Loading ...
Sorry, an error occurred while loading the content.

Re: [loopantennas] RE: Question About Tuned Magnetic Loop

Expand Messages
  • Andy
    ... That s what I used to think too. But I have read otherwise. And it makes at least some sense that having an unbalanced pickup loop near the main loop
    Message 1 of 13 , Sep 19, 2013
    • 0 Attachment
      3ym3ym@... wrote:

      > I think the pickup loop itself can be seen as the secondary winding of a
      > balun (main loop is the primary). Don't see why you would need yet
      > another balun when there is already one.

      That's what I used to think too. But I have read otherwise. And it
      makes at least some sense that having an unbalanced pickup loop near
      the main loop upsets the balance in the main loop too, which could
      mess up the depth of the nulls. That was specifically given as the
      reason why the pickup loop wants to be kept balanced too. Your
      magloop will work without the balun, but it may lack the sharp nulls
      of a well balanced loop.

      Andy
    • maxwellmclellan
      G day all. I have ben following the loopantenna saga. I do not use pickup loops anymore. Prefer to use a capacitor to tune the loop and another variable to
      Message 2 of 13 , Sep 21, 2013
      • 0 Attachment
        G'day all. I have ben following the loopantenna saga. I do not use pickup loops anymore. Prefer to use a capacitor to tune the loop and another variable to match the impedance to the radio. What I pick up on the swings I lose on the roundabouts, the loop becomes unbalanced the radiation pattern is distorted and the impedance is sensitive to the size of the Loop. However I am aware of the shortcomings and live with it. The old 80/20 rule applies 20% of effort will get a you 80% return but that last 20% return will only be got with another 80% of effort. Regards to all Max VK2TTI


        ----- Original Message -----
        From:
        loopantennas@yahoogroups.com

        To:
        <loopantennas@yahoogroups.com>
        Cc:

        Sent:
        Thu, 19 Sep 2013 18:03:28 -0400
        Subject:
        Re: [loopantennas] RE: Question About Tuned Magnetic Loop


         

        3ym3ym@... wrote:

        > I think the pickup loop itself can be seen as the secondary winding of a
        > balun (main loop is the primary). Don't see why you would need yet
        > another balun when there is already one.

        That's what I used to think too. But I have read otherwise. And it
        makes at least some sense that having an unbalanced pickup loop near
        the main loop upsets the balance in the main loop too, which could
        mess up the depth of the nulls. That was specifically given as the
        reason why the pickup loop wants to be kept balanced too. Your
        magloop will work without the balun, but it may lack the sharp nulls
        of a well balanced loop.

        Andy


        Email sent using Optus Webmail
      • Maxwell Mclellan
        G day all again. Some more thoughts re main loop/pickup loop thing. If you consider them as a transformer a multi turn (say 10 turns) and a pickup loop (1
        Message 3 of 13 , Sep 21, 2013
        • 0 Attachment
          G'day all again. Some more thoughts re main loop/pickup loop thing. If you consider them as a transformer a multi turn (say 10 turns) and a pickup loop (1 turn).Voltage (in the secondary) is reduced by 10 and the current available increased by 10 ( to keep P=RI). Impedance transformation is to the square of the turns ratio, assuming a 50 ohm secondary the the primary winding will be 50 x 100= 5000 ohms. A parallel tuned loop exhibits a high impedance. If you assume a 100ohm secondary we get a transformation of a 100 x100= 10,000 ohms ( I hope my Maths is right. If we consider a 1 turn loop and pickup the square of 1 is 1 ie no impedance transformation. That is why I gave away pickup loops for single turn loops. Copper pipe is good but expensive, for small loops I prefer aluminum strip, gets an oxide film but can be brushed clean with a brass wire brush. I believe ( religion ) that an unbalanced pickup will unbalance the system. Regards again, Max VK2TTI.
          Sent from my iPad
        • Tony Magon
          Hi Max Have a look at G0CWT website. 73 Tony VK2IC
          Message 4 of 13 , Sep 21, 2013
          • 0 Attachment
            Hi Max

            Have a look at G0CWT website.

