Store 20dB Pad and how to add Pre-amp

Hi I utilize Scalar Network Analysis-mode with SA44B + TG44A. It is really useful for my work! I’d like to ask 2 question.

(1) “Store 20dB pad” for accurate measurement:
Is it OK to remove a 20dB attenuator from TG or SA after clicking “Store 20dB pad” button? Or should be left as it is?

(2) using External Pre-amp:
I’m measuring very low S21 on DUT with Scalar Network mode. I’d like to add an external Pre-amp (like +40dB or something) in front of SA44B. After the calibration of Scalar Network mode (Store Thru and Store 20dB pad), simply just connecting pre-amp to the SA44B has no issue? or should have a special care for it?

Best Regards
Hiroshi

Hiroshi,
I’m glad you like it!
1. Yes. Remove the 20 dB pad after it has been measured. We use the 20 dB pad to measure both high gain and low gain and compute an internal offset.
2. Make sure you don’t exceed +20 dBm into the SA44B. You will need to compensate your measurement for the additional gain after the store thru, but otherwise it should work just fine.

Thanks Justin,
I got it.
About 1, what if executing “store thru” attaching 20dB attenuator and execute “store 20dB pad” with no connection change? Just to be made a calibration as S21 is 0dB including 20dB attenuator but both high and low gain are still ensured?

Best Regards,
Hiroshi

Hiroshi,
Yes, you can Store Thru and Store 20 dB pad, both with the 20 dB pad in place (leave the 20 dB pad in place for testing). This will enable high dynamic range sweeps, with 20 dB additional gain available.

Thanks Justin, I got it. Your advices brought me much more utilities!

Best Regards,
Hiroshi

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