Coax cable: 15 m of RG58 lose more than the antenna gains
How much signal coax loses between antenna and receiver, worked out from manufacturer datasheets: RG174, RG58, RG213 and LMR-400 at 144, 868 and 1090 MHz, connectors, what 3 dB means, and why an ADS-B preamp belongs at the top of the mast.