The LNB — Low-Noise Block downconverter — sits at the focal point of the dish and does two jobs: it amplifies an extremely weak signal without adding much noise of its own, and it shifts that signal down to a frequency ordinary coaxial cable can carry to your decoder. It is the only powered component outdoors, it lives in full sun and rain year-round, and it is consequently the part that fails most often.
The types you will encounter
- Universal single LNB — one output, one decoder. The cheapest option and fine for a single-view household.
- Twin / quad LNB — two or four independent outputs, one cable per decoder tuner. The traditional way to run Extra View.
- Smart LNB — carries multiple decoders down a single cable. Fewer cable runs, fewer connectors, fewer things to corrode, and the current standard for a new multi-room installation.
How an LNB fails
Almost always through water. The weatherproof boot at the cable entry perishes in UV, moisture wicks down the cable into the housing, and corrosion does the rest. The classic symptom is a picture that works fine in dry weather and disappears for a day or two after rain — then comes back, then stops coming back. Lightning-induced surges are the other common killer, and they usually take the LNB and sometimes the decoder tuner with them.
Repair or replace?
Replace. An LNB is a sealed unit and a modest part cost; nobody sensibly repairs one. The important part is fitting the right type for your setup and re-sealing the connection properly — a new LNB with a badly sealed boot will fail again in the same way, in about the same time.
Brands we fit and service
The lnb (low-noise block) market splits into hardware built for South African conditions and lookalikes that fail at the first hard season. These are the manufacturers we trust on our installations:
- Inverto
- Ellies
- Smart LNB (MultiChoice-compatible)
See our brand guides for how these manufacturers compare.
When the lnb (low-noise block) goes wrong
These are the failures we're called to most often — each with its symptoms, causes and our fix on the dedicated problems page:
- Faulty LNB — no signal on any channelE48-32, E30 — Total loss of signal across every channel, with the dish visibly still pointing where it always did and no storm or knoc…
- Water in the LNB after rainE48-32 (intermittent) — Reception fails during or after rain and returns a day or two later once things dry out. Each cycle it takes longer to c…
- Extra View needs a Smart LNBE48-32 on the second decoder — Your main decoder works perfectly but a newly added second decoder will not get signal, or the two decoders interfere wi…
- Corroded LNB connectorE48-32 (intermittent) — Signal quality has been slowly deteriorating for months, with increasing pixelation, and the F-connector at the LNB look…
Need this fixed or installed?
Our Smart LNB Installation service covers lnb (low-noise block) work — from R750, quoted upfront and backed by our 12-month workmanship warranty.