Barn link not working? The five usual causes

1. The cable run is over 328 ft (100 m)

Symptoms: no link light, a link that comes up at 100 Mbps instead of 1,000, drops under load.

Why: copper Ethernet is limited to 328 ft for the whole channel, patch cords included.

Fix: measure the actual cable, not the yard. If it’s a little over, an outdoor PoE extender in the middle ($37.99) resets the limit once. If it’s well over, swap to fiber ($60.06–$79.98 for the converters) or a bridge.

2. The bridge has no real line of sight

Symptoms: weak signal in the radio app, slow speeds, drops in wind or rain, worse in summer.

Why: trees and leaves add loss at 5 GHz, and the radio beam needs about 60% of the Fresnel zone clear, not just a thin line.

Fix: raise one or both radios, re-aim, or go around with a relay hop. If no clear path exists, dig fiber.

3. Lightning or a surge killed ports or cameras

Symptoms: after a storm, one end has dead switch ports, a dead camera or a radio that won’t power up.

Why: a copper cable between buildings ties their grounds together; a nearby strike can push current through it.

Fix: replace the damaged gear, then add a surge protector ($11.69–$14.14) at each building, bonded to that building’s ground. If it keeps happening, replace the copper with fiber. Full guide.

4. Cameras need inbound access, and you’re behind CGNAT

Symptoms: cameras or a recorder work on home Wi-Fi but not from your phone in town; DDNS or port-forward setup fails.

Why: By default Starlink uses CGNAT for IPv4 (100.64.0.0/10), which blocks all inbound ports.

Fix: switch to the maker’s cloud or P2P app, or set up Tailscale. Three fixes, step by step.

5. The wrong cable went in the ground

Symptoms: worked fine for weeks or months, then errors, slow speeds or drops, often after heavy rain or a thaw.

Why: indoor or plain outdoor cable isn’t built to sit in wet soil. Direct-burial cable has a polyethylene jacket and water-blocking gel or tape.

Fix: replace it with direct-burial cable ($149.99 for 500 ft), ideally in conduit so the next swap is a pull, not a dig.

Questions people ask