CLOSE CALL doesn't work with simplex DMR. But if you program the frequency it will work. The only oddness is that since simplex DMR only transmits 50% of the time, a scanner only has a 50% chance of detecting a signal on the frequency. If it scans the frequency between DMR transmit pulses, it will move on to the next frequency because there's nothing to detect when the transmitter isn't transmitting.
Where I live at schools here seem they use simplex and can't hear them even when close. I tried different threshold settings still nothing. That was on the x36 and both sds1/200. Even sometimes dsdplus has trouble with it on/off.