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Re: [softrock40] SoftRock 6 QRP Exiter - First CW Contacts?

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  • Bill Tracey
    Hoo hah - a transceiver is born! Congratulations Jan -- very glad to hear the software seems to be working. As far as I know you re the 1st to get an on air
    Message 1 of 4 , Oct 1, 2006
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      Hoo hah - a transceiver is born! Congratulations Jan -- very glad to hear
      the software seems to be working. As far as I know you're the 1st to get
      an on air QSO w/ the setup.

      I just finished doing a little breakout board to hookup the little exciter
      to the computer serial port to try and get a look at it on a spectrum
      analyzer. Once I get some results from that will post what it looks like.

      As to staying away from the edges - at 48khz you should not be able to go
      more than +/- 24 khz; at 96 +/- 48 khz. I'll have to check the software to
      see if it is enforcing those limits for transmit. I know I want to look
      at some of the sound cards I have here and see how much the output falls
      off above 24 khz when running at 96 khz sampling -- there's some suspicion
      we may start running into the sound card's output filter stop band above
      24khz.

      Cheers,

      Bill (kd5tfd)

      At 09:25 AM 10/1/2006, you wrote:
      >Bill, Tony, All,
      >
      >I made my first CW contact this morning with the SR6 Exciter Alpha
      >prototype using the latest Version of PowerSDR Software which Bill
      >released last Friday. Very pleased with this!!
      ><....>
      > - With this particular soundcard it is advisable to stay away from
      >the maximum sampling rate; otherwise output power and sideband
      >suppression start to suffer. For example sampling freq 48K, I find I
      >need to limit TX within 22 Khz range 7034 KHz - 7088 KHz. With 96K
      >sampling rate I can cover 7014 KHz - 7096 KHz
      ><...>
      >best 73s
      >
      >Jan
      >
      >G0BBL - M0PUB - G8BTR (QRP2K Design team)
    • Terry
      ... received ... somebody ... from ... I ... Antenna ... reading. ... check ... the ... to ... below ... via ... Congrats Jan!! My exciter just came to life,
      Message 2 of 4 , Oct 1, 2006
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        --- In softrock40@yahoogroups.com, "verduynj" <Jan.Verduyn@...> wrote:
        >
        > Bill, Tony, All,
        >
        > I made my first CW contact this morning with the SR6 Exciter Alpha
        > prototype using the latest Version of PowerSDR Software which Bill
        > released last Friday. Very pleased with this!!
        >
        > http://www.tracey.org/wjt/sdr1k/SoftRock40/PowerSDR-KD5TFD-srxmit-
        > 20060928.zip - thanks Bill!!
        >
        > I worked ON5CBK, Patrick at 11:15 UTC on 7015 Khz and received 599
        > report .. Not bad for 0.6 Watt RF output!!
        > Second contact was a solid 15 minute QSO with Joe, DM0K and
        received
        > a 559 report.
        >
        > Is this the first CW contact with the Softrock Exciter or has
        somebody
        > else beaten me to it?
        >
        > Some additional info from us who prototyped to Exciter:
        >
        > - Using (Dell on board Sigmatel STAC 92xx)s unwanted sideband and
        > carrier suppression is at more -30dB down from full rated output as
        > shown on a spectrum analyser. -30dB is the FCC requirement I
        > understand.
        >
        > - With this particular soundcard it is advisable to stay away
        from
        > the maximum sampling rate; otherwise output power and sideband
        > suppression start to suffer. For example sampling freq 48K, I find
        I
        > need to limit TX within 22 Khz range 7034 KHz - 7088 KHz. With 96K
        > sampling rate I can cover 7014 KHz - 7096 KHz
        >
        > - Before putting the exciter you should do a sanity check by
        > monitoring your transmission on a separate receiver.
        > Connect the SR6 Exciter to a Dummyload.
        > a) Tune the RX to the Transmit Frequency and position the RX
        Antenna
        > lead near the Dummy load until you obtain an S9+10dB Smeter
        reading.
        > b) Insert a 30dB attenuator in the antenna lead and note the new S-
        > Meter reading.
        > c) Now tune to Carrier Frequency (7056 KHz) and check whether the S-
        > Meter reading is same or less as in step b)
        > d) Tune to the unwanted sideband freq (7056 KHz +/- TX freq and
        check
        > whether S-Meter reading is same or less as in step b.
        >
        > - Recent correspondence "Big signal at 0 Hz" on the reflector: I
        > confirm that Exciter Carrier Suppression depends significantly on
        the
        > amount of 1/f noise which a particular soundcard produces. I plan
        to
        > tailor the I and Q response of the Exciter so it starts to drop
        below
        > 200Hz and see what difference this makes. Results will be updated
        via
        > Tony.
        >
        >
        > best 73s
        >
        > Jan
        >
        > G0BBL - M0PUB - G8BTR (QRP2K Design team)
        >
        Congrats Jan!! My exciter just came to life, I can get the PowerSDR
        to do an ID, then send constant dots and dashes. I am not familiar
        with PowerSDR, having used Rocky for SDR experiments up to now.

