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PVC Loop Suggestions and Advise for the Tecsun PL-390

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  • ed_plopenio
    Hi everybody. This is my first post after a few months of reading and learning for the group I would like to build a recieve only MW loop from magnetic wire
    Message 1 of 4 , Sep 4 2:14 AM
      Hi everybody. This is my first post after a few months of reading and learning for the group

      I would like to build a recieve only MW loop from magnetic wire and a recieve only coax cable SW shielded loop antenna using the same PVC frame. What would be the width and height of the collapsible/portable PVC frame? How many turns of magnetic wire and the spacing between turns for the MW loop? I am assuming that the SW coax would have only 1 turn. I imagine also that both loops can have a common connection to the ground terminal of the 3.5 mm socket with the MW connected to the socket's middle terminal and the SW connectcted to the tip's terminal. I plan to use thses antennas on a Tecsun PL-390 which is on
      order. Is it possible that both the MW and SW antennas to have an inductance between 10 and 20 uH using a 1:5 turn ratio following the Si4734 DSP chip specs so that both antennas can be tuned directly with the modified PL-390 describe here

      (http://f1.grp.yahoofs.com/v1/ELmATP_lM160pzEINc06OhFQCLxtBEPdEKGPXU1pJo8oqgEIcSd2ZN6fdSGe42olHclNp8H-x8u_jPYJGioj-s3FK8IJ823EPgI/6%20Alignment%20%26%20Modification/PL-390%20External%20LW%20MW%20Antenna%20Mod.pdf)

      What is a 1:5 turn ratio inductor and how do I make one?

      Also, would it be possible to improve the PL-390's ferrite loopstick sensitivity by either replacing it with one of better quality and/or by rewinding the litz wire. I have read about a 3-coil design by Hugo described at the Herculodge website

      (http://herculodge.typepad.com/herculodge/2010/03/is-it-true-the-saying-that-the-bigger-the-ferrite-the-better-am-sensitivity-.html)

      or his more recent post

      (http://herculodge.typepad.com/herculodge/2010/09/hugo-shows-the-best-way-to-maximize-performance-on-your-ferrite-antenna.html)?

      I believe the Tecsun PL-390 can turn out to be a "Super DX" portable radio with Mr. Mann's modification, a collapsible/portable common framed MW & SW PVC Loop antenna and a modified ferrite loopstick,

      Many thanks for any and all comments, suggestions and advise.


      Ed Plopenio
      Naga City, Philippines
      ed_plopenio@...
    • airchecklover
      Hi Ed; Welcome to the world of radio. I will address a portion of your post ... the internal ferrite of the PL-390 and external loop - and also caution you to
      Message 2 of 4 , Sep 4 3:04 PM
        Hi Ed;

        Welcome to the world of radio. I will address a portion of your post ... the internal ferrite of the PL-390 and external loop - and also caution you to ask many many questions before you think you fully understand, because there is much to learn and many opinions on what and will not work. And please be aware you are asking "experimenter questions" ... questions which maybe only you can answer after you have tried :)


        That said, I wonder in what order you want to make these modifications and antennas? You have outlined an ambitious amount of work!


        Whether mounting a MW multi-turn open loop alongside a coax single turn loop is a good or bad idea - I don't know. My gut instinct says you may have interference problems between the two antennas windings ... capacitive and possibly inductive too. Good question and hoping someone else has tried it and can comment. However, I know that making both an external multi-turn open MW loop AND modifying the internal ferrite with Litz wire seems counter-productive. If you are going to make a pickup loop mounted to your multi-turn and direct-connect that to the PL-390, what is the purpose of the Litz re-wire of the ferrite? If you are going to inductively couple the multi-turn loop to the PL-390, the internal ferrite will work great just as it is. I doubt you would see much performance gain by re-winding the ferrite for this application. If you are itching to wind Litz wire on a ferrite, I would suggest investing in a long ferrite rod and winding an external tunable "super-ferrite". You can always cascade the super-ferrite and the multi-turn loop together with inductive coupling and you will achieve extra signal gain plus the ability to play one antennas' nulls against the other for some amazing daytime DX. A tried and proven way to achieve MW & SW on one frame is to use tap points on a open multi-turn winding, making the open winding anything from one to several turns, depending on your tap point. Whether the shielded coax will give you better noise reduction over an open single turn magnet wire has been debated. It's output will probably be lower.

