Specifications

What Is in the Box

Compatible UK Mobile Networks

The C100 boosts Band 20 (800 MHz) 4G LTE, which is deployed by every major UK operator. The table below confirms network-by-network compatibility.

Pricing, Shipping & Returns

Pros & Cons

An objective assessment based on the C100's hardware, price point and intended use case.

Pros

• Lowest price in class: At £109.99 the C100 undercuts comparable single-band UK boosters (typically £150–£300) by 30–60%.
• All four UK networks: Band 20 800 MHz is used by EE, O2, Vodafone and Three, so one device covers every network and MVNO.
• Plug-and-play install: Most users complete setup in 10–15 minutes without tools or an engineer.
• Up to 5 bars guaranteed: In areas with at least 1 bar of outdoor signal, the C100 delivers a full 5-bar indoor signal.
• Multiple simultaneous users: No per-device limit — households and small offices can all connect.
• 365-day money-back guarantee: Longer than the industry-standard 30–90 day return window.
• Free UK shipping: No hidden delivery costs; standard delivery 10–15 business days.
• Ofcom licence-exempt: Operates within the UK's mobile repeater licence-exemption parameters.

Cons

• Single-band only (Band 20): Does not boost 5G, 3G (2100 MHz) or higher 4G bands (Band 3 / 7 / 38). If your area has no 800 MHz 4G, coverage will be limited.
• 100 m² max coverage: Suitable for one room or a small flat; larger homes need the 300 m² or 500 m² models or an extended antenna kit.
• Requires at least 1 bar outdoors: A booster cannot create signal where none exists — the outdoor antenna must receive a usable signal from the nearest mast.
• Standard cable is 5 m: Homes needing the antenna on the roof may require the 15 m cable upgrade (£30.99).
• No built-in LCD / signal meter: Unlike premium units, the C100 uses LED indicators only — fine for most users but less precise for optimisation.
• Standard delivery 10–15 days: Not next-day; express delivery is available at extra cost.

How the C100 Works

The C100 is a bidirectional RF repeater. It follows a three-step signal path:

1. Capture: The outdoor omni antenna picks up the weak 800 MHz 4G LTE signal from the nearest mobile mast.
2. Amplify: The booster unit filters and amplifies both downlink (tower-to-phone) and uplink (phone-to-tower) signals by up to 65 dB.
3. Redistribute: The indoor whip antenna rebroadcasts the amplified signal throughout the 100 m² coverage zone, and relays phone signals back to the mast.

Installation Steps (10–15 Minutes)

1. Find the strongest outdoor signal spot (usually near a window or on the roof) using your phone's signal bars.
2. Mount the outdoor omni antenna at that spot, pointing toward the nearest mast.
3. Run the 5 m coaxial cable from the outdoor antenna to the booster unit inside.
4. Screw the indoor whip antenna onto the booster unit.
5. Plug in the 12 V power adapter. The LED indicators will show power and signal status.
6. Wait 30–60 seconds for the booster to sync with the network, then test signal bars on your phone indoors.

Frequently Asked Questions (10 Real UK User Questions)

1. Does the C100 work with 5G?

No. The C100 is a 4G LTE Band 20 (800 MHz) booster only. It does not amplify 5G frequencies (700 MHz n28, 3.5 GHz n78, etc.). However, 4G LTE remains the primary voice and data layer for most UK users, and VoLTE calls work perfectly. For 5G boosting, consider a multi-band 5G booster.

2. Will this booster work with my specific network — EE, O2, Vodafone or Three?

Yes. All four major UK networks use Band 20 (800 MHz) for 4G LTE coverage, especially in rural areas. The C100 is compatible with EE, O2, Vodafone, Three and every MVNO running on those networks (giffgaff, Tesco Mobile, Lebara, Lycamobile, Plusnet, ASDA Mobile, SMARTY, iD Mobile, BT Mobile, Vectone Mobile).

3. How many square metres does the C100 cover?

The C100 covers up to 100 m² (approximately 1,076 ft²), which is typically one large room, a small flat or a home office. Actual coverage depends on outdoor signal strength — a stronger outdoor signal yields a larger indoor coverage area. For homes larger than 100 m², consider the 300 m² or 500 m² models or add the extended antenna kit.

4. Is a mobile signal booster legal in the UK?

Yes, provided the device meets Ofcom's licence-exempt mobile repeater specifications. The C100 is UKCA / CE certified and operates within Ofcom's Technical Standard for Mobile Repeaters (2024), which permit licence-exempt use of repeaters that meet strict power and filtering limits. Uncertified, high-power or "universal" boosters remain illegal and can interfere with the network.

5. Do I need an outdoor signal for the booster to work?

Yes. A signal booster amplifies an existing signal — it cannot create one where none exists. You need at least 1 bar of usable 4G LTE (Band 20) signal at the outdoor antenna location. If you have zero bars outdoors even with the antenna mounted high, a booster will not help and you should contact your network operator about a femtocell or network upgrade.

6. How long does installation take and do I need an engineer?

Most customers install the C100 in 10–15 minutes without any tools or professional help. The kit includes everything needed: booster, indoor antenna, outdoor antenna, 5 m cable, power adapter and mounting bracket. Only basic DIY is required. If you need the antenna on a high roof or have a listed building, a professional installer may be advisable.

7. Can multiple people use the boosted signal at the same time?

Yes. The C100 supports unlimited simultaneous users and devices. There is no per-device cap — the whole household or office can make calls, stream video and browse simultaneously. Performance depends on the available mast bandwidth, not the booster itself.

8. What is the difference between the C100 and more expensive boosters?

The C100 is a single-band (Band 20 only) booster optimised for the UK's most widely deployed 4G frequency. More expensive units (£250–£600) typically offer multi-band support (3G + 4G + 5G), larger coverage (300–500 m²), built-in signal meters and app-based monitoring. For users who only need 4G LTE in a space up to 100 m², the C100 delivers equivalent core performance at a fraction of the cost.

9. What is the return policy and warranty?

The C100 comes with a 365-day money-back guarantee — if you are not satisfied, return it within 365 days for a full refund. Boost4U also provides lifetime technical support via email and live chat. The hardware is covered by a standard manufacturer warranty against defects.

10. How long does UK delivery take and is shipping free?

Standard UK shipping is free and takes 10–15 business days. Orders are dispatched within 1–2 business days. Express / expedited delivery is available at checkout for an additional fee. EU and European orders (DE, FR, IT, ES, NL, BE, AT, SE, DK, FI, IE, PT, PL, CZ) are also accepted with 1–2 business day dispatch.

Related Guides & Reviews

• Best Mobile Signal Booster UK 2025: Top 5 Compared (C100 Ranked #1 Budget)
• Boost4U C100 Review: Best Budget 4G Signal Booster Under £150?
• How to Boost Mobile Signal at Home UK: 7 Proven Methods (2025)
• Are Mobile Signal Boosters Legal in the UK? Ofcom Guide 2025