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Re: [loopantennas] Mobius Loop Antenna

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  • Chris Trask
    ... Look at this tutorial of mine in the group files section: Shielded Loop Aerials Rev 0.pdf It covers the subject of the Meobius Strip shielded loop with a
    Message 1 of 9 , Aug 21, 2013
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      >
      >I am fairly new to this group and have been somewhat intrigued by the Mobius loop antenna. Is there any
      >place on the web that describes the construction of the antenna? More specifically I am interested in
      >the VLF/LF arena but I can't seem to locate any links that discuss this.
      >

      Look at this tutorial of mine in the group files section:

      Shielded Loop Aerials Rev 0.pdf

      It covers the subject of the Meobius Strip shielded loop with a few references that can be found online.




      Chris
    • hmaxim2000us
      Hello I am thinking of replacing my single wire loop with a Mobius loop. I looked at several diagrams, including the one in Rev 0.pdf. Most show the shield
      Message 2 of 9 , Aug 22, 2013
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        Hello
        I am thinking of replacing my single wire loop with a Mobius loop. I looked at several diagrams, including the one in Rev 0.pdf. Most show the shield as not grounded, but the one in Rev0.pdf shows the shield as being grounded at the feedpoint. I don't get this. I can see where the 2 center conductors go to the input of my balanced amp, but if I ground the shield it becomes a dead short to the feedline coax.
        I am thinking of using coax to form the loop, snaking it inside a flexible PVC conduit. Thats what I do now with a single wire. I suppose the shieled continuity must be maintained where I cut the coax to bring the two center wires out to the amp? But grounding?
        Thanks a bunch!
        Jim

        >
        > Look at this tutorial of mine in the group files section:
        >
        > Shielded Loop Aerials Rev 0.pdf
        >
        > It covers the subject of the Meobius Strip shielded loop with a few references that can be found online.
        >
        >
        >
        >
        > Chris
        >
      • Evverettsharp
        Hi Jim, Contact me at everettsharp (at) aol com and I will send you some pictures and a wiring digram for a möbius loop antenna. I have been experimenting
        Message 3 of 9 , Aug 23, 2013
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          Hi Jim,

          Contact me at everettsharp (at) aol com and I will send you some pictures and a wiring digram for a möbius loop antenna. I have been experimenting with this configuration now for the last several days and have it working very well. 

          73 Everett

          Sent from my iPad

          On Aug 22, 2013, at 8:18 AM, "hmaxim2000us" <jimk2tl@...> wrote:

           



          Hello
          I am thinking of replacing my single wire loop with a Mobius loop. I looked at several diagrams, including the one in Rev 0.pdf. Most show the shield as not grounded, but the one in Rev0.pdf shows the shield as being grounded at the feedpoint. I don't get this. I can see where the 2 center conductors go to the input of my balanced amp, but if I ground the shield it becomes a dead short to the feedline coax.
          I am thinking of using coax to form the loop, snaking it inside a flexible PVC conduit. Thats what I do now with a single wire. I suppose the shieled continuity must be maintained where I cut the coax to bring the two center wires out to the amp? But grounding?
          Thanks a bunch!
          Jim

          >
          > Look at this tutorial of mine in the group files section:
          >
          > Shielded Loop Aerials Rev 0.pdf
          >
          > It covers the subject of the Meobius Strip shielded loop with a few references that can be found online.
          >
          >
          >
          >
          > Chris
          >

        • hmaxim2000us
          Thank you very much! email sent. Jim K2TL
          Message 4 of 9 , Aug 23, 2013
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            Thank you very much! email sent.

