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Re: [FT897] Bandwidth for PSK31

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  • Roger J. Buffington
    ... What you describe is normal, and a BW of 3 Khz is about right. Remember that your center frequency is 1000hz. When you work a PSK signal, be sure that it
    Message 1 of 7 , Jul 1, 2007
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      William A Lathan wrote:
      >
      > I've had the 897D for only a few weeks, and I just got it on PSK31
      > using MixW (I'm using the US Interface Navigator)as the interface to
      > the radio). When I set the frequency of the 897 to 14.070, only about
      > 3KHz shows up in the waterfall display. I've enabled DSP and set the
      > low cut and high cut values so that I should now have a BW of about
      > 6KHz. Unfortunately, that still doesn't work as I only see the 3KHz
      > BW. Does anyone have any ideas what is limiting the BW?
      >
      > TIA,
      >
      > Bill, AK5K

      What you describe is normal, and a BW of 3 Khz is about right.

      Remember that your center frequency is 1000hz. When you work a PSK
      signal, be sure that it is centered at 1000hz. That way you can use
      whatever narrow filters, i.e. 300hz, 500hz that you have installed on
      your 897. Narrow filters make all the difference on PSK.

      Check out DM780. It is free for download and works fabulously with the
      FT897.

      de Roger W6VZV
    • Curt Givens
      Bill just got a MARS net and switched back to BPSK-31 and on my waterfall I have only about 4.5 showing. I suspect it has more to do with MiXW than the radio.
      Message 2 of 7 , Jul 2, 2007
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        Bill just got a MARS net and switched back to BPSK-31 and on my waterfall I
        have only about 4.5 showing. I suspect it has more to do with MiXW than the
        radio.



        Curt



        Curt Givens KC8STE, AAR5VR Army MARS
        Earthdog and Special Programs Director
        GCDOC/GCAC
        Dayton, OH

        _____

        From: FT897@yahoogroups.com [mailto:FT897@yahoogroups.com] On Behalf Of
        William A Lathan
        Sent: Friday, June 29, 2007 3:22 PM
        To: FT897@yahoogroups.com
        Subject: [FT897] Bandwidth for PSK31



        I've had the 897D for only a few weeks, and I just got it on PSK31
        using MixW (I'm using the US Interface Navigator)as the interface to
        the radio). When I set the frequency of the 897 to 14.070, only about
        3KHz shows up in the waterfall display. I've enabled DSP and set the
        low cut and high cut values so that I should now have a BW of about
        6KHz. Unfortunately, that still doesn't work as I only see the 3KHz
        BW. Does anyone have any ideas what is limiting the BW?

        TIA,

        Bill, AK5K




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      • dalite01@bellsouth.net
        You can chose a smaller magnification of the waterfall to increase visible bandwidth. Better yet, simply go to View- Spectrum- and select Sound Then you
        Message 3 of 7 , Jul 2, 2007
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          You can chose a smaller magnification of the waterfall to increase visible
          bandwidth.

          Better yet, simply go to View->> Spectrum->> and select Sound

          Then you will see the audio bandwidth and eliminate the confusion.

          When you select the frequency, 3KHz is the total bandwidth of both
          sidebands.

          For example, a center frequency of 14.070 would yield a LSB Dial Frequency
          of 14071.5 KHz and a USB Dial Frequency of 14068.5 KHz. When you subtract
          14068.5 from 14071.5, you get the 3KHz bandwidth possible.

          Conversly, a dial frequency of 14070.0 KHz in USB node will be center
          frequency of 14068.5 KHz; in LSB Mode, the same dial frequency would be a
          center frequency of 14067.0 KHz.




          -----Original Message-----
          From: FT897@yahoogroups.com [mailto:FT897@yahoogroups.com] On Behalf Of Curt
          Givens
          Sent: Monday, July 02, 2007 8:12 PM
          To: FT897@yahoogroups.com
          Subject: RE: [FT897] Bandwidth for PSK31


          Bill just got a MARS net and switched back to BPSK-31 and on my waterfall I
          have only about 4.5 showing. I suspect it has more to do with MiXW than the
          radio.



          Curt



          Curt Givens KC8STE, AAR5VR Army MARS
          Earthdog and Special Programs Director
          GCDOC/GCAC
          Dayton, OH

          _____

          From: FT897@yahoogroups.com [mailto:FT897@yahoogroups.com] On Behalf Of
          William A Lathan
          Sent: Friday, June 29, 2007 3:22 PM
          To: FT897@yahoogroups.com
          Subject: [FT897] Bandwidth for PSK31



          I've had the 897D for only a few weeks, and I just got it on PSK31 using
          MixW (I'm using the US Interface Navigator)as the interface to the radio).
          When I set the frequency of the 897 to 14.070, only about 3KHz shows up in
          the waterfall display. I've enabled DSP and set the low cut and high cut
          values so that I should now have a BW of about 6KHz. Unfortunately, that
          still doesn't work as I only see the 3KHz BW. Does anyone have any ideas
          what is limiting the BW?

