I noticed something interesting about IBOC on WFAN 660 and WWJZ 640. The IBOC noise between 640 and 660 seems to be less than the IBOC noise on 670 and 630. Could it be that the upper sideband IBOC from WWJZ is cancelling the lower sideband IBOC from WFAN? Both stations are about the same signal strength here. Tom Harrisburg Pennsylvania