want to make a 6m dipole, need measurements

Discussion in 'General Technical Questions and Answers' started by AG3Y, Dec 1, 2005.

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  1. K6BTM

    K6BTM Ham Member QRZ Page

    I was shaking my head at the beginning of this thread.
    At this point, I'm just sadly amazed. [​IMG]
    Where are we going !?? But...
     
  2. G7HEU

    G7HEU Ham Member QRZ Page

    And now I feel bad for not spoon feeding you the answer. Since I am a very clever radio expert I managed to enter ' dipole length calculator' in to Google. The very first link appears to be quite useful:

    http://www.csgnetwork.com/antennaedcalc.html

    What was you proposed beacon for?

    Steve.
     
  3. G7HEU

    G7HEU Ham Member QRZ Page

    (your)
     
  4. KJ3N

    KJ3N Ham Member QRZ Page

    Gee, another "How do I make a dipole?" question. [​IMG]

    Has it been 4 weeks already? [​IMG] [​IMG]

    I'd like to say I'm surprised, but I'd be lying. [​IMG]
     
  5. KI4BNC

    KI4BNC Ham Member QRZ Page

    468/f=length in feet.
    sorry.couldn't help it.
    [​IMG]
     
  6. G7HEU

    G7HEU Ham Member QRZ Page

    Shhh - it's a secret just for the brother hood.

    I'm going to bed at 02:00 local.
     
  7. KJ3N

    KJ3N Ham Member QRZ Page

    No, just a typically uneducated American ham radio operator, who apparently is too lazy (or too disinterested) to learn something.

    Open a book and read? Nah......

    All part of the wonderful ham radio testing system we have here in the U.S.A.

    Are we EVER going to see the end of published question pools? I won't hold my breath. [​IMG]
     
  8. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    Seriously, you really don't want to use a dipole, at least a horizontally polarized dipole, for a beacon. A dipole has a "figure 8" pattern and definitely is NOT omni-directional. For a beacon you definitely want to cover all directions, not just less than half of the compass. That is why a vertical dipole or a ground plane type of antenna is suggested. They are easy to build and are omni-directional.

    If you want to vertically polarize the antenna then you will find instructions for building a vertical dipole that can be side mounted from a tower on either of my websites:

    http://home.comcast.net/~zcomco

    or

    http://home.comcast.net/~k9sth

    K5USS has also posted the article on the SLANT net (Six Listeners Around North Texas) website which is

    http://home.comcast.net/~slantnet

    The formula for a wire dipole is

    468 / F where F is in MHz and the answer is in feet.

    or

    5616 / F and the answer is in inches

    That will give you the total length of a 1/2 wave dipole. The length of each half will be

    234 / F for feet

    or

    2808 / F for inches.

    However, always cut the wire long and trim for best SWR / reflected power.

    If using tubing (i.e. aluminum or copper) the actual length will usually be shorter than what the formulas say. This is because the larger the diameter of the material the shorter the antenna will be (larger material has a lower velocity factor).

    Also, the final length will be affected by the height above the ground, nearby objects, and so forth. Always use the lengths given by formulas as rough estimates and cut the material a bit longer. It is MUCH easier to remove material than it is to add material.

    Glen, K9STH
     
  9. W5LJM

    W5LJM Ham Member QRZ Page

    x 12"= length in inches.
     
  10. KF0RT

    KF0RT Ham Member QRZ Page

    The dipole question is "newbie" stuff here and is frequently ridiculed because it's so basic (and comes up so often). Google "dipole" and you'd have the answer a thousand times over. Every ham should "just know this."

    KI4BNC gave the answer, though:

    468/50.070 = 9.35 feet for overall length. Divide this by 2 (4.67 feet) for each side, so 4 feet, 8 inches is the rough length for each side. Start a bit longer and tune for max smoke.

    Those of us who operate 6 want more active Rhode Islanders. It's a rare state.

    73, Rob
     
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