WSPR on LF and MF at respectively 136 kHz and 474 kHz. I listened with my loop antenna and was able to pick up a few stations, MF (11 stations seen) was easier than LF (4 stations seen). On LF there are two strong digital signals near the narrow band that we are interested in. One problem to solve is the frequency stability of the SDR. The airspy LO is somewhat temperature compensated, but it tends to drift. but there is a possibility to connect it to a frequency reference. I’m not sure how amateurs make an transmit antenna for these frequencies, that could be a challenge.
Lowriders are also cars.