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Re: Is OPERA a valid QSO mode (Was:RF Contents (was: Updated PIC Code))

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  • martin_ehrenfried
    Hi Graham, For beaconing it s fine, but if OPERA ever becomes a QSO mode then I d say no. For discussion purposes I d suggest that EME procedure is the least
    Message 1 of 11 , Jan 12, 2012
      Hi Graham,

      For beaconing it's fine, but if OPERA ever becomes a QSO mode then I'd say no.

      For discussion purposes I'd suggest that EME procedure is the least exchange of information over the air that could be accepted as being a valid two way QSO.

      I was looking for a suitable reference and came across this in the WSJT user guide. Which can be found at:-

      http://physics.princeton.edu/pulsar/K1JT/WSJT_User_600.pdf

      A typical minimal QSO in FSK441 or JT6M modes might look something like the following:

      1. CQ K1JT
      2. K1JT W8WN
      3. W8WN K1JT 27
      4. JT R26
      5. WN RRR
      6. 73 W8WN

      Also similar from the EME Operating Guide

      http://www.nitehawk.com/rasmit/g3sek_op_proc.pdf

      Minimum QSO

      The definition of a minimum valid QSO is that both stations have copied all of the following:

      1. Both callsigns from the other station
      2. Signal report from the other station (or some other previously unknown piece of information, e.g. the other station's Locator grid)
      3. R from the other station, to acknowledge complete copy of 1 and 2.

      This has been the standard definition of a minimum EME QSO for many years.

      I think the key part is the exchange of both callsigns over the air so it is clear who is in contact with who. Also the passing of an item of information such as signals strength or QRA, and the final return confirmation acknowledging that the exchange has been completed.

      I think that it should be possible to convey all of these standard exchanges within the OPERA data string by using a lookup or hash code

      Just my thoughts.

      Regards,

      Martin - G8JNJ

      www.g8jnj.webs.com




      --- In O_P_E_R_A_@yahoogroups.com, "graham787" <g0nbd@...> wrote:
      >
      > Just as a mtter of interest - How much content of a ROS QSO is actually
      > > exchanged via the internet ?
      >
      > You can run Ros and Op on non web linked PC' and of course, non time synchronised as well, Ros is a live data mode and sends what ever is typed,Op sends the call sign in a encoded format.
      >
      > Web linking, Ros , Announces Tx and reports uploaded to the psk-report system are displayed ..in passing
      >
      > Op announces the Tx start and retains the psk-report uploads in the scrolling left side screen
      > Either mode can be used with no web connection.
      >
      > So in a exchange of calls OP could be considered a qso ?
      >
      > 17:26 10135 G0NBD de EA5HVK Op2 1757 km -23 dB in Cartagena 5W FT-897
      > 16:58 10135 EA5HVK Op8 -30 dB 1757 km @ 174
      >
      > G..
      >
      >
      >
      >
      >
      > --- In O_P_E_R_A_@yahoogroups.com, "siegfried jackstien" <siegfried.jackstien@> wrote:
      > >
      > > Ros sends out locator and call ... so what else is needed??? Signal report?
      > > There is a macro to send out the signal report from last transmission ... so
      > > actually the internet is not needed to have a valid qso
      > > Dg9bfc
      > > Sigi
      > >
      > >
      > > > -----Ursprüngliche Nachricht-----
      > > > Von: O_P_E_R_A_@yahoogroups.com [mailto:O_P_E_R_A_@yahoogroups.com] Im
      > > > Auftrag von martin_ehrenfried
      > > > Gesendet: Mittwoch, 11. Januar 2012 18:35
      > > > An: O_P_E_R_A_@yahoogroups.com
      > > > Betreff: [O_P_E_R_A_] Re: Is OPERA a valid QSO mode (Was:RF Contents (was:
      > > > Updated PIC Code))
      > > >
      > > >
      > > >
      > > > Hi Andy,
      > > >
      > > > OK - well in that case, I guess more data would have to be included in teh
      > > > data string and exchanged via the either, before it could be considered to
      > > > be valid for QSO's.
      > > >
      > > > Rule of thumb - if you can't complete an exchange of callsigns and
      > > > confirmation of the exchange without using an internet connection (or data
      > > > which has been previously downloaded via the internet and stored locally)
      > > > then it isn't a QSO.
      > > >
      > > > Just as a mtter of interest - How much content of a ROS QSO is actually
      > > > exchanged via the internet ?
      > > >
      > > > Regards,
      > > >
      > > > Martin - G8JNJ
      > > >
      > > > www.g8jnj.webs.com
      > > >
      > > > --- In O_P_E_R_A_@yahoogroups.com <mailto:O_P_E_R_A_%40yahoogroups.com> ,
      > > > "IMR" <ac.talbot@> wrote:
      > > > >
      > > > > Just the callsign is transmitted over the air.
      > > > >
      > > > > If you assume no hard source compression, and a simple alphabet of
      > > > letters/numbers/space, suggests the callsign needs around 30 - 35 bits,
      > > > which when expanded to 239 symbols (which I suspect is actually 119 bits
      > > > in the self-clocking code, and is why I call them 'symbols') is about
      > > > right for an error correcting code capable of losing 33%.
      > > > >
      > > > > Everything else is derived from the database, including the locators
      > > > used for distance calculation.
      > > > >
      > > > > Andy
      > > > > www.g4jnt.com
      > > >
      > > >
      > > >
      > > >
      > >
      >
    • g4ilo
      The same suggestion has been made about WSPR spots many times. I think it is more or less accepted in ham radio that an exchange is not a QSO unless calls and
      Message 2 of 11 , Jan 12, 2012
        The same suggestion has been made about WSPR spots many times. I think it is more or less accepted in ham radio that an exchange is not a QSO unless calls and signal reports are exchanged - hence the exchange of "599" in contests. Meaningless as a signal report, but wouldn't be a contact without it.

