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Re: [Q15X25] Signal Distortion and the Yaesu FT847 - Q15X25

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  • Mark Miller
    ... Is this PEP or average? I run 75 W PEP on my IC746 on 15 M. The watt meter shows
    Message 1 of 9 , Feb 1, 2003
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      At 13:46 1/30/03 +0000, ka2hzo <ronchap@...> wrote:
      >Had a another nice QSO on 21.133 MHZ USB yesterday.
      >
      >We did some more testing.
      >I found that the upper limit on the Yaesu FT847 before distortion in
      >the signals set in was 60 watts. I could still hold the link at this
      >point. But at 75 Watts. The link stopped working.

      Is this PEP or average?

      I run 75 W PEP on my IC746 on 15 M. The watt meter shows < 20 watts when
      sending Q15X25 tones. I use the tune transmitter function of MixW and set
      the power just below where the ALC action occurs. On 15 Meters this is 75
      watts, on 20M I can usually get closer to 100W.

      I have been out of town and sorry to miss all of this action. Will be
      sending some unproto's this weekend and will look for you guys. One thing
      that is nice when sending beacons is that you add a date time stamp to each
      tx. This is for us guys that leave the rig on and just want to know how
      long ago we missed the beacon. I had the rig on 21.133 (dial) and saw lots
      of beacons, but had no idea when they occurred.

      73
      Mark N5RFX
    • Ron
      AVERAGE. The watt meter shows 40 watts on both the radio and Antenna tuner. Is this PEP or average? If you would like to see what my tones look like going out
      Message 2 of 9 , Feb 1, 2003
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        AVERAGE.
         
        The watt meter shows 40 watts on both the radio and Antenna tuner.
        Is this PEP or average?
         
        If you would like to see what my tones look like going out over the air
         
        Please Checkout:
         
         
        I've been getting on at 20:00 UTC.
         
        So I'll look for you around then.
         
        It's a Shame about the space shuttle.
         
         
        73
        Ro nKA2HZO

        I run 75 W PEP on my IC746 on 15 M.  The watt meter shows < 20 watts when
        sending Q15X25 tones.  I use the tune transmitter function of MixW and set
        the power just below where the ALC action occurs.   On 15 Meters this is 75
        watts, on 20M I can usually get closer to 100W.

        I have been out of town and sorry to miss all of this action.  Will be
        sending some unproto's this weekend and will look for you guys.  One thing
        that is nice when sending beacons is that you add a date time stamp to each
        tx.  This is for us guys that leave the rig on and just want to know how
        long ago we missed the beacon.  I had the rig on 21.133 (dial) and saw lots
        of beacons, but had no idea when they occurred.

        73
        Mark N5RFX


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      • Tomi Manninen
        ... Again, a typical power meter probably shows something _between_ peak and average, when you transmit Q15X25. The crest factor, or peak to average power
        Message 3 of 9 , Feb 1, 2003
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          On Sat, 1 Feb 2003, Ron wrote:

          > AVERAGE.
          >
          > The watt meter shows 40 watts on both the radio and Antenna tuner.
          > Is this PEP or average?

          Again, a typical power meter probably shows something _between_ peak and
          average, when you transmit Q15X25.

          The crest factor, or peak to average power ratio with Q15X25 is
          approximately 12dB. That means with 40W average your peaks would be
          at about 630 watts..! Not likely. :-)

          I looked at the picture you sent and to me it looks like there is some
          distortion already.

          > It's a Shame about the space shuttle.

          It is, really!

          --
          Tomi Manninen Internet: oh2bns@...
          OH2BNS AX.25: oh2bns@...
          KP20ME04 Amprnet: oh2bns@...
        • Ron
          Hi, I m using a MFJ Versa Tuner V. The switch is set to Average Power reading. Both the 847 and Versatuner show the same Powere reading on the meters 40
          Message 4 of 9 , Feb 1, 2003
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            Hi,
             
            I'm using a MFJ Versa Tuner V.  The switch is set to Average Power reading.
            Both the 847 and Versatuner show the same Powere reading on the  meters 40 watts for Q15X25 and 100 W for test tone.
            When I key the rig with the Test Tone.  It shows 100 watts on both the tuner and the Rig.. 
             
            My AUDIO going from my soundcard to my radio is very very clean.
            May be some hum or ripple way way down like at -160DB but not enough to bother anything.
             
             
            73 Ron KA2HZO
             
             
             
            ----- Original Message -----
            Sent: Saturday, February 01, 2003 12:29 PM
            Subject: Re: [Q15X25] Signal Distortion and the Yaesu FT847 - Q15X25

            On Sat, 1 Feb 2003, Ron wrote:

            > AVERAGE.
            >
            > The watt meter shows 40 watts on both the radio and Antenna tuner.
            > Is this PEP or average?

            Again, a typical power meter probably shows something _between_ peak and
            average, when you transmit Q15X25.

            The crest factor, or peak to average power ratio with Q15X25 is
            approximately 12dB. That means with 40W average your peaks would be
            at about 630 watts..! Not likely. :-)

            I looked at the picture you sent and to me it looks like there is some
            distortion already.

            > It's a Shame about the space shuttle.

            It is, really!

            --
            Tomi Manninen           Internet:  oh2bns@...
            OH2BNS                  AX.25:     oh2bns@...
            KP20ME04                Amprnet:   oh2bns@...


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          • Mark Miller
            I run 100 W PEP. The only way I am sure is by adjusting my power using the MixW tune transmitter signal. When I transmit Q15X25 by Watt meter shows
            Message 5 of 9 , Feb 1, 2003
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              I run 100 W PEP. The only way I am sure is by adjusting my power using the
              MixW tune transmitter signal. When I transmit Q15X25 by Watt meter shows
              <20 Watts. If the peak to average power is 12 dB, then my true average
              power is a bit over 6 watts. That sounds very reasonable.

