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Homebrew Butterfly capacitor, 12,000 volts!

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  • n4zou
    I just finished a project I have been working on the last few weeks. A large Butterfly capacitor for my soon to be built 20 and 40 meter transmitting type
    Message 1 of 9 , Oct 21, 2004
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      I just finished a project I have been working on the last few weeks.
      A large Butterfly capacitor for my soon to be built 20 and 40 meter
      transmitting type Magloop. It is 10-pF minimum and 100 pF maximum
      with spacing for 12,000 volts. It is made from 15 gauge copper sheet
      metal, 1/4-20 all thread, 1/4-20 nuts, and Plexiglas. I used aviation
      snips to cut the copper, a drill press for the holes and a skill saw
      for the Plexiglas. Testing on another 20 and 40-meter loop requires
      17-pF at 14.350 and 91-pF at 7.0 MHz. The loop will also work on 30
      meters as well. I just uploaded photos of the capacitor in the photo
      section. Just click on the N4ZOU folder. The old test loop used RG-8
      coax as the element and a split stator capacitor. You had to add a
      second capacitor to get it to work on 40 meters. This new setup will
      use 3/4 inch copper pipe for the element and will have continuous
      coverage between 14.350 and 7 MHz.
    • furman2020
      Please post pictures and diagrams of your new loop and butterfly cap. I am very interested in building the same thing, except mabe for 80 & 160. Also, please
      Message 2 of 9 , Oct 21, 2004
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        Please post pictures and diagrams of your new loop
        and butterfly cap. I am very interested in building
        the same thing, except mabe for 80 & 160. Also,
        please give us details on the performance of your
        new loop system, compared to dipole or vertical if
        possible. Thanks.
        Furman2020 K5QA

        --- In loopantennas@yahoogroups.com, "n4zou" <n4zou@y...> wrote:
        >
        > I just finished a project I have been working on the last few
        weeks.
        > A large Butterfly capacitor for my soon to be built 20 and 40
        meter
        > transmitting type Magloop. It is 10-pF minimum and 100 pF maximum
        > with spacing for 12,000 volts. It is made from 15 gauge copper
        sheet
        > metal, 1/4-20 all thread, 1/4-20 nuts, and Plexiglas. I used
        aviation
        > snips to cut the copper, a drill press for the holes and a skill
        saw
        > for the Plexiglas. Testing on another 20 and 40-meter loop
        requires
        > 17-pF at 14.350 and 91-pF at 7.0 MHz. The loop will also work on
        30
        > meters as well. I just uploaded photos of the capacitor in the
        photo
        > section. Just click on the N4ZOU folder. The old test loop used RG-
        8
        > coax as the element and a split stator capacitor. You had to add a
        > second capacitor to get it to work on 40 meters. This new setup
        will
        > use 3/4 inch copper pipe for the element and will have continuous
        > coverage between 14.350 and 7 MHz.
      • Scott Erwin
        I already have a photo of the capacitor uploaded in the photo section as stated in the original post. Here is a web page that details how to build your on
        Message 3 of 9 , Oct 22, 2004
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          I already have a photo of the capacitor uploaded in
          the photo section as stated in the original post. Here
          is a web page that details how to build your on
          capacitors.
          http://www.qsl.net/mnqrp/Loop/Mag_Loops.htm
          It takes some time for all the pictures to load. The
          drawings for the stator, rotor, and endplates are all
          in metric. I made my capacitor slightly larger to
          allow using 1/4-inch hardware. 6 mm is close but
          slightly smaller and the 1/4-20 nuts would have
          extended out past the stator vanes slightly and I did
          not want it looking like that. Here is a direct link
          to the photo of my homebrew capacitor; I hope it works
          anyway hi!
          http://photos.groups.yahoo.com/group/loopantennas/vwp?.dir=/N4ZOU&.src=gr&.dnm=capmin.jpg&.view=t&.done=http%3a//photos.groups.yahoo.com/group/loopantennas/lst%3f%26.dir=/N4ZOU%26.src=gr%26.view=t
          My test loop was made from RG-8 coax used as the
          element and an old split stator capacitor. It was
          everything you did not want to do in building one!
          Small diameter and high loss in the element as it's
          not a solid conductor and the capacitor was not welded
          across the top of the rotor. I still made contacts on
          it! The new Magloop is going to be built without the
          built-in losses of the test or fold up portable loop
          but will still transport nicely in the pickup bed of
          my truck.

          --- furman2020 <k5qa@...> wrote:

          >
          >
          > Please post pictures and diagrams of your new loop
          > and butterfly cap. I am very interested in building
          > the same thing, except mabe for 80 & 160. Also,
          > please give us details on the performance of your
          > new loop system, compared to dipole or vertical if
          > possible. Thanks.
          > Furman2020 K5QA
          >
          > --- In loopantennas@yahoogroups.com, "n4zou"
          > <n4zou@y...> wrote:
          > >
          > > I just finished a project I have been working on
          > the last few
          > weeks.
          > > A large Butterfly capacitor for my soon to be
          > built 20 and 40
          > meter
          > > transmitting type Magloop. It is 10-pF minimum and
          > 100 pF maximum
          > > with spacing for 12,000 volts. It is made from 15
          > gauge copper
          > sheet
          > > metal, 1/4-20 all thread, 1/4-20 nuts, and
          > Plexiglas. I used
          > aviation
          > > snips to cut the copper, a drill press for the
          > holes and a skill
          > saw
          > > for the Plexiglas. Testing on another 20 and
          > 40-meter loop
          > requires
          > > 17-pF at 14.350 and 91-pF at 7.0 MHz. The loop
          > will also work on
          > 30
          > > meters as well. I just uploaded photos of the
          > capacitor in the
          > photo
          > > section. Just click on the N4ZOU folder. The old
          > test loop used RG-
          > 8
          > > coax as the element and a split stator capacitor.
          > You had to add a
          > > second capacitor to get it to work on 40 meters.
          > This new setup
          > will
          > > use 3/4 inch copper pipe for the element and will
          > have continuous
          > > coverage between 14.350 and 7 MHz.
          >
          >
          >
          >
          >
          >
          >


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        • aa0ni@yahoo.com
          I just took a moment to look at your great work on this butterfly capacitor. I m curious if you could give an estimate on what your materials cost were. I m
          Message 4 of 9 , Oct 26, 2004
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            I just took a moment to look at your great work on this butterfly
            capacitor.

            I'm curious if you could give an estimate on what your materials cost
            were. I'm trying to determine if this is the route I should take - or
            if I should acquire one of MFJ's butterfly capacitors (just recently
            advertised in the latest MFJ catalog for ~ $70 along with their two
            new 'loop' tuners).

            - Daniel / AA0NI
            (normal disclaimer - no affiliation with MFJ - just happen to own one
            of their Antenna Analyzers)

            --- In loopantennas@yahoogroups.com, "n4zou" <n4zou@y...> wrote:
            >
            > I just finished a project I have been working on the last few weeks.
            > A large Butterfly capacitor for my soon to be built 20 and 40 meter
            > transmitting type Magloop. It is 10-pF minimum and 100 pF maximum
            > with spacing for 12,000 volts. It is made from 15 gauge copper sheet
            > metal, 1/4-20 all thread, 1/4-20 nuts, and Plexiglas. I used aviation
            > snips to cut the copper, a drill press for the holes and a skill saw
            > for the Plexiglas. Testing on another 20 and 40-meter loop requires
            > 17-pF at 14.350 and 91-pF at 7.0 MHz. The loop will also work on 30
            > meters as well. I just uploaded photos of the capacitor in the photo
            > section. Just click on the N4ZOU folder. The old test loop used RG-8
            > coax as the element and a split stator capacitor. You had to add a
            > second capacitor to get it to work on 40 meters. This new setup will
            > use 3/4 inch copper pipe for the element and will have continuous
            > coverage between 14.350 and 7 MHz.
          • n4zou
            I got the copper sheet metal at a local sheet metal shop. It was 4 3/4 inches wide by 8 feet long and I used 5 feet of it for my capacitor. I gave $6 for it.
            Message 5 of 9 , Oct 26, 2004
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              I got the copper sheet metal at a local sheet metal shop. It was 4
              3/4 inches wide by 8 feet long and I used 5 feet of it for my
              capacitor. I gave $6 for it. It was in a rack with other bits and
              peaces of sheet metal that was large enough not to put in the scrap
              copper drum to be sold as scrap. The owner likes to sell these bits
              and pieces to people (like me) that are not big enough to use for
              contracted jobs. Look in your telephone directory for sheet metal
              shops and ask if they have copper or aluminum scrap suitable for your
              use that they will sell to you. Basically; I had a scrounge fest in
              this sheet metal shop! I also bought some aluminum sheet and made an
              enclosure for the control box as well and he even cut and bent the
              aluminum sheet for me.
              The hardware used was a 3 foot long peace of steel 1/4-20 all thread
              rod for 99 cents and 100 1/4-20 nuts in a package for $3.89. The
              hardware store also had a small sheet of Plexiglas in there "left
              over bin" that was just large enough to make the end plates for 25
              cents.
              Back a several months ago I did email MFJ if they would sell me just
              the capacitor used for there Magloop antennas and got an answer back
              that they were not set up to do that but told me it was a good idea
              as they could not ship a large Magloop that would work below 30
              meters. I guess some other people asked the same question and now
              they're doing it!
              $70 bucks for a MFJ capacitor made for a Magloop is not a bad price
              at all! I had plenty of time to hand craft my capacitor and having
              had major brain surgery a few months ago I am now in home therapy to
              try and recover from some of the disabilities I have now. The therapy
              people wanted me to do some dumb craft items so I had my Wife drive
              me around to get the stuff for my capacitor craft item. They looked
              at me strange when I showed them my capacitor instead of a decorated
              paper holder. ;<) If I was still working a job I would have just
              bought the MFJ capacitor if it had been available at the time.

