Answer first: fix the 5 dBi omni high on the roof or an outside wall at least 10 m vertically above and separated from the indoor whip, run the included 10 m low-loss coax through a sealed entry, plug the outdoor lead into the BS donor port and the whip into the MS server port, power the 5V DC adapter after both antennas are connected, read the steady LED, and test data plus 3G calls across the room with up to 10 handsets; the job takes 10 to 15 minutes with no tools, a weak rural donor triggers the paid Yagi upgrade, a long roof reach triggers the 20 to 50 m cable upgrade, and a strong outside reading funds a 2-way splitter with a second indoor antenna. The CW100 suits an EE, O2, Vodafone or Three household or small office that loses 4G data and the 3G fallback indoors; it does not carry 2G voice on Band 8 or Band 3, does not do 5G, and stays rated for 100 m² rather than a whole large house.

What Comes in the CW100 Kit Before You Start

Confirm the box before the first hole or bracket. The standard CW100 kit contains the booster chassis, the outdoor 5 dBi omni antenna, the indoor 3 dBi whip, the 10 m low-loss coaxial feed, and the UK 5V DC power adapter; the high-gain Yagi directional aerial, the 20/30/40/50 m external cable, the 18KA lightning surge protector and the splitter with a second antenna are ordered upgrades rather than standard parts.

Tools you actually need

No crimping or soldering is required for the standard install: a drill or bracket for the wall mount, a sealed entry grommet for the cable, a phone field-strength read-out for the spot check, and a spirit level for the roof omni. Keep the 10 m feed coiled loosely rather than twisted, place the whip where it will not be hidden behind a bookcase or metal appliance, and survey the outside donor reading before choosing the omni, Yagi, cable length or splitter.

Step 1: Outdoor Omni Placement and the 10m Vertical Isolation Rule

The 5 dBi omni captures the outside donor before the roof, wall and floor slab shield it, and its height and separation decide whether the CW100 works without feeding itself. Fix it high on the chimney stack, roof ridge or a gable wall where it sees the widest sky in the direction of the mast, rather than tucked under the eaves or behind a tall hedge.

High and clear beats hidden and low

A high omni on the ridge gives a 360° view in all directions; a position under the eaves or behind a chimney blocks one horizon and cuts the donor reading. On a rural cottage in Devon, Norfolk or Cornwall, walk the roof or garden with the phone and mark the spot where the bar count and RSRP are strongest before fixing; the omni should sit where that reading peaks, not simply where a bracket is easiest to reach.

10m vertical separation between donor and whip

Keep the outdoor omni at least 10 m vertically above the indoor whip and on the opposite face of the building where possible. This gap, the antenna isolation, stops the whip radiating the amplified field straight back into the donor omni, which would make the chassis feed its own output and oscillate. In a small flat where 10 m is impossible, place the omni on the street-facing wall and the whip on the rear room, maximise the physical gap, and keep the two antennas on opposite sides; a tight separation lowers the gain you can safely use and may require the Yagi to focus the donor rather than the omni radiating broadly.

Step 2: Route the 10m Feed and Choose a Longer Cable Upgrade

The omni connects to the chassis by the included 10 m low-loss coax, routed from the mounting point through a sealed roof or wall entry to the chassis indoors. Every metre spends signal, so route the shortest practical path and avoid sharp bends that compress the shield.

Sealed entry and tidy routing

Pass the coax through a sealed grommet or drill a small angled hole with a drip loop below the entry so rain runs away rather than down the wire. Keep the feed clear of mains wiring, TV aerial coax and metal ducting, which can inject noise, and avoid tight coils beside the chassis where the bundle distorts the field. Terminate at the wall plate or chassis with a firm connector; a loose BS connection is the most common dark-LED cause.

When the 20/30/40/50m upgrade applies

Where the donor-strong roof point sits more than 10 m from the proposed chassis room, order the 20, 30, 40 or 50 m external cable upgrade instead of splicing the standard lead; a spliced joint adds mismatch and water risk, and a longer low-loss run preserves the signal better than a join. A Wales home office that needed a much longer run to reach the roof saw the reading go solid once the feed matched the reach, which is the pattern: choose the upgrade by measured distance, not guesswork, and keep the longest run on the BS donor side where loss matters most.

Step 3: Chassis Placement and the BS versus MS Ports

The compact chassis sits in a airing cupboard, wall cupboard, under a desk or on a shelf in the covered room, kept ventilated and away from direct heat. The two ports are labelled, and swapping them inverts the loop and causes oscillation, so match lead to port on the first attempt.

Why a port swap causes a loop

If the omni feed plugs into MS and the whip into BS, the interior whip radiates straight back into the donor antenna, the chassis feeds its own output, and automatic gain control drives gain toward oscillation until the LED flickers and the room drops. The fix is to swap the two leads; once BS carries the outside donor and MS carries the indoor whip, the two antennas face opposite environments and the loop stays open. Keep the whip upright on a shelf or stand, not pressed against the omni feed or a metal cabinet.

