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Slideshow english

  1. 1. 80 m antenna <ul><li>Full size </li></ul><ul><li>Limited space </li></ul><ul><li>Omnidirectional </li></ul><ul><li>Low noise </li></ul><ul><li>Effective </li></ul><ul><li>Cheap </li></ul>
  2. 2. Feedpoint 1 <ul><li>Balun balance the antenna, so that the dipole radiate even on the two legs </li></ul><ul><li>Veldefinet radiation </li></ul><ul><li>Less BCI tendency </li></ul>
  3. 3. Feedpoint 2 <ul><li>Lexan sheet </li></ul><ul><li>2 toroids w. 3 vdg. </li></ul><ul><li>Impregnated w. linenoil </li></ul><ul><li>Baked at 70 dg C for 2days </li></ul><ul><li>Holding cable </li></ul><ul><li>Holding antenna wire </li></ul><ul><li>Feedcabel RG58 </li></ul>
  4. 4. Feedpoint 3 <ul><li>3 windings pr core </li></ul><ul><li>Each gives 500 Ohm </li></ul><ul><li>2 in serie gives 1000 Ohm </li></ul><ul><li>Wire ø 1,25 mm </li></ul><ul><li>Wire and cabel solderet </li></ul><ul><li>Silikoneprotected </li></ul>
  5. 5. Feed cable <ul><li>For each 2,5 m on feeder ferritetubes are placed </li></ul><ul><li>Each tube gives 100 Ohm </li></ul><ul><li>Feeder do not resonate, or disturb radiation diagram </li></ul><ul><li>BCI advantage </li></ul><ul><li>½ wavelength X 0,66 </li></ul>
  6. 6. Antenna mast <ul><li>6 m flagpole </li></ul><ul><li>Wooden pole 3,6 m </li></ul><ul><li>Totalheigth 8 m </li></ul><ul><li>Supporting wire </li></ul>
  7. 7. Endpoints of antenna <ul><li>Endpoints in trees </li></ul><ul><li>Springs in stainless steel to eleminate the movement of the trees </li></ul><ul><li>8/6 m heights </li></ul><ul><li>105 grader </li></ul>
  8. 8. Calculation of balun <ul><li>Z=AL x N x N </li></ul><ul><li>Example: J-42915 –TC, at 4 Mhz AL = 30 </li></ul><ul><li>3 turns gives 30 x 9 = 270 Ohm </li></ul>
  9. 9. Groundplane <ul><li>Wires on ground </li></ul><ul><li>Internally connected </li></ul><ul><li>Not connected to earth </li></ul><ul><li>Less loss to ground </li></ul><ul><li>Less noise from mains supply </li></ul><ul><li>More radiated power </li></ul>
  10. 10. Horisontal radiation diagram <ul><li>105 dg horisontal wires </li></ul><ul><li>Almost omnidirectional </li></ul><ul><li>Ideel to localtrafic </li></ul><ul><li>Working fine up to 2000 Km </li></ul>
  11. 11. Vertikal radiation diagram 1 <ul><li>Antenna height means all for the vertical radiation </li></ul>
  12. 12. Vertikal radiation diagram 2 <ul><li>Big heights are not always an advantage!! </li></ul>
  13. 13. Bandwith <ul><li>3500 KHz: 136 Ohm </li></ul><ul><li>3600 Khz: 78 Ohm </li></ul><ul><li>3700 Khz: 50 Ohm </li></ul><ul><li>3800 Khz: 80 Ohm </li></ul>

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