Boost your UniFi WiFi range with the right settings: Secret 5 GHz Band B for extra power in the UK.

Most UniFi Wi-Fi problems are not solved by buying more access points. They are solved by getting four settings right: the country, the band, the channel width and the transmit power. This guide explains each one in plain English for both US and UK installs, then gives you an interactive planner so you can see what a change will do before you touch your network.

What actually decides your Wi-Fi range

Range is not one setting. It is the result of four choices that pull against each other. Understand these and every UniFi radio screen starts to make sense.

Set the right country, and know what it does not change

The country (region) setting selects the regulatory domain for your access points. It decides which channels are available, including the 5 GHz and 6 GHz channels, whether DFS radar detection is required on certain 5 GHz channels, and the maximum legal transmit power (EIRP) per band and channel.

The Transmit Power setting on each AP (Auto, High, Medium, Low or Custom) works within that cap. The country setting does not choose your power level, but it sets the ceiling. In some regions, high-power settings are limited or unavailable.

How to tell what you have

• Site-wide country: go to Settings > System (older versions: Settings > Site) and look for Country / Region. Menu names shift a little between UniFi Network versions.
• What each AP is really doing: open UniFi Devices, click the AP and check its radio settings for channel, channel width and Transmit Power. The device page also shows live values, which can differ from the setting when you are on Auto.
• Region-locked hardware: some models are sold as region-specific SKUs. If the country dropdown is greyed out or offers a single option, the device or controller is locked to that region.
• Quick sanity check: if channels you expect (certain DFS or 6 GHz channels) are missing, or maximum power looks low, check the country first.

US and UK limits compared

The UK 5 GHz and 6 GHz figures below come from Ofcom's information sheet on 5 GHz RLANs (equipment must meet Interface Requirement IR 2030). The US figures are approximate. Always confirm against the regulator (FCC in the US, Ofcom in the UK) before relying on them.

United States (FCC)

• 2.4 GHz: up to about 36 dBm EIRP.
• 5 GHz: roughly 30 to 36 dBm EIRP depending on the channel range. Channels 52 to 144 need DFS; 36 to 48 and 149 to 165 do not.
• 6 GHz: indoor low-power rules, where the cap rises with channel width (5 dBm per MHz, up to 30 dBm EIRP).

United Kingdom (Ofcom)

• 2.4 GHz: 20 dBm EIRP (100 mW).
• 5 GHz Band A, 5150 to 5350 MHz (channels 36 to 64): 200 mW (23 dBm) EIRP, indoor only. DFS and TPC are required above 5250 MHz (channels 52 to 64).
• 5 GHz Band B, 5470 to 5730 MHz (channels 100 to 144): 1 W (30 dBm) EIRP, DFS and TPC required, and permitted indoors and outdoors without a licence. This is the high-power band: 7 dB above Bands A and C, which is about five times the power, or roughly 70% more range indoors on the AP-to-device direction.
• 5 GHz Band C, 5725 to 5850 MHz (channels 149 to 165): 200 mW (23 dBm) EIRP, no fixed outdoor use. Higher-power or fixed outdoor use here needs a paid licence and registration (up to 4 W), so ordinary UniFi installs should treat it as 23 dBm indoor.
• 6 GHz Band D, 5925 to 6425 MHz: 250 mW (about 24 dBm) EIRP for low-power indoor use only. Very low power (25 mW) is allowed for indoor and mobile outdoor devices, not fixed outdoor APs.

dBm to watts

Regulators quote power in milliwatts and watts, while UniFi and this article use dBm. This table converts between them.

dBmPowerWhere you will see it

01 mWThe reference point: dBm is simply power measured against 1 milliwatt.

1010 mWTen times the reference point. Every +10 dBm multiplies power by ten.

1425 mWRoughly what a phone or laptop transmits (about 12 to 15 dBm, or 16 to 32 mW). Also the UK very-low-power 6 GHz limit.

20100 mWUK limit on 2.4 GHz (EIRP).

