miranParticipantmiran October 15, 2021 at 11:44 am
I want to use directional couplers For measurement the out of band signals on FM transmitters. The coupling of directional coupler is frequency dependent and is about -50 dB. I made correspondent frequency correction table. Then I transfer this date to Path loss Table and enable correction. So far everything ok.
Then I tried to correct reference level to +60 dBm. Unfortunately that was not possible. The maximum reference level that was possible to set was only +20 dBm. I was really surprised. I’m sure that this is not correct and you should change the software.
For the reference level you have to taking in account also the sum of Path loss tables!
I found also temporary solution. I write for reference level offset in the setting +40 dB. Only then was possible to change reference level to +60 dBm. After changing the reference level to +60 dBm I put for the reference level in settings back to 0 dB.
Fortunately the reference level stayed on +60 dBm. Now the measurement was possible 🙂
I don’t like use this method in the future so please correct the software in the next release.
The reference level should not be only dependent from reference level in settings but also from Path loss table!
I use software version 3.5.19 and SM200B and sometimes also BB60C and SA44B.
AndrewModeratorAndrew October 15, 2021 at 12:51 pm
Yes, you are correct in your understanding about the limitations of the Spike software.
Until we are able to add something to address this in the software, I would take a combined approach, setting the ref level offset to 40dB and then adjusting your path loss table by 40dB. Together you will get the same result with the ability to set the ref level to +60dBm. You should be able to save the path loss table with a preset for quick loading of this setup.
I will add this to our request log and determine the best approach to this.
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