Answer first: the CG200 is a plug-and-play dual-band repeater for up to 200 m², repeating Band 20 at 800 MHz for O2, Vodafone and Three 4G data and Band 8 at 900 MHz for O2 and Vodafone 2G voice calls and SMS, with ≥60 dB uplink and ≥65 dB downlink gain, a ≥10 dBm output, a ≤5 dB noise figure and 20 active sessions. The whole job breaks into ten factual steps: (1) read the outdoor 4G signal in dBm at the wall before mounting; (2) fix the 5 dBi omni on the roof edge, gable or chimney stack; (3) lay the 10 m outdoor coax from roof to chassis and the 5 m indoor cable from chassis to whip; (4) hold the omni and whip at least 10 m apart vertically; (5) connect the outdoor cable to BS and the indoor cable to MS; (6) plug the 5 V DC adapter in last; (7) let the automatic gain control warm up for 3 to 5 minutes; (8) read the steady green band LEDs; (9) test a 4G session and a normal call on each floor of the 200 m² plan; (10) confirm the setup holds across 20 users before leaving the bracket alone on an exposed rural rooftop.

CG200 Snapshot Before You Start Fixing the Outdoor Antenna

A short spec table keeps every number this guide relies on in one place. The CG200 delivers uplink gain of at least 60 dB and downlink gain of at least 65 dB on both bands, a maximum output of at least 10 dBm, a noise figure no higher than 5 dB, a rated indoor space of up to 200 m² and 20 active sessions, and ships with both a 10 m outdoor coax and a 5 m indoor cable.

Step 1: Read the Outdoor 4G Signal in dBm at the Wall Before Mounting

A home repeater can only amplify the signal the outdoor antenna actually receives; brick, reinforced concrete, solid stone and a tiled roof all hide the tower from a handheld phone. The pre-mount check happens on foot beside the house, not on the sofa, and it decides where the omni sits and whether the included aerial is enough or the optional Yagi earns its keep. The higher ≥60/65 dB gain recovers a fainter donor than a 45/50 dB unit, but it still cannot manufacture a band the survey never picked up.

The dBm ranges the CG200 expects at the outdoor antenna

-97 dBm on 4G reads as a healthy rooftop donor that the ≥65 dB downlink gain and ≥10 dBm output turn into a usable indoor signal across both floors. -105 dBm sits at the edge of the recommended band and still produces a stable data session once the omni clears the wall; the extra gain absorbs aerial loss, rendered stone and the pitch-side shelter more comfortably than a lower-rated unit. -112 dBm on 4G is the practical floor: roughly -112 dBm the LTE receiver loses the control channel, the phone falls back to a slower service or shows no service, and no booster manufactures a donor the outdoor antenna never receives. The ≥60 dB uplink gain recovers a weak outdoor donor better than holding a phone to the glass, but it cannot invent a band the survey never found.

How to read dBm rather than bars in a home survey

Phone bars are subjective and differ between iPhone and Android; the dBm figure is the measurement the amplifier actually sees. On an iPhone, enter field-test mode from the dialler and watch the RSRP value while standing beside the house. On Android, use the engineering or network diagnostics menu, or a free field-test app that lists RSRP by band. Hold the phone away from your body, because a hand and head absorb 3 to 5 dB, and read the value on the side of the house facing the nearest mast rather than the sheltered courtyard side.

Where to survey: roadside, side wall, garden gable, layby

Stand on the roof-facing side of the house, the open garden side at the rear, and the far side of the driveway; record the reading for your own SIM and a household member on a different network, because the strongest combined spot is where the omni goes. On a rural lane the open gable or roof edge usually beats the side sheltered by a hedge or a barn; on a town house the hard side facing the street typically beats the enclosed courtyard. Survey warning: if your Band 20 reads below -112 dBm at every position beside the house, the CG200 cannot manufacture that band inside. You may still improve voice on the other network's service, but the missing 4G stays missing; in that case re-check facing the proper mast rather than expecting the amplifier to close the gap by itself.

Step 2: Mount the 5 dBi Omni-Directional Antenna for an Open Horizon

The 5 dBi omni outdoor antenna gathers signal equally from all horizontal directions rather than focusing one narrow beam, which suits a home where the usable O2 or Vodafone mast can sit in any compass direction. On a tiled or slated roof it fixes without drilling tiles; on a chimney stack, gable wall or fascia it uses the supplied bracket; on a flat roof the weighted base or adhesive pad settles the omni in clear air.

