When NOT to Use 75 Ohm Coax
- High power (legal limit) with significant SWR Voltage peaks on the line can approach cable ratings
- When a matching network requires a specific 50Ω impedance Some phasing harnesses and hybrid combiners are impedance-critical
- When your radio/tuner can't handle the mismatch Most radios can handle SWR up to about 2:1 — check your manual Most internal tuners handle up to about 3:1 — check your manual External (and some internal) tuners can handle higher SWR
Best Use Cases for 75 Ohm Coax
- Half-wave dipoles (horizontal or vertical)
- Full-wave loops (current fed)