With 0 dB selected the sweep showed about 2.4 to 2.6 dBinsertion loss .
The VSWR was between 1.05 and 1.1. These values will work well for anything I plan on doing.
I then did a series of sweeps at 10 dB incremnts on the attenuator. The linearity is within about 1 dB throughout the range.
The linearity looks good across the entire range, within 1 dB. With an insertion loss of around 2-3 dB in all ranges, which is more than adequate for what I need. Trying to decide if I want to modify the attenuator firmware to show the actual attenuation or leve it as is.
The autoscale feature of thes PC software really makes it easy to to get values across such a wide range without loosing resolution. The noise on the sweeps at higher attenuation levels, is due to the sensitivity of the VNA, but is still quite remarkable for a $50 instrument. I am quite happy with both of these pieces of equipment. The VNA does many of the things I wanted to do with a version 3 SNA Jr, so I will put off that project and work on several othr things I have been planning.