Roof edge or gable: clear sky line over 3 to 5 metres height

Wipe the roof or stack clean, peel the adhesive pad or bolt the small bracket, and press or fix the omni to the roof edge, chimney breast or gable, away from roof rails, satellite dishes, vent pipes and the TV aerial. Keep the omni at least 3 metres above any roof-mounted clutter, ideally 3 to 5 metres up, because metal near the base absorbs the 5 dBi pickup. The roof-edge position favours an all-round donor on a rural lane; the central ridge position balances all directions for a town house. Keep the omni at least a metre clear of roof-mounted air horns, spotlights and satellite dishes, because metal near the base defeats the omni pickup.

Solid chimney, rendered wall or fascia: bracket rather than suction

A suction cup holds on a smooth tiled roof for short jobs but weathers; a permanent fix uses the small screw bracket on a brick gable, chimney stack or painted fascia. Drill a 6 mm pilot hole through the rendered wall, fit the wall plug, screw the bracket level, then clip the omni onto it. Never rely on an adhesive pad on a windy exposed ridge without the bracket as backup. The omni points straight up by design; do not tilt it toward the mast unless you have switched to the directional Yagi, because tilting an omni cancels part of its circular pattern.

When the omni falls short: the optional high-gain Yagi

Where the donor sits at -105 to -112 dBm on one identifiable mast, the omni's all-round pattern wastes half its pickup in open sky; the optional high-gain Yagi focuses a narrow beam straight at that tower and recovers several decibels more. This is the weak-donor upgrade, not a requirement for a normal suburban home, and this guide returns to the Yagi trigger in the rural optimisation section below.

Step 3: Route the 10 m Outdoor Coax and the Separate 5 m Indoor Cable

The CG200 ships two cables rather than one: the 10 m outdoor low-loss coaxial cable carries the recovered donor from the roof to the booster chassis, and the separate 5 m indoor cable carries the amplified field from the chassis to the 3 dBi whip. Keeping them separate means the outdoor feed stays low-loss on the long roof run, while the short indoor lead keeps the whip flexible around the room plan.

What the 10 m outdoor coax reaches

A 10 m outdoor run comfortably reaches a first-floor chassis position from the eaves or a two-storey landing from the rear gable, and it crosses a normal loft into a central cupboard or under-stairs location without splitter loss. Measure the wall-to-chassis distance before unboxing, because an outdoor cable that ends short on the loft floor cannot be stretched without a connector; the 20, 30, 40 and 50 m upgrade options exist for a longhouse roof on the far side of the plot.

What the 5 m indoor cable does, and why it is shorter

The 5 m indoor cable runs from the MS port to the whip, which stands near the centre of the 200 m² lived zone rather than beside the chassis. A short indoor lead keeps amplified loss low on the way to the radiator; the whip then spreads the ≥10 dBm field across the rooms. On a two-storey home the chassis sits on the ground-floor hall and the whip stands in the central landing or living room within those 5 m, rather than dragging the outdoor cable indoors.

Cable upgrades for a long outdoor run: 20 m, 30 m, 40 m, 50 m

Every extra outdoor metre adds cable loss, which is why the 30 to 50 m upgrades assume a donor healthier than -105 dBm; pairing a long thin run with a -110 dBm donor starves the booster even at ≥65 dB gain. The optional surge protector adds a fuse point at the outdoor end for exposed rural roofs and sits in series before the booster rather than replacing any connector. The indoor 5 m lead does not get an upgrade in the standard box; if the whip must sit far from the chassis, reposition the chassis nearer the zone instead.

Route both cables: loft, sealed window bush or drilled wall entry

Feed the outdoor coax through the loft void rather than down a rain gutter, keep bends smooth and larger than the hand-sized radius, avoid sharp kinks around a joist, and enter the building through a blanking bush in a drilled wall or a sealed window gap rather than pinching it under a closing sash. Run the 5 m indoor cable along a skirting or under a stair carpet, and keep it clear of power leads and metal conduit where it can. Seal the outdoor entry point with the supplied grommet or silicone to keep weather and draughts out, and leave a service loop of 30 cm at both ends so the booster can be moved without cutting either lead.

Step 4: Keep the Outdoor Omni and Indoor Whip at Least 10 m Apart

The minimum antenna separation of 10 m vertical between the outdoor donor antenna and the indoor server whip protects the amplifier from feedback. When the indoor whip radiates into the outdoor omni, the chassis hears its own output as an extra donor, raises gain, hears it again, and oscillates into an unstable state; the 10 m gap plus building mass breaks that loop. With ≥60/65 dB gain the chassis amplifies harder than a lower-rated unit, so the feedback loop forms more readily when the two antennas sit close, which makes the separation rule non-negotiable rather than optional.

