Know that the gain of an antenna is measured in dB,
and understand how to calculate the e.r.p. for a known RF power and antenna
gain (in multiples of 3 dB).
Know that a three-element yagi has a half-wave
driven element, a reflector that is slightly longer than the driven element
and a director that is slightly shorter than the driven element.
Know that yagi antennas may have more than one
Know that electromagnetic radiation comprises
both an electrical field and a magnetic field.
Know that the two fields are at right-angles to each
other and that the direction of propagation is at right-angles to both fields.
Know that it is the electrical field that defines
polarisation of the wave.
Know that VHF and UHF signals will normally be
received best when the transmitter and the receiver have the same antenna
Know that polarisation is less important at HF due
the effects of ionospheric reflection.
Know the concept of an antenna polar diagram.
Know how to recognise the directions of maximum and
Know how to recognise polar diagrams for the
half-wave dipole and yagi antennas.
Know the use of a dummy load and its construction.