For SWL, I use a 40M diameter LOG (loop-on-ground) antenna, instead of my HF transmit antenna. Literally just some scrap wire thrown in a big circle on the ground or in the grass in my back yard, plus a small 9:1 isolation transformer between it and the feedline. On the lower HF bands, the LOG seems to pick up significantly less noise, thus gives me a better S/N (more FT8 DX decodes, etc.) than my HF antennas in the air.