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High SWR on SSB, but good on AM???

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  • twin_otter_99
    Hello... I have a new FT-897 and have been trying to get a dipole working on 20m. I have it tuned properly (I think) and have it almost flat (no SWR movement
    Message 1 of 6 , May 2, 2011
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      Hello...

      I have a new FT-897 and have been trying to get a dipole working on 20m. I have it tuned properly (I think) and have it almost flat (no SWR movement on the radio) when checking with AM. On sideband, the SWR is quite high.

      I don't have an external meter and don't have access to one, so have to use the internal one. Any idea why the big difference in SWR between SSB and AM? I've checked at 5w and 100w and the behavior is the same.

      Thanks for any useful info...please don't tell me to go buy an external SWR meter...I don't have funds for that right now and don't know anyone that has an extra one I can borrow.

      73
    • carl.krauthauser
      Usually, I would always recommend using an good external meter as I find them to be generally more accurate. Addressing your more immediate question, I m not
      Message 2 of 6 , May 3, 2011
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        Usually, I would always recommend using an good external meter as I find them to be generally more accurate.

        Addressing your more immediate question, I'm not sure I would trust the reading on SSB, as you are not transmitting a constant signal, but one that is generally varying. To test the SWR, I would set the output power to about 5W, and in CW mode, FM or AM, I would simply send a very brief unmodulated carrier, and get your SWR reading that way. This is the most reliable. Thus, at first glance, I would trust what you have measured on AM far more than what you measured on SSB.

        Hope this helps!

        73 de Carl - NT3H

        --- In FT897@yahoogroups.com, "twin_otter_99" <mmgf49202@...> wrote:
        >
        > Hello...
        >
        > I have a new FT-897 and have been trying to get a dipole working on 20m. I have it tuned properly (I think) and have it almost flat (no SWR movement on the radio) when checking with AM. On sideband, the SWR is quite high.
        >
        > I don't have an external meter and don't have access to one, so have to use the internal one. Any idea why the big difference in SWR between SSB and AM? I've checked at 5w and 100w and the behavior is the same.
        >
        > Thanks for any useful info...please don't tell me to go buy an external SWR meter...I don't have funds for that right now and don't know anyone that has an extra one I can borrow.
        >
        > 73
        >
      • graham787
        Is the meter a SWR meter or simply showing the reflected power ?
        Message 3 of 6 , May 3, 2011
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          Is the meter a SWR meter or simply showing the reflected power ?

          --- In FT897@yahoogroups.com, "carl.krauthauser" <carl@...> wrote:
          >
          > Usually, I would always recommend using an good external meter as I find them to be generally more accurate.
          >
          > Addressing your more immediate question, I'm not sure I would trust the reading on SSB, as you are not transmitting a constant signal, but one that is generally varying. To test the SWR, I would set the output power to about 5W, and in CW mode, FM or AM, I would simply send a very brief unmodulated carrier, and get your SWR reading that way. This is the most reliable. Thus, at first glance, I would trust what you have measured on AM far more than what you measured on SSB.
          >
          > Hope this helps!
          >
          > 73 de Carl - NT3H
          >
          > --- In FT897@yahoogroups.com, "twin_otter_99" <mmgf49202@> wrote:
          > >
          > > Hello...
          > >
          > > I have a new FT-897 and have been trying to get a dipole working on 20m. I have it tuned properly (I think) and have it almost flat (no SWR movement on the radio) when checking with AM. On sideband, the SWR is quite high.
          > >
          > > I don't have an external meter and don't have access to one, so have to use the internal one. Any idea why the big difference in SWR between SSB and AM? I've checked at 5w and 100w and the behavior is the same.
          > >
          > > Thanks for any useful info...please don't tell me to go buy an external SWR meter...I don't have funds for that right now and don't know anyone that has an extra one I can borrow.
          > >
          > > 73
          > >
          >
        • P Grant
          Hello all, I have 3 different models of FT8**, all of which have a built in swr strip meter. and they all show HISWR when antenna is not matched to the
          Message 4 of 6 , May 3, 2011
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            Hello all,

            I have 3 different models of FT8**, all of which have a "built in" swr strip meter. and they all show "HISWR" when antenna is not matched to the radio, and the radio reduces power accordingly. Great feature.!!

            None of the radios built in "meters" show any thing close to accuracy when compared to a "genuine" SWR meter or a peak reading reflected power meter.

            SO, I would not put ANY trust in the AM readings never mind the SSB readings.

            My opinion is the "built in " SWR meter is another gimmick which is added for the convenience of the sharp salesman, who is using this as a selling point, for the unwary. The alternative meter scales I cannot vouch for, but I think the "power out" could be a bit unsure ?

