Answer first: the CG1000 is the commercial Band 20+8 repeater for 1000 m²: it lifts O2, Vodafone and Three 4G data through the 800 MHz layer, keeps O2 and Vodafone ordinary 2G voice calls and SMS alive through the 900 MHz layer, with ≥70 dB uplink and ≥75 dB downlink gain about ten times the amplification of a 60/65 dB unit, a fixed ≥20 dBm licence-exempt output, a ≤5 dB noise figure, 1000 m² of indoor space and 100 simultaneous sessions, and an included high-gain Yagi for weak rural donors. It suits the O2 and Vodafone office, hotel, warehouse, retail unit or farm that loses both data and calls inside concrete, metal and render; it does not repeat EE 2G voice on Band 3 at 1800 MHz, does not carry 3G Band 1, does not carry 5G, and stays rated for 1000 m² rather than a multi-building campus.

Band 20 (800 MHz): The Long-Range 4G Layer for O2, Vodafone and Three

Band 20 occupies the 800 MHz spectrum Ofcom freed up after the analogue TV switch-off. Its longer wavelength travels farther from the macro mast, bends around hills and hedgerows, and penetrates brick better than the higher-capacity bands, which is why O2, Vodafone and Three deployed it as the rural and deep-road 4G layer. On a village lane or industrial fringe, Band 20 is the layer that keeps a data session alive between masts where higher bands fade.

Paired transmit and receive frequency blocks for Band 20

A building repeater works on a paired FDD block: the phone transmits on one block and receives on another, and the amplifier repeats both directions without mixing them. The CG1000 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 4G reply amplified across all floors of the 1000 m² site, with the included Yagi aimed at the single rural mast when the donor is faint.

Why 800MHz reaches the far mast but carries less capacity

Lower frequency propagates farther and passes a stone wall, metal sheet or hillside with less loss, but each MHz block carries fewer simultaneous data sessions than the higher bands. Band 20 is therefore the coverage band in the countryside and on the industrial fringe: it keeps a phone connected at the edge of the mast range, while denser town capacity lives on other layers the CG1000 does not tune. A Three user in a Scottish workshop, an O2 giffgaff office in Cornwall, or a Vodafone Lebara retail unit relies on Band 20 being repeated inside; the CG1000 does that on the donor side before the ≥75 dB gain and fixed ≥20 dBm output spread it across the zones.

Band 8 (900 MHz): The O2 and Vodafone 2G Voice and SMS Layer

Band 8 sits at 900 MHz, the original GSM cellular band O2 and Vodafone maintain for circuit-switched 2G voice calls and SMS where VoLTE or 3G fallback is unavailable. Its wavelength passes internal stone, rendered walls, concrete slabs and metal partitions more cheaply than 1800 or 2600 MHz, which is why an ordinary call often rings indoors even when the 4G bar count looks thin.

Paired transmit and receive frequency blocks for Band 8

The CG1000 repeats the 890 to 915 MHz uplink and the 935 to 960 MHz downlink so an O2 or Vodafone handset places and receives a normal circuit call inside the property even where the 4G data layer is weak. This is the feature that separates CG1000 from a Band 20-only box: data alone does not keep a dropped call fixed, and field reports describe O2 calls in Yorkshire stopping dropping once the chassis carried the voice layer.

Why 900MHz survives rendered walls, concrete and metal where a higher data layer fades

Band 8 at 900 MHz and Band 20 at 800 MHz sit close, but the 900 MHz GSM layer has decades of indoor building penetration behind it, travels through solid stone, rendered partitions and warehouse metal with modest loss, and remains the circuit layer older phones dial on. In a shared office, hotel corridor or warehouse where many handsets ring at once, that wall-penetrating call layer matters as much as the data session; the 800 MHz Band 20 carries data over distance on the mast route, the 900 MHz Band 8 keeps the call legible inside, and the commercial chassis runs both at once.

The Unique Band 20 + 8 Combo: 4G Data and Voice From One Commercial Box

Across the Boost4U CG range, Band 20 repeats 4G data and Band 8 repeats 2G voice, and combining them in one chassis is the Band 20+8 defining placement. A Band 20-only unit keeps data but drops the call when VoLTE is unavailable; a Band 8-only unit keeps the call but never accelerates the data session. The CG1000 keeps both across 1000 m², which matches the O2 and Vodafone office, hotel, warehouse, retail unit or farm that complains of both slow internet and dropped calls across many rooms and floors.

