I've done some measurements on my KH1 (Serno 00845 FW 1.25)
Basics
Meter - SIGLENT SSA3021X
40dB PAD - Weinschel 58-40-33
Fully charged internal battery and ATU bypassed
7.0 MHz

10.1 MHz

14.0 MHz

18.1 MHz

21.0 MHz

Summary
| Band | Pwr | 3rd Harmonic | 5th Harmonic |
| 7 MHz | 5,93W | -65,75dB | -54,3dB |
| 10MHz | 5,72W | -56,24dB | -60,5dB |
| 14MHZ | 5,78W | -59,57dB | |
| 18MHz | 5,93W | -53,23dB | |
| 21MHz | 5,92W | -60,95dB |