Realization of antennas for radiosonde balloons

• ANTENNA YAGI 403 MHz 6 elements

  
  
  
  
  
  
  
  
  
  

• ANTENNA 1/4 D’ONDA “GROUND PLANE” 403MHz

  Receiver coverage area here

This is an antenna that can be built very easily and allows a gain of around 3 ~ 4dBi. It consists of 1 active vertical radial and 4 passive elements that configure the reflecting plane. The vertical radial element [A], with a length of 1 / 4λ or 186 mm from the base of the connector, will be welded (for ease of installation) on the central part of a "SO-239" panel-type connector. On the base of the connector we find 4 holes and we can weld (or screw) the elements of the reflecting plane, placing them at about 135 ° with respect to the vertical element (45 ° from the base) and will be 1 / 4λ - 5% in length. 176 mm [B]

 

• ANTENNA IN DIPOLES OF COAXIAL  “COLLINEAR” 403MHz

 Of construction more "cumbersome" than the previous ones, it is certainly a good test for the most willing. Generally made with RG213 coaxial cable, the antenna is composed of a series of dipoles of different wavelengths. The realization consists in cutting pieces of cable and welding the central one of the sock of the other as explained in the attached New Electronics article. The measurements to build our collinear antenna using RG213 coaxial cable are the following: from the bottom to the top we will have the cable where the connector will be connected (about 20cm from the first dipole) and that will act as the first dipole of 186mm, the second dipole of 123mm, the third of 246mm, the fourth dipole of 123mm but we take great care because this element is also the last and we have to "advance" as much as 186mm of the central, while cutting the stocking of the coax. This antenna gives us a gain of around 6dBi

 

• ANTENNA QFH

This QFH antenna, Filar Helix squares, omnidirectional circular right-handed polarization antenna, or better RHCP, excellent for receiving the radio antennas, which transmit in the 400-406 MHz frequency range, the particular shape of the antenna is perfectly adapted to receive the data transmissions APRS, GPS, DATA Weather irradiated by these balloons that reach typical heights of 31.000 meters of height, follows the explosion of the balloon and the fall to ground, through parachute, of the probe that continues to transmit data, if not the "burst killer" has been activated to try and recover and reuse, for the purposes of the APRS radio station, the sonte itself.