UK Network and MVNO Mapping: Which SIM Rides Which Band

The table below maps every SIM named on the CG1000 product page to its host network and the band the booster repeats for it. Before ordering, check the SIM's host carrier rather than the shop brand, because the MVNO name itself does not appear on the tower.

An O2 giffgaff office phone sees both bands light up, a Vodafone Lebara retail handset keeps its circuit call on Band 8, and a Three data-only session rides Band 20 without a Band 8 call path. In a mixed-tenancy building or hotel on two networks, different members benefit from different halves of the chassis, which is the practical reason a dual-band commercial box beats a single-band purchase.

Gain, Output and the +10dB Commercial Step: ≥70/≥75dB Gain With Fixed ≥20dBm

Gain, measured in decibels, is the factor by which the amplifier lifts the weak donor signal before re-radiating it; output power, in decibel-milliwatts, is the transmit level the indoor whip or split branches radiate into the room. The CG1000 carries both: ≥70 dB uplink and ≥75 dB downlink gain recover a faint rural or fringe donor, while a fixed ≥20 dBm spreads the recovered field across 1000 m² for 100 sessions.

What +10dB over a 60/65dB unit means in real amplification

Decibels are logarithmic: a +10 dB step roughly multiplies the recovered field tenfold, so +10 dB from a 60/65 dB gain chassis to 70/75 dB equals about ten times the amplification. That extra recovery is the CG1000's commercial differentiator over the CG500, and it matters specifically on a faint rural or industrial-fringe donor where a 60/65 dB unit stops hearing the control channel; the fixed ≥20 dBm output then distributes what was recovered across four split whips and a hundred shared sessions. The output does not rise with gain, and the AGC balances recovered donor against fixed output as daytime traffic and weather change.

Why 70/75dB gain still pairs with a fixed licence-exempt output

The ≥70/75 dB gain sits in the recovery stage that listens for the faint rooftop donor; the ≥20 dBm output stays fixed inside Ofcom's permitted class and does not rise with gain. Raising gain does not raise output past the limit, and the automatic gain control backs off when a tower looms close and recovers when the donor fades behind a cloud or ridge. The commercial edge is hearing a donor the smaller unit misses, not shouting louder indoors.

Noise figure ≤5dB across 100 shared sessions

A perfect amplifier adds no noise; every real amplifier adds some, measured as the noise figure. The CG1000's ≤5 dB figure keeps added noise low enough that the amplified signal decodes cleanly rather than arriving louder but garbled, which matters when a hundred staff, guests or customers share the building. A high noise figure raises the indoor floor, causes the phone to select a louder but noisier cell, and reduces usable uplink; a ≤5 dB figure is the standard repeater quality level.

Dual-Band CG1000 vs Single-Band C100, the CG500 and the CD1000

The commercial range splits by tuned band, rated size, shared sessions and gain, and choosing the wrong one leaves a whole service, a whole wing or a whole branch absent indoors.

C100: Band 20 alone for data, no circuit call path

The C100 reaches O2, Vodafone and Three 4G on Band 20 alone and suits a data-only site whose calls already ride VoLTE, but it leaves the Band 8 voice layer absent; an older O2 handset without VoLTE sees no boosted call even though data improves, and it cannot serve a 100-user building at all.

CG500 to CG1000: same bands and output, double the area and users, +10dB gain

The CG1000 keeps the identical Band 20+8 combo and the same fixed ≥20 dBm output as the CG500 but adds 500 m² of coverage, 50 users, a +10 dB gain step rising to 70/75 dB (roughly tenfold recovery), a fourth indoor antenna through the splitter, and the same included Yagi. Pick CG500 for a 500 m² office with three whips and CG1000 for a 1000 m² commercial site with four; neither changes which services are carried.

CD1000: Band 20 + Band 3 for EE voice, not O2/Vodafone calls

The CD1000 repeats Band 20 4G plus Band 3 at 1800 MHz for EE 2G voice on the same 1000 m² and 100-user rating, but leaves the O2/Vodafone Band 8 circuit call unboosted. The two units share size, output, gain and the included Yagi but solve opposite voice problems: CG1000 for an O2/Vodafone site, CD1000 for an EE site.

VoLTE and the Band 8 Circuit Fallback

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 CG1000 supports both routes where the network offers them, but its support differs by band.

