measure VSWR with Autotester

hi,
Ive a Wiltron swr-Autotester ( not swr-bridge ), RF generator hp8350 and good multimeter.

on DET port I measure "mV" with good multimeter.
I set "1mV" when I connect dummy load on port device
How I convert mV to VSWR ?

thanks

You will have to calibrate your system by introducing known SWRs on the RF line. Different detector diodes have different responses, so each must be calibrated.
Find a SWR meter with a calibrated detector. Multimeters are good for other tests.

Thanks for reply.
I test with power meter USB ( satori ) and no power detect.
I test with spectran, but no power detect.
with multimeter I see mV, I think that power meter dosent measure Vdc. it works only in frequency > 0.
Can you explain me ?

It looks to me that your equipment is not good. Find a good power meter and a good signal source, then introduce a known SWR to calibrate your reflectometer.
You can use resistors different than 50 Ohms to generate a known SWR.

Much better in dB and calibration easiest as well. For instance load 6dB it is -12dB matching and so on.