TV Aerial Types Explained: Yagi, Log-Periodic, High-Gain and Grouped

Most UK homes use a Yagi aerial — the classic rows-of-elements design, with good gain and a directional pattern. Log-periodic aerials trade some gain for a flat response and excellent rejection of electrical interference, which is why professionals quietly favour them in decent signal areas. High-gain XB aerials exist for fringe reception, at the cost of size and wind load. Beyond shape, aerials are also either grouped (tuned to part of the UHF band) or wideband (covering all of it).

The quick comparison

Type	Gain	Bandwidth behaviour	Best use case
Yagi (standard, 10–18 element)	Good	Peaky across the band	Most homes, moderate to good signal
Log-periodic	Modest	Flat, consistent	Good signal areas, interference-prone locations
High-gain / XB (extra bay)	High	Peaky, narrower beam	Fringe and weak-signal areas
Grid/mesh reflector Yagi	Good–high	As Yagi, better front-to-back	Areas with signal arriving from behind (reflections, co-channel)
Indoor / set-back	Poor	Varies	Strong-signal areas only, as a compromise
Contract aerial (obsolete)	Low	Poor	None — replacement candidate

Gain (the aerial’s amplification of signal from the direction it points, measured in dB against a reference aerial) is the headline number on every box, but as we’ll see, it isn’t the only number that matters.

Yagi: the default

The Yagi-Uda aerial — invented in Japan in the 1920s and universally shortened to Yagi — is what most people picture when they hear “TV aerial”. It has a single driven element (the part actually connected to the cable), a reflector behind it, and a row of director elements (the short cross-pieces along the boom) in front. Each director adds a little gain and narrows the beam slightly.

Yagis are popular for good reasons: they deliver respectable gain for their size, they’re cheap to manufacture, and their directionality helps reject signals from other directions. Their weakness is that the gain is not even across the frequency band — it’s peaky, higher on some channels than others. On a transmitter whose multiplexes (MUXes — the bundles of channels sharing one frequency) are spread across the band, a Yagi can receive some MUXes noticeably better than others. Usually there’s enough margin that it doesn’t matter. Sometimes, on marginal installs, it’s exactly why one group of channels breaks up while the rest are fine — a pattern we discuss in why some Freeview channels go missing.

A standard 10–18 element Yagi suits the large majority of UK homes within normal range of a main transmitter such as Winter Hill or Emley Moor.

Log-periodic: the quiet professional favourite

A log-periodic aerial looks like a slimmer, tidier Yagi, but every element is driven — connected to the feed — with element lengths and spacing scaled logarithmically along the boom. The result is an aerial whose performance is almost perfectly flat across the whole band: no peaks, no troughs, every MUX received equally.

Its second virtue matters even more in the real world: impulse-noise rejection. Impulse interference (short bursts of electrical noise from thermostats, fridge motors, LED drivers, vehicle ignition and central-heating pumps) is one of the most common causes of picture break-up in urban Britain. The log-periodic’s balanced feed arrangement makes it markedly better at rejecting this kind of noise than a standard Yagi.

The trade-off is gain: a log-periodic delivers less of it than a similarly sized Yagi. In a good signal area that’s irrelevant — you have signal to spare, and what you actually want is clean, consistent, interference-resistant reception, which is exactly what a log-periodic provides. This is why experienced installers fit them by default wherever signal allows and reserve high-gain Yagis for where they’re genuinely needed. If a quote specifies a log-periodic, that’s usually a sign of someone who knows what they’re doing, not a cost-cut.

High-gain and XB aerials: for the fringes

Where signal is genuinely weak — deep fringe areas, relay shadows, long paths over hills — you need more gain, and that means more metal. High-gain aerials extend the Yagi principle: longer booms, more directors, and in XB (“extra bay”) designs, multiple stacked bays of elements feeding a single output.