23200 mWUK limit on 5 GHz Bands A (channels 36 to 64) and C (149 to 165), EIRP.

24250 mWUK limit for low-power indoor 6 GHz (Band D), EIRP.

27500 mWA UniFi U7 Lite in the US showed this EIRP on 2.4 GHz.

29800 mWThe same U7 Lite showed this EIRP on 5 GHz.

301 WUK limit on 5 GHz Band B (channels 100 to 144), EIRP. Also close to the US limit on parts of 5 GHz.

364 WApproximate US limit on 2.4 GHz. Also the UK ceiling for licensed, registered Band C links.

Choose the band: 2.4, 5 or 6 GHz

Each band is a trade between how far the signal travels and how much room there is to move data.

Pick the right channel width

Speed scales almost linearly with width, because each doubling roughly doubles the number of data-carrying subcarriers. The gain is slightly better than 2× because wider channels waste proportionally less on guard bands. Wi-Fi 7 adds about 20% on top of the Wi-Fi 6 figures below, and 6 GHz Wi-Fi 7 can use 320 MHz for double the 160 MHz figure.

The decibel helper needs JavaScript. As a rule of thumb, 3 dB doubles or halves the signal power, and in a typical house it changes your range by about a fifth.

Decibel helper: what does that many dB really mean?

Pick a dB figure from this article, or drag the slider, to see what it means for signal power, distance, walls and speed.

Losing signal Gaining signal

Channel width doubled (3 dB) 20 to 80 MHz (6 dB) 20 to 160 MHz (9 dB) UK Band B vs Band A or C (7 dB)

Amount

Your current distance (metres)

Typical figures only. "Indoors" assumes a typical house or office layout; "open air" assumes a clear line of sight. Wall, floor and speed equivalents use typical 5 GHz values.

~287

20 MHz

~574

40 MHz

~1,200

80 MHz

~2,400

160 MHz

What you lose by going narrower

Going from 80 to 40 MHz cuts peak speed roughly in half. From 80 to 20 MHz you lose about three quarters. In practice a 2×2 client on 80 MHz might see roughly 600 to 800 Mbps, about 300 to 400 on 40 MHz and 150 to 200 on 20 MHz. If your internet line is 300 Mbps, 40 MHz is already enough for a 2×2 client.

What you gain: range and quality

A radio spreads its transmit power across the whole channel. Double the width and the same power is spread over twice the spectrum, while the receiver also listens to twice as much noise. The net effect is about 3 dB less sensitivity per doubling, so roughly 6 dB between 20 and 80 MHz. In open space 6 dB is about half the usable distance for the same data rate. Indoors the difference is smaller, roughly a third, but still real. Try your own figures in the decibel helper above.

• Close to the AP: signal is strong, so wide channels deliver their full speed.
• Mid-range: the client drops to a slower modulation on wide channels, and part of the speed advantage disappears.
• Edge of coverage: a 20 or 40 MHz channel can hold a usable link where an 80 MHz channel is flaky. Narrow often wins here despite the lower peak.
• Interference: one interferer anywhere inside a wide channel causes retries across the whole thing, which shows up as jitter and lag spikes.

Channel plan, DFS and exclusions

Channel AI is UniFi's built-in tool for proposing a channel plan across all your APs. Under AirView > Channel AI > Channel Plan you can expand the plan and click channels to omit them, so the controller never picks one you know is bad. Ubiquiti says Channel AI changes channels only and leaves channel width and transmit power as they are, so set those first.

