Chris,
It’s clear that the BS170 maximum Vds rating is greatly exceeded on 80 and 160 meters and this is indeed due to higher gain in the FETs at lower frequencies. I saw this gain difference vs frequency in the sims I ran using JZ’s model long ago. I proposed TN0110 as an alternative to the BS170 back then to handle the voltage spikes in the QDX. QMX fixed the spikes but that was prior to opening up the 80 and 160 bands where high voltage is now showing up for an entirely different reason. I know Hans planned to limit the drain voltage in these two bands but I don’t know if he completed this effort. From your graphs, it appears that this feature isn’t working in whatever firmware version you have. In any event, lowering the supply voltage when operating on 80 or 160 should lower the PA excursions but they might still be exceeded to some degree. Have you tried running your tests at a lower supply voltage?
Tony
FYI?
On my plot I should of suppressed "0" and "-1" on the x axis?
