[HCARC] Balun Toroid Question

Mon Aug 5 21:02:11 EDT 2013

What does doubling the height of the T200 toroid do to the balun??

http://www.ebay.com/itm/Large-1-25-2-Iron-Powder-Toroidal-Core-T-200A-2-/180979806402?pt=LH_DefaultDomain_0&hash=item2a233cb0c2

Gary J
N5BAA
  ----- Original Message ----- 
  From: Dale Gaudier 
  To: 'Gary and Arlene Johnson' 
  Sent: Monday, August 05, 2013 5:59 PM
  Subject: RE: Amidon Balun Kit

  Gary:

  The website is correct. 

  The type of 1:1 balun shown in the article is known as a Ruthoff/Turrin balun. It uses three trifilar wires wound on the core. If you have Jerry Sevick, W2FMI's book ("Building and Using Baluns and Ununs"), you'll see this type of 1:1 balun described in Sec. 1.3.

  The type of 4:1 balun shown in the article is also a Ruthoff balun. See Sec. 2.3 of Sevick's book.

  73,

  Dale - K4DG

  From: Gary and Arlene Johnson [mailto:qltfnish at omniglobal.net] 
  Sent: Monday, August 05, 2013 1:13 AM
  To: Dale Gaudier
  Subject: Re: Amidon Balun Kit

  Here is where things get even more confusing for the non-electrical engineer Ham.  The Amidon instructions (such as they are) indicate that Bifilar gets you 4:1, trifilar gets you 9:1 and quadrifilar 16:1.  The website you sent says the Trifilar is 1:1.

  I'll be darned if I know which is right.

  Gary J

  N5BAA

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

    From: Dale Gaudier 

    To: 'Gary and Arlene Johnson' 

    Sent: Sunday, August 04, 2013 10:48 PM

    Subject: RE: Amidon Balun Kit

    Gary:

    Read the article carefully. 

    For a T200-2 toroid you will need enough wire to make 17 turns through the toroid for each length of wire (3 wires wound side by side for a 1:1 balun; 2 wires for a 4:1 balun) as shown in the illustration and the chart. 

    First, take a single wire and wind 17 turns around the toroid. Remove the wire. Measure the length of the wire. This is the length for each of the (2 or 3) wires you will be winding. Add 6" to 12" to this length so you will have some "pigtails" to work with to make connections to the input and output of the balun. 

    For a 1:1 balun cut three identical lengths as noted above. Label each end of each wire so you will know which one goes where per the illustration. I suggest using a good electrical tape to hold the wires next to each other. Tape them together every few inches so you have three flat wires lying side by side before you begin winding. Then, after leaving a length of wire for the pigtails, begin winding the bundle of 3 wires through the toroid 17 full turns. Make sure the wires lie tightly against the toroid and that the wires are not twisted or crossed over each other. When you're done, you should have some unwound wire sticking out for the pigtails for the other end. The direction of winding doesn't matter. 

    When you have the windings completed, adjust the windings so they are approximately spaced equally around the toroid. Tape the windings, at least at their beginning and end, so they don't come loose. I also like to use electrical ties to be sure the windings are held down firmly.

    Connect the inputs and outputs per the illustration in the article.

    The 4:1 balun is wound similarly, but with only two wires laid side-by-side. Connections are per the illustration.

    I use PVC water pipe large enough to fit the balun inside. Add two caps to seal. Connections to an antenna can be made via stainless steel eyebolts bolted to the sides of the pipe. Add another eyebolt to the top cap for hanging the balun from a support. Connection to the feedline can be through an SO-239 mounted in the base cap. Use RTV silicone to seal all the bolt holes and the SO-239.

    If you're still having problems figuring this out, give me a shout and come out to my place and we'll put one together - you supply the parts, of course. It will probably take less time than it has taken me to write this up.

    73,

    Dale - K4DG 

    From: Gary and Arlene Johnson [mailto:qltfnish at omniglobal.net] 
    Sent: Sunday, August 04, 2013 9:48 PM
    To: Dale Gaudier
    Subject: Re: Amidon Balun Kit

    Just realized that you sent along an attachment.  How hard and how much liabiliy would the company have in putting in such a set of instructions, and/or making a reference to the link.  Amazing!!    Thankl You.  I will forward them also to Kerry S.  Now to figure out how they decided that the $:1 and the 1:1 needed to have 12 windings i.e.  12 passes through the toroid center.

    Gary J

    N5BAA

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

      From: Dale Gaudier 

      To: 'Gary and Arlene Johnson' 

      Sent: Sunday, August 04, 2013 8:44 PM

      Subject: RE: Amidon Balun Kit

      Gary:

      See attached article. The core you have is probably the T200-2. It is one of the ones listed in the article. It is good for power output up to around 400 watts.  Let me know if you need further help. This is about as clear an explanation as I have been able to find on how to wind 1:1 and 4:1 baluns.
      73,
      Dale - K4DG

      From: Gary and Arlene Johnson [mailto:qltfnish at omniglobal.net] 
      Sent: Sunday, August 04, 2013 6:21 PM
      To: Dale Gaudier
      Subject: Amidon Balun Kit

      Dale,

      Goy my kits in the other day and the instructions are garbage.  I don't understand them and neither do Kerry S. or Bob Ritchie.  Care to provide some clear instructions on what to do to make both 1:1 and 4:1 baluns from the kit??

      Gary J

      N5BAA

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