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Re: Antenna Tuner

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  • Yannick
    Happy new year to everyone. Like a lot of devices, an Antenna Tuner is an important part of many ham stations and give a lot of help in having an effective
    Message 1 of 32 , Jan 1, 2012
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      Happy new year to everyone.

      Like a lot of devices, an Antenna Tuner is an important part of many ham stations and give a lot of help in having an effective station.
      Like a lot of devices : don't over-use it.

      Of course a resonant antenna put high in the sky with a short low loss feeder is the best.
      A highly mismatched antenna buried in the ground with long high loss line is the worst.
      Anything between could be useful sometime but never forget its limitations.

      If the only thing you can have is a low efficiency antenna but if it can put you on the air, it is better than nothing. The probability that the "rare DX" hear you is still low but 0,01% is higher than 0 so give it a try but don't dream...

      Automatic ATU made with discrete capacities and small toroids on ferrite core have losses. Between 10% in the better case, 50-80% in the worst (high mismatch). Manual ATU with good quality air capacities and air wound inductors are better, but still have losses.
      10% loss is nothing you will notice "on the air", 50% is 3dB, half a S point.

      The bad news is when you have a high mismatch you have both losses in the ATU and in the feeders. Losses could go as high as 95% in the total, this will be noticed by the other end of the QSO. If the feeder is short and for portable or "secondary usage" conditions, why not, but for a "fixed" station you should think about improving this situation.

      I will not go into maths.
      If you want "proofs" read the "ARRL Handbook" everything is clearly explained for both ATU and feeder losses.
      Also have a look here :
      http://www.g4ilo.com/antenna.html
      http://en.wikipedia.org/wiki/Antenna_tuner
      You can read ATU or transceivers (with integrated ATU) reviews in QST. ARRL lab always give losses measurements.
      http://www.ldgelectronics.com/assets/documents/pdf/AT-1000ProReview.pdf

      My own opinions about ATU :
      - Near the antenna ATU are like any impedance matching device (impedance transformer, stub, beta-Match...) they are necessary for some antennas and have some losses.
      - Near the transceiver 3:1 ATU are useful for extending the usable frequency range of an antenna and protecting your rig finals. Keep in mind that you will have some losses depending on the feeder length.
      - Near the transceiver 10:1 ATU are only meant for portable usage. 100 input to a 10:1 mismatch through a 10m long RG-58 feedline will give near nothing to the antenna. With luck you could still make some QSO however.

      73 and have fun with the FT-100.
      Yan - XV4Y
      ---
      http://xv4y.radioclub.asia/
      http://www.qslwatch.com/
      --- In FT100@yahoogroups.com, "kb7gp_dave" <kb7gp@...> wrote:
      >
      > Hmm..
      >
      > Transmatches typically have inductors consisting of turns of wire. Wire has resistance and skin-effect will also come into play. Probably the 'largest' losses would be I^2 * R losses. Have current flow, will have losses; Novice level theory. The significance of these losses will vary from opinion to opinion. Bottom line, measurable losses do exist.
      >
      > Dave
      > KB7GP, East Olympia, WA
      >
      >
      > --- In FT100@yahoogroups.com, Tony <s0l0_me@> wrote:
      > >
      > > 'Anything' introduced into the feeder will cause 'some' loss.. and that's a fact.
      > > The amount of loss is subjective and may............>
      > >
      > > ________________________________
      > > From: "john-ab8ko@" <john-ab8ko@>
      > > To: FT100@yahoogroups.com
      > > Sent: Saturday, December 24, 2011 7:01 PM
      > > Subject: Re: [FT100] Antenna Tuner
      > >
      > >
      > >  
      > > Just curious..... exactly how does an antenna tuner ( misnomer ) Rather a trans-match introduce loss in the circuit?
      > > Do you have technical details? or.....
      >
      > > [Non-text portions of this message have been removed]
      > >
      >
    • Yannick
      Wrong QST review file. This one the right one : http://www.sgcworld.com/Publications/Articles/211qst1104.pdf 73, Yan.
      Message 32 of 32 , Jan 1, 2012
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        Wrong QST review file.
        This one the right one :
        http://www.sgcworld.com/Publications/Articles/211qst1104.pdf

