Logperiodic antenna for 145-146 MHz
HS1 XSJ

รุ่นภาษาไทย

    Content

    1. characteristic
    2. picture
    3. material&making
    4. matching
    5. dimention
    6. calculation (new homepage)

characteristic
      A. general characteristic
    1. Can design both very wide beam width and very narrow beamwidth, up to user.
    2. Very high gain.
    3. If compare with the other type which same character, this antenna is very smaller,
      and more efficiency.
      B. characteristic of this antenna
    1. Very small, boom is 40 cm. only, can be setup at bedroom ceiling
    2. Beamwidth about 2 MHz, it is very well unidirection.
    3. Even hard rainy and strom, it's VSWR is very contant.
    4. From testing, it"s efficiency better than 10E-2 bay antenna.
      1. Both station of 2-meter are same position.
      2. 2-meter of end station antenna at the same.
      3. 2-meter of start station change between 10E-2 bay antenna
        and logperiodic antenna
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picture

Small unidirectional and high efficiency antenna
Boom 40 cm. lenght

potocol potocol Actual antenna, ceiling setup Actual antenna, outdoor setup
Actual antenna, ceiling setup construction picture theory picture reference book
graph1 graph2 graph3 graph4

    picture1 to 2 are potocol antenna, element by copper tube
    picture3 to 5 are actual antenne, element by brass welding wire.
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material&making
  1. Boom is copper tube. medium thick, "u" bench, dimemtion upto design.
  2. Drilling T-connection (PVC), set in middle boom before welding,
    after element welding, T-connection can be adjust position.
  3. Element is 3 mm. dimention size brass welding wire. ( not smaller than this size, it will be effect to wide Beamwidth and reduce gain.)
  4. Element upto design.
  5. Element welding side must be same as construction picture.
  6. Drill boom and insert in brass wire before welding
    can be both solder and gas welding
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matching
  1. Tempary setup, but must easy move up and down antenna.
  2. 3 meter height from land and 2 meter distance from tree and house.
  3. connect antenna to 2-meter and vswr-meter.
  4. Matching by cut each element 0.5 per time (ezch side).
  5. Check VSWR after one cutting.
  6. if still VSWR high, cut the other side.
  7. cutting until VSWR is between 1.4 to 1.2
  8. After actual setting, VSWR can be reduce again.
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dimention
  1. Boom lenhgt = N1+N2+N3+N4+7ซ.ม. = 43 ซ.ม.
  2. L1 is 1st element = 51 ซ.ม.
  3. L2 is 2st element = 48.0 ซ.ม.
  4. L3 is 3st element = 46.1 ซ.ม.
  5. L4 is 4st element = 43.8 ซ.ม.
  6. L5 is 5st element = 46.1 ซ.ม.
  7. Some more lenght for matching
    1. if copper tube element, 3 cm. lenght more.
    2. if brass wie element, 5 cm. lenght more.
  8. N1 is L1-L2 distance = 10.2 cm.
  9. N1 is L2-L3 distance = 9.8 cm.
  10. N1 is L3-L4 distance = 9.0 cm.
  11. N1 is L4-L5 distance = 9.0 cm.
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reference book:- เทคนิคการออกแบบและติดตั้งสายอากาศโทรทัศน์-เอฟเอ็ม
อ.ยืน ภู่วรวรรณ/////อ.สุธี จันทรัตนวงศ์/////ซีเอ็ดยูเคชั่น
This book is Thai language.
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