• 2.4 GHz: leave only 1, 6 and 11 enabled. 40 MHz on 2.4 GHz uses two of the three clean channels, and a typical home already shows heavy channel use from neighbours.
• 5 GHz without DFS (US and UK): only 36 to 48 and 149 to 165 are usable. That is nine 20 MHz channels, four at 40 MHz and just two at 80 MHz. With several APs, 80 MHz forces them to share channels and interfere with each other, so 40 MHz is the sensible default.
• Enabling DFS (Extended 5 GHz Spectrum) opens up channels 52 to 64 and 100 to 144, which gives much more room for 80 MHz. UniFi leaves DFS off by default because a radar event can force an immediate channel change, so it favours consistency unless you need the extra capacity.
• US tip: if you enable DFS, consider excluding channels 120 to 128. They overlap weather radar (TDWR) and tend to cause repeated radar-triggered channel changes.
• Where the DFS tick box lives: go to Settings > WiFi > Default WiFi Speeds, choose Custom, then tick Extended 5 GHz Spectrum (DFS). If the box is greyed out while a preset such as Conservative is selected, switch to Custom first.

How to check for interference

Interference is the usual reason a clean-looking setup still feels slow. UniFi gives you several places to look, and none of them need extra hardware.

• Air Stats channel utilisation. On the AP's device page, Ch. Util shows Busy, Rx and Tx. Busy is the total airtime in use, while Rx and Tx are your own AP's traffic. Whatever is left over belongs to other people's Wi-Fi or to non-Wi-Fi noise. The U7 Lite we looked at earlier showed 48% busy on 2.4 GHz with 0% Rx and 9% Tx, so roughly 39% of the airtime was taken by something else, while 5 GHz showed only 10% busy.
• Retries. Tx Retry shows how often frames had to be sent again. Lower is better. If retries climb whenever utilisation climbs, suspect interference or weak signal rather than a faulty AP.
• Channel AI view. AirView > Radios > Channel AI View shows each AP's neighbours and channel utilisation, and the Optimize button proposes a better plan.
• Neighbour signal levels. When you compare channels, pick the one where neighbours are weakest. A neighbour at -90 dBm is far less of a problem than one at -80 dBm.
• Non-Wi-Fi noise. 2.4 GHz is shared with microwave ovens, baby monitors and Bluetooth. If 2.4 GHz utilisation spikes at the same time every day, look for one of those.
• The client view. Open a single device and compare its signal with its TX and RX rates. A big imbalance between the two directions points at a weak client transmitter or interference near one end of the link.
• Scanning tools. Ubiquiti's WiFiman app or any phone Wi-Fi scanner will show neighbouring networks. On older UniFi versions the per-AP RF scan can take that AP offline for several minutes, so run it out of hours.

What to change when interference is high

• Use 20 MHz on 1, 6 and 11 for 2.4 GHz, and consider keeping 2.4 GHz for IoT and older devices only.
• Use 40 MHz on 5 GHz, and enable DFS if you need cleaner channels (excluding 120 to 128 in the US).
• Move capable devices to 6 GHz, which has the cleanest spectrum.
• Lower the power on APs that overlap too much, and fix placement: high on a ceiling or wall, away from TVs, metal and the floor.
• Run Channel AI, review its plan, and omit channels you know are poor.
• Enforce minimum data rates and AP-level multicast filtering, which Ubiquiti's own design guidance recommends for stopping chatty devices such as Apple TVs and printers from dominating airtime.

Transmit power: Auto or High?

Higher AP power mostly makes the coverage area look bigger than it is. Your phone or laptop has to reply, and its transmitter is far weaker than the AP's, so the link fails on the upload side first. Extra AP power cannot fix that. The AP will also never exceed the legal limit for your country, whatever you choose.

• One AP: High is fine. There is no neighbouring AP to collide with, and you are capped by hardware and law anyway. Auto is also reasonable. Check Air Stats afterwards to see what you actually got.
• Several APs: use Auto, or Medium and Low after a survey. If neighbouring APs all shout at full power, their coverage cells overlap heavily, devices cling to a distant AP instead of moving to a closer one, and weak clients eat extra airtime. This is the near-far problem.
• Dense sites: more APs at reduced power beat fewer APs at full power, because each cell is smaller and each device gets a stronger, faster link.
• UK Band B (5 GHz, channels 100 to 144): set High if you want the full 30 dBm, since this is the range where the extra legal headroom exists.
• Auto is managed by UniFi, so what it chooses can change with firmware. Watch the live EIRP in Air Stats rather than assuming.