            73

            Tony VK2IC


            On Sun, Sep 22, 2013 at 9:44 AM, Maxwell Mclellan <vk2tti@...> wrote:
             

            G'day all again. Some more thoughts re main loop/pickup loop thing. If you consider them as a transformer a multi turn (say 10 turns) and a pickup loop (1 turn).Voltage (in the secondary) is reduced by 10 and the current available increased by 10 ( to keep P=RI). Impedance transformation is to the square of the turns ratio, assuming a 50 ohm secondary the the primary winding will be 50 x 100= 5000 ohms. A parallel tuned loop exhibits a high impedance. If you assume a 100ohm secondary we get a transformation of a 100 x100= 10,000 ohms ( I hope my Maths is right. If we consider a 1 turn loop and pickup the square of 1 is 1 ie no impedance transformation. That is why I gave away pickup loops for single turn loops. Copper pipe is good but expensive, for small loops I prefer aluminum strip, gets an oxide film but can be brushed clean with a brass wire brush. I believe ( religion ) that an unbalanced pickup will unbalance the system. Regards again, Max VK2TTI.
            Sent from my iPad


          • maxwellmclellan
            G day Tony and all. Thank you for the heads up re G0CWT website have gone straight   to it. Very impressive video with the neon tube and the high voltage and
            Message 5 of 13 , Sep 21, 2013
            • 0 Attachment
              G'day Tony and all. Thank you for the heads up re G0CWT website have gone straight   to it. Very impressive video with the neon tube and the high voltage and the clamp on current measure. My youngest daughter joined the human race and went to uni studdied engineering as a mature age student, now she am be one wiff a first and second class honours to her credit. She came homn one day said " You know Dad when you try to measure something you change it! ". It seems to me that G0CWT has demonstrated that adding an unbalanced pickup loop to a tuned loop alters the theoretical current and voltage distribution expected. I would like to see the same demonstration done without the pickup loop. The problem then becomes how to excite the loop in free space! Still an interesting website. Max VK2TTI.


              ----- Original Message -----
              From:
              loopantennas@yahoogroups.com

              To:
              <loopantennas@yahoogroups.com>
              Cc:

              Sent:
              Sun, 22 Sep 2013 09:48:19 +1000
              Subject:
              Re: [loopantennas] Question About Tuned Magnetic Loop


               

              Hi Max

              Have a look at G0CWT website.

              73

              Tony VK2IC


              On Sun, Sep 22, 2013 at 9:44 AM, Maxwell Mclellan <vk2tti@...> wrote:
               

              G'day all again. Some more thoughts re main loop/pickup loop thing. If you consider them as a transformer a multi turn (say 10 turns) and a pickup loop (1 turn).Voltage (in the secondary) is reduced by 10 and the current available increased by 10 ( to keep P=RI). Impedance transformation is to the square of the turns ratio, assuming a 50 ohm secondary the the primary winding will be 50 x 100= 5000 ohms. A parallel tuned loop exhibits a high impedance. If you assume a 100ohm secondary we get a transformation of a 100 x100= 10,000 ohms ( I hope my Maths is right. If we consider a 1 turn loop and pickup the square of 1 is 1 ie no impedance transformation. That is why I gave away pickup loops for single turn loops. Copper pipe is good but expensive, for small loops I prefer aluminum strip, gets an oxide film but can be brushed clean with a brass wire brush. I believe ( religion ) that an unbalanced pickup will unbalance the system. Regards again, Max VK2TTI.
              Sent from my iPad



              Email sent using Optus Webmail
            • Tony Magon
              Hi Max and all I have made one up for 40 meters and tried it out briefly and it worked quite well. The balun tubes can be purchased from Jaycar. 73 Tony VK2IC
              Message 6 of 13 , Sep 21, 2013
              • 0 Attachment
                Hi Max and all

                I have made one up for 40 meters and tried it out briefly and it worked quite well. The balun tubes can be purchased from Jaycar.

