Why does my TV keep losing channels?

Broadcast television arrives as a set of multiplexes, each carrying a group of channels. Losing all of them at once, losing one group, and losing individual channels are three different symptoms with three different causes. That distinction is the fastest way through the problem, and it is why the built-in signal strength screen is worth finding before you touch anything.

Step by step

1. Note exactly which channels are missing.All of them, one block of them, or scattered individual ones. A whole missing block points at one multiplex, which is a signal-strength problem. Everything missing points at the aerial connection or a retune.
2. Run a full retune, not an update scan.In the channel settings, choose the full or first-time tuning option rather than an automatic update, which sometimes just refreshes what is already there. Expect it to take several minutes and to renumber some channels.
3. Find the signal strength and quality screen.Most sets have one buried in the tuning or diagnostics menu, showing strength and quality separately. Quality is the one that matters: strong but poor quality usually means interference or an over-amplified signal, and weak but clean quality means a reception problem.
4. Check the aerial connections physically.Unplug and reseat the coaxial lead at the wall plate and at the television. Look at the end of the cable: a bent or missing centre pin, corrosion, or braid strands touching the pin will all cause exactly this.
5. Bypass splitters and amplifiers temporarily.A splitter feeding several rooms halves the signal each time it divides. A signal booster can also make things worse by amplifying interference along with the wanted signal, or by overloading the tuner if the signal was already strong. Connect one television straight to the aerial lead and retune to test.
6. Look for a pattern in when it happens.Worse in rain or high wind suggests a physical aerial or cable fault. Worse in warm still weather can be atmospheric interference from distant transmitters, which passes. Worse at a particular time of day suggests something in the house being switched on.
7. Rule out interference from your own equipment.Cheap power supplies, LED lighting drivers and some chargers radiate interference that lands squarely on television frequencies. Turn things off one at a time and watch the quality reading.
8. Check whether neighbours have the same problem.If the whole street has lost the same channels, it is transmitter work or a fault at the broadcaster's end and there is nothing to do but wait. Broadcasters publish planned engineering work by transmitter and postcode.
9. Call an aerial installer rather than going on the roof.If the aerial is misaligned, corroded or facing the wrong transmitter, that is roof work. It is not a job to do off a ladder, and a professional will also confirm which transmitter your area should be using.

Tips

• Write down your channel list before a retune if you use a favourites arrangement — a full retune usually discards it.
• A loft aerial is easier to reach but loses signal through the roof, and loses far more through foil-backed insulation or a solar array. A weak loft aerial is a very common cause of a set that drops channels in bad weather.
• If you have both an aerial and streaming, remember that streaming working perfectly proves nothing about the aerial path — they are entirely separate routes into the house.

Common mistakes

• Fitting a signal booster as a first response — It amplifies interference as well as signal, and can overload a tuner that was receiving too much already. Establish that the signal is genuinely weak before amplifying anything.
• Retuning repeatedly without changing anything — If the signal is not reaching the tuner cleanly, another scan will find the same nothing. One full retune settles the question.

If it doesn't work

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