          TIA,

          Bill, AK5K




          _____

          No viruses found in incoming message
          Scanned by iolo AntiVirusR 1.1.8.4
          http://www.iolo.com <http://www.iolo.com/iav/iavpop3>


          _______________________________________
          No viruses found in outgoing message
          Scanned by iolo AntiVirusR 1.1.8.4
          http://www.iolo.com

          [Non-text portions of this message have been removed]




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        • Lee Jorgensen
          Huh? Sidebands are the full 3 kHz above and below the center frequency. This is why if you attempt to transmit at 14350 with USB, you d actually be
          Message 4 of 7 , Jul 3, 2007
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            Huh? Sidebands are the full 3 kHz above and below the center
            frequency. This is why if you attempt to transmit at 14350 with USB,
            you'd actually be transmitting at 14551.5 +- 1.5kHz, or you would
            definately be out of band. However, if you transmitted LSB, you'd be in
            band from 14348.5 +- 1.5kHz.

            Check out: http://en.wikipedia.org/wiki/Sideband

            Each sideband has a full 3 hHz bandwidth, with everything together (both
            USB and LSB) you get about 6kHz bandwidth, which is AM modulation.

            But getting back on topic, the best results for PSK31 in the waterfall
            lies between about 750 - 2500. Yes, you can operate above and below
            this a bit, but from my observations, the power output is reduced.

            -Lee.
            n0wq


            dalite01@... wrote:
            > You can chose a smaller magnification of the waterfall to increase visible
            > bandwidth.
            >
            > Better yet, simply go to View->> Spectrum->> and select Sound
            >
            > Then you will see the audio bandwidth and eliminate the confusion.
            >
            > When you select the frequency, 3KHz is the total bandwidth of both
            > sidebands.
            >
            > For example, a center frequency of 14.070 would yield a LSB Dial Frequency
            > of 14071.5 KHz and a USB Dial Frequency of 14068.5 KHz. When you subtract
            > 14068.5 from 14071.5, you get the 3KHz bandwidth possible.
            >
            > Conversly, a dial frequency of 14070.0 KHz in USB node will be center
            > frequency of 14068.5 KHz; in LSB Mode, the same dial frequency would be a
            > center frequency of 14067.0 KHz.
            >
          • Geoff Blake
            ... Err, no. It is a matter of definition. In upper sideband mode, theoretically (and in a properly adjusted transmitter) the sideband will extend from between
            Message 5 of 7 , Jul 3, 2007
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              On Tue, 3 Jul 2007, Lee Jorgensen wrote:

              > Huh? Sidebands are the full 3 kHz above and below the center
              > frequency. This is why if you attempt to transmit at 14350 with USB,
              > you'd actually be transmitting at 14551.5 +- 1.5kHz, or you would
              > definately be out of band. However, if you transmitted LSB, you'd be in
              > band from 14348.5 +- 1.5kHz.

              Err, no. It is a matter of definition. In upper sideband mode,
              theoretically (and in a properly adjusted transmitter) the
              sideband will extend from between 200Hz to perhaps 2.7kHz above
              the carrier frequency. For lower sideband mode the sideband will
              be below the carrier frequency by similar amounts. The actual
              limits will be dependant on the transmitter.

              Again, theoretically, you couls put the carrier on exactly
              14.000MHz and transmit USB. To do this, you will have to have
              great faith in the frequency calibration of your transmitter, and
              a skin thick enough to withstand the 10 million or so CW operators
              that will be crawling all over you.

              Although the wiki definition correctly refers to the carrier
              frequency, some (many) amateur equipment manufacturers do not use
              the carrier frequency as the 'tuned to' frequency, instead using
              the centre of the sideband, as you describe. This is wrong and
              should be avoided.

              > Each sideband has a full 3 hHz bandwidth, with everything together (both
              > USB and LSB) you get about 6kHz bandwidth, which is AM modulation.

              Again no, is SSB, the sidebands occupy typically 0.3-2.7kHz above
              or below the carrier

              > But getting back on topic, the best results for PSK31 in the waterfall
              > lies between about 750 - 2500. Yes, you can operate above and below
              > this a bit, but from my observations, the power output is reduced.

              I would add, although LSB is accepted practice below and USB above
              10MHz, in data modes, USB is always used.

              73 Geoff
              --
              Geoff Blake G8GNZ located near Chelmsford, Essex, U.K.
              Please reply to: geoff(at)palaemon(dot)demon(dot)co(dot)uk
              Using Linux on Intel & Linux or NetBSD on Sun Sparc platforms

              Please avoid sending me Word or PowerPoint attachments.
              See <http://www.gnu.org/philosophy/no-word-attachments.html>
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