              It is tragic about the shuttle. I was at the rig at 1400z when I heard
              what I now believe was a sonic boom. It was slightly different than the
              sonic booms I have heard in the past. The shock waves rattled the windows
              on the QTH. I thought something had blown up in the neighborhood. Went
              outside and everything seemed ok. Turned on the local news and heard of
              the tragedy.

              73 Mark N5RFX

              At 19:29 2/1/03 +0200, you wrote:
              >On Sat, 1 Feb 2003, Ron wrote:
              >
              > > AVERAGE.
              > >
              > > The watt meter shows 40 watts on both the radio and Antenna tuner.
              > > Is this PEP or average?
              >
              >Again, a typical power meter probably shows something _between_ peak and
              >average, when you transmit Q15X25.
              >
              >The crest factor, or peak to average power ratio with Q15X25 is
              >approximately 12dB. That means with 40W average your peaks would be
              >at about 630 watts..! Not likely. :-)
              >
              >I looked at the picture you sent and to me it looks like there is some
              >distortion already.
              >
              > > It's a Shame about the space shuttle.
              >
              >It is, really!
              >
              >--
              >Tomi Manninen Internet: oh2bns@...
              >OH2BNS AX.25: oh2bns@...
              >KP20ME04 Amprnet: oh2bns@...
              >
              >
              >To unsubscribe from this group, send an email to:
              >Q15X25-unsubscribe@yahoogroups.com
              >
              >
              >
              >Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
            • n7mjw <n7mjw@yahoo.com>
              Its just amaizing with all that stuff falling from the sky, nobody on the ground got hit or otherwise hurt... Sometimes we can do more more than count our
              Message 6 of 9 , Feb 3, 2003
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                Its just amaizing with all that stuff falling from the sky, nobody on
                the ground got hit or otherwise hurt...

                Sometimes we can do more more than count our blessings.

                Dave



                >
                > It is tragic about the shuttle. I was at the rig at 1400z when I
                heard
                > what I now believe was a sonic boom. It was slightly different
                than the
                > sonic booms I have heard in the past. The shock waves rattled the
                windows
                > on the QTH. I thought something had blown up in the neighborhood.
                Went
                > outside and everything seemed ok. Turned on the local news and
                heard of
                > the tragedy.
                >
                > 73 Mark N5RFX
                >
              • Tomi Manninen
                ... I downloaded what I think is the Versa Tuner V manual from the MFJ site and it doesn t really tell anything about the way the average power metering is
                Message 7 of 9 , Feb 3, 2003
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                  On Sat, 1 Feb 2003, Ron wrote:

                  > I'm using a MFJ Versa Tuner V. The switch is set to Average Power
                  > reading. Both the 847 and Versatuner show the same Powere reading on the
                  > meters 40 watts for Q15X25 and 100 W for test tone. When I key the rig
                  > with the Test Tone. It shows 100 watts on both the tuner and the Rig..

                  I downloaded what I think is the Versa Tuner V manual from the MFJ site
                  and it doesn't really tell anything about the way the average power
                  metering is done. If they had a true-RMS detector I think they would have
                  mentioned that and with bold letters... :-)

                  Anyway it's a simple fact that a _real_ 40 Watts average power would mean
                  that either your peak output power is abt. 630 Watts or your transmitter
                  is severely clipping the waveform and potentially generating lots of
                  interference. I find it more probable that your power meters are showing
                  a bit too big figures.

                  --
                  Tomi Manninen Internet: oh2bns@...
                  OH2BNS AX.25: oh2bns@...
                  KP20ME04 Amprnet: oh2bns@...
                • Ron
                  I agree with you. I m just telling you that the two meters readings show.. Maybe both YAESU and MFJ are using the same circuits to determine the power
                  Message 8 of 9 , Feb 3, 2003
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                    I agree with you.
                    I'm just telling you that the two meters readings show..
                    Maybe both YAESU and MFJ are using the same circuits to determine the power readings.
                     
                    Don't really know.  I checked agn today.
                    I started with the meter readig of 5 watts and went up by 5w
                    These are power readings determined on the meters by bringing the auido level up.
                     
                     
                    5W = OK
                    10W = OK
                    15W= OK
                    20W = OK
                    25W = OK
                     
                    30W=OK
                    35W=OK
                    40W=OK
                    45W = Some Distortion could be seen in the wav form. But link was still holding.
                    50W = You can see more distortion in the Wav form and could hear the clipping with the radio's audio monitor.  But link still worked.
                    55W = NO GO.  Went into Recovery.  Disconnected and tried to re-connect.  I was able to re-connect.  But that was it.  Could not pass any traffic.
                    60 W = NO good. Wav was filled with all kinds of distortion.  Could not make out the stair steps at all,
                    No link could be established.
                     
                    So maybe the when the Meters on the MFJ AND FT47 are showing 60 watts.  They are really showing 20 watts.
                    Don't know.  Seems strange.  I'm getting the same values on two meters and hard to believe both meters have not been corrctly calibrated.  Who knows?  I guess anything is possible.
                     
                    I guess I'm going to have to see if I can find someone with a bird and do a real test. HI HI.
                     
                     
                    73
                    Ron
                     
                     
                     
                     
                     
                     
                    Anyway it's a simple fact that a _real_ 40 Watts average power would mean
                    that either your peak output power is abt. 630 Watts or your transmitter
                    is severely clipping the waveform and potentially generating lots of
                    interference. I find it more probable that your power meters are showing
                    a bit too big figures.
                     
                     
                     
                     
                     
                     
                     
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