You are twenty minutes into a film when the sky turns the colour of a wet slate roof and the picture collapses into a mosaic of frozen blocks. Or the video call stutters, a page that loaded instantly a minute ago refuses to finish, and the router keeps blinking away as if nothing were wrong. Satellite links and heavy rain have never been friends, and in the UK that friendship gets tested most weeks between October and March. The mechanics are simple, and most of the fixes are things you can do yourself.

What rain fade actually is

Rain fade is the loss of signal strength as a radio beam passes through precipitation. Satellite links run on microwave frequencies, and water is remarkably good at interfering with microwaves: raindrops absorb some of the energy and scatter the rest in directions that are not your dish. What arrives at the antenna is weaker than what the satellite sent.

It rarely fails all at once. Digital reception degrades until the error correction in the receiver runs out of room, and then it gives up in a hurry. That is why you get a perfect picture one second and a pixelated mess the next.

There is a second, more mundane effect. Rain does not just sit in the air; it lands. A film of water on the dish face, on the plastic cap over the LNB, or in a connector that was never sealed properly all add loss. A well-aligned dish can ride out a serious downpour while a marginally set-up one drops out in a light shower.

The frequency band decides how bad it gets

The higher the frequency, the shorter the wavelength — and the closer that wavelength gets to the size of the raindrops it has to travel through. That single fact explains most of what follows.

• L-band (around 1–2 GHz). Satellite phones and some marine and emergency systems. Rain barely touches it, which is why a satellite phone often keeps working when everything else has given up.
• C-band (around 4–8 GHz). Long used for broadcast distribution. Noticeable fade only in genuinely torrential rain, and a bigger concern in the tropics than in Britain.
• Ku-band (around 10.7–12.75 GHz). The workhorse for consumer satellite television and some broadband. It copes with drizzle, struggles in moderate rain, and can lose lock during a heavy convective shower.
• Ka-band (around 18–31 GHz). Used by modern high-throughput satellite broadband. Far more capacity per satellite, far more vulnerable: fades are deeper and can begin within seconds of the first big drops.

Whichever band you are on, remember the link works in two directions. Rain over the ground station or over your own terminal matters as much as the downpour over your house.

Why UK weather makes it worse

British rain arrives in two flavours: frontal rain from Atlantic lows, which can be steady and long-lived, and convective showers, which dump a great deal of water in a short time. The second type is the troublemaker. A shower cell passing overhead can push rain rates high enough to knock out a Ku-band television signal for two or three minutes, and leave a Ka-band broadband link crawling for longer.

Geography matters too. Because the satellites serving the UK sit over the equator, dishes here point fairly low — often somewhere between twenty and thirty degrees above the horizon. A low look angle means the beam travels through more atmosphere, and more of whatever is falling through it, than a dish in a country where the satellite sits almost overhead. Wind-driven rain, common on western coasts and in Scotland, adds to the effect.

Winter brings its own version of the problem. Snow sitting in the dish, ice on the LNB, or a wet, leafy branch that has grown into the signal path all look identical on screen: no signal, no explanation.

What it looks like on your screen

For television, the sequence is familiar. A brief stutter, then the picture breaks into blocks, sound drops for a beat, and the receiver reports no signal. When the shower passes, everything returns without you touching a thing.

For broadband, rain fade shows up as latency spikes, packet loss, stalls and dropped calls rather than a clean outage. A speed test run mid-storm tells you almost nothing useful, because the bottleneck is the sky, not the router. If the connection recovers the moment the shower clears, you have found your answer.

A useful rule of thumb: if it only fails in heavy rain, it is rain fade. If it fails in light drizzle, suspect alignment, cabling, or something growing into the dish's line of sight.

Practical steps before the next storm

1. Check the dish has not moved. Storms, ladders and stray footballs all nudge dishes. Signal strength and quality readings in your receiver's settings menu are the quickest test, and a small improvement in alignment can buy you worthwhile margin.
2. Deal with water ingress. Inspect the connectors. Any that are green, corroded or wrapped in cracking tape need redoing properly, with self-amalgamating tape and a drip loop so water runs off rather than into the cable.
3. Keep the line of sight clear. Trees grow. Check the path between dish and sky at least once a year and trim anything that has crept in.
4. Clear snow and ice gently. Never scrape the dish face or the LNB. A soft brush, or a gentle spray of lukewarm water from the ground, is enough — and do not climb a ladder in icy weather for a television picture.
5. Consider a larger dish where it is practical. More dish area means more gain and more margin. It is not a cure, but it does raise the rain rate at which things fall over.
6. Plan for the worst week of the year. If you work from home, a mobile hotspot or a fixed-line backup for the handful of hours when the satellite link is degraded is money well spent.

What to do during a storm

Mostly, wait. Rain fade from a passing shower is measured in minutes. Check a weather radar to see whether a band of heavy rain is moving through or parking itself over you; if it is the latter, you know roughly how long you are in for. Do not power-cycle the router repeatedly mid-shower, and do not reset the receiver, or you will lose your stored channels for nothing.

If the signal does not come back once the sky has cleared, that is a different problem. Check for a wet or snowy LNB, look for fresh damage to the cable run, and consult your provider's service status. And if dropouts are happening in weather that barely wets the pavement, book an engineer. Rain fade is inevitable; constant failure in light rain is not.

Photo: TheOtherKev / Pixabay