Water in the LNB: Signs and What to Do
Water inside an LNB is the classic slow-motion failure. The signal works fine for months, then pixelates every time it rains, and one day stops working altogether. Here is how to recognise it and what to do.
How Water Gets In
Rain runs down the outer sheath of the coax, creeps past an un-taped F-connector, and sits in the LNB body. The LNB is sealed against rain from the front, but the back — where the cable plugs in — is the weak point.
Signs of Water Damage
- Pixelation only when it rains; perfect picture when dry.
- Condensation visible inside the LNB cover.
- Rust or green corrosion on the connector.
- Intermittent dropouts that come and go with humidity.
Can You Dry It Out?
Sometimes, if you catch it early. Remove the LNB, shake out any water, and leave it in a warm dry place for 48 hours. Re-fit with a properly weatherproofed connector. A few LNBs recover; most have already corroded internally and will fail again within weeks.
The Real Fix: Replace and Seal
For anything other than the very earliest signs, replacement is the right answer. Buy a universal LNB, fit it, and this time weatherproof the connector properly:
- Make a clean, tight F-connector.
- Wrap the joint in self-amalgamating tape, stretched to half its width, overlapping by half.
- Extend the tape a few centimetres up the cable and over the back of the LNB.
- Wind a second layer of ordinary PVC tape over it for UV protection.
Check the Cable Itself
If water has reached the LNB, it may also have sat in the cable. If the new LNB still plays up, cut half a metre off the cable end and re-fit the connector — sometimes the cable braid is corroded too.
Preventing Recurrence
Do not skip the weatherproofing. It is the step people rush, and it is the step that fails. Ten seconds of tape saves a future rainy-day panic.
Water in the LNB is almost always a sealing failure, not an LNB failure. Replace the box, but more importantly, seal the joint.