        I am hoping to be one of the first to have a SoftRock-to-SoftRock QSO
        (assuming I can figure out PowerSDR). Anybody else interested?

        My unit draws about 250ma in transmit, and puts out around 1/2 Watt.
        Still playing with it, I should be on the air later today (Sunday).

        Terry
        WB4JFI
      • Terry
        ... Alpha ... Bill ... 599 ... and ... as ... find ... 96K ... S- ... S- ... I ... PowerSDR ... QSO ... Watt. ... Sorry for the add-on reply, but has anyone
        Message 3 of 4 , Oct 1, 2006
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          --- In softrock40@yahoogroups.com, "Terry" <wb4jfi@...> wrote:
          >
          > --- In softrock40@yahoogroups.com, "verduynj" <Jan.Verduyn@> wrote:
          > >
          > > Bill, Tony, All,
          > >
          > > I made my first CW contact this morning with the SR6 Exciter
          Alpha
          > > prototype using the latest Version of PowerSDR Software which
          Bill
          > > released last Friday. Very pleased with this!!
          > >
          > > http://www.tracey.org/wjt/sdr1k/SoftRock40/PowerSDR-KD5TFD-srxmit-
          > > 20060928.zip - thanks Bill!!
          > >
          > > I worked ON5CBK, Patrick at 11:15 UTC on 7015 Khz and received
          599
          > > report .. Not bad for 0.6 Watt RF output!!
          > > Second contact was a solid 15 minute QSO with Joe, DM0K and
          > received
          > > a 559 report.
          > >
          > > Is this the first CW contact with the Softrock Exciter or has
          > somebody
          > > else beaten me to it?
          > >
          > > Some additional info from us who prototyped to Exciter:
          > >
          > > - Using (Dell on board Sigmatel STAC 92xx)s unwanted sideband
          and
          > > carrier suppression is at more -30dB down from full rated output
          as
          > > shown on a spectrum analyser. -30dB is the FCC requirement I
          > > understand.
          > >
          > > - With this particular soundcard it is advisable to stay away
          > from
          > > the maximum sampling rate; otherwise output power and sideband
          > > suppression start to suffer. For example sampling freq 48K, I
          find
          > I
          > > need to limit TX within 22 Khz range 7034 KHz - 7088 KHz. With
          96K
          > > sampling rate I can cover 7014 KHz - 7096 KHz
          > >
          > > - Before putting the exciter you should do a sanity check by
          > > monitoring your transmission on a separate receiver.
          > > Connect the SR6 Exciter to a Dummyload.
          > > a) Tune the RX to the Transmit Frequency and position the RX
          > Antenna
          > > lead near the Dummy load until you obtain an S9+10dB Smeter
          > reading.
          > > b) Insert a 30dB attenuator in the antenna lead and note the new
          S-
          > > Meter reading.
          > > c) Now tune to Carrier Frequency (7056 KHz) and check whether the
          S-
          > > Meter reading is same or less as in step b)
          > > d) Tune to the unwanted sideband freq (7056 KHz +/- TX freq and
          > check
          > > whether S-Meter reading is same or less as in step b.
          > >
          > > - Recent correspondence "Big signal at 0 Hz" on the reflector:
          I
          > > confirm that Exciter Carrier Suppression depends significantly on
          > the
          > > amount of 1/f noise which a particular soundcard produces. I plan
          > to
          > > tailor the I and Q response of the Exciter so it starts to drop
          > below
          > > 200Hz and see what difference this makes. Results will be updated
          > via
          > > Tony.
          > >
          > >
          > > best 73s
          > >
          > > Jan
          > >
          > > G0BBL - M0PUB - G8BTR (QRP2K Design team)
          > >
          > Congrats Jan!! My exciter just came to life, I can get the
          PowerSDR
          > to do an ID, then send constant dots and dashes. I am not familiar
          > with PowerSDR, having used Rocky for SDR experiments up to now.
          >
          > I am hoping to be one of the first to have a SoftRock-to-SoftRock
          QSO
          > (assuming I can figure out PowerSDR). Anybody else interested?
          >
          > My unit draws about 250ma in transmit, and puts out around 1/2
          Watt.
          > Still playing with it, I should be on the air later today (Sunday).
          >
          > Terry
          > WB4JFI
          >
          Sorry for the add-on reply, but has anyone looked at the exciter/amp
          on a spectrum analyzer? I used my homemade analyzer (Wes Hayward
          W7ZOI unit), and found the 2nd harmonic on 20 meters was only about
          12db down. I am looking at construction for errors. I assume its
          not the audio phasing (I/Q), as that would create an image within the
          40 meter band. I will feed a 20 meter signal into the board, and see
          if the receiver hears it strong, an indication the input filter is
          messed up. Then, I guess I will sweep the filter on the amplifier
          board.

          Is my assumption about the audio phasing correct?
          Terry
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