Design, Construction and Evaluation of a Portable HF Measurement Station Using KiwiSDR and WSPR

Sammanfattning

HF (high frequency) communication relies on skywave propagation through the ionosphere, and the propagation paths can be monitored using measurement stations. Noise interference is a major problem when receiving HF signals, especially in urban settings. This thesis presents the design, construction, and evaluation of a portable HF measurement station based on a KiwiSDR receiver and Weak Signal Propagation Reporter (WSPR) protocol. Four objectives were defined for the thesis project: HF performance, remote accessibility, battery power, and outdoor usability. The station was designed and built using the following chosen components: MLA-30 Plus active loop antenna, ASUS 4G-N16 router, Sandberg Outdoor Solar Powerbank (24Ah), and a plastic box. Two main tests were conducted for evaluation. First, a field test at a remote location (Väsby hage Nature Reserve near Stockholm), and then a battery endurance test at home. The results showed that the station was able to receive WSPR signals successfully, and the signals can be decoded remotely and uploaded to the WSPR database, thus fulfilling the HF performance and remote accessibility objectives. However, the powerbank ran the station for between 18 and 20 hours, thus not achieving the 24-hour goal set by the battery power objective. This happened because the initial power consumption estimation was flawed. This could be improved by a powerbank with a larger capacity. The outdoor durability objective was not completely met since overheating of the powerbank under sunlight was a persistent issue. This was partially solved using a white cardboard cover, but it can be further improved by using a waterproof reflective fabric instead.