                73

                Tony VK2IC


                On Sun, Sep 22, 2013 at 11:55 AM, <vk2tti@...> wrote:
                 

                G'day Tony and all. Thank you for the heads up re G0CWT website have gone straight   to it. Very impressive video with the neon tube and the high voltage and the clamp on current measure. My youngest daughter joined the human race and went to uni studdied engineering as a mature age student, now she am be one wiff a first and second class honours to her credit. She came homn one day said " You know Dad when you try to measure something you change it! ". It seems to me that G0CWT has demonstrated that adding an unbalanced pickup loop to a tuned loop alters the theoretical current and voltage distribution expected. I would like to see the same demonstration done without the pickup loop. The problem then becomes how to excite the loop in free space! Still an interesting website. Max VK2TTI.


                ----- Original Message -----

                To:
                <loopantennas@yahoogroups.com>
                Cc:

                Sent:
                Sun, 22 Sep 2013 09:48:19 +1000
                Subject:
                Re: [loopantennas] Question About Tuned Magnetic Loop



                 

                Hi Max

                Have a look at G0CWT website.

                73

                Tony VK2IC


                On Sun, Sep 22, 2013 at 9:44 AM, Maxwell Mclellan <vk2tti@...> wrote:
                 

                G'day all again. Some more thoughts re main loop/pickup loop thing. If you consider them as a transformer a multi turn (say 10 turns) and a pickup loop (1 turn).Voltage (in the secondary) is reduced by 10 and the current available increased by 10 ( to keep P=RI). Impedance transformation is to the square of the turns ratio, assuming a 50 ohm secondary the the primary winding will be 50 x 100= 5000 ohms. A parallel tuned loop exhibits a high impedance. If you assume a 100ohm secondary we get a transformation of a 100 x100= 10,000 ohms ( I hope my Maths is right. If we consider a 1 turn loop and pickup the square of 1 is 1 ie no impedance transformation. That is why I gave away pickup loops for single turn loops. Copper pipe is good but expensive, for small loops I prefer aluminum strip, gets an oxide film but can be brushed clean with a brass wire brush. I believe ( religion ) that an unbalanced pickup will unbalance the system. Regards again, Max VK2TTI.
                Sent from my iPad



                Email sent using Optus Webmail


              • Maxwell Mclellan
                Tony and all, I am troubled by the repeated reference to the word balun, unless I have read incorrectly, nowhere does G0CWT refer to his transformer feed as a
                Message 7 of 13 , Sep 22, 2013
                • 0 Attachment
                  Tony and all, I am troubled by the repeated reference to the word balun, unless I have read incorrectly, nowhere does G0CWT refer to his transformer feed as a balun! And rightly so, whether or no it affects the balance of the loop I have no way of measuring. In practice it would not matter much, if I can't hear the difference does it matter? Regards to all, Max vk2tti.

                  Sent from my iPad

                  On 22/09/2013, at 13:20, Tony Magon <temagon@...> wrote:

                   

                  Hi Max and all

                  I have made one up for 40 meters and tried it out briefly and it worked quite well. The balun tubes can be purchased from Jaycar.

                  73

                  Tony VK2IC


                  On Sun, Sep 22, 2013 at 11:55 AM, <vk2tti@...> wrote:
                   

                  G'day Tony and all. Thank you for the heads up re G0CWT website have gone straight   to it. Very impressive video with the neon tube and the high voltage and the clamp on current measure. My youngest daughter joined the human race and went to uni studdied engineering as a mature age student, now she am be one wiff a first and second class honours to her credit. She came homn one day said " You know Dad when you try to measure something you change it! ". It seems to me that G0CWT has demonstrated that adding an unbalanced pickup loop to a tuned loop alters the theoretical current and voltage distribution expected. I would like to see the same demonstration done without the pickup loop. The problem then becomes how to excite the loop in free space! Still an interesting website. Max VK2TTI.


                  ----- Original Message -----

                  To:
                  <loopantennas@yahoogroups.com>
                  Cc:

                  Sent:
                  Sun, 22 Sep 2013 09:48:19 +1000
                  Subject:
                  Re: [loopantennas] Question About Tuned Magnetic Loop



                   

                  Hi Max

                  Have a look at G0CWT website.

