SDR with LO input

[bnevins]

Is there a way to apply a "local oscillator" input to an SDR, so that the
SDR output is the down converted spectrum in the vicinity of the LO frequency?

[A.Z.]

check out this

https://www.rtl-sdr.com/hooking-up-an-si5351a-voltage-controlled-oscillator-to-the-local-oscillator-input-on-an-rtl-sdr/

[radiolistener]

Is there a way to apply a "local oscillator" input to an SDR, so that the

just use some Chinese mixer, like that:
https://www.aliexpress.com/item/1005004266323916.html