Why 10 m, and why vertical beats horizontal on a two-storey home

On a two-storey home the omni sits on the ridge and the whip stands on the ground-floor hall or central landing, giving a vertical drop of roughly 10 m through at least one ceiling and a wall; on a bungalow extended across 200 m² the omni fixes high on the gable while the whip stays in the far living zone. A horizontal separation across one open floor fails because line-of-sight feedback leaks across the same ceiling height, so climb rather than slide the two antennas apart when the plan allows.

What too-close installation looks like on the LEDs

If the two antennas sit closer than 10 m, the AGC backs off hard, the band LEDs flicker or stay dim, the indoor signal jumps between strong and dead across the rooms, and calls break up the moment you move near the whip. Moving the whip a floor down or the omni higher on the stack clears the oscillation faster than turning gain up manually, because this unit sets gain itself.

Step 5: Connect the BS and MS Ports Across the Two Cables

The booster chassis carries two labelled sockets: BS (base station, the outdoor donor port) and MS (mobile station, the indoor server port). The 10 m outdoor omni cable lands on BS, and the 5 m indoor whip cable lands on MS. Each connector finger-tightens; do not force a threaded SMA, and do not swap the two because the labels describe the direction of amplification.

BS: where the 10 m outdoor antenna cable plugs in

The BS port accepts the 10 m outdoor coax from the roof omni and carries the faint recovered donor into the amplifier. Route the cable to BS first, finger-tighten the adapter, and give the plug a light clockwise turn until firm; overtightening strips the SMA thread on a plastic-faced chassis.

MS: where the 5 m indoor whip cable plugs in

The MS port accepts the short 5 m whip lead and radiates the ≥10 dBm recovered field into the lived zone. The whip stands upright on its small base near the centre of the 200 m² plan, away from a metal filing cabinet, a steel desk frame and a wall-mounted TV, which all absorb the 3 dBi spread.

Swapping the two and what it looks like

If the roof cable lands on MS and the whip cable on BS, the weak donor is sent to the whip as if it were output, and the amplified field feeds back toward the omni; the LEDs stay dim or flicker and both floors show no improvement. Match the labelled ports, check once more before powering on, and record the pairing on the small service sticker.

Step 6: Power-On Sequence and the 5 V DC Adapter

The CG200 runs from an AC 100–240 V 50/60 Hz to DC 5 V adapter with a UK 3-pin plug. The sequence matters: connect both antennas and both cables before applying power, because a chassis driven with only the indoor whip connected can oscillate, and the automatic gain control reads the real donor only when both ends are live.

Order: antennas and cables first, adapter last

Step A: plug the 10 m outdoor omni cable into BS and the 5 m indoor whip cable into MS. Step B: place the whip in the centre of the 200 m² seating zone on its stand. Step C: plug the 5 V DC barrel into the booster, then plug the UK adapter into the wall. Step D: switch on at the wall; never connect the adapter while the whip is close to the omni.

Automatic gain control warm-up of 3 to 5 minutes

On switch-on the AGC scans the donor, measures path loss and sets the uplink and downlink level by itself for 3 to 5 minutes; do not adjust anything during this window. At ≥60/65 dB the controller has more headroom to balance, so it backs off when a tower looms close and recovers when the donor fades behind a cloud or roof, and it settles to a steady green once locked to the nearest Band 20 cell and the Band 8 voice layer.

Step 7: Read the Band LEDs After the AGC Settles

After warm-up the front-panel LEDs report the locked bands rather than the phone's subjective bars. A steady green on the Band 20 LED means the 800 MHz 4G layer is locked; a steady green on the Band 8 LED means the 900 MHz voice layer is carrying O2 or Vodafone calls; a flashing light means weak donor, searching, or the whip sitting too near the omni.

Step 8: Test Every Zone of 200 m² for 20 Simultaneous Users

The rated space of 200 m² covers a two-bedroom flat, a small family home or a small office; the 20-user count means 20 active calls and data sessions, not every registered device on the household bill. Test with real phones rather than trust the LEDs alone, because the far upstairs corner is where a two-storey install fails.

Zone map: ground hall, living room, kitchen, landing, both bedrooms

Walk the zone at a time: stand by the whip for the baseline, then move to the far living-room corner, the kitchen through an internal wall, the upstairs landing, bedroom one, and bedroom two. At each point run a 4G speed check, open a browser session, place a normal O2 or Vodafone voice call, and read the RSRP; the goal is a steady 4 to 5 bars and a call that does not drop after 2 minutes on each floor.