                  73

                  Tony VK2IC


                  On Sun, Sep 22, 2013 at 9:44 AM, Maxwell Mclellan <vk2tti@...> wrote:
                   

                  G'day all again. Some more thoughts re main loop/pickup loop thing. If you consider them as a transformer a multi turn (say 10 turns) and a pickup loop (1 turn).Voltage (in the secondary) is reduced by 10 and the current available increased by 10 ( to keep P=RI). Impedance transformation is to the square of the turns ratio, assuming a 50 ohm secondary the the primary winding will be 50 x 100= 5000 ohms. A parallel tuned loop exhibits a high impedance. If you assume a 100ohm secondary we get a transformation of a 100 x100= 10,000 ohms ( I hope my Maths is right. If we consider a 1 turn loop and pickup the square of 1 is 1 ie no impedance transformation. That is why I gave away pickup loops for single turn loops. Copper pipe is good but expensive, for small loops I prefer aluminum strip, gets an oxide film but can be brushed clean with a brass wire brush. I believe ( religion ) that an unbalanced pickup will unbalance the system. Regards again, Max VK2TTI.
                  Sent from my iPad



                  Email sent using Optus Webmail


                • ve3uk
                  No, the feed point should be very close to 50 ohms that is what the transformer is doing. However, a 1:1 balun does have its place in further limiting the
                  Message 8 of 13 , Sep 22, 2013
                  • 0 Attachment

                    No, the feed point should be very close to 50 ohms that is what the transformer is doing. However, a 1:1 balun does have its place in further limiting the noise picked up by the loop and sent to your RX via common mode.

                    Hope that helps.


                    73 Bob VE3UK 



                    --- In loopantennas@yahoogroups.com, <vk2tti@...> wrote:

                    Tony and all, I am troubled by the repeated reference to the word balun, unless I have read incorrectly, nowhere does G0CWT refer to his transformer feed as a balun! And rightly so, whether or no it affects the balance of the loop I have no way of measuring. In practice it would not matter much, if I can't hear the difference does it matter? Regards to all, Max vk2tti.

                    Sent from my iPad

                    On 22/09/2013, at 13:20, Tony Magon <temagon@...> wrote:

                     
                    Hi Max and all

                    I have made one up for 40 meters and tried it out briefly and it worked quite well. The balun tubes can be purchased from Jaycar.

                    73

                    Tony VK2IC


                    On Sun, Sep 22, 2013 at 11:55 AM, <vk2tti@...> wrote:
                     

                    G'day Tony and all. Thank you for the heads up re G0CWT website have gone straight   to it. Very impressive video with the neon tube and the high voltage and the clamp on current measure. My youngest daughter joined the human race and went to uni studdied engineering as a mature age student, now she am be one wiff a first and second class honours to her credit. She came homn one day said " You know Dad when you try to measure something you change it! ". It seems to me that G0CWT has demonstrated that adding an unbalanced pickup loop to a tuned loop alters the theoretical current and voltage distribution expected. I would like to see the same demonstration done without the pickup loop. The problem then becomes how to excite the loop in free space! Still an interesting website. Max VK2TTI.


                    ----- Original Message -----

                    To:
                    <loopantennas@yahoogroups.com>
                    Cc:

                    Sent:
                    Sun, 22 Sep 2013 09:48:19 +1000
                    Subject:
                    Re: [loopantennas] Question About Tuned Magnetic Loop



                     
                    Hi Max

                    Have a look at G0CWT website.

                    73

                    Tony VK2IC


                    On Sun, Sep 22, 2013 at 9:44 AM, Maxwell Mclellan <vk2tti@...> wrote:
                     

                    G'day all again. Some more thoughts re main loop/pickup loop thing. If you consider them as a transformer a multi turn (say 10 turns) and a pickup loop (1 turn).Voltage (in the secondary) is reduced by 10 and the current available increased by 10 ( to keep P=RI). Impedance transformation is to the square of the turns ratio, assuming a 50 ohm secondary the the primary winding will be 50 x 100= 5000 ohms. A parallel tuned loop exhibits a high impedance. If you assume a 100ohm secondary we get a transformation of a 100 x100= 10,000 ohms ( I hope my Maths is right. If we consider a 1 turn loop and pickup the square of 1 is 1 ie no impedance transformation. That is why I gave away pickup loops for single turn loops. Copper pipe is good but expensive, for small loops I prefer aluminum strip, gets an oxide film but can be brushed clean with a brass wire brush. I believe ( religion ) that an unbalanced pickup will unbalance the system. Regards again, Max VK2TTI.
                    Sent from my iPad



