A less LO power dependence on the relative phase was found. The new 90 deg splitter works better.
From -3 dBm to 10 dBm in LO power, the relative phase is within 90 +/- 5 deg.
As a comparison I plot the phase that I measured when the handmade coil had been there (green curve in the plot).

I will also measure amplitude unbalances between I and Q.
Quote from #4554 |
A 90 degree splitter, PSCQ-2-51W, has arrived today and I installed it on a demod board called AS11.
Results of the I-Q phase measurement with the new splitter will be reported soon.
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