Masking a Radio Wave Effect

I'm trying to superimpose only certain portions of the radio wave over the rest of my composition but its not working out. I've applied masks to the layer with the radio wave effect but nothing changes, the entire wave is still visible. Then in a separate composition I created a black solid with masks and put it beneath the radio wave layer, which had "Preserve Transparency" on. This created somewhat the effect I am going for but the black of that solid is appearing with the effect when I want it to be transparent. I'm stumped so does anyone have any ideas on how to fix this?