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Re: [loopantennas] Loop for 60 kHz and power consumption question

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  • Ken Javor
    Private response to avoid more flaming. I have a wristwatch that tunes to the NIST atomic clock 60 kHz beacon. The loop antenna fits within the watch,
    Message 1 of 13 , Apr 4, 2007
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      Private response to avoid more flaming. I have a wristwatch that tunes to
      the NIST atomic clock 60 kHz beacon. The loop antenna fits within the
      watch, naturally. The watch battery has been going for over a year, and I
      think it is supposed to last for two or three years. I don't see how a 60
      kHz loop adds to battery drain, the loop is a passive element feeding the
      VLF converter input.

      From: Thomas Ashcraft <ashcraft@...>
      Reply-To: loopantennas@yahoogroups.com
      Date: Wed, 04 Apr 2007 09:43:20 -0600
      To: loopantennas@yahoogroups.com
      Subject: [loopantennas] Loop for 60 kHz and power consumption question




      For a project ( kind of art piece ) that will happen off the electric
      grid I am planning to run a battery operated radio to receive the 60 kHz
      time signal from WWVB.
      Right now I am testing how long my radio ( minus loop antenna) will run
      on batteries before the batteries are drained. I have not built the
      loop as yet for 60 kHz. My question is : will adding a loop antenna for
      60 kHz to the radio consume extra power out of the batteries when added
      to the circuit?

      The radio to be used is a Sangean ATS-803A short wave ( 6 D cell
      batteries), with a Palomar Engineers VLF converter ( single 9 volt
      battery) and I haven't figured out the length of wire for the loop as
      yet. My thinking is that the long length required for the VLF antenna
      might pull more current from the batteries.

      Thank you again for your information.

      Thomas Ashcraft






      [Non-text portions of this message have been removed]
    • gandalfg8@aol.com
      In a message dated 04/04/2007 16:44:30 GMT Daylight Time, ashcraft@heliotown.com writes: The radio to be used is a Sangean ATS-803A short wave ( 6 D cell
      Message 2 of 13 , Apr 4, 2007
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        In a message dated 04/04/2007 16:44:30 GMT Daylight Time,
        ashcraft@... writes:

        The radio to be used is a Sangean ATS-803A short wave ( 6 D cell
        batteries), with a Palomar Engineers VLF converter ( single 9 volt
        battery) and I haven't figured out the length of wire for the loop as
        yet. My thinking is that the long length required for the VLF antenna
        might pull more current from the batteries.



        ------------------------

        The antenna will have no direct effect on battery current.

        A more efficient antenna will produce a stronger signal and there may be
        some minor change to the current taken by the RF stages of the radio but this
        should make little difference to battery life.

        The biggest single factor affecting battery life will be the audio output
        stage.
        Providing loudspeaker output is what eats the current.
        Turn the volume up and battery life can go down dramatically.

        For a given volume control setting a better antenna might give more volume
        so I suppose could be said to affect current but that's really nit picking.
        If you want long battery life..... keep things as quiet as possible:-)

        regards

        Nigel
        GM8PZR






        [Non-text portions of this message have been removed]
      • Art
        Your current consumption will increase after you hook up an antenna, but not much. Since you are providing a signal and noise for the radio to process, it will
        Message 3 of 13 , Apr 4, 2007
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          Your current consumption will increase after you hook up an antenna,
          but not much.

          Since you are providing a signal and noise for the radio to process,
          it will use more power in the audio amp stages, but not much.

          In general, the agc will move to reduce the gain of the intermediate
          stages if you supply it with a good strong signal, so the increase
          will be somewhat minimal due to the agc action alone.

          Since you probably won't listen to wwvb using a speaker, you can save
          power by using the headphone jack if the radio has one. Sometimes
          they do not use the final speaker amp to drive headphones, so a lower
          power mode is possible if the radio disconnects the speaker amp when
          you plug into the headphone jack.

          The Palomar converter is not known for being a good performer
          although I don't know how much power it consumes. The Palomar is
          noisey and the oscillator is not stabilized, so it will not work well
          for LF/QRS. A homebrewed converter has the potential to save a great
          deal of power though.

          Enjoy.

          Art


          At 11:43 AM 4/4/2007, you wrote:


          >For a project ( kind of art piece ) that will happen off the electric
          >grid I am planning to run a battery operated radio to receive the 60 kHz
          >time signal from WWVB.
          >Right now I am testing how long my radio ( minus loop antenna) will run
          >on batteries before the batteries are drained. I have not built the
          >loop as yet for 60 kHz. My question is : will adding a loop antenna for
          >60 kHz to the radio consume extra power out of the batteries when added
          >to the circuit?
          >
          >The radio to be used is a Sangean ATS-803A short wave ( 6 D cell
          >batteries), with a Palomar Engineers VLF converter ( single 9 volt
          >battery) and I haven't figured out the length of wire for the loop as
          >yet. My thinking is that the long length required for the VLF antenna
          >might pull more current from the batteries.
          >
          >Thank you again for your information.
          >
          >Thomas Ashcraft
        • Thomas Ashcraft
          Nigel, Thank you. That is very helpful info. for my planning process. Thomas
          Message 4 of 13 , Apr 4, 2007
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            Nigel,

            Thank you. That is very helpful info. for my planning process.

