If the SWR on an antenna feed line is 5:1, and a matching network at the transmitter end of the feed line is adjusted to present a 1:1 SWR to the transmitter, what is the resulting SWR on the feed line?

An antenna tuner, or matching network, placed at the transmitter end of a feed line only changes the impedance presented to the transmitter. It ensures the transmitter sees a perfect 1:1 match, allowing it to deliver full power without activating built-in protection circuits. However, this matching network does absolutely nothing to fix the physical impedance mismatch at the far end of the cable where it connects to the antenna. The forward power still travels down the feed line, hits the mismatch, and reflects back. Because the reflection at the antenna feed point remains unchanged, the SWR on the feed line itself remains exactly 5:1. The tuner simply creates a localized match for the radio, masking the feed line's SWR from the transmitter.