OK, I live within a mile of Olivers Mount a 7KW FM and Freeview TV mast on the outskirts of Scarborough. I bought this filter to test a theory that the mast was dragging down 2m reception at my home QTH. I had previously tried activating the transmitter site as a HEMA summit but failed due to RX swamping causing me to hear nothing. I took delivery of the filter on Saturday. On Sunday I hooked up a Baofeng UV9R and tuned into the mast FM broadcast frequency 95.5. On WFM the signal could be received with a wet finger on the antenna socket it was so strong. I put the 9R onto a loft mounted slim Jim and the signal was so strong as to be breaking through several hundred KHZ adjacent. I then put the filter inline and tried again. There was nothing! Not even when tuned to 95.5 could I hear a single thing. I determine by experimentation that the rejection of broadcast FM is very very good. I think dialled up GB7RW a local repeater about 15 miles away. This repeater is usually scratchy at my QTH despite being able to open it. With the filter inline the RX from the repeater was a full 2 S points up and now breaks my squelch! Although I got the filter for SOTA I can see it becoming a permanent addition to the shack setup to. Wonderful, well made and works!