        Please report back if you try some of these ideas. Let us know how things worked or didn't work.

        Mark

        =+++++++++++++++++++++++++++++++



        --- In loopantennas@yahoogroups.com, "ed_plopenio" <ed_plopenio@...> wrote:
        >
        > Hi everybody. This is my first post after a few months of reading and learning for the group
        >
        > I would like to build a recieve only MW loop from magnetic wire and a recieve only coax cable SW shielded loop antenna using the same PVC frame. What would be the width and height of the collapsible/portable PVC frame? How many turns of magnetic wire and the spacing between turns for the MW loop? I am assuming that the SW coax would have only 1 turn. I imagine also that both loops can have a common connection to the ground terminal of the 3.5 mm socket with the MW connected to the socket's middle terminal and the SW connectcted to the tip's terminal. I plan to use thses antennas on a Tecsun PL-390 which is on
        > order. Is it possible that both the MW and SW antennas to have an inductance between 10 and 20 uH using a 1:5 turn ratio following the Si4734 DSP chip specs so that both antennas can be tuned directly with the modified PL-390 describe here
        >
        > (http://f1.grp.yahoofs.com/v1/ELmATP_lM160pzEINc06OhFQCLxtBEPdEKGPXU1pJo8oqgEIcSd2ZN6fdSGe42olHclNp8H-x8u_jPYJGioj-s3FK8IJ823EPgI/6%20Alignment%20%26%20Modification/PL-390%20External%20LW%20MW%20Antenna%20Mod.pdf)
        >
        > What is a 1:5 turn ratio inductor and how do I make one?
        >
        > Also, would it be possible to improve the PL-390's ferrite loopstick sensitivity by either replacing it with one of better quality and/or by rewinding the litz wire. I have read about a 3-coil design by Hugo described at the Herculodge website
        >
        > (http://herculodge.typepad.com/herculodge/2010/03/is-it-true-the-saying-that-the-bigger-the-ferrite-the-better-am-sensitivity-.html)
        >
        > or his more recent post
        >
        > (http://herculodge.typepad.com/herculodge/2010/09/hugo-shows-the-best-way-to-maximize-performance-on-your-ferrite-antenna.html)?
        >
        > I believe the Tecsun PL-390 can turn out to be a "Super DX" portable radio with Mr. Mann's modification, a collapsible/portable common framed MW & SW PVC Loop antenna and a modified ferrite loopstick,
        >
        > Many thanks for any and all comments, suggestions and advise.
        >
        >
        > Ed Plopenio
        > Naga City, Philippines
        > ed_plopenio@...
        >
      • Tony King
        I would recommend anyone looking at hot rodding the PL310 PL380 PL390 join the ultralightdx group. It is loaded with files and photos of all the mods and loops
        Message 3 of 4 , Sep 5 3:01 PM
          I would recommend anyone looking at hot rodding the PL310 PL380 PL390 join
          the ultralightdx group. It is loaded with files and photos of all the mods
          and loops that have elevated these models to become great DX sets.

          Tony King

          New Zealand



          [Non-text portions of this message have been removed]
        • ed_plopenio
          Thanks Tony. I have joined them too. Regards.
          Message 4 of 4 , Sep 5 7:39 PM
            Thanks Tony. I have joined them too. Regards.

            --- In loopantennas@yahoogroups.com, "Tony King" <tonyzl@...> wrote:
            >
            > I would recommend anyone looking at hot rodding the PL310 PL380 PL390 join
            > the ultralightdx group. It is loaded with files and photos of all the mods
            > and loops that have elevated these models to become great DX sets.
            >
            > Tony King
            >
            > New Zealand
            >
            >
            >
            > [Non-text portions of this message have been removed]
            >
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