Which of the following is a source of loss in coaxial feed line?

Signal loss in a coaxial feed line can come from a variety of mechanical and electrical issues. Water intrusion is one of the worst culprits; if moisture gets into the cable through an unsealed connector, it contaminates the dielectric, heavily increasing signal absorption and permanently altering the cable's impedance. High Standing Wave Ratio (SWR) also contributes to loss, as a portion of the signal reflects back and forth along the line, being subjected to the cable's natural attenuation multiple times. Finally, every connector or splice introduced into the feed line adds a slight impedance mismatch and contact resistance, causing incremental losses. Therefore, all the listed factors contribute to feed line loss.