            Thomas

            gandalfg8@... wrote:
            >
            > In a message dated 04/04/2007 16:44:30 GMT Daylight Time,
            > ashcraft@... writes:
            >
            > The radio to be used is a Sangean ATS-803A short wave ( 6 D cell
            > batteries), with a Palomar Engineers VLF converter ( single 9 volt
            > battery) and I haven't figured out the length of wire for the loop as
            > yet. My thinking is that the long length required for the VLF antenna
            > might pull more current from the batteries.
            >
            >
            >
            > ------------------------
            >
            > The antenna will have no direct effect on battery current.
            >
            > A more efficient antenna will produce a stronger signal and there may be
            > some minor change to the current taken by the RF stages of the radio but this
            > should make little difference to battery life.
            >
            > The biggest single factor affecting battery life will be the audio output
            > stage.
            > Providing loudspeaker output is what eats the current.
            > Turn the volume up and battery life can go down dramatically.
            >
            > For a given volume control setting a better antenna might give more volume
            > so I suppose could be said to affect current but that's really nit picking.
            > If you want long battery life..... keep things as quiet as possible:-)
            >
            > regards
            >
            > Nigel
            > GM8PZR
            >
            >
            >
            >
          • Keith Browning
            Thanks Jim, I thought the twist which you described and which fits my vision perfectly, would aid symetry. I thought that it would need several twists by the
            Message 5 of 13 , Apr 4, 2007
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              Thanks Jim,
              I thought the "twist" which you described and which fits my vision perfectly, would aid symetry. I
              thought that it would need several twists by the time it completed the circumference.
              That was an interesting idea to thread the coupling loop through the centre, but I recall that
              having the coupling too close affected the Q quite drasticaly. I would think that puting it through
              the centre would offer the closest coupling ever. But as you say, It would look interesting.

              From your comments I assume what is required then, is a tuned loop (possibly unshielded), mounted
              well away from every thing including ground. Coupled loosely and fed to the receiver via a twisted,
              balanced feed line with a balun at ground level.
              Yes I am interested mainly with MW and SW frequencies.

              I recall DF units using a whip with a loop.

              I appreciate your notes on the differences between shielded and unshielded loops.

              Thanks,
              Keith

              -------------------------------------------------
              Hi Keith,

              PS

              Another technique/trick that can be used to offset the imbalance caused by
              stray dielectric currents is to use a separate antenna ... eg a whip or
              piece of random wire. The signal will also be picked up by this wire and
              is fed to a circuit that couples it into the signal from the loop and
              'adjusts' the phase so as to cancel out dielectric current effects. This
              will sharpen the null. It is the same trick that can be used to cancel out
              noise caused by RFI like ignition noise from an automobile.

              Jim



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            • Jim Dunstan
              ... You are correct .... over coupling can be a problem .... it is just that when visualizing the loop it seemed an interesting idea. Adjustable coupling is
              Message 6 of 13 , Apr 4, 2007
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                At 09:10 AM 4/5/2007 +1200, you wrote:

                >Thanks Jim,
                >I thought the "twist" which you described and which fits my vision
                >perfectly, would aid symetry. I
                >thought that it would need several twists by the time it completed the
                >circumference.
                >That was an interesting idea to thread the coupling loop through the
                >centre, but I recall that
                >having the coupling too close affected the Q quite drasticaly. I would
                >think that puting it through
                >the centre would offer the closest coupling ever. But as you say, It would
                >look interesting.

                You are correct .... over coupling can be a problem .... it is just that
                when visualizing the loop it seemed an interesting idea. Adjustable
                coupling is very advantageous. If you get started on this project please
                let us know how it performs .... and how it looks hi hi ..

                Jim
              • Marc
                ... I ve used solar panels for that kind of use. Works great. a 20x30 cm panel (6V) can run any of sony 7600D, 7601 or 2001D/2010D . It works in very cloudy
                Message 7 of 13 , Apr 4, 2007
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                  Thomas Ashcraft schreef:
                  >
                  > Right now I am testing how long my radio ( minus loop antenna) will run
                  > on batteries before the batteries are drained.

                  I've used solar panels for that kind of use. Works great. a 20x30 cm
                  panel (6V) can run any of
                  sony 7600D, 7601 or 2001D/2010D . It works in very cloudy conditions
                  for the analoguie radio's..
                  Such a panel is about 200 mA.

                  Marc

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