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Re: [linuxham] Re: Frequency Error Adjustment

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  • Dick
    ... Tas, I don t think there is an option in fldigi to adjust the frequency acquired by CAT to compensate for errors. Dick AA5VU
    Message 1 of 9 , May 3 2:47 AM
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      On May 3, 2011, at 2:16 AM, tasfluser wrote:

      BTW, is there a way in fldigi itself using hamlib (not flrig)
      to adjust the frequency acquired by CAT by the known amount of error the rig produces at that frequency (or in percentage would be great!) 

      73
      Tas

      Tas, 

      I don't think there is an option in fldigi to adjust the frequency acquired by CAT to 
      compensate for errors.

      Dick AA5VU
    • Dick
      ... I wonder what kind of rig you have that has USB-CW and LSB-CW? Mine has USB, LSB and CW but does not have what you mentioned. The fldigi Frequency
      Message 2 of 9 , May 3 4:02 AM
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        On May 3, 2011, at 2:16 AM, tasfluser wrote:

        You could also use the simple method of comparing the difference between your rig's LSB and USB reception, thus nullifying the effect of any parameters you haven't yet adjusted, as sound card error.
        Tune to WWV and alternate between usb-cw and lsb-cw mode of your rig's. The displacement between your rig's cw pitch on the waterfall should be (set to) zero. 

        I wonder what kind of rig you have that has USB-CW and LSB-CW?  Mine has USB, LSB  and CW
        but does not have what you mentioned. 

        The fldigi Frequency Analysis Op Mode seems like the best way to check your calibration
        to WWV. Just tune down 1 to 9.999.000 MHz, click on the signal and read the data at the 
        bottom of the status bar.  The TS-590S has been pretty close since installing the TCXO.

        I agree with others W1AW is not the best place for a calibration test.   

        Dick AA5VU
      • Ed
        On Tue, 3 May 2011 06:02:46 -0500 ... From the Help file :: Fldigi can be used to accurately measure the frequency of a remote signal that is transmitting a
        Message 3 of 9 , May 3 4:24 AM
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          On Tue, 3 May 2011 06:02:46 -0500
          Dick <aa5vu@...> wrote:

          > On May 3, 2011, at 2:16 AM, tasfluser wrote:
          >
          > > You could also use the simple method of comparing the difference
          > > between your rig's LSB and USB reception, thus nullifying the
          > > effect of any parameters you haven't yet adjusted, as sound card
          > > error. Tune to WWV and alternate between usb-cw and lsb-cw mode of
          > > your rig's. The displacement between your rig's cw pitch on the
          > > waterfall should be (set to) zero.
          >
          > I wonder what kind of rig you have that has USB-CW and LSB-CW? Mine
          > has USB, LSB and CW but does not have what you mentioned.
          >
          > The fldigi Frequency Analysis Op Mode seems like the best way to
          > check your calibration to WWV. Just tune down 1 to 9.999.000 MHz,
          > click on the signal and read the data at the bottom of the status
          > bar. The TS-590S has been pretty close since installing the TCXO.
          >
          > I agree with others W1AW is not the best place for a calibration
          > test.
          >
          > Dick AA5VU

          From the Help file ::


          Fldigi can be used to accurately measure the frequency of a remote
          signal that is transmitting a steady carrier.
          I have set the sound card up using the WWV modem and have it adjusted
          for the proper PPM offset on receive. I followed the frequency
          calibration procedure that Icom recommends for the IC-746PRO, adjusting
          WWV at 10 MHz for a zero beat.

          Then fldigi was used in the "Freq Analysis" mode to track the WWV
          carrier at 10 MHz. In this mode the decoder is merely a very narrow
          band AFC tracking filter. The filter bandwidth is set to 2 Hz and the
          tracking time constants to about 5 seconds. Future releases will
          probably make both of these user adjustable. When the signal is being
          tracked the digiscope (right hand display) will be a horizontal line.
          If the signal is very noisy and tracking difficult the digiscope will
          jump and become wavy. You can see from the above image that I am
          tracking about 0.22 Hz high on WWV. I have repeated this measurement
          at various times during the day and on various days with nearly the
          same result. So I am comfortable with knowing that my local oscillator
          is just a little low (that is why the Frequency reads high).

          ARRL frequently announces a frequency measurement test (FMT) which
          takes placde on 160, 80 and 40 meters. This is a chance to test your
          skills in frequency measurement. You should be able to make a
          submission to the FMT using this technique. Make corrections to the
          FMT transmission based upon your WWV measurement. You may have to
          adjust for other local oscillator effects as well. If you have some
          good ways to measure and correct for these I would be glad to share
          them with the other fldigi users.