VoLTE on Band 20 for O2 and Vodafone

Where O2 or Vodafone has enabled VoLTE on Band 20, a modern handset places the call inside the boosted 800 MHz LTE session, and the CG1000 repeats that session like any other data call. The booster does not negotiate VoLTE itself; the phone and network do, and the unit carries the already established 4G call across the building where the ≥20 dBm output reaches.

Band 8 2G fallback where VoLTE is unavailable on a rural site

Where VoLTE is switched off or the phone is older, the call returns to the Band 8 900 MHz circuit layer on 890–915 MHz uplink and 935–960 MHz downlink, which the CG1000 repeats for O2 and Vodafone. In a village or rural estate with VoLTE not yet enabled, a basic feature phone or guest's handset still rings and completes a normal call over the boosted 2G layer rather than dropping to no service indoors, and the 900 MHz path survives the concrete or rendered wall that weakens the 4G session.

What the CG1000 does not carry for calls

The unit does not tune 3G Band 1 at 2100 MHz, so a network that still routes voice fallback through 3G on your street receives no boost on that layer. Where VoLTE is off and the network relies on 3G circuit fallback rather than Band 8, a call may not complete inside even though 4G data shows bars; checking VoLTE support on the handset before ordering avoids that surprise, and neither gain nor output can invent a band the chassis does not tune.

Ofcom Licence-Exempt Status, UKCA, CE and RoHS Alongside the Fixed 20dBm Output

Four marks sit on the CG1000: 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 fixed 20 dBm output figure.

Ofcom licence-exempt and the permitted output class

Ofcom's permitted-class rules allow a low-power fixed repeater on licensed mobile bands without the owner holding a spectrum licence. The CG1000 meets the output, isolation and installation conditions of that class, so no application, fee, annual renewal or registration number is required, provided the unit is used as supplied, the 10 m antenna separation is respected, and it is not modified to raise output. The ≥20 dBm figure sits inside this class rather than above it; the automatic gain control keeps the field balanced, and the commercial gain step compared with a 60/65 dB unit is still a permitted recovery level, not an unlocked amplifier.

UKCA, CE and RoHS

UKCA confirms the product meets the applicable UK safety, electromagnetic compatibility and radio-equipment requirements for sale in Great Britain. 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, cables and adapter comply with waste-electrical rules. None of these marks alters how the bands repeat; they confirm the unit may be sold and used without a separate permit.

Honest Limitations: No 3G Band 1, No 5G, EE Voice Not Carried, 1000m² Only

A guide that lists only benefits misleads a buyer. The CG1000 has four clear limits that should match your site before you order, and neither the 70/75 dB gain nor the fixed 20 dBm output removes any of them.

No 3G Band 1 at 2100 MHz

The CG1000 tunes only Band 20 and Band 8. 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 street or rural site that relies on 3G where 4G fails sees that fallback unboosted indoors; raising gain cannot manufacture a band the hardware never receives.

No 5G on any band

The CG1000 does not tune n78 (3.5 GHz), n8 (900 MHz 5G) 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 CG1000 only lifts the 4G Band 20 data layer plus the Band 8 voice layer. Expect reliable 4G calls and data across 1000 m², not boosted 5G speeds, no matter how high the recovery gain.

EE 2G voice is not carried; 1000m² ceiling

EE runs its 2G voice on Band 3 at 1800 MHz, which the CG1000 does not tune, so an EE member gets 4G data where reach applies but not a boosted EE circuit call; that gap belongs to the CD1000. The rated space is 1000 m² for a large office, multi-floor SME, hotel, warehouse, retail unit or farm estate supporting 100 sessions; it is not a multi-building campus system, and it will not blanket a separate outbuilding, annex across the yard or estate beyond the main footprint. A permanently sited multi-building space clearly beyond 1000 m² needs a dedicated commercial array rather than more output.

Article Keywords

CG1000 Band 20 Band 8 explained, 800MHz 900MHz UK commercial signal booster, 832-862 791-821 MHz B20 O2 Vodafone Three 4G, 890-915 935-960 MHz B8 O2 Vodafone 2G voice SMS, ≥70dB uplink ≥75dB downlink gain 10x vs 60/65dB, ≥20dBm fixed output, ≤5dB noise figure, included Yagi, MVNO giffgaff Tesco Lycamobile Sky Lebara Talkmobile TalkTalk map, dual band vs single band C100, CG1000 vs CG500 vs CD1000 Band 20+3, VoLTE fallback, Ofcom licence-exempt UKCA CE RoHS, 1000m² 100 users UK