        In WSPR and Opera nothing in the beacon text is addressed to another station, so without the internet there would be no way for two stations to know that each has received the other.

        Julian, G4ILO

        --- In O_P_E_R_A_@yahoogroups.com, "graham787" <g0nbd@...> wrote:
        >
        > So in a exchange of calls OP could be considered a qso ?
        >
      • G ..
        Could make up some code to send to each other , Gary did try what happened when you enter non calls .,but that was day 1 and now its day 12 hi
        Message 3 of 11 , Jan 12, 2012
          Could make up  some  code to  send to  each  other ,  Gary did  try  what  happened when  you  enter non  calls  .,but  that  was  day 1 and now its day  12 hi
          still  in test  , Jose is  working  on the  tx/rx  code / decode .. single  handed ... which  really is the main  task
           
          >>What is needed  is  some  one who  can do 
          something  with the  data , some  sort of  web  site  similar  to the wspr system  to  handle  the  amount of  data  and provide  sorting  etc<<
           
          Main  thing is everyone  seems  to  be having a  lot  of fun , I just had a  couple  of   2  / 3  dB over the limit  decodes  from  VK with  5  watts  to  40  ft  vertical
           
          73-All
           
          G.

          From: g4ilo
          Sent: Thursday, January 12, 2012 7:43 PM
          Subject: [O_P_E_R_A_] Re: Is OPERA a valid QSO mode (Was:RF Contents (was: Updated PIC Code))

           

          The same suggestion has been made about WSPR spots many times. I think it is more or less accepted in ham radio that an exchange is not a QSO unless calls and signal reports are exchanged - hence the exchange of "599" in contests. Meaningless as a signal report, but wouldn't be a contact without it.

          In WSPR and Opera nothing in the beacon text is addressed to another station, so without the internet there would be no way for two stations to know that each has received the other.

          Julian, G4ILO

          --- In O_P_E_R_A_@yahoogroups.com, "graham787" <g0nbd@...> wrote:

          >
          > So in a exchange of calls
          OP could be considered a qso ?
          >

        • siegfried jackstien
          Were is decoding limit for opera in the different speeds?!? Dg9bfc Sigi
          Message 4 of 11 , Jan 12, 2012
            Were is decoding limit for opera in the different speeds?!?
            Dg9bfc
            Sigi


            > -----Ursprüngliche Nachricht-----
            > Von: O_P_E_R_A_@yahoogroups.com [mailto:O_P_E_R_A_@yahoogroups.com] Im
            > Auftrag von G ..
            > Gesendet: Donnerstag, 12. Januar 2012 20:37
            > An: O_P_E_R_A_@yahoogroups.com
            > Betreff: Re: [O_P_E_R_A_] Re: Is OPERA a valid QSO mode (Was:RF Contents
            > (was: Updated PIC Code))
            >
            >
            >
            > Could make up some code to send to each other , Gary did try what
            > happened when you enter non calls .,but that was day 1 and now its
            > day 12 hi
            > still in test , Jose is working on the tx/rx code / decode .. single
            > handed ... which really is the main task
            >
            > >>What is needed is some one who can do something with the data ,
            > some sort of web site similar to the wspr system to handle the
            > amount of data and provide sorting etc<<
            >
            > Main thing is everyone seems to be having a lot of fun , I just had
            > a couple of 2 / 3 dB over the limit decodes from VK with 5
            > watts to 40 ft vertical
            >
            > 73-All
            >
            > G.
            >
            >
            > From: g4ilo <mailto:julian.g4ilo@...>
            > Sent: Thursday, January 12, 2012 7:43 PM
            > To: O_P_E_R_A_@yahoogroups.com
            > Subject: [O_P_E_R_A_] Re: Is OPERA a valid QSO mode (Was:RF Contents (was:
            > Updated PIC Code))
            >
            >
            >
            > The same suggestion has been made about WSPR spots many times. I think it
            > is more or less accepted in ham radio that an exchange is not a QSO unless
            > calls and signal reports are exchanged - hence the exchange of "599" in
            > contests. Meaningless as a signal report, but wouldn't be a contact
            > without it.
            >
            > In WSPR and Opera nothing in the beacon text is addressed to another
            > station, so without the internet there would be no way for two stations to
            > know that each has received the other.
            >
            > Julian, G4ILO
            >
            > --- In O_P_E_R_A_@yahoogroups.com <mailto:O_P_E_R_A_%40yahoogroups.com> ,
            > "graham787" <g0nbd@...> wrote:
            > >
            > > So in a exchange of calls OP could be considered a qso ?
            > >
            >
            >
            >
            >
          • Andy Talbot
            You can work it out to within a dB or two, from first principles. On-off keying has the same error rate / SNR performance as dual FSK for the same MEAN (**)
            Message 5 of 11 , Jan 12, 2012
              You can work it out to within a dB or two, from first principles.
               
