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

New to the group

Expand Messages
  • n4zou
    I just joined the group. I have built a Magloop for 20 and 40 meters and it s great for taking camping! It is made from 20 feet of old RG- 8 coax which I am
    Message 1 of 13 , Oct 1 2:28 PM
      I just joined the group. I have built a Magloop for 20 and 40 meters
      and it's great for taking camping! It is made from 20 feet of old RG-
      8 coax which I am using the shield for the element and an old split
      stator capacitor with a motor drive for tuning. Holding the motor
      drive, capacitor, and RG-8 coax loop element are two 8 feet long
      fiberglass round rods with a 3/8 inch bold running through both in
      the middle to form a X shape which folds for transport. No more
      slinging wire and rope in trees that might not be available and only
      take 5 minutes to setup and start operating! No tuner required so
      less stuff to take along. It outperforms mobile HF antennas and low
      hanging dipoles. I am thinking about improving the design by making
      the element of 3/4 inch copper plumbing pipe and make the shape to
      just fit the inside of my truck bed for transport. The copper tubing
      would work much better than the coax.
    • Danny
      ... meters ... RG- ... only ... tubing ... Hi Very interesting loop. If you can send photo in the photo section, that would be great. Danny
      Message 2 of 13 , Oct 2 9:25 AM
        --- In loopantennas@yahoogroups.com, "n4zou" <n4zou@y...> wrote:
        > I just joined the group. I have built a Magloop for 20 and 40
        meters
        > and it's great for taking camping! It is made from 20 feet of old
        RG-
        > 8 coax which I am using the shield for the element and an old split
        > stator capacitor with a motor drive for tuning. Holding the motor
        > drive, capacitor, and RG-8 coax loop element are two 8 feet long
        > fiberglass round rods with a 3/8 inch bold running through both in
        > the middle to form a X shape which folds for transport. No more
        > slinging wire and rope in trees that might not be available and
        only
        > take 5 minutes to setup and start operating! No tuner required so
        > less stuff to take along. It outperforms mobile HF antennas and low
        > hanging dipoles. I am thinking about improving the design by making
        > the element of 3/4 inch copper plumbing pipe and make the shape to
        > just fit the inside of my truck bed for transport. The copper
        tubing
        > would work much better than the coax.


        Hi
        Very interesting loop. If you can send photo in the photo section,
        that would be great.
        Danny
      • n4zou
        I just uploaded some photos of my foldup portable transmitting type loop in the photo section in the folder called N4ZOU. Note the strange motor drive setup! I
        Message 3 of 13 , Oct 3 3:55 PM
          I just uploaded some photos of my foldup portable transmitting type
          loop in the photo section in the folder called N4ZOU. Note the
          strange motor drive setup! I wanted to keep the amount of metal to a
          minimum inside the loop so I used two 4 foot by 3/8 inch
          fiberglass "electric fence post" rods and used copper tubing
          compression fittings to join them in the middle. It also balances the
          loop so it's not hard to pick it up and set it in the tripod mount.
          The loop uses an Armstrong rotor design....Mason string!
          --- In loopantennas@yahoogroups.com, "Danny" <dannibou@y...> wrote:
          >
          > --- In loopantennas@yahoogroups.com, "n4zou" <n4zou@y...> wrote:
          > > I just joined the group. I have built a Magloop for 20 and 40
          > meters
          > > and it's great for taking camping! It is made from 20 feet of old
          > RG-
          > > 8 coax which I am using the shield for the element and an old
          split
          > > stator capacitor with a motor drive for tuning. Holding the motor
          > > drive, capacitor, and RG-8 coax loop element are two 8 feet long
          > > fiberglass round rods with a 3/8 inch bold running through both
          in
          > > the middle to form a X shape which folds for transport. No more
          > > slinging wire and rope in trees that might not be available and
          > only
          > > take 5 minutes to setup and start operating! No tuner required so
          > > less stuff to take along. It outperforms mobile HF antennas and
          low
          > > hanging dipoles. I am thinking about improving the design by
          making
          > > the element of 3/4 inch copper plumbing pipe and make the shape
          to
          > > just fit the inside of my truck bed for transport. The copper
          > tubing
          > > would work much better than the coax.
          >
          >
          > Hi
          > Very interesting loop. If you can send photo in the photo section,
          > that would be great.
          > Danny
        • KABOONA
          Hello all, my name is Jimmy and I just joined the group. I am very curious about the working of loop antennas and hope to learn to build my own. Hopefully this
          Message 4 of 13 , Oct 25 7:37 PM
            Hello all, my name is Jimmy and I just joined the group. I am very curious about the
            working of loop antennas and hope to learn to build my own. Hopefully this group will
            provide good data to accomplish that. I hope to build one to work good on 40m.
            Regards
            Jim
            KB1KZI
          • Scott Erwin
            Welcome! I only joined a few weeks ago myself. So for so good! If you want to build your own capacitor for a transmitting Magloop go to the photo section and
            Message 5 of 13 , Oct 26 6:46 AM
              Welcome! I only joined a few weeks ago myself. So for
              so good! If you want to build your own capacitor for a
              transmitting Magloop go to the photo section and look
              at the pictures in the Butterfly folder. These
              pictures show how to build a Butterfly capacitor. If
              you use copper sheet metal you can cut out the rotor
              and stator vanes with aviation snips. No sliding
              contact to the rotor is required so there is no loss
              across this type of capacitor. Also like a split
              stator capacitor the capacitance is half what the
              surface area of a normal capacitor but the voltage
              rating is doubled! This is just what you need for a
              single turn transmitting loop antenna. Operating at
              100 watts is easy using 1/4-20 all thread rod and
              matching nuts from the hardware store for construction
              of the capacitor. You might also want to check the
              n4zou folder. There you will find a fold up portable
              Magloop antenna for 20,30, and 40 meters. I also have
              a picture of my homebrew 13-pF to 102-pF 12,000-volt
              Butterfly capacitor.
              --- KABOONA <kaboona@...> wrote:

              >
              >
              > Hello all, my name is Jimmy and I just joined the
              > group. I am very curious about the
              > working of loop antennas and hope to learn to build
              > my own. Hopefully this group will
              > provide good data to accomplish that. I hope to
              > build one to work good on 40m.
              > Regards
              > Jim
              > KB1KZI
              >
              >
              >
              >
              >
              >
              >




              __________________________________
              Do you Yahoo!?
              Read only the mail you want - Yahoo! Mail SpamGuard.
              http://promotions.yahoo.com/new_mail
            • Samuel Ernst-Fortin
              Interested in SWL, learning about antenna construction. Thus far, all I ve built is a 100ft longwire for my Realistic DX-160, and a short indoor 30ft simple
              Message 6 of 13 , Sep 9, 2008
                Interested in SWL, learning about antenna construction. Thus far, all I've built is a 100ft longwire for my Realistic DX-160, and a short indoor 30ft simple wire. I'd like to see what a loop would do. Heard they are pretty directional at lower frequencies.




                [Non-text portions of this message have been removed]
              • Jim Dunstan
                ... Hi, not quite .... an antenna is generally considered directional if the pattern (for reception or radiation as the case may be) is narrow ... either
                Message 7 of 13 , Sep 10, 2008
                  At 06:39 PM 9/9/2008 -0700, you wrote:

                  >Interested in SWL, learning about antenna construction. Thus far, all I've
                  >built is a 100ft longwire for my Realistic DX-160, and a short indoor 30ft
                  >simple wire. I'd like to see what a loop would do. Heard they are pretty
                  >directional at lower frequencies.

