How to Reduce Cable Loss (LMR200 vs LMR400)
Protect your dB budget by picking the right coax and planning the shortest, cleanest run you can.
Why cable loss matters
Every meter of coax attenuates signal. Too much loss reduces booster performance and can make a good donor signal look weak indoors.
Typical attenuation (rule‑of‑thumb)
- LMR200: higher loss; use only for short jumpers (e.g., 3–5 m).
- LMR400: much lower loss; suitable for longer outdoor runs (e.g., 10–30 m).
If you must run long lengths, step up the cable grade (LMR400) and avoid unnecessary connectors.
Design tips
- Keep outdoor run as short and straight as possible; avoid tight bends.
- Use weather‑sealed connectors; water ingress = catastrophic loss.
- Minimize adapters. Each connector can add ~0.2–0.5 dB loss.
- Ground the mast and use drip loops to protect against water.
Planning your run
- Measure roof‑to‑booster path; add slack for service loops.
- Pick cable grade that keeps total loss within your booster’s gain headroom.
- Test with phone field metrics (RSRP/SINR) before final fastening.
FAQ
Can I mix LMR200 and LMR400? Yes, but prefer LMR400 for the long segment and LMR200 only as a short pigtail if needed.
Do gold‑plated connectors help? Reliability matters more than plating; use quality N‑type connectors and proper crimp tools.