I played with the Doppler Loop on my SP Cab Forward through the DCS Wifi Ap. I have not tried this feature in years, and have never done it through the Ap. It is, IMHO, easier to use in the Ap.
The effect is pretty cool, even on a small layout.
I also measured the outside loop using the "Measure Route" command. It is larger than I thought at .28 scale miles in circumference.