                    Email sent using Optus Webmail

                  • Paramsothy Vaithia Lingham
                    Like the guy said if you want a symmetrical & noise reduction set up the balun would help. Bur what Thomas has done, is to use a wide band ferrite ring
                    Message 9 of 13 , Sep 22, 2013
                    • 0 Attachment
                      Like the guy said if you want a symmetrical & noise reduction set up the balun would help.
                      Bur what Thomas has done, is to use a wide band ferrite ring coupler, to give you a 50.Ohm secondary, ensuring optimum power transfer, to your receiver. If you are transmitting, it is worth worrying about, wanting a balun, to remove feeder radiation.Otherwise for listing purposes you will not notice the difference, as most broadcast stations run 10kW or more.
                      73s de Andy 9M2PV 


                      On Mon, Sep 23, 2013 at 2:11 AM, <leschyna@...> wrote:
                       

                      No, the feed point should be very close to 50 ohms that is what the transformer is doing. However, a 1:1 balun does have its place in further limiting the noise picked up by the loop and sent to your RX via common mode.

                      Hope that helps.


                      73 Bob VE3UK 



                      --- In loopantennas@yahoogroups.com, <vk2tti@...> wrote:

                      Tony and all, I am troubled by the repeated reference to the word balun, unless I have read incorrectly, nowhere does G0CWT refer to his transformer feed as a balun! And rightly so, whether or no it affects the balance of the loop I have no way of measuring. In practice it would not matter much, if I can't hear the difference does it matter? Regards to all, Max vk2tti.

                      Sent from my iPad

                      On 22/09/2013, at 13:20, Tony Magon <temagon@...> wrote:

                       
                      Hi Max and all

                      I have made one up for 40 meters and tried it out briefly and it worked quite well. The balun tubes can be purchased from Jaycar.

                      73

                      Tony VK2IC


                      On Sun, Sep 22, 2013 at 11:55 AM, <vk2tti@...> wrote:
                       

                      G'day Tony and all. Thank you for the heads up re G0CWT website have gone straight   to it. Very impressive video with the neon tube and the high voltage and the clamp on current measure. My youngest daughter joined the human race and went to uni studdied engineering as a mature age student, now she am be one wiff a first and second class honours to her credit. She came homn one day said " You know Dad when you try to measure something you change it! ". It seems to me that G0CWT has demonstrated that adding an unbalanced pickup loop to a tuned loop alters the theoretical current and voltage distribution expected. I would like to see the same demonstration done without the pickup loop. The problem then becomes how to excite the loop in free space! Still an interesting website. Max VK2TTI.


                      ----- Original Message -----

                      To:
                      <loopantennas@yahoogroups.com>
                      Cc:

                      Sent:
                      Sun, 22 Sep 2013 09:48:19 +1000
                      Subject:
                      Re: [loopantennas] Question About Tuned Magnetic Loop



                       
                      Hi Max

                      Have a look at G0CWT website.

                      73

                      Tony VK2IC


                      On Sun, Sep 22, 2013 at 9:44 AM, Maxwell Mclellan <vk2tti@...> wrote:
                       

                      G'day all again. Some more thoughts re main loop/pickup loop thing. If you consider them as a transformer a multi turn (say 10 turns) and a pickup loop (1 turn).Voltage (in the secondary) is reduced by 10 and the current available increased by 10 ( to keep P=RI). Impedance transformation is to the square of the turns ratio, assuming a 50 ohm secondary the the primary winding will be 50 x 100= 5000 ohms. A parallel tuned loop exhibits a high impedance. If you assume a 100ohm secondary we get a transformation of a 100 x100= 10,000 ohms ( I hope my Maths is right. If we consider a 1 turn loop and pickup the square of 1 is 1 ie no impedance transformation. That is why I gave away pickup loops for single turn loops. Copper pipe is good but expensive, for small loops I prefer aluminum strip, gets an oxide film but can be brushed clean with a brass wire brush. I believe ( religion ) that an unbalanced pickup will unbalance the system. Regards again, Max VK2TTI.
                      Sent from my iPad



