Figure 5: Fabricated QHA (left) and its S11 parameter (right)

LOW NOISE AMPLIFIER

Maximum transmit power of radiosonde is limited to 20 dBm [5]. Free space path loss for operating frequency of 406 MHz and path length of 100 km will be about 124 dB. Therefore to Mini-Circuits ultra-low noise PSA4-5043+ LNA is used to amplify the received signal. Key specifications are given in Table 4. More details can be found in part datasheet.
Table 4: Specification of LNA