Reply To: Using 10 dB coupler for return loss measurement & 20 dB pad placement

[jraymond]

Thanks for the info.

For cases where accuracy is needed below -40 dB the procedure is:
1. Connect TG to SA through circuit to use as 0 dB reference.
2. Store Thru
3. Connect 20 dB attenuator between TG and circuit.
4. Store 20 dB Pad
5. Remove 20 dB attenuator, reconnect circuit. Now system is corrected for readings below -40 dB.

It’s steps 3 – 5 that weren’t entirely clear to me from the manual.