              On-off keying has the same error rate / SNR performance as dual FSK for the same MEAN (**)  power.   We are told the FEC can cope with 33% of the bits being lost, so a Bit Error Rate of 0.1 is more than adequate for 100% reception.   Reading off the standard FSK vs S/N curve for M=2 Orthogonal signalling (see for example , Digital Communications ,  Proakis.  Fifth edition Figure 4.4-1  or FIgure 4.2-5)  suggests a 0.1 BER needs a S/N of 2dB.
               
              This is in the signalling bandwidth, so for OP2 this is in the 0.512s,symbol period  or 2Hz.  For OP32 this is in a bandwidth of 1/8s or 0.122Hz.
               
              Taking OP2, 2dB in 2Hz BW equates to 29dB S/N when normalised to the standard 2500Hz bandwidth Rad.Ams. seem to have adopted since WSJT days.
               
              This theshold assumes ideal decoding, and is roughly about what WSPR achieves with its 1.46Hz signalling bandwidth.
               
              For the other submodes, scale with bandwidth, so OP8 is going to be around -35dB, OP16 -38dB and OP32 -41dB.  
              A threshold of -38dB S/N  has been quoted on this group once for OP{presumably 32} so it looks as if there may be a 3dB shortfall.  That will be decoder efficiency
               
              (**)  the curves assume mean power.   For FSK this is, of course, the actual power, but for 50% OOK, is half the RF ouptut.  
               
              Whilst appreciatiing that Opera was designed specifically for simple one frequency transmitters, as a codign excercise as much as anythign else, this  does go to show why ON-OFF keying is so wasteful when compared with FSK, or better still, Multi-FSK as used in the WSJT suite.
               
              ANdy
               
               
               
               
              On 12 January 2012 20:51, siegfried jackstien <siegfried.jackstien@...> wrote:
               

              Were is decoding limit for opera in the different speeds?!?


              Dg9bfc
              Sigi

              > -----Ursprüngliche Nachricht-----
              > Von: O_P_E_R_A_@yahoogroups.com [mailto:O_P_E_R_A_@yahoogroups.com] Im
              > Auftrag von G ..
              > Gesendet: Donnerstag, 12. Januar 2012 20:37
              > An: O_P_E_R_A_@yahoogroups.com
              > Betreff: Re: [O_P_E_R_A_] Re: Is OPERA a valid QSO mode (Was:RF Contents
              > (was: Updated PIC Code))
              >
              >
              >
              > Could make up some code to send to each other , Gary did try what
              > happened when you enter non calls .,but that was day 1 and now its
              > day 12 hi
              > still in test , Jose is working on the tx/rx code / decode .. single
              > handed ... which really is the main task
              >
              > >>What is needed is some one who can do something with the data ,
              > some sort of web site similar to the wspr system to handle the
              > amount of data and provide sorting etc<<
              >
              > Main thing is everyone seems to be having a lot of fun , I just had
              > a couple of 2 / 3 dB over the limit decodes from VK with 5
              > watts to 40 ft vertical
              >
              > 73-All
              >
              > G.
              >
              >
              > From: g4ilo <mailto:julian.g4ilo@...>

              > Sent: Thursday, January 12, 2012 7:43 PM
              > To: O_P_E_R_A_@yahoogroups.com
              > Subject: [O_P_E_R_A_] Re: Is OPERA a valid QSO mode (Was:RF Contents (was:
              > Updated PIC Code))
              >
              >
              >
              > The same suggestion has been made about WSPR spots many times. I think it
              > is more or less accepted in ham radio that an exchange is not a QSO unless
              > calls and signal reports are exchanged - hence the exchange of "599" in
              > contests. Meaningless as a signal report, but wouldn't be a contact
              > without it.
              >
              > In WSPR and Opera nothing in the beacon text is addressed to another
              > station, so without the internet there would be no way for two stations to
              > know that each has received the other.
              >
              > Julian, G4ILO
              >
              > --- In O_P_E_R_A_@yahoogroups.com <mailto:O_P_E_R_A_%40yahoogroups.com> ,

              > "graham787" <g0nbd@...> wrote:
              > >
              > > So in a exchange of calls OP could be considered a qso ?
              > >
              >
              >
              >
              >


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