What the other end can do: phones, laptops, meshed APs and bridges

A link is only as strong as its weaker end. An AP can transmit at around 27 to 29 dBm EIRP, while a phone or laptop typically manages roughly 12 to 15 dBm. That gap is why range problems nearly always show up on the upload side first.

• Phones and laptops: they transmit at far lower power than the legal limit, whichever band you choose. In the UK, Band B allows up to 1 W EIRP, but an ordinary phone or laptop will not use it, so a higher AP power setting alone does not extend their range.
• Meshed UniFi APs and Wi-Fi bridges: a wirelessly meshed AP or a Wi-Fi-to-Wi-Fi bridge transmits at AP-class power in both directions. The link is balanced, so it can reach much further than a phone. In the UK, Band B is the natural choice for a long outdoor hop, because it is the one 5 GHz range that allows 1 W and fixed outdoor use.
• The trade-offs: a wireless hop uses airtime, so throughput is lower than a cable, and a DFS radar event can interrupt the link. For a fixed link that matters, run a cable if you can.
• Stay legal: EIRP includes antenna gain and must stay within the limit for the channel range. Never add an unapproved amplifier or change regulatory settings to squeeze out more power.
• See it in the planner: choose a device type in the planner and switch the chart to By device to compare a phone, a laptop, a hypothetical high-power laptop and a meshed AP or bridge on the same radio settings.

Single AP or multiple APs

Neighbouring APs: same channel, different channels or Auto?

Neighbouring APs should use different channels. Two APs that can hear each other on the same channel take turns on the air and share one pool of airtime. Channels that overlap without matching are worse, which is why 2.4 GHz uses only 1, 6 and 11.

• "As far apart as possible" is the wrong target. What matters is that the channels do not overlap. On 5 GHz, any two non-overlapping channels are fine. Plan so that APs which hear each other differ, and reuse a channel only on APs separated by enough walls and distance that they hear each other faintly.
• Auto or manual? Ubiquiti now recommends Channel AI throughout a deployment's life, and it applies changes without disrupting clients. Some installers found older Auto behaviour unreliable and prefer planning each AP by hand from a floor plan. A good middle path is to set width and power first, run Channel AI, review the result, then lock any AP where it chose badly.
• Count your clean channels. The planner below shows how many you have at each width. You want at least three for a tidy layout.

Roaming: Fast Roaming, Roaming Assistant and Minimum RSSI

Roaming is the device's decision. UniFi can nudge a device but cannot force it. Phones typically start looking for another AP somewhere around -70 to -75 dBm (a fair signal, well before it becomes unusable), according to figures Apple has published. The real fix is overlap: APs close enough that a better one is always available at that point. Roaming settings are a band-aid on top of that.

Fast Roaming (802.11r)

This speeds up the security handshake when a device moves between APs. It is off by default. At home, leave it off unless you actually see roaming problems. On business networks that use 802.1X or carry voice and video, enable it on that SSID and test. The client must support it, and some older printers, scanners and sensors have trouble joining an SSID that advertises it, so keep IoT on a separate SSID.

BSS Transition (802.11v)

This is on by default in UniFi and is best left on. It lets the AP suggest a better AP to a device in a standard way.

Minimum RSSI: the hard kick

Set per AP, Minimum RSSI disconnects any device whose signal, as the AP hears it, drops below your threshold, so the device reconnects to a closer AP. Two cautions from Ubiquiti's own documentation: a kicked device may reconnect to the same AP if nothing else is in range and then be kicked again, so never use it with a single AP, and Ubiquiti reportedly reserves it for high-density deployments because it can disrupt real-time traffic such as VoIP. If you use it, start around -75 dBm and adjust after walking the site. Older Ubiquiti guidance quoted a range of -70 to -90 dBm. Anything stronger than about -70 dBm will boot devices that still have a perfectly usable signal.