              --- In loopantennas@yahoogroups.com, aa0ni@y... wrote:
              >
              > I just took a moment to look at your great work on this butterfly
              > capacitor.
              >
              > I'm curious if you could give an estimate on what your materials
              cost
              > were. I'm trying to determine if this is the route I should take -
              or
              > if I should acquire one of MFJ's butterfly capacitors (just recently
              > advertised in the latest MFJ catalog for ~ $70 along with their two
              > new 'loop' tuners).
              >
              > - Daniel / AA0NI
              > (normal disclaimer - no affiliation with MFJ - just happen to own
              one
              > of their Antenna Analyzers)
              >
              > --- In loopantennas@yahoogroups.com, "n4zou" <n4zou@y...> wrote:
              > >
              > > I just finished a project I have been working on the last few
              weeks.
              > > A large Butterfly capacitor for my soon to be built 20 and 40
              meter
              > > transmitting type Magloop. It is 10-pF minimum and 100 pF maximum
              > > with spacing for 12,000 volts. It is made from 15 gauge copper
              sheet
              > > metal, 1/4-20 all thread, 1/4-20 nuts, and Plexiglas. I used
              aviation
              > > snips to cut the copper, a drill press for the holes and a skill
              saw
              > > for the Plexiglas. Testing on another 20 and 40-meter loop
              requires
              > > 17-pF at 14.350 and 91-pF at 7.0 MHz. The loop will also work on
              30
              > > meters as well. I just uploaded photos of the capacitor in the
              photo
              > > section. Just click on the N4ZOU folder. The old test loop used
              RG-8
              > > coax as the element and a split stator capacitor. You had to add
              a
              > > second capacitor to get it to work on 40 meters. This new setup
              will
              > > use 3/4 inch copper pipe for the element and will have continuous
              > > coverage between 14.350 and 7 MHz.
            • pop_vasile
              I can build for u any air variable capacitors Butterfly capacitor,single and split stator capacitor kits and parts for ham radio projects This capacitor has a
              Message 6 of 9 , Jan 29, 2014
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                I can build for u any air variable capacitors
                Butterfly capacitor,single and split stator capacitor kits and parts for ham radio projects

                This capacitor has a 160pF/15kV


                I produce this plates using a CNC machine.

                https://www.youtube.com/watch?v=PVGZryuLwQ0

                https://www.youtube.com/watch?v=xISBBh5LK7o

                http://www.flickr.com/photos/93005502@N08/page3/

                https://www.youtube.com/watch?v=PVGZryuLwQ0


                Variable Butterfly Capacitor for a Homebrew Magnetic Loop Antena,HF AMPLIFIER,ANTENNA TUNER


                BUTTERFLY CAPACITOR FOR YOURS :
                -MAGNETIC LOOP ANTENNA,
                - KW HF AMPLIFIER,
                -ANTENNA TUNER

