Re: Many uBitx's have reduced power on 40m CW
Evan,toggle quoted messageShow quoted text
I have no idea if you will have trouble with IMD on 80m.
Increasing R83 would cure IMD and also further improves the impedance seen by the filter,
but reduces power on all bands.
Could just rotate RV1 for suitable 80m power levels.
Could use TXC (turns on the 80m LFP) to turn on a FET which attenuates the signal at RV1
Could add something at Q911,912 that reduces gain at low frequencies similar to C81,R83
Having Q90 as a buffer should give the filter and mixer a proper load impedance.
On Thu, Apr 8, 2021 at 09:41 AM, Evan Hand wrote: