Im sure that you could …
T/R switching might be needed for some applications …
Its still unknown what the unfiltered , unmatched output of the LimeSDR is …
The Mixer’s Lo is a square wave and should be rich and powerful ODD harmonics.
My Avatar shows a spectrum analyser depiction of my UHFSDR output. Fundamental is set at 28Mhz and 3rd harmonic is 9db below the fundamental. Each odd harmonic out is less and less reduced. The 17th harmonic is 30db down (UHFSDR) …
Im not sure it a trippling amplification is needed … It depends on what your after – are you looking to achieve a specific freq?
7th harmonic of 3.456Ghz (24.192Ghz) is getting up there … I wonder when the board material becomes a factor in signal loss … Theres no way that the existing board components – especially the I/Q transformer – will pass that kind of a signal, i don’t think.
Oh … here is my Avatar !!!