                  Hi,

                  not quite .... an antenna is generally considered directional if the
                  pattern (for reception or radiation as the case may be) is narrow ...
                  either bi-directional or uni-directional. A Hi-Q loop has a narrow
                  bi-directional null. As a consequence the radiation pattern is also
                  bi-directional and rather broad. These small loops are good at nulling out
                  interference from particular directions while maintaining a rather broad
                  reception pattern.

                  The small loop is also more immune (but not immune) to noise than most
                  other antennas. The other useful characteristic is that since most of
                  these loops are small they can be located to positions with less noise ....
                  you would be surprised that moving the loop to a different location a few
                  feet away can result in meaningful reduction in locally generated interference.

                  Jim
                • sernstfortin
                  ... a feet away can result in meaningful reduction in locally generated interference. ... Jim, Thanks for the response. I am very interested in building a loop
                  Message 8 of 13 , Sep 11, 2008
                    --- In loopantennas@yahoogroups.com, Jim Dunstan <dunstan@...> wrote:

                    > Hi,
                    >
                    > not quite ....
                    > Hi-Q loop has a narrow bi-directional null.

                    > The small loop is also more immune (but not immune) to noise than

                    >you would be surprised that moving the loop to a different location
                    a feet away can result in meaningful reduction in locally generated
                    interference.
                    >
                    > Jim
                    >
                    Jim,
                    Thanks for the response.
                    I am very interested in building a loop antenna to try it and compare
                    to the 100ft longwire I have.

                    What I meant by my comment, is I thought in the upper frequencies,
                    maybe about 3-4MHz, the directionality of the antenna for SW
                    listening (no broadcasting, no license (yet)) would be less than that
                    at lower-frequencies. Maybe I'm wrong about that, but I'm willing to
                    learn more and give it a go.

                    Is there a particular design which would work well enough up through
                    30MHz which you might recommend or point me to for researching?

                    I like the characteristics w.r.t. nulling, but also placement and the
                    reduction in noise. Ideally, this would be something I could place on
                    my deck at the rear of the house for evening listening /
                    experimentation.

                    Putting up and taking down my longwire is a bit cumbersome /
                    inconvenient. By the time we've finished up dinner, the dishes,
                    volleyball, baths, stories, bed, I'm toast.
                    Any help appreciated.
                    Sam
                  • Jim Dunstan
                    ... Hi Sam, A small (e.g 3 diam approx) tuned loop for frequencies ... 2-10 mhz makes a vy good antenna for the balcony. My downtown apt in the big city on
                    Message 9 of 13 , Sep 11, 2008
                      At 11:36 AM 9/11/2008 +0000, you wrote:

                      >--- In
                      ><mailto:loopantennas%40yahoogroups.com>loopantennas@yahoogroups.com, Jim
                      >Dunstan <dunstan@...> wrote:
                      >
                      > > Hi,
                      > >
                      > > not quite ....
                      > > Hi-Q loop has a narrow bi-directional null.
                      >
                      > > The small loop is also more immune (but not immune) to noise than
                      >
                      > >you would be surprised that moving the loop to a different location
                      >a feet away can result in meaningful reduction in locally generated
                      >interference.
                      > >
                      > > Jim
                      > >
                      >Jim,
                      >Thanks for the response.
                      >I am very interested in building a loop antenna to try it and compare
                      >to the 100ft longwire I have.
                      >
                      >What I meant by my comment, is I thought in the upper frequencies,
                      >maybe about 3-4MHz, the directionality of the antenna for SW
                      >listening (no broadcasting, no license (yet)) would be less than that
                      >at lower-frequencies. Maybe I'm wrong about that, but I'm willing to
                      >learn more and give it a go.
                      >
                      >Is there a particular design which would work well enough up through
                      >30MHz which you might recommend or point me to for researching?
                      >
                      >I like the characteristics w.r.t. nulling, but also placement and the
                      >reduction in noise. Ideally, this would be something I could place on
                      >my deck at the rear of the house for evening listening /
                      >experimentation.
                      >
                      >Putting up and taking down my longwire is a bit cumbersome /
                      >inconvenient. By the time we've finished up dinner, the dishes,
                      >volleyball, baths, stories, bed, I'm toast.
                      >Any help appreciated.
                      >Sam


                      Hi Sam,

                      A small (e.g 3' diam approx) tuned loop for frequencies ... 2-10 mhz makes
                      a vy good antenna for the balcony. My downtown apt in the big city on the
                      9th flr uses such an antenna. I have it fastened to the balcony
                      railing. As I mentioned orientation is for minimum noise and as
                      consequence is a one time rotation ... and the receiving directions are
                      broad. Tuning the antenna to the frequency of interest is the trick. One
                      method is to make the loop from coax and feed it with a standard unbalanced
                      tuner. I deviated from this approach and constructed the loop from
                      ordinary copper tubing and fed it with 300 ohm twin lead and tuned it with
                      a small balanced tuner ... located inside the apt. about 8' from the loop.

                      I could tune the loop from approx 3 to 11 mhz. The performance is head and
                      shoulders above the built in whip ... or any wire antenna i could jury rig
                      in the apartment.

                      At my country home ... eg ... small city on lake superior, i use a wire
                      antenna ... certainly not 100' ft long ... more like 40ft. It terminates
                      at a ground connection out in the garden and is then coupled to coax which
                      comes to the house ... buried a few inches under the lawn. The idea is to
                      keep the antenna away from local noise sources which are inevitably located
                      in the house. There is no need for a long antenna like 100 ft. After all
                      we are not using xtal sets ... modern receivers have more than enough gain
                      ... the key is to keep the ratio of signal to noise as low as possible.

                      Jim



                      >


                      [Non-text portions of this message have been removed]
                    • sernstfortin
                      ... we are not using xtal sets ... modern receivers have more than enough gain ... the key is to keep the ratio of signal to noise as low as possible. I think
                      Message 10 of 13 , Sep 11, 2008
                        --- In loopantennas@yahoogroups.com, Jim Dunstan <dunstan@...> wrote:
                        >>There is no need for a long antenna like 100 ft. After all
                        we are not using xtal sets ... modern receivers have more than enough
                        gain ... the key is to keep the ratio of signal to noise as low as
                        possible.

                        I think you meant the key is to maximize the SNR ratio. If the SNR were
                        low, then the signal would be approxiately equal to or less than the
                        noise. Not good. ;)

                        I'll hunt for some designs. Maybe the ARRL wire antenna book will have
                        something. Any chance you'd post the configuration of the tuning
                        section you are using in Files or Photos? How about a pic of the
                        antenna itself? Type / gauge of wire? Spacing of the loops to avoid
                        self inductance? Values of the variable cap and inductor you're using?

                        I was hoping a loop could be made that would be workable up through
                        30MHz; I guess that might be asking too much of a loop - too much
                        compromise. Again, I have to do some research.
                        Thanks.
                      • Jim Dunstan
                        At 10:51 PM 9/11/2008 +0000, you wrote ... Not that complicated.... 1 loop (3 in dia.) anything at hand .. bigger the gauge the better. No tuning capacitor,
                        Message 11 of 13 , Sep 11, 2008
                          At 10:51 PM 9/11/2008 +0000, you wrote



                          >I'll hunt for some designs. Maybe the ARRL wire antenna book will have
                          >something. Any chance you'd post the configuration of the tuning
                          >section you are using in Files or Photos? How about a pic of the
                          >antenna itself? Type / gauge of wire? Spacing of the loops to avoid
                          >self inductance? Values of the variable cap and inductor you're using?

                          Not that complicated.... 1 loop (3' in dia.) anything at hand .. bigger the
                          gauge the better. No tuning capacitor, up to 12' balanced feed line, 1
                          balanced tuner (I use a Z-match). The idea is to tune it from a distance
                          ... eg up to 12'. As you change bands/frequencies you tune the loop with
                          the tuner .... very clear noise rush at resonance. Will work to 15 mhz
                          .... in fact even made a few contacts on 20m. The objective was SWL.


