Rasmus SA5RJS on Nostr: 3) Signal Generator My options for generating the input signal are basically by ...

3) Signal Generator

My options for generating the input signal are basically by BITX40 and my QMX. The BITX40 has a trimpot for its PA driver. But instead I went with the QMX and used its "SWR meter" mode.

The QMX lets you adjust the SWR test output power as a percentage of the voltage used for full power. So "100%" is full power, but "50%" is a quarter of full power (due do P∝V²). I measured the power for various settings using my oscilloscope (12.0 V, 7.100 MHz):

* 10%, 5.8 Vpp, 0.08 W, 19.2 dBm
* 20%, 10.1 Vpp, 0.26 W, 24.1 dBm
* 30%, 14.2 Vpp, 0.50 W, 27.0 dBm
* 40%, 18.6 Vpp, 0.86 W, 29.4 dBm
* 50%, 22.8 Vpp, 1.30 W, 31.1 dBm
* 60%, 27.0 Vpp, 1.82 W, 32.6 dBm
* 70%, 31.0 Vpp, 2.40 W, 33.8 dBm
* 80%, 35.2 Vpp, 3.10 W, 34.9 dBm
* 90%, 39.2 Vpp, 3.84 W, 35.8 dBm
* 100%, 42.6 Vpp, 4.54 W, 36.6 dBm

I also looked at the QMX output on the TinySA Ultra spectrum analyzer. There weren't any visible harmonics at all, so I trust that this signal is suitable as a test signal.