                      Email sent using Optus Webmail


                    • Maxwell Mclellan
                      Bob VE3UK, It s late afternoon here, in Canada you ll be asleep, makes communication a little difficult. In your last? Email No, the feed point.... you
                      Message 10 of 13 , Sep 23, 2013
                      • 0 Attachment
                        Bob VE3UK, It's late afternoon here, in Canada you'll be asleep, makes communication a little difficult. In your last? Email "No, the feed point...." you reacted negatively to a statement, what was that statement mon ami? In anticipation Max vk2tti.

                        Sent from my iPad

                        On 23/09/2013, at 4:11, <leschyna@...> wrote:

                         

                        No, the feed point should be very close to 50 ohms that is what the transformer is doing. However, a 1:1 balun does have its place in further limiting the noise picked up by the loop and sent to your RX via common mode.

                        Hope that helps.


                        73 Bob VE3UK 



                        --- In loopantennas@yahoogroups.com, <vk2tti@...> wrote:

                        Tony and all, I am troubled by the repeated reference to the word balun, unless I have read incorrectly, nowhere does G0CWT refer to his transformer feed as a balun! And rightly so, whether or no it affects the balance of the loop I have no way of measuring. In practice it would not matter much, if I can't hear the difference does it matter? Regards to all, Max vk2tti.

                        Sent from my iPad

                        On 22/09/2013, at 13:20, Tony Magon <temagon@...> wrote:

                         
                        Hi Max and all

                        I have made one up for 40 meters and tried it out briefly and it worked quite well. The balun tubes can be purchased from Jaycar.

                        73

                        Tony VK2IC


                        On Sun, Sep 22, 2013 at 11:55 AM, <vk2tti@...> wrote:
                         

                        G'day Tony and all. Thank you for the heads up re G0CWT website have gone straight   to it. Very impressive video with the neon tube and the high voltage and the clamp on current measure. My youngest daughter joined the human race and went to uni studdied engineering as a mature age student, now she am be one wiff a first and second class honours to her credit. She came homn one day said " You know Dad when you try to measure something you change it! ". It seems to me that G0CWT has demonstrated that adding an unbalanced pickup loop to a tuned loop alters the theoretical current and voltage distribution expected. I would like to see the same demonstration done without the pickup loop. The problem then becomes how to excite the loop in free space! Still an interesting website. Max VK2TTI.


                        ----- Original Message -----

                        To:
                        <loopantennas@yahoogroups.com>
                        Cc:

                        Sent:
                        Sun, 22 Sep 2013 09:48:19 +1000
                        Subject:
                        Re: [loopantennas] Question About Tuned Magnetic Loop



                         
                        Hi Max

                        Have a look at G0CWT website.

                        73

                        Tony VK2IC


                        On Sun, Sep 22, 2013 at 9:44 AM, Maxwell Mclellan <vk2tti@...> wrote:
                         

                        G'day all again. Some more thoughts re main loop/pickup loop thing. If you consider them as a transformer a multi turn (say 10 turns) and a pickup loop (1 turn).Voltage (in the secondary) is reduced by 10 and the current available increased by 10 ( to keep P=RI). Impedance transformation is to the square of the turns ratio, assuming a 50 ohm secondary the the primary winding will be 50 x 100= 5000 ohms. A parallel tuned loop exhibits a high impedance. If you assume a 100ohm secondary we get a transformation of a 100 x100= 10,000 ohms ( I hope my Maths is right. If we consider a 1 turn loop and pickup the square of 1 is 1 ie no impedance transformation. That is why I gave away pickup loops for single turn loops. Copper pipe is good but expensive, for small loops I prefer aluminum strip, gets an oxide film but can be brushed clean with a brass wire brush. I believe ( religion ) that an unbalanced pickup will unbalance the system. Regards again, Max VK2TTI.
                        Sent from my iPad



                        Email sent using Optus Webmail

                      Your message has been successfully submitted and would be delivered to recipients shortly.