[Edit: I got even better performance out of it, check my update here:
   • Update: HP 8568B Spectrum Analyzer wi...  ]

I was curious how an HP8444A tracking generator option 59 would work with a HP8568B spectrum analyzer. Answer is: much better than anticipated. These units were not really designed to work together, as you can tell from the cabinet design that doesn't even match at all (but the design is an exact match for the older 8554B spectrum analyzer). They are a generation or two apart, one is a relatively simple all analog tracker, the other a very sophisticated, reference locked, computerized machine. That said the option -59 did add the 500 MHz local 3rd LO oscillator and extended operation to 1.5GHz, so the two match in range and operation. I wasn't expecting too much, and the tracker says it's only good down to 10 kHz resolution bandwidth, I presume due to the drift of the analog oscillators. But actually it is much better than that. The output is rather flat, stable enough to measure down to a 1 kHz resolution bandwidth. And with an external synthesized 500 MHz 3rd LO, I could go down to 300 Hz. Not bad for an old analog horse! This HP equipment was really well designed.
Caveats: you have to use Shift-T on the 8568B for the thing to work across all spans and frequencies, in order to lock the spectrum analyzer 1st LO to the down frequency. If not it will jump up and down 4 MHz and the tracker will be off.
Here I show how to calibrate out the small remaining flatness ripples, how to use it with the internal and external 500 MHz 3rd LO, and do a test measurement on a quartz crystal, just because I can.