Answer first: the CD1000 is a dual-band FDD LTE commercial repeater that tunes Band 20 (800 MHz) for O2, Vodafone, Three and their MVNOs, and Band 3 (1800 MHz) for EE, ASDA, BT, Orange, T-Mobile, The People's Operator and Virgin 4G plus circuit-switched 2G voice and SMS. Its >=70 dB uplink and >=75 dB downlink gain, about ten times the amplification of the >=60/65 dB mid-size class, recover a weak donor and penetrate concrete and metal, while output holds at the >=20 dBm Ofcom ceiling and up to four zone antennas spread the field across 1000 m2 for 100 users. It stays Ofcom licence-exempt and carries UKCA, CE and RoHS marks, but it does not repeat 3G Band 1 at 2100 MHz, does not carry any 5G band, and should not be stretched beyond 1000 m2.

Band 20 (800 MHz): The Long-Range Layer for O2, Vodafone and Three

Band 20 occupies the 800 MHz spectrum that Ofcom reallocated to 4G LTE after the analogue TV switch-off. Its low wavelength travels farther from the macro mast, bends around terrain and penetrates brick and foliage more cheaply than higher bands, which is why O2, Vodafone and Three deployed Band 20 as the rural and deep-building 4G layer. Inside a large commercial building, Band 20 is the band that reaches the upper guest floor, the stock mezzanine, the workshop bay and the yard-facing office where the higher-capacity band fades.

Uplink and downlink frequency pairs for Band 20

A repeater works on a paired FDD block: the phone transmits on one block and receives on another, and the amplifier must repeat both directions without mixing them. The CD1000 repeats the 832 to 862 MHz uplink and the 791 to 821 MHz downlink together so a phone that sends a request to the Band 20 tower hears the reply amplified indoors.

Why 800 MHz reaches the far wing but carries less capacity

Lower frequency propagates farther and passes walls with less loss, but each MHz block carries fewer simultaneous data sessions than the higher bands. Band 20 is therefore the coverage band: it keeps a phone connected at the edge of the property, while EE's Band 3 carries the capacity where many devices gather. A rural Devon farm, a Yorkshire office or a Wales warehouse on O2, Vodafone or Three relies on Band 20 being repeated indoors; the CD1000 does that on the donor side before the >=75 dB downlink spreads it inside.

Band 3 (1800 MHz): The EE Capacity Layer and 2G Voice Path

Band 3 sits at 1800 MHz, the original GSM cellular band that EE and its family use for both 4G LTE capacity and legacy circuit-switched 2G voice and SMS. Its shorter wavelength carries more data capacity per block but attenuates faster through brick, double-glazing, concrete and floor slabs, which is why it reads weaker deep inside a building even in a well-covered city.

Uplink and downlink frequency pairs for Band 3

The CD1000 repeats the 1710 to 1785 MHz uplink and the 1805 to 1880 MHz downlink so EE-family phones get both LTE data and the 2G GSM voice and SMS path on the same layer. An older feature phone, a guest's handset, or a phone in an area where VoLTE has not yet been enabled still completes a normal call over the repeated 1800 MHz GSM layer rather than dropping to no service.

Why EE customers need this band rather than Band 20

EE does not rely on Band 20 for its domestic 4G in the same way; an EE SIM placed on a Band 20-only single-band unit would see no EE layer indoors. The CD1000's dual-band chassis keeps Band 3 live alongside Band 20 so one box serves an EE guest-room block and an O2 staff network at the same large address, which is the practical reason dual-band beats buying a single-band C1000 for a mixed-carrier commercial site.

UK Network and MVNO Mapping: Which SIM Works on Which CD1000 Band

The table below maps every SIM named on the CD1000 product page to its host network and the band the booster repeats for it. Before ordering, check your SIM's host carrier rather than the shop brand, because the MVNO brand name itself does not appear on the tower.

A mixed-carrier office or hotel benefits from different halves of the CD1000: the O2 staff network sees Band 20 light up, the EE guest-room block sees Band 3 light up, and a shared building where one team uses Giffgaff and another uses BT Mobile gets both bands boosted at once, which is the practical reason a dual-band chassis beats two single-band boxes across a 1000 m2 property.

