As indicated by ham users the schematic is low quality in the PDF article released by TAPR. Here sharing a better quality picture, hopefully that helps.
The V3 version RTL-SDR blog dongle is perfectly fits for WSPR reception as per my tests. As it has internal switches it uses only one SMA connector for HF (500kHz to 24 MHz) and UHF operation, no need for changing connectors for direct sampling mode. This makes the RTL-SDR V3 dongle really convenient and easy Read more about Receiving WSPR With An RTL-SDR V3 Dongle[…]
“An ocean going marine buoy containing a GPS and QRP-Labs Ultimate3S based transmitter. This project is intended to drift in the Pacific Ocean at the mercy of the tides, currents and wind directions while sending its position, battery voltage and temperature information via HF radio telemetry in WSPR and JT9 modes.” Source: http://www.qsl.net/zl1rs/oceanfloater1.html