What matters for receiving is S/N, not pure S level.
We want low noise antennas, or if the antenna is just standard, we want to place it outdoor where the signal is higher and where the noise is lower.
Then, for a distant antenna, we need a 'down' line. That line can carry the house noise to the antenna (common mode or outside of the coax), and that noise may be carried backwards to the shack in differential mode or inside the coax.
Also, the tuning accessories can be not well shielded and can pick up noise directly. Then, if there is RFI noise in the shack, the ATU must really tune the antenna to get the more of signal coming from the backyard, above the fixed noise level from the shack.
If a coax line can be buried all the way to the antenna, and grounded both at the antenna bottom and house entry, that's the best, but the antenna impedance should be not too far from the coax impedance on the bands of interest. Then the antenna should be also not too bad from itself about the neigborhood noise (so verticals are not very good in a typical suburban location). My own attempts with coax lines are not good so far, for practical reasons.