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1335Re: WANTED 8KHz OP4H OPERA TESTER’S

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  • paulwijnand
    May 1, 2012
    • 0 Attachment
      Yes indeed Graham,

      My home build LF/MF/HF/VHF transceiver can TX from about 40 Khz to 700 KHz for the LF/MF part with 3 sets of lowpass filters for 73, 136 and 500 kHz and the RX is usable down to about 4 kHz in USB mode.
      Antenna however is the LF1010 which is usable a bit at 9 Khz and the MiniWhip from pa0rdt which I have not connected yet, due to other hamradio work hi.

      Yes there are for shortwave listeners recievers around which can do the 9 Khz and perhaps a lot lower.
      Like the AOR7030(+), which is used by many SW listeners. Probably the SDR receivers and transceivers can go also very low.

      Furthermore there are also converters to convert the band to 10 MHz.

      So best would be to have also the option to feed the Op4H with the normal SSB audio for RX, which make the numbers of possible listeners bigger.


      Yes about the Op4H SDR RX/TX :

      This is very nice!

      Will see how I get that running on RX soon.
      What would be the right way to secure the soundcard from statics and strange currents and so from the antenna ?.

      73

      Paul, pa0ocd




      --- In O_P_E_R_A_@yahoogroups.com, "graham787" <g0nbd@...> wrote:
      >
      > Paul,
      >
      > Do you mean , you are using a conventional RX for 8Khz reception , so would have a audio o/p in the audio ssb range ?
      >
      > That was not anticipated , as the sound card will function directly at 8Khz so the RX function is centered on the 8K band, to date, all the testing has utilized sound-card based SDR tx / rx
      >
      > You say 'many others' is this a wide spread problem ?
      >
      > Tnx -G.
      >
      >
      >
      > --- In O_P_E_R_A_@yahoogroups.com, "paulwijnand" <paulwijnand@> wrote:
      > >
      > > Hello Graham,
      > >
      > > Is it possible to have for OP4H for RX, also the normal audio input for the soundcard??
      > >
      > > In that way I can use, like many others, my normal SSB Receiver for 9 KHz.
      > >
      > > 73
      > >
      > >
      > > Paul, pa0ocd
      > >
      > >
      > >
      > >
      > >
      > >
      > > --- In O_P_E_R_A_@yahoogroups.com, "graham787" <g0nbd@> wrote:
      > > >
      > > >
      > > > WANTED 8KHz OP4H OPERA TESTER'S
      > > >
      > > >
      > > >
      > > > Dreaming of sending data ?
      > > >
      > > >
      > > >
      > > > After testing , the Dreamer's Band 8KHz version of the
      > > > Opera Beacon system is ready for AIR testing (OR) GROUND
      > > > testing. The Opera beacon tx time has been extended to 4 hours
      > > > to give maximum sensitivity , while maintaining transmit times in
      > > > keeping with the 8K activity at the moment
      > > >
      > > >
      > > >
      > > > At approximately 50 % duty cycle , the system will transmit 2
      > > > hours of carrier in every 4, so should reduce the electricity bill
      > > > !, while sending the full call sign , as in the LF>HF versions ,
      > > > the decode criteria remains at approx randomly 50% of the data
      > > > during the Tx time required to achieve a decode.
      > > >
      > > >
      > > >
      > > > Decode sensitivity is estimated to be approx -47 dB , but this
      > > > is based on the sim-path calibration and may extend lower in actual
      > > > use.
      > > >
      > > >
      > > >
      > > > In tests , a signal , modulated by the Opera on/off keying , level
      > > > reduced to 'normal off air' was demonstrated to leave a trace on
      > > > `Spec Lab' so station's using Opera will also show as
      > > > per normal on the web based grabbers etc, with the additional
      > > > possibility of Opera decodes.
      > > >
      > > >
      > > >
      > > > As in the LF>HF versions , Opera utilises the PC sound card for
      > > > both Tx and Rx and requires NO high stability oscillators or time
      > > > synchronisation , all testing being conducted with normal
      > > > soundcards, mostly with local Tx and Rx using very small Ae's
      > > > over short MK1 back garden test ranges.
      > > >
      > > >
      > > >
      > > > Users operating at 8Khz will show on the psk-reporting map as band
      > > > `unknown', both Tx and Rx stations are included in the
      > > > display to ensure maximum visability.
      > > >
      > > >
      > > >
      > > > Transmit Keying
      > > >
      > > >
      > > >
      > > > Tx keying is provided by way of a direct audio drive from the
      > > > sound card or by way of on/off keying by the com-port ptt key
      > > > output from the software. An additional com port may be addressed to
      > > > perform station Tx/Rx functions at change over. Due to the longer time
      > > > scales, the switching times of heaver 'power' relays will not
      > > > affect system performance, simplifying switching if need be.
      > > >
      > > >
      > > >
      > > > Rx requirements
      > > >
      > > >
      > > >
      > > > Receive is facilitated by the direct input to the sound card at the
      > > > 8Khz operating frequency , no filtering or pre processing is
      > > > required, however, the receiver is of fixed bandwidth so if using
      > > > external oscillator , its important to ensure the signal falls
      > > > within the bass band.
      > > >
      > > >
      > > >
      > > > Compatibility ,
      > > >
      > > >
      > > >
      > > > Opera is designed to operate with all `new' versions of
      > > > window's and is compatible with running multiple sessions of
      > > > Spec-Lab and Opera on the same PC
      > > >
      > > >
      > > >
      > > > Function
      > > >
      > > >
      > > >
      > > > The OP4H system , will provide the same data as the high frequency
      > > > variants , s/n reporting via the web or local s/n copy if not
      > > > web linked. The full call sign is transmitted , so the system
      > > > may be classed as a data mode .
      > > >
      > > >
      > > >
      > > >
      > > >
      > > > If there are any questions etc ,pls contact myself Graham G0NBD
      > > > or Gary G4WGT ,
      > > >
      > >
      >
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