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Alford Slot antennas in theory and practise. By Mart Sakalov, SM0ERR.

Alford Slot antennas in theory and practise. By Mart Sakalov, SM0ERR. Andrew Alford. Born Aug 5 1904 - Died Jan 25 1992 Birthplace: Samara, Russia Localizer Antenna System Patent Number(s) 2,682,050. Alford-Slot Advantages. Vertical but Horizontally polarized Omni-directional

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Alford Slot antennas in theory and practise. By Mart Sakalov, SM0ERR.

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  1. Alford Slot antennas in theory and practise. By Mart Sakalov, SM0ERR.

  2. Andrew Alford Born Aug 5 1904 - Died Jan 25 1992 Birthplace: Samara, RussiaLocalizer Antenna SystemPatent Number(s) 2,682,050

  3. Alford-Slot Advantages • Vertical but Horizontally polarized • Omni-directional • Easy to build • Small, light, cheap • Six dBd gain ?

  4. Babinet’s Principle“ Diffraction pattern from an opaque body is identical to that from a hole of the same size “ Note, that H and E field change place in an slot compared with a dipole.

  5. A stealth approach. Flag pole extended with an Alford slot for 23cm.

  6. Top ball of flag pole is removed, replaced with a rubber reduction holding the 7/8 inch hardline coax and antenna.

  7. Bottom hinge of flag pole with the 7/8 coax burried into lawn. Not even the wife will notice this installation, stealth is the word.

  8. 35x32mm Au • 750mm total • 510mm slot 2,15λ • 7mm gap • Six dBd gain 23 cm dimentions of an Alford slot antenna

  9. Radiation plots by courtesy Hannes Illipe SM6PGP.

  10. 23cm PA with 4xTUG delivering 400+W. Best DX using Alford slot is OK 1000+km. And, yes there was good tropo at the time.

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