TNX for the ideas so far.
Even in the lowest setting there must be some TX output to be measured by a power meter. That's not the cause. I already went through all menu settings.
Meanwhile I found out there must be some mW output which my power meter does not display. With another RX I can detect a carrier and hear the modulation.
May there be a problem with the ALC? The meter doesn't show any ALC on AM but on FM. I think on AM there also should be almost some ALC be displayed.
73,
Michael