We make heavy use of https://github.com/kholia/Easy-Digital-Beacons-v1 for testing RF amplifiers. This single board is a versatile WiFi VFO and FT8 / FT4 / WSPR beacon. You can also use our CW-SigGen project to generate a suitable test signal.
This ~1W to ~5W WSPR beacon runs continuously on the 10m band. It handles extreme environmental temperatures pretty well (it is 42°C plus here). Our article on this beacon's design and operation will appear in the May/June 2025 issue of the QEX magazine soon. References: http://www.carnut.info/WSPR_Tx/WSPR_Tx.htm QEX May-June 2025 TOC QEX May-June 2025 Perspectives ...