        73,
        Yan.
        --- In FT100@yahoogroups.com, "Yannick" <yannick.devos@...> wrote:
        >
        > Happy new year to everyone.
        >
        > Like a lot of devices, an Antenna Tuner is an important part of many ham stations and give a lot of help in having an effective station.
        > Like a lot of devices : don't over-use it.
        >
        > Of course a resonant antenna put high in the sky with a short low loss feeder is the best.
        > A highly mismatched antenna buried in the ground with long high loss line is the worst.
        > Anything between could be useful sometime but never forget its limitations.
        >
        > If the only thing you can have is a low efficiency antenna but if it can put you on the air, it is better than nothing. The probability that the "rare DX" hear you is still low but 0,01% is higher than 0 so give it a try but don't dream...
        >
        > Automatic ATU made with discrete capacities and small toroids on ferrite core have losses. Between 10% in the better case, 50-80% in the worst (high mismatch). Manual ATU with good quality air capacities and air wound inductors are better, but still have losses.
        > 10% loss is nothing you will notice "on the air", 50% is 3dB, half a S point.
        >
        > The bad news is when you have a high mismatch you have both losses in the ATU and in the feeders. Losses could go as high as 95% in the total, this will be noticed by the other end of the QSO. If the feeder is short and for portable or "secondary usage" conditions, why not, but for a "fixed" station you should think about improving this situation.
        >
        > I will not go into maths.
        > If you want "proofs" read the "ARRL Handbook" everything is clearly explained for both ATU and feeder losses.
        > Also have a look here :
        > http://www.g4ilo.com/antenna.html
        > http://en.wikipedia.org/wiki/Antenna_tuner
        > You can read ATU or transceivers (with integrated ATU) reviews in QST. ARRL lab always give losses measurements.
        > http://www.ldgelectronics.com/assets/documents/pdf/AT-1000ProReview.pdf
        >
        > My own opinions about ATU :
        > - Near the antenna ATU are like any impedance matching device (impedance transformer, stub, beta-Match...) they are necessary for some antennas and have some losses.
        > - Near the transceiver 3:1 ATU are useful for extending the usable frequency range of an antenna and protecting your rig finals. Keep in mind that you will have some losses depending on the feeder length.
        > - Near the transceiver 10:1 ATU are only meant for portable usage. 100 input to a 10:1 mismatch through a 10m long RG-58 feedline will give near nothing to the antenna. With luck you could still make some QSO however.
        >
        > 73 and have fun with the FT-100.
        > Yan - XV4Y
        > ---
        > http://xv4y.radioclub.asia/
        > http://www.qslwatch.com/
        > --- In FT100@yahoogroups.com, "kb7gp_dave" <kb7gp@> wrote:
        > >
        > > Hmm..
        > >
        > > Transmatches typically have inductors consisting of turns of wire. Wire has resistance and skin-effect will also come into play. Probably the 'largest' losses would be I^2 * R losses. Have current flow, will have losses; Novice level theory. The significance of these losses will vary from opinion to opinion. Bottom line, measurable losses do exist.
        > >
        > > Dave
        > > KB7GP, East Olympia, WA
        > >
        > >
        > > --- In FT100@yahoogroups.com, Tony <s0l0_me@> wrote:
        > > >
        > > > 'Anything' introduced into the feeder will cause 'some' loss.. and that's a fact.
        > > > The amount of loss is subjective and may............>
        > > >
        > > > ________________________________
        > > > From: "john-ab8ko@" <john-ab8ko@>
        > > > To: FT100@yahoogroups.com
        > > > Sent: Saturday, December 24, 2011 7:01 PM
        > > > Subject: Re: [FT100] Antenna Tuner
        > > >
        > > >
        > > >  
        > > > Just curious..... exactly how does an antenna tuner ( misnomer ) Rather a trans-match introduce loss in the circuit?
        > > > Do you have technical details? or.....
        > >
        > > > [Non-text portions of this message have been removed]
        > > >
        > >
        >
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