They work, but they carry real costs:

Wind load. A big XB aerial presents a lot of surface to the wind, on a long mast, on the highest point of your house. Everything below it — mast, bracket, fixings, and the wall or chimney itself — has to be sized for the worst gale of the decade, not the day of installation. An oversized aerial on an undersized bracket is a common storm-damage casualty.
Narrow beam. More gain means a tighter acceptance angle. Alignment becomes critical, and anything that shifts the aerial a few degrees costs real signal.
No magic. Gain amplifies whatever arrives, including interference. If the location’s problem is signal quality rather than quantity, a bigger aerial doesn’t fix it.

The right approach in weak areas is to fit the smallest aerial that achieves target measurements with margin — not the biggest one the bracket will hold.

Grid and mesh reflectors

Some Yagis and XB designs carry a large grid or mesh reflector — a lattice of metal behind the driven element instead of a few simple rods. The mesh acts as a more complete mirror, improving the front-to-back ratio (how strongly the aerial rejects signal arriving from behind). That matters in two situations: where a strong reflection bounces off a building or hillside behind the property, and where a second transmitter on similar frequencies lies in roughly the opposite direction, causing co-channel interference. The mesh adds wind load, so it’s a targeted tool rather than a default.

Grouped vs wideband

Separately from its shape, every UK aerial is either grouped — tuned to one section of the UHF band, historically labelled Group A, B, C/D and so on with colour codes — or wideband, covering the whole band at slightly lower efficiency.

Since the 700MHz clearance completed in 2020 (the reallocation of the top of the TV band to mobile networks), all UK television sits between roughly 470 and 700MHz, and the old group boundaries matter less than they did. But they still matter: a grouped aerial matched to your transmitter delivers more gain per pound and per square metre of wind load than a wideband, while an old grouped aerial that no longer matches its transmitter’s post-clearance frequencies is a genuine problem. The full story — including which transmitters like Rowridge and Belmont have quirks worth knowing — is in our dedicated guide to UK TV aerial groups.

Indoor and set-back aerials: the honest verdict

Indoor aerials — the loop, panel or “flying saucer” designs that sit on the TV cabinet — obey the same physics as everything above, with two handicaps: they’re small, and they’re inside your house at head height, surrounded by walls, wiring, people and Wi-Fi. Amplified models advertise big dB numbers, but amplification of a poor signal produces a louder poor signal; see boosters vs amplifiers for the mechanics.

The honest verdict: in a strong-signal area, upper floor, window facing the transmitter, an indoor aerial can work acceptably. Anywhere else, it’s a source of intermittent frustration. “Set-back” aerials (compact outdoor designs meant for fascia or balcony mounting) are a step up — outside the building, at least — but remain a compromise on gain and height. If a proper install isn’t possible, television over broadband may honestly serve you better: see can you watch TV without an aerial.

The relics still on British roofs

Two obsolete types are still bolted to chimneys all over the country:

Contract aerials. The minimal few-element Yagis fitted in bulk by housebuilders — chosen for price, not performance. Low gain, poor build quality, and a common culprit behind marginal reception that “was never quite right”. If your house came with one and your Freeview misbehaves, it’s a prime suspect; our guide to why your TV aerial won’t work covers the other suspects.
Band III VHF aerials. The big X- or H-shaped aerials from the 405-line era, obsolete since the mid-1980s, receiving nothing whatsoever for forty years. They survive purely because taking them down costs money and leaving them up is free. They’re harmless apart from wind load and the occasional rusty descent into the garden — a curiosity from the history of British television. If you’re paying for roof work anyway, have them removed.

Which type do you actually need?

For most homes the decision tree is short: good signal area → log-periodic or standard Yagi; marginal area → grouped high-gain Yagi chosen after measurement; strong reflections or co-channel trouble → mesh-reflector design. The type matters less than the match between aerial, transmitter and location — which is a measurement job, not a catalogue job. Our companion guide what TV aerial do I need walks through the decision for your circumstances, and a typical supplied-and-fitted install of any of these runs around £150–£250 — see the full cost breakdown.

If you’d rather not become an aerial taxonomist, that’s what installers are for. Check your postcode or contact us and we’ll pass your enquiry to a local installer who knows which designs actually work on your area’s transmitter — we route enquiries to independent local trade rather than running our own fleet, so the recommendation comes from someone who fits these aerials on your streets every week.