In early 2018 it was observed that a number summits in Oregon appear to have installed new RF equipment that have strong signals that block the receiver of even quality HT (Yaesu). Continuous S9 noise on 2m FM can sometimes be observed and sometimes the blocking signal appears to have a period of several seconds. If you are calling CQ on 2m FM and really are expecting folks to answer you (for a planned S2S, for example), but you hear nothing - your receiver might be blocked. Open you squelch and observe the signal strength meter.