Store Thru *Warning* Signal Level Higher than Ref Level

Greetings,

Whilst doing tracking generator scalar sweeps when I set up the reference by pressing “Store Thru” button I get the subject warning message even though the signal level is well below the reference.

I wonder why I am getting this false message and how I might get rid of it.

Thanks in advance!

TMA

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Hi tma,

Thanks for letting us know about this. I was able to reproduce the issue immediately. This is something I can address on the next release of Spike. There is currently a trick to get rid of the message. If you set the “Ref Level” above the peak of your signal, for instance, in your picture, the peak is ~5.5. Set the Ref Level to +6dBm or higher and the error will go away. In short, the software is comparing the VSWR sweep to the dBm reference level and not the VSWR reference level.

Let me know if you have additional questions or need further clarifications.

Regards,
Andrew

Hi Andrew,

Many thanks for your prompt response! I am glad you were able to reproduce the issue and that I wasn’t doing something wrong, (:/).

I need to get back up to try the work around. If I change the reference will that upset the thru reference calibration resulting in an “Uncalibrated” message at the bottom?

Thanks Again!
tma

Hi tma,

It will, good point. It would be best to set the reference level to the maximum value (+40) before switching over to the VSWR plot, this way you don’t have to worry about needing another store-thru.

Regards,
Andrew

Hi Andrew,

I must admit I don’t understand the logic of using +40 dBm as the reference considering that level is much higher than the tracking generator output.

I believe the store-thru cycle always must be done to set the calibration reference. When I get back to this project I will give that a try but I am not optimistic. I don’t think that I will have proper calibration without first doing the store thru cycle to measure the test bed insertion loss across the relevant frequency spectrum.

Thanks!
tma

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