Roaming Assistant: the soft nudge

Roaming Assistant arrived with UniFi Network 9.2.87 and is the newer option. Instead of disconnecting the device, it uses BSS transition frames to tell it a better AP is available as the signal falls, which modern devices tolerate better. It is still a band-aid, but a more supported one. Where your version and devices support it, prefer it over Minimum RSSI. We would start at a similar threshold of about -75 dBm, because that is where phones begin looking anyway, then adjust after a walk test.

When to optimise: peak hours or the middle of the night?

Ubiquiti describes Channel AI as non-disruptive, applying its changes without impacting active clients, so timing matters less than it used to. What matters more is whether the scan sees a representative picture.

• Run the analysis when the airwaves are busy. At 3 am, neighbours' Wi-Fi and most household devices are quiet, so the tool sees a rosier picture than you live with. Run it in the evening at home or during the working day in an office, then review the result.
• Do disruptive jobs out of hours. Older per-AP RF scans, firmware updates, and manual channel, width or DFS changes can drop devices briefly, so do those overnight or at the weekend.
• Re-run after changes. Repeat it after adding or moving an AP, when a neighbour changes their network, and whenever users report slow patches.
• DFS can change channels at any time. A radar event forces an immediate move, so if reliability matters more than capacity, leave DFS off.

Indoor and outdoor installs

Choosing outdoor does not give you more transmit power. The legal ceiling depends on the channel range, not on where the AP sits. In the UK, the 1 W (30 dBm) Band B limit applies to indoor and outdoor use alike. What outdoor changes is which ranges you are allowed to use, so it removes options rather than adding power. Outdoor-rated UniFi models can have different antennas or hardware, so check the model's spec sheet and the live EIRP in Air Stats rather than assuming.

In the UK, Bands A (channels 36 to 64) and C (149 to 165) and the low-power 6 GHz band do not allow fixed outdoor use, so a fixed outdoor 5 GHz AP in the UK must use Band B, channels 100 to 144, with DFS and TPC. In both countries the 6 GHz low-power rules are for indoor use. Outdoors you have line of sight working in your favour, but trees, vehicles and buildings eat range quickly. Always set the country to where the AP is physically installed.

Wi-Fi 6 or Wi-Fi 7 access points

A Wi-Fi 7 AP gives you 4096-QAM (about 20% higher peak rates than Wi-Fi 6 in good signal), Multi-Link Operation, and 320 MHz channels in 6 GHz. Wi-Fi 6E adds the 6 GHz band to Wi-Fi 6. The catch is that your devices must support these features too: a Wi-Fi 6 phone on a Wi-Fi 7 AP still connects as Wi-Fi 6. Some Wi-Fi 7 APs are dual-band only (2.4 and 5 GHz), so check whether your model has a 6 GHz radio before planning around it.

Try it yourself: the UniFi Wi-Fi range and speed planner

Everything above is wired into the planner below. Pick your country, access point, the device on the other end, and the band, then move the distance and wall sliders. You will see the estimated speed, how far you can go and still get the speed you need, the frequency and DFS status of the channel, and which band and width wins for your situation. Building options cover a US wood-frame home, a typical UK brick-and-plasterboard home, older solid-brick buildings and offices. Switch the chart to By device to see how a phone, a laptop and a meshed AP or bridge compare. It includes iPhone 17 and iPhone 18 Pro class phones, among other devices.

The planner needs JavaScript to run. Everything else in this article works without it.

Your setup

Quick presets

Flat House Office Garden Bridge

Country / region

United States United Kingdom

Where is the AP installed?

Indoor Outdoor

Access point

Device on the other end of the link

Phones and laptops transmit at far lower power than an AP. A meshed AP or Wi-Fi bridge uses full AP power both ways.

Radio settings

Band

2.4 GHz 5 GHz 6 GHz

Channel range Allow DFS channels

Channel width (MHz)

Power reduction

0 dB is the maximum the AP and the law allow.

