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Re: [linuxham] Re: Frequency Tests Using W1AW RTTY Bulletin

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  • G6CKR
    If it is a few Hz then TX offset under sound card settings might work for you. if it is the same for TX and RX setting the same amount of RIT and XIT on the
    Message 1 of 9 , May 3 1:48 AM
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      If it is a few Hz then TX offset under sound card settings might work
      for you. if it is the same for TX and RX setting the same amount of RIT
      and XIT on the radio may be better.
      73 Roger G6CKR
      On 03/05/11 08:16, tasfluser wrote:
      > Hello,
      > 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.
      >
      >
      > 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
      >
      >
      > --- In linuxham@yahoogroups.com, Martin Ewing <martin.s.ewing@...> wrote:
      >>
      >> Dick,
      >>
      >> W1AW is not a standard frequency service!* They use ordinary Icom rigs as
      >> exciters, and I'm not aware that they do anything special about frequency
      >> control for normal transmissions. And I don't know how precisely they
      >> generate RTTY tones, either. Check http://www.arrl.org/w1aw or email Joe
      >> Carcia nj1q@... for more info.
      >>
      >> It's much better to use WWV or CHU for frequency checking. You don't have
      >> to zero beat. (Zero beating is the same now as it ever was! But you need a
      >> wide enough IF and good low freq. audio response.) Just tune 1 kHz below the
      >> nominal freq. in USB mode and measure the 1 kHz beat note with fldigi. You
      >> can also receive WWV in AM mode and measure the 600 Hz modulation. (That
      >> checks your soundcard's clock.)
      >>
      >> 73
      >> Martin
      >> AA6E
      >>
      >> *It would be great if the League would do this, but it takes time and money
      >> to do it right. Talk to your Division Director.
      >>
      >> On Sat, Apr 30, 2011 at 8:20 AM, Dick <aa5vu@...> wrote:
      >>
      >>> Last week I installed a Kenwood SO-3 TCXO in the TS-590S and used
      >>> fldigi's Frequency Analysis as a tool to tweak in the calibration.
      >>>
      >>> As a test to check my calibration I copied the W1AW RTTY Bulletin
      >>> that I understand is transmitted in AFSK to be received by ham rigs
      >>> in RTTY or FSK mode at 14.095 MHz. I was using the TS-590S in
      >>> AFSK USB-DATA mode.
      >>>
      >>> W1AW had a rock solid, easy to copy signal and fldig-3.21.9 had no
      >>> problem decoding the signal. I used 1500 Hz for the RTTY sweet spot
      >>> setting in fldigi so I should have found W1AW at 14.093.500 as the
      >>> dial frequency.
      >>>
      >>> I put the TS-590's VFO exactly on 14.093.50 and 14.093.000 was
      >>> displayed in the fldigi RigCAT TS-590S Frequency box. I then mouse
      >>> clicked on the W1AW signal on the waterfall and let the AFC do its
      >>> thing. Copy was rock solid as expected.
      >>>
      >>> Now for the strange part. The QSO Freq. box in fldigi displayed
      >>> 14.095.936 and the Freq readout in the status bar (below the waterfall)
      >>> was displaying 14095932.79 Hz. This kind of stuff bugs me and that was
      >>> why I ordered the TCXO from Kenwood. Does this mean my calibration
      >>> of the TCXO is in error or was W1AW transmitting a little low?
      >>>
      >>> With a good calibration I was would expected the fldigi QSO Freq box
      >>> to round to 14.095.0. Mine rounded to 14.094.9 but the Freq in fldigi
      >>> status bar rounded to 14.095.9. Now I am really confused?
      >>>
      >>> When I used the Frequency Analysis mode in fldigi to calibrate the TS-590's
      >>> TCXO, I was getting final readings between 1499998.65 to 15000000.32.
      >>> It was really hard to get numbers to settle on the WWV 15 MHz signal. The
      >>> SO-3 TCXO adjustment pot is really touchy.
      >>>
      >>> I have heard people say to zero beat the WWV signal as a test and I have
      >>> no idea what they mean or how to zero beat anything with the newer rigs.
      >>> Back in the old days with a SB-101 I understood the term.
      >>>
      >>> I have decided to just leave it alone that the TS-590's calibration is
      >>> probably
      >>> close enough for general amateur use.
      >>>
      >>> Thanks for reading
      >>>
      >>> 73 Dick AA5VU
      >>>
      >>>
      >> --
      >> Martin Ewing
      >> Branford, Connecticut
      >> martin.s.ewing@...
      >>
      >
      >
      >
    • 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 2 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 3 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 4 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 5 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 6 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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