          Ed W3NR
        • tasfluser
          ... Hi Dick, well yes it s a do-it-all rig, with plenty of new exotic modes, it can even brew some tea if you like (!) (or coffe) HI :) You are right of
          Message 4 of 9 , May 4 12:52 AM
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            --- In linuxham@yahoogroups.com, Dick <aa5vu@...> wrote:
            ...
            > I wonder what kind of rig you have that has USB-CW and LSB-CW? Mine has USB, LSB and CW
            > but does not have what you mentioned.
            >

            Hi Dick,
            well yes it's a do-it-all rig, with plenty of new exotic modes, it can even brew some tea if you like (!) (or coffe) HI :)
            You are right of course, sorry, it's only my English betraying me. I meant to say the difference between receiving in conventional CW as opposed to CW reverse. As an example, if you depress the 'CW' button, on this Yaesu FT-847 I like to play with, you select CW mode, and "CW" appears on the display. If you depress the 'CW' button a second time "LSB CW" appears on the dispaly, mode remains cw of course. On the other hand an FT-920 would show briefly a blinking LSB or USB respectively (but it also changes freq accordignly)

            An advantage of using the method of comparing the frequency of the cw pitch is that the error is doubled and is more accurately measured on the waterfall scale or even being heard. Using it, this particular FT-847 is found to be off by ~70Hz at 10MHz(!). The Ft-847 is controlled by a single oscillator so the error is proportional to frequency.I canconfirm this error by tuning for the other guy's normal voice (in SSB).
            As a comparison, the FT-920 although without a TCXO, is off at 10MHz by only 5Hz!
            At the moment, flrig does not include them in the list of rigs it could communicate with, however both behave well with hamlib and fldigi. Now with the FT-847 showing e.g. 10200.07KHz, and with a sweet spot shift of 1KHz, fldigi will log 10201.07KHz, although the actual working frequency would be 10201.00KHz. Not a big deal, but it would be nice to be able to trim it just a little :).I may be missing something, but adjustment of the Rx under Configure/Audio/Settings, requires -50000 ppm to reduce the error to ~15Hz.

            cheers
            Tas
          • G6CKR
            ... Hi the first 2 items are sound card The third (TX offset) would correct for the TX side but you would still have the RX the adjust. My TS570 does not
            Message 5 of 9 , May 4 2:48 AM
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              On 04/05/11 08:52, tasfluser wrote:
              > --- In linuxham@yahoogroups.com, Dick <aa5vu@...> wrote:
              > ...
              >> I wonder what kind of rig you have that has USB-CW and LSB-CW? Mine has USB, LSB and CW
              >> but does not have what you mentioned.
              >>
              >
              > Hi Dick,
              > well yes it's a do-it-all rig, with plenty of new exotic modes, it can even brew some tea if you like (!) (or coffe) HI :)
              > You are right of course, sorry, it's only my English betraying me. I meant to say the difference between receiving in conventional CW as opposed to CW reverse. As an example, if you depress the 'CW' button, on this Yaesu FT-847 I like to play with, you select CW mode, and "CW" appears on the display. If you depress the 'CW' button a second time "LSB CW" appears on the dispaly, mode remains cw of course. On the other hand an FT-920 would show briefly a blinking LSB or USB respectively (but it also changes freq accordignly)
              >
              > An advantage of using the method of comparing the frequency of the cw pitch is that the error is doubled and is more accurately measured on the waterfall scale or even being heard. Using it, this particular FT-847 is found to be off by ~70Hz at 10MHz(!). The Ft-847 is controlled by a single oscillator so the error is proportional to frequency.I canconfirm this error by tuning for the other guy's normal voice (in SSB).
              > As a comparison, the FT-920 although without a TCXO, is off at 10MHz by only 5Hz!
              > At the moment, flrig does not include them in the list of rigs it could communicate with, however both behave well with hamlib and fldigi. Now with the FT-847 showing e.g. 10200.07KHz, and with a sweet spot shift of 1KHz, fldigi will log 10201.07KHz, although the actual working frequency would be 10201.00KHz. Not a big deal, but it would be nice to be able to trim it just a little :).I may be missing something, but adjustment of the Rx under Configure/Audio/Settings, requires -50000 ppm to reduce the error to ~15Hz.
              >
              > cheers
              > Tas
              >
              > adjustments for the accuracy of the sample rate.
              >
              >
              Hi the first 2 items are sound card
              The third (TX offset) would correct for the TX side but you would still
              have the RX the adjust.
              My TS570 does not indicate added XIT and RIT to the display frequency
              passed to fldigi remains same.
              In my case on 30 m adding +4 of RIT and XIT gets me very close to 10.147
              MHz for example and fldigi displays 10.147 MHz which is correct.
              I need the better check with a frequency standard. but it work for me on
              the 30m pskmail servers.
              Roger
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