Ground Plane Quarter Wave Antenna

cults3d

This part allows to realize a ground plane quarter wave antenna. The impedance of this antenna is close to 50 ohm. The base is designed to be fixed on a 40mm diameter tube (I use 40mm PVC tube). The radiating element and the radiants are made with anodized aluminium tubes of 10mm diameter (in DIY stores). The length of the tubes is to be adjusted according to the chosen frequency (1/4 wave). The connection is made using a UHF socket or an N socket. A brass or copper part is prepared and then forced into the radiating strand socket, a very short wire is then soldered between this part and the connector. 4 stainless steel self-drilling screws simultaneously secure the radiators, their connection to the connector's ground and the connector's attachment to the baseplate. A 10x1.8mm O-ring can be placed in the sub-base to seal the radiating strand. If necessary (when the wavelength dictates a larger strand, a screw can be added to lock the vertical tube into the baseplate. A small plug prevents water from entering the vertical tube. The model shown on the pictures is tuned to 403MHz (radiosonde reception).