I compare them with my old ESP-03 and see that on the same firmware at the same place ESP-03 shows -60 dB, wemos D1 mini shows -96 dB.
All my 8 pcs D1 mini have the same issue.
3.3 V is stable. I tried to power d1 mini from 3.3V , not from USB, the same result, -96dB.
Of course, because of weak signal i have issues with connection.
Can you suggest anything? (