So what is the coding, the error correction, the decoding scheme.
Come on, in the amateur radio world there's no need for keeping such
things secret
You can't beat Shannon - ON/OFF in a particular bandwidth with decent
FEC will always give the same performance, so what are the innards of
this one?
Andy
www.g4jnt.com
On 2 January 2012 00:08, Graham <[email protected]> wrote:
> All,
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> After some time in development the 136/500 version of the Opera
> data mode is ready for experimental use .
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> Download links are available from myself or Gary, G4WGT as the
> versions may change , these may also change ,
>
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> Users are invited to join the Opera yahoo group
> http://groups.yahoo.com/group/O_P_E_R_A_/?yguid=131323118
>
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> At the moment , spots are distributed to other OP users on line at
> the time ,. future intent is to link to the PSK-Reporting network
> and for a HF version and possible limited QSO mode , allowing
> under the noise qso's with a simple xtal tx
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> There is a on line chat mode to facilitate tests etc
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> The software is available for all , free to use ,
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> Happy new year to all and good luck
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> 73-G ..
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> OPERA The new CW/ QRSS replacement data mode
>
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> There is always the assumption that all armature radio stations
> can effectively translate what ever new soundcard data mode that
> is coded to radio frequency..
>
>
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> The question I posed was ‘What about those who cannot , and only
> have CW transmission facility’s’? …
>
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> Never did get a reply
>
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>
> So after a long exchange of emails , the concept of a serial data
> mode that used only one tone , on/off keyed , with a eye on the
> qrss system, was finally discussed and coding work begun, an
> initial statement that in software , could be achieved a lower level
> of detection than that required to produce a line on a spectrum plot
> set the scene for a what was originally proposed to be a simple
> data mode, turned into to a race to the noise floor.
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> OPERA
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> Is a totally new Data / Beacon mode , profiled for the 136 and
> 500 bands , with HF possibility’s later in the project . The beacon
> mode is the version under test at the moment.
>
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> Opera was designed as an alternative to the QRSS transmission system
> and provides for a limited number of characters to be transmitted by
> a serial single keyed tone , as is QRSS or live CW, 6 at the
> moment.
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> It is live ‘data’ mode and there is no requirement for time
> synchronisation of the tx/rx station .
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> The mode can be transmitted by any transmitter SSB/CW , there
> being provided a keyed tone and Comm. Port CW key interface
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> There is a windows ‘gui’ interface and the requirement for RX
> audio feed, based round 1500 Hz , Tx audio at 1500 Hz may also be
> used to drive a audio/rf conversion , changes of Tx audio tone
> prevent collisions, and the software scans for a slot of minimum noise .
> to place the TX carrier in.
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> If the CW key option is used, then the Tx frequency is selected by
> the Tx master oscillator only.
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> Once a signal is decoded, the decode-spot is distributed to other
> web-connected users, future development will link to the PSK-Reporting
> network .
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> OPERA is coded at the moment for 136 and 500 Khz and still under
> development.
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> As a basic out line the system (at the moment) codes the six
> characters of the call sign and transmits them as a serial ‘pulse’
> train using either conventional audio to RF translation , or by
> the use of a COM port and transistor keying cct that simply
> replaces the CW key ,
>
>
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> Reception, as the data is spread out along a time line , decoding
> is completed during the final stages of the transmission , due to this
> ,,it is not possible to include a receive progress monitor, however
> the system will track and decode multiple transmissions of both time
> bases simultaneously
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> Transmit times are used to denote the mode
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> 500 Khz
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> 2 Minuets
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> 16 Minuets
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> 136 Khz
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> 8 Minuets
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> 65 Minuets
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> S/N, The mode is capable of decoding under the noise level , beyond
> that of WSPR or the ROS-MF-2 system with a maximum data loss of
> 33% before the decode Fails.
>
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> Opera 2 similar to WSPR
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> Opera 8 6dB better than WSPR.
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> Opera 65 9 dB better than Opera8,
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