Frequency change of Voice of Tibet

TIBET(non)   Frequency change of Voice of Tibet:
1430-1445 on 15612 DB  100 kW / 131 deg to CeAs Tibetan, QRM WEWN on 15610
1445-1500 NF 15617 DB  100 kW / 131 deg to CeAs Tibetan, ex 15612
The frequencies are jammed by China on xxxx0 / xxxx5
Changes between frequencies vary from 3 to 5 minutes