Thanks for all that did reply and giving me useful hints. For now I will try to reduce the audio level feeded to the FT857 to get less power out. Maybe next week I try to find time to build the attenuator but I see this only as a temporary solution. Instead of feeding 5 Ampere into the FT857, transform at least 4,5 Watts into heat and in the end send with 500 mW I am now considering to buy an SDR. So far the Genesis 3020 looks most comfortable to me, also because of the price.
Well, I am not the "solder-god" but I think I can make it, also there seems to be much support online.
Thanks to Myles, WJ2V, for leading me into that direction.
Do I see it right that the Genesis 3020 has a serial port to connect to the PC? If some of you say this kit is perfect for QRP and WSPR this thing is pretty close to be bought by me.
Anyway, thanks again for replying.
Good morning, Good day, Good night, which time zone you may be.
Cheers, DM1RG Gregor