For higher frequencies, I'd suggest a PLL setup.
A VCO running at the right range, also feeding a frequency divider [help square up a sine wave] and phase detector. Reference signal from Si570, low pass filter and feed back to VCO.

From memory, the Si570 has better phase noise the the Si5350 so you might get something working the way you want.

--Alan

---In PHSNA@..., wrote :

Hi Jim,

                Is a HF/VHF/UHF PHSNA possible. I am thinking about Si570 chip with an Ardunio NANO controller as hardware. In fact I had already one rigged up and waiting for a suitable software.

73

DE AB9XC

(Pravin)