Can a VNA replace a tracking generator on a SA?

[ballsystemlord]

Hello,
From what I have read, the tracking gen on a spectrum analyzer allows the SA to perform measurement S12. Is that all? Like, given the choice of using a SA or VNA wouldn't you just go with the VNA? Am I missing something? Is there some feature that the SA+TG can do that a VNA cannot?

Thanks!

[shabaz]

An SA can do things a VNA cannot (and vice-versa). An SA can operate without internally generated stimulus from a tracking generator; i.e., an SA will show what's present solely from its input channel. A VNA requires a locally generated stimulus signal for it to operate.

I suspect you're confusing the term "VNA" with "Spectrum Analyzer with Integrated VNA". Some basic spectrum analyzers come with built-in VNA.

[tautech]

Hello,
From what I have read, the tracking gen on a spectrum analyzer allows the SA to perform measurement S12.

S21 actually. Typo ?

Is that all?

Without a RLB, yes.

Like, given the choice of using a SA or VNA wouldn't you just go with the VNA? Am I missing something? Is there some feature that the SA+TG can do that a VNA cannot?

A few years back and not too long after getting my first SA to explore the black magic field of RF I was in a similar dilemma and all my wishes were answered with the release of the SVA1000X range. SA and VNA in one unit ! 
I've had 2 of these,1.5 and 3.2 GHz and SVA1032X remains one of my all time fav instruments.