I'm setting up an far field antenna range, and have an option of several NA's (5062a, 8752a,8714). Trying (2) analyzers - 1 @ range antenna and 1 @ the AUT side.
The problem is that phase measured at the receive end 'drifts' with time. For example, it starts at 0degrees, and in 15mns will be 10degrees off. Have simulated in the lab so far using a common 10MHz source (disciplined source & also an 8341B synthesizer). I have tried various combinations of NA's as well as using the 8341B as an RF source - they all eventually drift.
Also varied the IF BW settings - no luck.
Any thoughts?
Thank you,
Kurt
The problem is that phase measured at the receive end 'drifts' with time. For example, it starts at 0degrees, and in 15mns will be 10degrees off. Have simulated in the lab so far using a common 10MHz source (disciplined source & also an 8341B synthesizer). I have tried various combinations of NA's as well as using the 8341B as an RF source - they all eventually drift.
Also varied the IF BW settings - no luck.
Any thoughts?
Thank you,
Kurt
10 degrees in 15 minutes seems high, but it depends on the frac-n used in the synthesizers. (I think the VNAs you mention all have frac-n synthesizers.)
The only way I know of to prevent this is to use the same LO fed to all the VNAs involved in the setup. If you're going to do that, you might as well use a single VNA with external coupler/receiver access.