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348Re: [loopantennas] Information on Loop Antennas Wanted

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  • Scott Erwin
    Jan 6, 2005
    • 0 Attachment
      I currently run a Magloop for 20 and 40 meters using a
      single turn element made of 20 feet of 3/4 inch copper
      plumbing pipe. I use a homebrew copper butterfly
      capacitor rated at 12,000 volts and is 10-pF to 100-pF
      capacitance. The efficiency on 20 meters is 91.2
      percent compared to a 20 meter dipole at 1/2
      wavelength above ground and on 40 meters it's
      efficiency is 45.7 percent also compared to a 40 meter
      dipole at 1/2 wavelength above ground using KI6GD
      Magnetic loop antenna calculator V 1.6 software. This
      is calculated with a Magloop operated 6 inches above
      an aluminum ground screen to prevent earth loss. The
      aluminum ground screen in my case is a small aluminum
      camper roof. Actual operation shows that on 20 and 40
      meters a high dipole is slightly better in some
      instances than the Magloop and in other cases the
      Magloop will outperform the dipole. The advantage is
      that the Magloop is easy and fast to setup where as
      the dipole takes time to install in trees or other
      supports and in some instances may not be allowed in
      the parking lot of a disaster shelter or other areas
      where you might need to operate. What you need to do
      is research magnetic loop operation and design and
      form your own opinion. Here are some good links to get
      you started.
      http://www.laud.no/la6nca/loop/
      http://www.geocities.com/gw0tqm/magloop/magloop.htm
      http://www.standpipe.com/w2bri/index.htm
      http://www.ve3gk.com/newmagnetic.htm
      http://www.binkhorst.org/html/compact_magnetic_loop.php
      http://homepage.ntlworld.com/bill.g4kki/radio.html
      http://www.iri.tudelft.nl/~geurink/magnloop.htm
      To get the best performance from small Magloop
      antennas built with copper plumbing pipe and used with
      45 and 90-degree fittings is to apply a silver-plating
      across the joints. You don't need or even want to
      silver plate the entire element, just at the point
      where the joints overlap. A good and cheap way to do
      this is with a Caswell Inc. Plug N' Plate
      silver-plating kit. The link is
      http://www.caswellplating.com/kits/plugnplate.htm
      Now as for as having a VENDETTA with QST, I do not
      have one with them. I simply stated a fact that at
      times in the past some articles published in QST did
      not achieve a quality level that some think that all
      articles published in QST must be. Like any other
      magazine some information published will slip through
      that was for doing something other than providing a
      successful project to be built. If you download some
      of the Magloop calculation programs and punch in the
      numbers you find out just how bad that antenna would
      be. I am just trying to give you some good information
      so you can build a Magloop antenna that will actually
      work, and work well.

      --- John Kinnunen <kb0add@...> wrote:

      > Hi Scott,
      >
      > WHAT is this????? The Blind trying to lead the
      > Blind????? You should open your eyes and see what
      > is
      > out there. Your comments suggest that the only way
      > for
      > me to get anything to work is to go with a Purists
      > Ideals. With this thought in mind, you might say
      > that
      > no one would get out of the back yard unless there
      > 80
      > meter dipole is up over 67 feet. I wonder how many
      > contacts you have made on 80 meters with other hams
      > who have there 80 meter Antennas way under that
      > hight?????
      >
      > Purity of Theory is good but NOT PRACTICAL. I am NOT
      > a
      > Theorist I am a very practical person who wants to
      > see
      > how much fun one can have with the prevailing
      > conditions. If that means having that 80 meter
      > antenna
      > only 15 feet above the ground, SO BE IT.
      >
      > The Article in Question HAS Merit!!!!!!!!!!!!
      > Whether
      > or not it was written for the purpose you state has
      > NO
      > barring on the article itself. TAKE YOUR VENDETTA UP
      > WITH QST NOT ME.
      >
      > I am looking for Practical information and not some
      > very NON-practical theories. But thanks for you
      > interest anyway.
      >
      > John Kinnunen
      > KB0ADD
      >
      >
      >
      >
      > --- Scott Erwin <n4zou@...> wrote:
      >
      > > It's a variation of a magnetic loop or Magloop
      > > antenna. On 160 meters even a single turn Magloop
      > at
      > > 10% efficiency is large. This article involves the
      > > use
      > > of capacitors on each turn in an effort to
      > increase
      > > the efficiency and of a multi-turn Magloop element
      > > while at the same time reducing the size of it.
      > The
      > > simple fact of it is this is a QST "filler"
      > article
      > > used to attract non-ARRL hams to buy the magazine
      > > off
      > > bookstore shelves when the ARRL was still trying
      > to
      > > sell there QST magazine this way. Needless to say
      > > they
      > > no longer provide QST for sell in this way, as it
      > > was
      > > a money loser. This antenna "might" work at 1%
      > > efficiency. A 100-watt light bulb would most
      > likely
      > > provide more contacts. I build and use Magloop
      > > antennas so I know what to expect. Just building a
      > > single element Magloop involves using silver
      > solder
      > > on
      > > all copper connections or welding joints on
      > aluminum
      > > connections and none of this is done at all in
      > this
      > > article. This article should have shown up in the
      > > April, 1993 QST.
      > > --- kb0add <kb0add@...> wrote:
      > >
      > > >
      > > >
      > > > Hi, I am new to this list and have a few
      > questions
      > > > on a particular
      > > > Loop Antenna. The Antenna in question is from
      > the
      > > > July, 1993 QST
      > > > called "Honey, I shrunk the Antenna" by Rod
      > > Newkirk
      > > > W9BRD/VA3ZBB. I
      > > > would like to find some one who has built this
      > > > antenna and used it.
      > > >
      > > > John Kinnunen
      > > > KB0ADD
      > > >
      > > >
      > > >
      > > >
      > > >
      > > >
      > > >
      > >
      > >
      > >
      > >
      > > __________________________________
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      >
      >
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