Measured EIRP at full power (optional, dBm)

Enter the EIRP your AP shows in Air Stats for this band to calibrate the estimate.

Your space

Distance from the AP

Building construction

Typical losses only. Real walls vary a lot, so test with a walk survey.

Internal walls in the way

Heavy walls in the way

Exterior walls, thick brick or block, or concrete.

Floors in the way

Layout

Neighbouring Wi-Fi and interference

Speed you need at the far end

Number of APs on site

Speed against distance

By channel width By device

Same radio settings, different devices

How far each type of device on the other end can go with the band, channel range and width you have selected. The device's own transmit power is usually what limits range.

Which band wins for you?

What to set in UniFi

Copy these settings

Notes for your setup

How the estimates work

This is a planning model, not a site survey. It uses a log-distance path-loss model with fixed losses per wall and floor, the noise floor for the chosen channel width, the minimum signal-to-noise ratio for each Wi-Fi modulation (MCS) and a real-world efficiency factor. Both directions are modelled: the AP to the device (download) and the device back to the AP (upload), and the link only works if both do.

Assumed values you can change or calibrate: AP hardware EIRP ceilings, a 4 dBi AP antenna, 2 spatial streams on the AP, and typical wall and floor losses for each building type. Phones and laptops are assumed to transmit at roughly 12 to 15 dBm depending on band. The iPhone profile uses Apple's N1 chip: Wi-Fi 7 with 2×2 MIMO and a maximum width of 160 MHz, which FCC filings confirmed for the iPhone 17 family. Apple lists the iPhone 18 Pro series with the same chip but has not published widths or transmit power, so the figures are carried over.

The high-power laptop profile is hypothetical: it assumes an adapter able to transmit up to the legal limit of the band, which ordinary laptops and phones do not do. The meshed AP or bridge profile assumes the other end is a UniFi-class AP using the same hardware power as your AP, capped at the legal limit. In every case the device's output is capped at the legal EIRP for the channel range you picked. Treat results as accurate to within roughly 30 to 50% and confirm with Air Stats on site. Regulatory limits are approximate; check the FCC or Ofcom for the authoritative values.

Apply it in UniFi: the checklist

1. Set the country

   Check Settings > System and confirm the country matches where the APs are physically installed. Fix it first, because everything else depends on it.

2. Set default widths

   Under Settings > WiFi > Default WiFi Speeds, choose Custom if you want to set widths or enable DFS yourself: 20 MHz on 2.4 GHz, 40 or 80 MHz on 5 GHz, and 80 or 160 MHz on 6 GHz. Use Apply to all APs once you are happy.

3. Run Channel AI and tidy the plan

   Open AirView > Radios > Channel AI View, click Optimize while the network is busy, review the summary and apply. Omit any channels you know are poor under Channel AI > Channel Plan, and repeat for each band.

4. Set transmit power sensibly

   High for a single AP, or for UK Band B if you want the full 30 dBm. Auto, or lower after a survey, for several APs. Remember the cap in your country and the limit of your devices' own transmitters.

5. Keep roaming simple

   Leave BSS Transition on. Add Roaming Assistant if devices cling to a distant AP, starting around -75 dBm. Reserve Minimum RSSI for dense sites, and Fast Roaming for 802.1X or voice networks.

6. Verify in Air Stats

   Open the AP's device page and check live EIRP, retries and channel utilisation during busy hours. If retries and utilisation stay low, you can try going wider. If they climb, go narrower.

Quick recipes

Sources and further reading

• Ubiquiti: UniFi Channel AI and automated WiFi optimisation
• Ubiquiti: Understanding and implementing Minimum RSSI
• Ubiquiti: UniFi WiFi SSID and AP settings overview
• HostiFi: What is Roaming Assistant within UniFi?
• HostiFi: Basic UniFi wireless optimisation
• Ofcom: information sheet on 5 GHz RLANs

If you would rather have this designed, surveyed and installed properly, take a look at our Ubiquiti Universe and network installation services.