            You could pick up a decent used "branded" SWR meter at a rally or ham fest second hand for say $20.oo, and if you purchase for VHF it will cover all lower bands with ease, but not the reverse, HF meter will not cover VHF ! There is also the option of "build your own" from a kit, check www.. or from your parts box.

            Sorry I cannot be more supportive.

            73 Peter EI4HX ei4hxperimental@...
            ----- Original Message -----
            From: graham787
            To: FT897@yahoogroups.com
            Sent: Tuesday, May 03, 2011 9:02 PM
            Subject: [FT897] Re: High SWR on SSB, but good on AM???



            Is the meter a SWR meter or simply showing the reflected power ?

            --- In FT897@yahoogroups.com, "carl.krauthauser" <carl@...> wrote:
            >
            > Usually, I would always recommend using an good external meter as I find them to be generally more accurate.
            >
            > Addressing your more immediate question, I'm not sure I would trust the reading on SSB, as you are not transmitting a constant signal, but one that is generally varying. To test the SWR, I would set the output power to about 5W, and in CW mode, FM or AM, I would simply send a very brief unmodulated carrier, and get your SWR reading that way. This is the most reliable. Thus, at first glance, I would trust what you have measured on AM far more than what you measured on SSB.
            >
            > Hope this helps!
            >
            > 73 de Carl - NT3H
            >
            > --- In FT897@yahoogroups.com, "twin_otter_99" <mmgf49202@> wrote:
            > >
            > > Hello...
            > >
            > > I have a new FT-897 and have been trying to get a dipole working on 20m. I have it tuned properly (I think) and have it almost flat (no SWR movement on the radio) when checking with AM. On sideband, the SWR is quite high.
            > >
            > > I don't have an external meter and don't have access to one, so have to use the internal one. Any idea why the big difference in SWR between SSB and AM? I've checked at 5w and 100w and the behavior is the same.
            > >
            > > Thanks for any useful info...please don't tell me to go buy an external SWR meter...I don't have funds for that right now and don't know anyone that has an extra one I can borrow.
            > >
            > > 73
            > >
            >





            [Non-text portions of this message have been removed]
          • twin_otter_99
            Thanks for your useful reply, Sir. 73...
            Message 5 of 6 , May 3, 2011
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              Thanks for your useful reply, Sir.

              73...

              --- In FT897@yahoogroups.com, "carl.krauthauser" <carl@...> wrote:
              >
              > Usually, I would always recommend using an good external meter as I find them to be generally more accurate.
              >
              > Addressing your more immediate question, I'm not sure I would trust the reading on SSB, as you are not transmitting a constant signal, but one that is generally varying. To test the SWR, I would set the output power to about 5W, and in CW mode, FM or AM, I would simply send a very brief unmodulated carrier, and get your SWR reading that way. This is the most reliable. Thus, at first glance, I would trust what you have measured on AM far more than what you measured on SSB.
              >
              > Hope this helps!
              >
              > 73 de Carl - NT3H
              >
              > --- In FT897@yahoogroups.com, "twin_otter_99" <mmgf49202@> wrote:
              > >
              > > Hello...
              > >
              > > I have a new FT-897 and have been trying to get a dipole working on 20m. I have it tuned properly (I think) and have it almost flat (no SWR movement on the radio) when checking with AM. On sideband, the SWR is quite high.
              > >
              > > I don't have an external meter and don't have access to one, so have to use the internal one. Any idea why the big difference in SWR between SSB and AM? I've checked at 5w and 100w and the behavior is the same.
              > >
              > > Thanks for any useful info...please don't tell me to go buy an external SWR meter...I don't have funds for that right now and don't know anyone that has an extra one I can borrow.
              > >
              > > 73
              > >
              >
            • Radio_Randy
              Do you have a dummy load (even a 5 watt one) that you can confirm your SWR readings with? The modulation type should have no effect on SWR, at all. Also,
              Message 6 of 6 , May 4, 2011
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                Do you have a dummy load (even a 5 watt one) that you can confirm your SWR readings with? The modulation type should have no effect on SWR, at all.

                Also, double check to insure you were actually looking at SWR and not ALC, Modulation, etc.

                73, Randy N7CKJ

                --- In FT897@yahoogroups.com, "twin_otter_99" <mmgf49202@...> wrote:
                >
                > Hello...
                >
                > I have a new FT-897 and have been trying to get a dipole working on 20m. I have it tuned properly (I think) and have it almost flat (no SWR movement on the radio) when checking with AM. On sideband, the SWR is quite high.
                >
                > I don't have an external meter and don't have access to one, so have to use the internal one. Any idea why the big difference in SWR between SSB and AM? I've checked at 5w and 100w and the behavior is the same.
                >
                > Thanks for any useful info...please don't tell me to go buy an external SWR meter...I don't have funds for that right now and don't know anyone that has an extra one I can borrow.
                >
                > 73
                >
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