Gain Explained: >=70 dB Uplink and >=75 dB Downlink, the Commercial Step

Gain, measured in decibels, is the factor by which the amplifier boosts the weak donor signal before re-radiating it. The CD1000's >=70 dB uplink gain and >=75 dB downlink gain are asymmetric: a tower transmits with high power while a phone transmits at low power from a battery, so the uplink path loses more energy on the way back and the amplifier still only needs to restore the faint phone signal to a level the tower can decode. The 5 dB gap between the two figures is normal for a repeater and not a defect.

Why +10 dB over the CD500 is about ten times amplification

Decibels are logarithmic: +10 dB multiplies the amplification factor by ten. Moving from the >=60/65 dB mid-size class to >=70/75 dB means the CD1000 recovers a donor roughly ten times more faint, which is decisive on a rural farm behind a hill or inside a concrete-and-steel warehouse where a >=65 dB unit still loses the cell. This is the commercial differentiator; output does not change, because the Ofcom ceiling caps watts.

How the 75 dB downlink margin buys concrete, steel and floor slabs

Every indoor surface costs signal: a plasterboard partition costs a few dB, an external brick wall costs 10 to 20 dB, a concrete or steel warehouse wall costs more, a ceiling slab between hotel floors adds its own loss, and metal racking or machinery adds attenuation on top. The >=75 dB downlink margin absorbs that cumulative loss so the phone still shows bars in the upper guest room, the stock mezzanine and the workshop bay, where a >=65 dB mid-size margin runs dry.

Noise figure <=5 dB at 100 sessions

A perfect amplifier adds no noise; every real amplifier adds some, measured as the noise figure. The CD1000's noise figure of no more than 5 dB keeps added noise low enough that the amplified signal decodes cleanly rather than arriving louder but garbled, which matters far more at 100 concurrent sessions than at a handful of phones. A high noise figure would raise the indoor noise floor, cause the phone to select a louder but noisier cell, and reduce the usable uplink; a <=5 dB figure is the standard repeater quality level.

Gain is not the same as output power

Gain describes amplification factor; output power describes the fixed ceiling the repeater may transmit at from its indoor antenna. The CD1000 raises gain to recover a fainter donor while holding output at >=20 dBm, rather than over-amplifying into interference; reach through structure and weak-signal recovery come from gain, and the automatic gain control backs off when the donor is strong.

Why >=70/75 dB Gain Is the Flagship: vs CD500 60/65, CD250 60/65, CD200 60/65, CD100 45/50

The CD1000 keeps the >=20 dBm output ceiling of the CD500 rather than raising it, because Ofcom licence-exempt rules cap radiated watts; the commercial upgrade is gain, not louder output. The table below compares the gain and output ladder across the range.

What 70/75 dB of commercial gain does in practice

Gain decides whether a faint donor survives to be repeated at all; output decides how loud the already-recovered field reaches past partitions. The CD500's >=60/65 dB fills 500 m2 from a healthy donor; the CD1000's >=70/75 dB pulls a weaker donor back from the edge and spreads the recovered signal across 1000 m2 through up to four zone antennas for 100 sessions. The extra 10 dB is weak-signal recovery and concrete penetration, not louder distortion, because the <=5 dB noise figure and AGC keep the field clean.

More gain does not raise the Ofcom output ceiling

More gain inside the box does not force the indoor field past the >=20 dBm regulated limit; the automatic gain control balances the two so a 75 dB stage still ends at the controlled ceiling rather than blowing past it. A weak donor needs a better-aimed aerial position and the higher gain, not a higher output that the Ofcom class does not permit.

Ofcom Licence-Exempt Status, UKCA, CE and RoHS Explained

Four marks sit on the CD1000: Ofcom licence-exempt status, UKCA for the UK market, CE for European conformity, and RoHS for restricted hazardous substances. Each answers a different regulatory question, and none changes the tuned bands, the >=70/75 dB gain or the >=20 dBm output figure.

Ofcom licence-exempt and the >=20 dBm ceiling

Ofcom's permitted-class rules allow a low-power indoor repeater on licensed mobile bands without the owner holding a spectrum licence. The CD1000 meets the output and isolation conditions of that class, so no application, fee, annual renewal or registration number is required, provided the unit is used as supplied, kept separated from its own donor antenna, and not modified to raise output. The >=20 dBm figure sits inside this class because the automatic gain control caps the radiated field; the commercial gain recovers the donor but does not lift the watts above the permitted ceiling.

