- Antenna Load & Feed -
This pages is about HOW-TO Load and Feed your Antenna propper,- to avoid TVI/RFI problems and gain maximum out of your antenna and your equipment.

- Principle -
First i State some simple facts:
  • The impedance in the dipole is resistive and dependes on the distance between any two points along the resonant dipole. The value of the impedance is changed if the distance between the two points is changed.

  • At the dipoles resonant frequenzy is the impedance at the dipole center always equal to zero (0 Ohm)

  • The dipole is an balanced array and an coaxial-cable feed line is unbalanced


    Antenna current curve

    To Solve the problem
    If you have the above statments in mind,- it is quite easy to realise that feeding the antenna at the propper point solves most problems,- se the fig. below. Many Antenna 'Homebrewers' insists that any dipole simply can be feed with an coaxial cable without any problem, this is not true, one big problem is that: If a point along the dipole that correspond to the feedline impedance is obtained the matching in correct,- but only exactly at the dipole resonant frequenzy,- the antenna will be extremly narrow in band-width and in practice unusable for transmitting.

    Gamma-MATCH
    Air BALUN
    Ferrit BALUN


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    ©1999/2000/2001/2002 SM2YER Goran