                          >I was hoping a loop could be made that would be workable up through
                          >30MHz; I guess that might be asking too much of a loop - too much
                          >compromise. Again, I have to do some research.
                          >Thanks.

                          I suppose if you adjust the components you could resonant to 30mhz. The
                          most dramatic improvements in reception are in that 5mhz to 10mhz
                          range. I'll check my photos .... I know I have a couple of pics.

                          Jim, VE3CI


















                          >


                          [Non-text portions of this message have been removed]
                        • tenorman1952
                          ... wrote: (trimmed) ... The broad reception range and narrow null (fat figure 8 pattern) make loops ideal for noise reduction. I use mine placed on an old
                          Message 12 of 13 , Sep 12, 2008
                            --- In loopantennas@yahoogroups.com, "sernstfortin" <sernstfortin@...>
                            wrote:
                            (trimmed)
                            >I like the characteristics w.r.t. nulling, but also placement and the
                            > reduction in noise. Ideally, this would be something I could place on
                            > my deck at the rear of the house for evening listening /
                            > experimentation.
                            >
                            > Putting up and taking down my longwire is a bit cumbersome /
                            > inconvenient. By the time we've finished up dinner, the dishes,
                            > volleyball, baths, stories, bed, I'm toast.
                            > Any help appreciated.
                            > Sam

                            The broad reception range and narrow null (fat figure 8 pattern) make
                            loops ideal for noise reduction.

                            I use mine placed on an old "Lazy Susan" and rotate it for best
                            effect. If you are using it with a portable radio, and coupling by
                            placing the radio near it you will notice the radio needs to be in a
                            particular orientation with the loop for best effect. In that case,
                            the radio may be placed on the Lazy Susan and both rotated together.

                            I have a "pickup loop" added to my MTM Scientific loop and feed my
                            tuner with a twisted pair, but it works as well with 300 ohm twinlead.

                            Paul C.
                            tenorman1952
                          • airchecklover
                            Paul; Nice job on the MTM home-brew. It looked so good i thought I was seeing the full MTM kit, not a home-brew version. -Mark
                            Message 13 of 13 , Sep 14, 2008
                              Paul; Nice job on the MTM home-brew. It looked so good i thought I
                              was seeing the full MTM kit, not a home-brew version.

                              -Mark

                              ============================

                              > --- In loopantennas@yahoogroups.com, "sernstfortin" <sernstfortin@>
                              > wrote:
                              > (trimmed)
                              > >I like the characteristics w.r.t. nulling, but also placement and the
                              > > reduction in noise. Ideally, this would be something I could place on
                              > > my deck at the rear of the house for evening listening /
                              > > experimentation.
                              > >
                              > > Putting up and taking down my longwire is a bit cumbersome /
                              > > inconvenient. By the time we've finished up dinner, the dishes,
                              > > volleyball, baths, stories, bed, I'm toast.
                              > > Any help appreciated.
                              > > Sam
                              >
                              > The broad reception range and narrow null (fat figure 8 pattern) make
                              > loops ideal for noise reduction.
                              >
                              > I use mine placed on an old "Lazy Susan" and rotate it for best
                              > effect. If you are using it with a portable radio, and coupling by
                              > placing the radio near it you will notice the radio needs to be in a
                              > particular orientation with the loop for best effect. In that case,
                              > the radio may be placed on the Lazy Susan and both rotated together.
                              >
                              > I have a "pickup loop" added to my MTM Scientific loop and feed my
                              > tuner with a twisted pair, but it works as well with 300 ohm twinlead.
                              >
                              > Paul C.
                              > tenorman1952
                              >
                            Your message has been successfully submitted and would be delivered to recipients shortly.