UKCA, CE and RoHS

UKCA confirms the product meets the applicable UK safety, electromagnetic compatibility and radio-equipment requirements for sale in Great Britain after the CE transition, the UK-market conformity declaration appearing on units supplied to UK customers. CE confirms conformity with the European Union Radio Equipment Directive and related health and safety standards, which is why the same kit ships across the EU delivery list including Germany, France, Italy, Spain, the Netherlands, Belgium, Austria, Sweden, Denmark, Finland, Ireland, Portugal, Poland and the Czech Republic as well as the UK. RoHS restricts lead, mercury, cadmium and other hazardous substances in electronics, so the chassis, cable and adapter comply with waste-electrical rules rather than containing banned materials. None of these marks alters how the bands repeat; they confirm the unit may be sold and used without a separate permit.

VoLTE and 2G Voice: How Calls Stay Connected Across 1000 m2

Modern phones place calls over the 4G data layer using Voice over LTE (VoLTE), while older handsets and areas without VoLTE fall back to circuit-switched 2G GSM. The CD1000 supports both routes where the network offers them, but its support differs by band.

VoLTE on Band 20 for O2, Vodafone and Three

Where the host network has enabled VoLTE on Band 20, a modern O2, Vodafone or Three handset places the call inside the boosted 800 MHz LTE session and the CD1000 repeats that session like any other data call. The booster does not negotiate VoLTE itself; the phone and network do, and the unit simply carries the already established 4G call across the large building where the >=75 dB margin reaches.

2G circuit-switched voice on Band 3 for EE

EE maintains a 2G layer in the 1800 MHz region, and the CD1000's Band 3 path repeats circuit-switched voice and SMS for EE, ASDA, BT, Orange, T-Mobile, The People's Operator and Virgin handsets that cannot or do not use VoLTE. A basic feature phone, a guest's handset, or a phone in a VoLTE-not-yet-enabled area still rings and completes a normal call over the boosted 2G layer.

What the CD1000 does not carry for calls

The unit does not tune 3G Band 1 at 2100 MHz, so a network that still routes voice or data fallback through 3G in your location receives no boost on that layer. Where VoLTE is unavailable and the network relies on 3G circuit fallback, a call may not complete indoors even though 4G data shows bars; checking VoLTE support on your handset before ordering avoids that surprise, and the higher gain cannot invent a band the chassis does not tune.

Honest Limitations: No 3G Band 1, No 5G, and Only 1000 m2

A guide that lists only benefits misleads a buyer. The CD1000 has three clear limits that should match your situation before you order, and neither the >=70/75 dB gain nor the >=20 dBm output removes any of them.

No 3G Band 1 at 2100 MHz

The CD1000 tunes only Band 20 and Band 3. It does not repeat Band 1 at 2100 MHz, the 3G UMTS layer some networks still use for data fallback or circuit-switched voice. A site that relies on 3G where 4G fails will see that fallback unboosted indoors; raising gain to 70/75 dB cannot manufacture a band the hardware never receives, and this is the single most important technical limit for areas already served only by Band 20 or Band 3 4G rather than 3G-only locations.

No 5G on any band

The CD1000 does not tune n78 (3.5 GHz), n8 (900 MHz) or any other 5G band, and it does not convert 4G into 5G. A 5G phone still receives its normal unboosted 5G signal from the macro tower, and the CD1000 only lifts the 4G Band 20 plus Band 3 layers. Expect reliable 4G calls and data across 1000 m2, not boosted 5G speeds, no matter how high the gain.

Only 1000 m2 for 100 simultaneous users

The rated footprint of 1000 m2 (10,764 ft2) fits a large office, retail floor, hotel or guest house, warehouse, factory unit, pub or cafe, and supports up to 100 active sessions. A multi-block campus, a factory floor clearly beyond 1000 m2, or a separate linked estate needs a larger unit or a second unit rather than more gain from this chassis. The 100-user count means active calls and data sessions, not every registered device on the premises, and beyond that ceiling the network itself schedules phones.

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