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Re: [FT897] Bandwidth for PSK31

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  • Lee Jorgensen
    Bill, PSK is limited to a sideband, which is about 2.5-3khz. The software is limiting where you can transmit, not the radio. You could always turn the dial up
    Message 1 of 7 , Jun 30, 2007
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      Bill,

      PSK is limited to a sideband, which is about 2.5-3khz. The software is
      limiting where you can transmit, not the radio.
      You could always turn the dial up and down a bit to move on the band,
      and it shouldn't affect your reception of others. Typically, it's
      14070.15 ... but if you're at 14070, we'd still be able to talk, just
      your offset inside the waterfall will be different than what I would be
      displaying.

      You may want to actually turn off all DSP on the signal, since some of
      the faint (but workable) signals may be blocked. The software is where
      the signal processing is, not the radio.

      BTW, you may want to look at Ham Radio Deluxe for PSK31. It's
      intimidating at first, however, once I started actively playing with it,
      it's much nicer than some of the other packages out there. Plus it has
      a built in logging package, which really makes things a snap to save.

      -Lee.
      n0wq


      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
      >
      >
      >
      >
      > Yahoo! Groups Links
      >
      >
      >
      >
      >
      >
    • 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 2 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 3 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 4 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]




            Yahoo! Groups Links
          • 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 5 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 6 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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