Running 20 users without a paid test lab

Gather family members or colleagues on O2, Vodafone and an MVNO such as giffgaff, Tesco or Lebara, place ten simultaneous calls and open ten background data sessions, then walk the far upstairs corner together. The ≥10 dBm output spreads enough field for 20 sessions across 200 m²; more than that count pushes the AGC to its limit and the far edge thins out, which is a coverage ceiling rather than a fault.

Before-and-after bar comparison

Record the bare-handset reading at the far bedroom corner before the booster runs, then repeat with the unit locked; field reports describe a move from one bar to full five bars in a Devon cottage, dropped O2 calls stopping in Yorkshire, and reliable 4G arriving in a rural village after three years without. Those reports describe the typical result, not a guarantee for a donor the survey never found.

200 m² Coverage Tuning and the Second Indoor Antenna

A 200 m² plan rarely fills evenly from one whip, so tuning the room layout matters as much as mounting the omni.

Whip placement: central landings beat hallway corners

Stand the whip on a bookshelf or a small stand near the centre of the lived area, not against an exterior stone wall and not inside a metal cupboard. A central landing on a two-storey home lets the field bleed both downstairs and upstairs; a hallway corner wastes half the signal into the front door. Keep the whip upright, clear of curtain fabric, and within the 5 m indoor lead.

Expandable coverage: add a second indoor antenna where the donor is strong

The product page states that coverage is expandable by adding an indoor antenna if the outside signal is strong. Where the donor reads -70 to -90 dBm, a splitter feeds a second 3 dBi whip into the far bedroom or adjoining zone, up to a total of two indoor antennas, extending the field to a second area rather than enlarging the 200 m² ceiling. This expansion needs a healthy donor; with a faint donor the split thins both whips and helps no one.

10–15 Minute Installation Timeline and Tools

The basic plug-and-play setup takes 10 to 15 minutes; a wall-bracket or cable-upgrade route adds 20 to 30 minutes for drilling and sealing. The table below budgets each step for a first-time installer.

Basic tools for a basic install

No electrician is needed: a tape measure, a step ladder, a pencil, a blanking bush or silicone sealant, and a phone with field-test mode. A permanent wall bracket adds a 6 mm masonry drill, wall plug and screwdriver; the surge protector adds an in-line fuse at the outdoor end. No soldering, no crimping and no network configuration is involved, because the unit sets its own gain and locks the donor automatically.

Rural Weak-Signal Optimisation and the Yagi Trigger

A rural cottage often reads a weaker donor than a suburban flat, and two adjustments recover what the omni misses without changing the booster itself.

Yagi trigger: -105 to -112 dBm on one clear mast

When the survey reads -105 to -112 dBm on a single identifiable Band 20 mast and the omni cannot hold a steady green, swap to the optional high-gain directional Yagi, aim it at that tower over the hill line, and re-check the AGC. The ≥60/65 dB gain inside the chassis already recovers more than a lower unit, but the Yagi concentrates the pickup the omni spreads around; it suits a lone mast, not a town served by several towers in different directions, where the omni's all-round pattern is the better fit.

Long-cable and donor checks before buying more

Before ordering a longer 30 to 50 m outdoor cable, confirm the donor on the intended roof point first; a long run with a weak edge signal wastes the extra dB in feed loss rather than the air. Keep the outdoor omni clear of the chimney stack top, where metal and mortar reflect the pattern, and re-survey after clearing a hedge or pruning a tree line, which often adds 3 to 5 dB the omni can use without any new hardware.

What the CG200 Cannot Fix at Install Time

An honest guide names the ceiling before the purchase. The CG200 repeats Band 20 4G data and Band 8 voice only; it does not manufacture 3G Band 1 at 2100 MHz, does not carry any 5G band, and is rated for 200 m² rather than a whole house or a farmyard. A donor below -112 dBm on every side stays missing, a metal-clad outbuilding with no line to the mast cannot be reached by a longer cable alone, and more than 20 simultaneous sessions thin the far edge. Where those limits bite, a larger rated model rather than a louder setting is the answer; this unit sets gain itself and cannot be opened up beyond its licence-exempt class.

Article Keywords

CG200 installation guide UK, dual-band signal booster 200m² setup, outdoor omni antenna roof gable placement, 10m outdoor low-loss coax plus 5m indoor whip cable routing, BS MS booster ports, 5V DC adapter power-on sequence, 10m vertical antenna separation, 20 simultaneous users, two-bedroom flat small family home zone tuning, rural weak signal Yagi upgrade, second indoor antenna expansion O2 Vodafone UK