Retracting mechanism for antenna ground plane radials

A portable aerial consisting of a vertical whip element and a number of laterally extending arms forming a ground plane. The arms are resiliently pivoted at their inner ends in a mechanism which permits the arms to be deflected downwards and to return to their operative positions but which locks them in an upward position if they are deflected too far upwardly. The aerial can then be inserted through small apertures in trees etc. the obstructing branches deflecting the arms downward, temporarily, on entry and upward, permanently, on withdrawal.