            Jim K2TL

            --- In loopantennas@yahoogroups.com, Evverettsharp <everettsharp@...> wrote:
            >
            > Hi Jim,
            >
            > Contact me at everettsharp (at) aol com and I will send you some pictures and a wiring digram for a möbius loop antenna. I have been experimenting with this configuration now for the last several days and have it working very well.
            >
            > 73 Everett
            >
            > Sent from my iPad
            >
            > On Aug 22, 2013, at 8:18 AM, "hmaxim2000us" <jimk2tl@...> wrote:
            >
            > >
            > >
            > > Hello
            > > I am thinking of replacing my single wire loop with a Mobius loop. I looked at several diagrams, including the one in Rev 0.pdf. Most show the shield as not grounded, but the one in Rev0.pdf shows the shield as being grounded at the feedpoint. I don't get this. I can see where the 2 center conductors go to the input of my balanced amp, but if I ground the shield it becomes a dead short to the feedline coax.
            > > I am thinking of using coax to form the loop, snaking it inside a flexible PVC conduit. Thats what I do now with a single wire. I suppose the shieled continuity must be maintained where I cut the coax to bring the two center wires out to the amp? But grounding?
            > > Thanks a bunch!
            > > Jim
            > >
            > > >
            > > > Look at this tutorial of mine in the group files section:
            > > >
            > > > Shielded Loop Aerials Rev 0.pdf
            > > >
            > > > It covers the subject of the Meobius Strip shielded loop with a few references that can be found online.
            > > >
            > > >
            > > >
            > > >
            > > > Chris
            > > >
            > >
            > >
            >
          • AlienRelics
            Could you upload them here to the Files or Photos section? Thanks, Steve Greenfield AE7HD moderator loopantennas
            Message 5 of 9 , Aug 23, 2013
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              Could you upload them here to the Files or Photos section?

              Thanks,
              Steve Greenfield AE7HD
              moderator loopantennas

              --- In loopantennas@yahoogroups.com, Evverettsharp <everettsharp@...> wrote:
              >
              > Hi Jim,
              >
              > Contact me at everettsharp (at) aol com and I will send you some pictures and a wiring digram for a möbius loop antenna. I have been experimenting with this configuration now for the last several days and have it working very well.
              >
              > 73 Everett
              >
              > Sent from my iPad
              >
            • Evverettsharp
              Hi Steve, In the next few days I will write an article on my project and post it in the files section, as I have with many of my past experiments and projects.
              Message 6 of 9 , Aug 23, 2013
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                Hi Steve,

                In the next few days I will write an article on my project and post it in the files section, as I have with many of my past experiments and projects. It is too early to post anything yet, but at this point I know that it is working very well. 

                73 Everett N8CNP

                Sent from my iPad

                On Aug 23, 2013, at 6:42 AM, "AlienRelics" <alienrelics@...> wrote:

                 

                Could you upload them here to the Files or Photos section?

                Thanks,
                Steve Greenfield AE7HD
                moderator loopantennas

                --- In loopantennas@yahoogroups.com, Evverettsharp <everettsharp@...> wrote:
                >
                > Hi Jim,
                >
                > Contact me at everettsharp (at) aol com and I will send you some pictures and a wiring digram for a möbius loop antenna. I have been experimenting with this configuration now for the last several days and have it working very well.
                >
                > 73 Everett
                >
                > Sent from my iPad
                >

              • Andy
                ... It is no more than a dead short, than a loop antenna is a short on the feedline. And yet we know loop antennas work. The short is only at DC. Think of
                Message 7 of 9 , Aug 23, 2013
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                  > ... but if I ground the shield it becomes a dead short to the feedline coax.

                  It is no more than a dead short, than a loop antenna is a short on the
                  feedline. And yet we know loop antennas work. The "short" is only at DC.

                  Think of it as a balanced loop antenna where the center-tap of the
                  loop is grounded.

                  Andy
                • hmaxim2000us
                  Hello Using a balanced amp as I do, the loop is not a direct short to ground at DC. The shield of the feedline is not involved in the loop itself. What
                  Message 8 of 9 , Aug 24, 2013
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                    Hello
                    Using a balanced amp as I do, the loop is not a direct short to ground at DC. The shield of the feedline is not involved in the loop itself. What confused me was in the Mobius design where the feedline is indeed shorted to the center conductor, which is fine until you also connect it to the feedline shield. Everett cleared that up nicely with his diagram he sent me.
                    I understand that many antenna designs use matching transformers and such that provide a direct DC path to ground but at RF it not a problem. Not so with a 3 foot diameter loop at VLF or even at 30 Mhz.
                    All good stuff. Great group here.
                    Jim K2TL


                    --- In loopantennas@yahoogroups.com, Andy <ai.egrps@...> wrote:
                    >
                    > > ... but if I ground the shield it becomes a dead short to the feedline coax.
                    >
                    > It is no more than a dead short, than a loop antenna is a short on the
                    > feedline. And yet we know loop antennas work. The "short" is only at DC.
                    >
                    > Think of it as a balanced loop antenna where the center-tap of the
                    > loop is grounded.
                    >
                    > Andy
                    >
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