I did calibrate it via the two port cal procedure. The calibration standards are total rubbish -- my objective is to characterise twisted pair and bits of bent wire for use with those cheesy 434MHz OOK radios. The setup is a female dupont connector soldered onto an SMA and the reference standards are a short and 50R metal film resistor soldered on a bit of 2.5mm header.
The procedure for segmented sweeps is not perfectly laid out in the manual. Steps 2,3,4 below are set out, but not the rest. Here is what I did.
(1) toggle sweeps off
(2) enter span 10Mhz, press enter
(3) enter start 420Mhz, press enter
(4) enter top, 470Mhz, press enter
(5) press Segment. At this point the start and stop values begin to change, cycling through the required segments. I wait for them to stop changing.
(6) I press sweep and the start and stop values once again change, cycling through the required segments.
The displayed SWR/return loss chart updates for each segment and within the segment appear plausible. When the segment sweep is complete, the graph is drawn with the complete (or almost complete) X range specified. Most times the final graph is a total mess.
Once I got the whole thing, sometimes I get all but the last segment like here.