1.Helical aerials

Looking into the direction of transmission, helical beam aerials shall have a right-hand thread.

2.Moonbounce aerials

The polarisation of microwave signals used for communication via moonbounce shall be right-hand circular, i.e. the wave travelling away from the observer should rotate in a clockwise direction for operation below 3 GHz.

For operation above 3 GHz linear polarisation shall be used. European stations should use vertical polarisation. All stations shall include provision for adjustable polarisation and be prepared to agree the offset beforehand. Exact polarisation offsets shall be checked at the commencement of activity.

Should technical developments occur to make circular polarisation practical for general adoption this will be considered at a future conference.

3. NBFM Repeater aerials

Vertical ( see recommendation FM.2.)