Although my purpose was not so much to test the attenuator or filter, I found both of them to be excellent performers, especially given their price.
Prior to all measurements I calibrated each VNA according to instructions for that particular unit. Both were allowed to warm up for an hour before the first calibration.
The nanoVNA was operated via my PC with NanoVNA Saver from Rune Broberg 5Q5R and was calibrated via the software (the nanoVNA may be calibrated stand-alone as well).
I am quite happy with the results of the test. They show that - at least at HF frequencies - the small nanoVNA is dead-on accurate.
Tomorrow I'll be comparing the two at higher frequencies: a 2/440 antenna and a 1.03 GHz band-pass filter. The upper limit for the nanoVNA is 900 MHz (the Keysight's is 4 GHz) so it'll make for an interesting test to see if the nanoVNA's accuracy deteriorates at higher frequencies.
The photos and graphs of today's HF tests speak for themselves:
|The Bypass switch accounts for .25dB to .5dB of attenuation with none dialed in via the switches|
And now on to the band-reject filter: