Extending the range of an o'scope or SA

Hi all.

I'd like to look at the time/frq domain in the 2.4Ghz Wifi and bluetooth band.
Perhaps to tune antennae, VSWR, cabling or just see how spread spectrum works.

I have a 1.5Ghz DSA 815 TG SA.

Is it reasonable to build a 2Ghz L.O. and mixer followed by a 2Ghz hi pass filter, allowing for 300Mhz of roll off bandwidth, so that I can reasonably look at the 2.3Ghz to 3.5Ghz band on the DSA 815?

I have a 35mhz to 4.4Ghz signal source.

I use a WiFi Radar software that reads the chip RSSI signal with < 1dB resolution. It's very effective at tuning the antenna for fading loss reflections. It gives graphs in log dB and time scale

Any phasor info?