                I have available for ham radio

                3" OD 1 ROTOR + 2 STATOR PLATES $ 5.00
                4" OD 1 ROTOR + 2 STATOR PLATES $ 6.50
                5" OD 1 ROTOR + 2 STATOR PLATES $ 7.75
                6" OD 1 ROTOR + 2 STATOR PLATES $ 8.75
                8" OD 1 ROTOR + 2 STATOR PLATES $ 10.50
                10" OD 1 ROTOR + 2 STATOR PLATES $ 14.00

                73 de VA6POP
                yo5bzz(at)gmail.com

              • Craig F. Simmons
                What is the lowest capacitance on one of your kits, along with the max. I keep seeing the highest being listed but nothing about the low end. This is important
                Message 7 of 9 , Jan 29, 2014
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                  What is the lowest capacitance on one of your kits, along with the max. I keep seeing the highest being listed but nothing about the low end. This is important to me because I have one loop that works great on 30 meters and 40 meters but just lacks a going low enough to cover it. Both valuse would be great to know if possible. And yes I know if I make the loop length shorter that will change what is needed.  This will make it easy for me to order a few kits. thank you



                  Date: Thu, Jan 30, 2014 at 7:49 AM
                  Subject: Re: [loopantennas] Re: Homebrew Butterfly capacitor, 12,000 volts!
                  To: loopantennas@yahoogroups.com


                   

                  I can build for u any air variable capacitors
                  Butterfly capacitor,single and split stator capacitor kits and parts for ham radio projects

                  This capacitor has a 160pF/15kV


                  I produce this plates using a CNC machine.

                  https://www.youtube.com/watch?v=PVGZryuLwQ0

                  https://www.youtube.com/watch?v=xISBBh5LK7o

                  http://www.flickr.com/photos/93005502@N08/page3/

                  https://www.youtube.com/watch?v=PVGZryuLwQ0


                  Variable Butterfly Capacitor for a Homebrew Magnetic Loop Antena,HF AMPLIFIER,ANTENNA TUNER


                  BUTTERFLY CAPACITOR FOR YOURS :
                  -MAGNETIC LOOP ANTENNA,
                  - KW HF AMPLIFIER,
                  -ANTENNA TUNER

                  I have available for ham radio

                  3" OD 1 ROTOR + 2 STATOR PLATES $ 5.00
                  4" OD 1 ROTOR + 2 STATOR PLATES $ 6.50
                  5" OD 1 ROTOR + 2 STATOR PLATES $ 7.75
                  6" OD 1 ROTOR + 2 STATOR PLATES $ 8.75
                  8" OD 1 ROTOR + 2 STATOR PLATES $ 10.50
                  10" OD 1 ROTOR + 2 STATOR PLATES $ 14.00

                  73 de VA6POP
                  yo5bzz(at)gmail.com


                • Craig F. Simmons
                  Correction on wording , sorry. Date: Thu, Jan 30, 2014 at 10:33 AM Subject: Fwd: [loopantennas] Re: Homebrew Butterfly capacitor, 12,000 volts! To:
                  Message 8 of 9 , Jan 30, 2014
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                    Correction on wording , sorry.

                    Date: Thu, Jan 30, 2014 at 10:33 AM
                    Subject: Fwd: [loopantennas] Re: Homebrew Butterfly capacitor, 12,000 volts!
                    To: loopantennas@yahoogroups.com


                    What is the lowest capacitance on one of your kits, along with the max. I keep seeing the highest being listed but nothing about the low end. This is important to me because I have one loop that works great on 30 meters and 40 meters but just lacks a going low enough to cover 20 meters. Have minimum and maximum would help to calculate what length and size material will work. Both values would be great to know if possible. And yes I know if I make the loop length shorter that will change what is needed.  This will make it easy for me to order a few kits. thank you



                    Date: Thu, Jan 30, 2014 at 7:49 AM
                    Subject: Re: [loopantennas] Re: Homebrew Butterfly capacitor, 12,000 volts!
                    To: loopantennas@yahoogroups.com


                     

                    I can build for u any air variable capacitors
                    Butterfly capacitor,single and split stator capacitor kits and parts for ham radio projects

                    This capacitor has a 160pF/15kV


                    I produce this plates using a CNC machine.

                    https://www.youtube.com/watch?v=PVGZryuLwQ0

                    https://www.youtube.com/watch?v=xISBBh5LK7o

                    http://www.flickr.com/photos/93005502@N08/page3/

                    https://www.youtube.com/watch?v=PVGZryuLwQ0


                    Variable Butterfly Capacitor for a Homebrew Magnetic Loop Antena,HF AMPLIFIER,ANTENNA TUNER


                    BUTTERFLY CAPACITOR FOR YOURS :
                    -MAGNETIC LOOP ANTENNA,
                    - KW HF AMPLIFIER,
                    -ANTENNA TUNER

                    I have available for ham radio

                    3" OD 1 ROTOR + 2 STATOR PLATES $ 5.00
                    4" OD 1 ROTOR + 2 STATOR PLATES $ 6.50
                    5" OD 1 ROTOR + 2 STATOR PLATES $ 7.75
                    6" OD 1 ROTOR + 2 STATOR PLATES $ 8.75
                    8" OD 1 ROTOR + 2 STATOR PLATES $ 10.50
                    10" OD 1 ROTOR + 2 STATOR PLATES $ 14.00

                    73 de VA6POP
                    yo5bzz(at)gmail.com



                  • AlienRelics
                    You might want to email him directly. That is a very good question, BTW. Steve Greenfield AE7HD
                    Message 9 of 9 , Jan 30, 2014
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                      You might want to email him directly.

                      That is a very good question, BTW.

                      Steve Greenfield AE7HD

                      --- In loopantennas@yahoogroups.com, "Craig F. Simmons" <k910dog@...> wrote:
                      >
                      > Correction on wording , sorry.
                      >
                      > Date: Thu, Jan 30, 2014 at 10:33 AM
                      > Subject: Fwd: [loopantennas] Re: Homebrew Butterfly capacitor, 12,000 volts!
                      > To: loopantennas@yahoogroups.com
                      >
                      >
                      > What is the lowest capacitance on one of your kits, along with the max. I
                      > keep seeing the highest being listed but nothing about the low end. This is
                      > important to me because I have one loop that works great on 30 meters and
                      > 40 meters but just lacks a going low enough to cover 20 meters. Have
                      > minimum and maximum would help to calculate what length and size material
                      > will work. Both values would be great to know if possible. And yes I know
                      > if I make the loop length shorter that will change what is needed. This
                      > will make it easy for me to order a few kits. thank you
                      >
                      >
                      >
                      > Date: Thu, Jan 30, 2014 at 7:49 AM
                      > Subject: Re: [loopantennas] Re: Homebrew Butterfly capacitor, 12,000 volts!
                      > To: loopantennas@yahoogroups.com
                      >
                      >
                      >
                      >
                      > I can build for u any air variable capacitors
                      > Butterfly capacitor,single and split stator capacitor kits and parts for
                      > ham radio projects
                      >
                      > This capacitor has a 160pF/15kV
                      >
                      >
                      > I produce this plates using a CNC machine.
                      >
                      > https://www.youtube.com/watch?v=PVGZryuLwQ0
                      >
                      > https://www.youtube.com/watch?v=xISBBh5LK7o
                      >
                      > http://www.flickr.com/photos/93005502@N08/page3/
                      >
                      > https://www.youtube.com/watch?v=PVGZryuLwQ0
                      >
                      >
                      > Variable Butterfly Capacitor for a Homebrew Magnetic Loop Antena,HF
                      > AMPLIFIER,ANTENNA TUNER
                      >
                      >
                      > BUTTERFLY CAPACITOR FOR YOURS :
                      > -MAGNETIC LOOP ANTENNA,
                      > - KW HF AMPLIFIER,
                      > -ANTENNA TUNER
                      >
                      > I have available for ham radio
                      >
                      > 3" OD 1 ROTOR + 2 STATOR PLATES $ 5.00
                      > 4" OD 1 ROTOR + 2 STATOR PLATES $ 6.50
                      > 5" OD 1 ROTOR + 2 STATOR PLATES $ 7.75
                      > 6" OD 1 ROTOR + 2 STATOR PLATES $ 8.75
                      > 8" OD 1 ROTOR + 2 STATOR PLATES $ 10.50
                      > 10" OD 1 ROTOR + 2 STATOR PLATES $ 14.00
                      >
                      > 73 de VA6POP
                      > yo5bzz(at)gmail.com
                      >
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