“No signal”: the message nobody wants
A well-installed satellite dish can run for years without any trouble. But it lives on the roof, exposed to wind, sun, rain and, on the coast, salt air. Sooner or later something gives, and the warning is always the same: “no signal” on the screen.
In this article we go through the most frequent satellite dish faults, how to recognise each one from its symptoms, and what you can check before asking for help. If you need a repair, everything is set out under TV aerials and satellite dishes.
Quick symptom table
| Symptom | Most likely causes |
|---|---|
| No signal on any channel | Dish knocked off alignment, failed LNB, damaged cable or connector, receiver not powering the LNB |
| Some channels missing, others fine | LNB with one band or polarity failed, DiSEqC switch, channels that have changed frequency |
| Drop-outs in heavy rain | Normal rain fade, made worse by a small or poorly aligned dish |
| Picture freezing or breaking up | Marginal signal: imprecise alignment, corroded connectors, obstructions |
| Only one television affected | The cable to that point, the receiver, or that multiswitch output |
| It started after a gale | Dish or mast moved |
| It has got worse over the years | A tree that has grown, a new building in the way, an ageing LNB |
The usual faults
1. A dish knocked off alignment
This is fault number one. Aiming a dish is very precise work: the smallest nudge is enough to lose the signal. The usual causes are wind (the mestral in the Camp de Tarragona can be fierce), a loose bracket, a poorly anchored mast, or somebody catching it while working on the roof.
Fix: realign with a satellite field meter and strengthen the fixing. If a dish keeps drifting off, the bracket or the anchor needs looking at.
2. A failed LNB
The LNB is the small unit on the arm of the dish. It receives the signal, amplifies it and sends it down the cable. It is permanently out in the weather, and over the years damp can get in and the components age.
Signs that it is the LNB:
- One polarity works, horizontal or vertical, and the other does not.
- The channels on one band, high or low, have gone.
- The signal has been dropping away gradually.
Fix: replace the LNB with one suited to the installation: single, twin, quad or a type made for a multiswitch.
3. Cable and connectors
Outdoor F connectors that are not properly protected corrode, especially near the sea. Coaxial cable also dries out and cracks in the sun, and water can get in through the damaged outer sheath and travel along inside.
Fix: replace the connectors, protect outdoor joints with boots or self-amalgamating tape, and renew any damaged runs of cable.
4. DiSEqC switch or multiswitch
If you receive several satellites or feed several televisions, there are parts in between that can fail too: the DiSEqC switch that selects the satellite, or a building’s multiswitch. The typical symptom is one satellite working and another not, or only some outlets failing.
5. Problems in the receiver
Sometimes the dish is fine and the receiver is at fault: the voltage it sends to the LNB has failed, the channel list is out of date after a frequency change, or the DiSEqC settings have been lost after a reset. If you are unsure about your equipment, read choosing a satellite receiver.
6. New obstructions
A tree that has grown, an awning, an extension on the building opposite or a new ventilation unit can all break the line of sight to the satellite. The signal does not pass through leaves or walls.
7. Motorised dishes
On a motorised dish, the motor itself, its positioning or its travel limits can drift out of adjustment, especially after a power cut or through simple wear.
What you can check yourself
Without going up on the roof, which you should never do without proper safety equipment:
- Try another television or receiver if you have one.
- Restart the receiver by unplugging it for a minute.
- Check the connectors you can reach behind the receiver and at the wall socket.
- Look at the dish from the ground: if it is visibly skewed, or something is in front of it, that is your clue.
- Check whether it is a general problem: if it is pouring down, wait for the rain to pass before concluding anything is broken.
- Rescan for channels: broadcasters change frequencies, and some channels “disappear” only because they have moved.
How to prevent faults
- A mast and bracket anchored firmly, and sized for the wind in your area.
- Corrosion-resistant materials on installations near the sea, as in Salou or Cambrils.
- Outdoor connectors properly sealed.
- A dish sized correctly for the satellite, so there is signal margin when it rains.
- A check after any serious storm.
Repair or replace?
If the dish itself is sound, repairing is normally the answer: realign it, change the LNB or renew the connectors. If the installation is very old, corroded, or you want to add satellites or televisions, replacing the lot can work out better. In blocks with an individual dish on every balcony, the best medium-term answer is often one communal satellite dish distributed through the building’s ICT communal installation.
If your satellite dish in Tarragona or along the coast has stopped working, ask us for a quote with no obligation. We measure the signal, trace the fault and tell you what is worth doing.