver audio may be overdriven.

        Grounding problems can result in these spurious signals being spaced at 60Hz (or 50 Hz for overseas).

         

        73,

        Jim – N4ST

         

         

        From: JT9digitalhams@yahoogroups.com [mailto:JT9digitalhams@yahoogroups.com] On Behalf Of markg@...
        Sent: Wednesday, November 13, 2013 21:44
        To: JT9digitalhams@yahoogroups.com
        Subject: [JT9digitalhams] Multiple Signals on JT9

         

         

        I am noticing a lot of duplicate signals on JT9 form the same person and have had this happen on my signal. Will see the same call sign , say at , 1190 and 1210 . Is this perhaps a band condition causing this? I usually operate at 5 watts and no ALC or Processing.

      • Ken
        +1. The couple that I have heard have been spaced at 120 Hz and 25 to 30 db down. I guess that tells us two things: 1) JT9 is great at decoding extremely
        Message 3 of 3 , Nov 14, 2013
        • 0 Attachment
          +1.   

          The couple that I have heard have been spaced at 120 Hz and 25 to 30 db down.   I guess that tells us two things:
          1) JT9 is great at decoding extremely close by signals that are 30 db different in strength (incredible!)
          2) those well surpressed spurs that are 25 db down are still readable!   They are not insignificant!

          I would assume transmissions like these are caused by some 60 Hz hum in the audio.

          Ken WA8JXM

          On Nov 13, 2013, at 11:42 PM, Jim - N4ST wrote:



          This usually happens when a signal is very strong, +15dB or more.
          Usually one of the signals is strong and the others are down by 20-30 dB.
          It can be caused by the transmitted signal being overdriven or by your receiver audio may be overdriven.
          Grounding problems can result in these spurious signals being spaced at 60Hz (or 50 Hz for overseas).
           
          73,
          Jim – N4ST
           
           
          From: JT9digitalhams@yahoogroups.com [mailto:JT9digitalhams@yahoogroups.com] On Behalf Of markg@...
          Sent: Wednesday, November 13, 2013 21:44
          To: JT9digitalhams@yahoogroups.com
          Subject: [JT9digitalhams] Multiple Signals on JT9
           
           

          I am noticing a lot of duplicate signals on JT9 form the same person and have had this happen on my signal. Will see the same call sign , say at , 1190 and 1210 . Is this perhaps a band condition causing this? I usually operate at 5 watts and no ALC or Processing.




        Your message has been successfully submitted and would be delivered to recipients shortly.