I'm a bit confused, I've looked everywhere 3 times and I can't find what you're talking about, I don't think its there because:
1. There is no opacity/alpha sliders anywhere in the in-game settings.
2. in the .cfg @ line 69: UI_OPACITY = 0.5 which gets rest after closing the game but even with the file set to read only setting it to 1.0 or 0.1 does nothing at all anywhere as far as I can tell.
3. I don't see why this would be a user changeable setting at all, its a feature working as intended; the lines get more faint as the signal gets more faint, it just does so way too much.
Sorry if I'm still not getting something.Thanks for trying help!