Where the whip radiates best

The 3 dBi whip radiates the amplified field across the covered living room, kitchen or desk; place it centrally rather than tucked behind a sofa, where furniture masks the reach. Coverage is rated to 100 m² for one room or a small connected space, and a far corner or a second room that reads light is the reason to add a second antenna through the splitter rather than moving the whip endlessly.

Step 4: 5V DC Power, Power-On Order and the LEDs

The chassis runs from the included UK adapter converting AC 100-240V to DC 5V, and the order matters: mount and connect both antennas before powering on, so the gain stage does not latch into a self-fed loop the moment it wakes.

Correct power-on sequence

First the outdoor omni or Yagi is fixed and the feed reaches the BS port; second the 3 dBi whip connects to the MS port; only then the 5V DC adapter receives mains power. Powering up before the MS whip is connected lets the chassis radiate into an open port and can trigger oscillation; matching the antennas first lets automatic gain control settle on the real outside donor rather than its own leak. Wait ten seconds after power before judging the LED.

Reading the status LEDs

A steady bright LED on the chassis confirms both Band 20 and Band 1 are locked and the gain stage has settled; a flickering or climbing pattern points to oscillation, a port swap or an overloaded donor, while a permanently dark LED with power present means a loose BS lead, a blown adapter fuse or a donor absent outside. As the outside signal swings with weather and traffic, the LED may dim momentarily as the gain rebalances, which is normal; keep the adapter earthed and add the 18KA surge protector where lightning exposure on the roof run justifies it.

The 18KA surge protector on the roof run

For a tall chimney mount, an exposed gable or a rural property prone to storms, the optional 18KA lightning surge protector sits on the coax between the omni and the chassis, diverting a static or lightning spike away from the indoor electronics. It does not improve signal and is not required on a sheltered mid-wall install, but it protects the long outdoor run and the chassis where the aerial stands highest on the property.

When to Add the Yagi Directional Aerial for Weak Signal

The standard omni works where the outside reading already lands around -90 dBm or better on the wall; where the cottage sits in a deep valley, a Scottish glen, Welsh valley or Cornish lane and the outside reads below -100 dBm on one visible tower, the omni averages many directions and misses the single mast, so the paid high-gain Yagi becomes the right move.

Donor readings that trigger the Yagi

A reading between -90 and -105 dBm on a single visible tower favours the aimed Yagi over the omni: the directional panel focuses the narrow beam on that one mast, rejects clutter from other directions, and recovers a control channel the omni averages away. Aim it at the tower the phone selects on the outside reading and re-check the LED after locking the beam. Below -112 dBm, where no tower decodes at all, no aerial manufactures a signal and a dedicated fixed multi-array system applies instead.

Do not over-aim a town property

On an estate or town street with many masts and a strong donor, the flexible omni suits the property and a fixed Yagi must be re-aimed as the nearest tower changes; the Yagi suits the rural weak-signal cottage, farm edge or workshop where one consistent mast carries the service. The upgrade changes the capture side only; it does not raise the ≥10 dBm output past the class or extend beyond the 100 m² rating.

Splitter Expansion: Two Indoor Antennas When the Outside Signal Is Strong

The CW100 page states, verbatim, "Expandable coverage by adding indoor antenna, splitter, cable if the outside signal is strong." That condition matters: a weak donor cannot afford split loss, and only a strong outside reading funds a second whip.

How the 2-way splitter adds a second room

When the roof omni reads strong, fit a 2-way splitter on the MS side after the chassis, run an extra low-loss cable to a second whip in the next room or through a doorway, and balance the two branches. Each division spends radiated power, so the second antenna only reaches its room while the donor stays strong; a weak outside signal after splitting produces two lighter readings rather than one solid one. Keep both whips separated from the omni and from each other so neither feeds the other, and measure each room before committing the second cable.

When not to split

A donor between -100 and -112 dBm already strains a single whip, and adding a splitter halves the field without adding reach; in that case aim the Yagi first, improve the roof position, or step to a higher-rated model rather than dividing a weak signal. Splitting is an expansion of a strong baseline, never a rescue for a faint donor.

The 10-User Test: 4G Data and 3G Calls Across 100m²

The CW100 supports up to 10 simultaneous handsets across a 100 m² room or small flat; the acceptance test checks that the living area, kitchen corner and desk all hold a 4G session and a 3G call at once rather than one phone beside the whip.

How to run the test

Place mixed handsets on EE, O2, Vodafone, Three, giffgaff, Tesco, Sky and Smarty SIMs across the room, desk and kitchen; start a data session on one group and a voice call on another, hold both for a minute, then walk the reading around the space. Record the bar count before fitting, after fitting near the whip, and after fitting at the far corner; a Devon cottage that went from one bar to full five on EE, a Yorkshire O2 home whose calls stopped dropping, and a Cornwall home office whose video calls stopped freezing match the reported pattern. With 10 users in a small office, stagger sessions so the gain stage balances the load rather than piling every handset on the whip.

Expected coverage by space

CW100 Against the Same-Price Range: Why Band 20+1 Adds 3G All-Networks

The Boost4U 100 m² range splits by tuned band at the same price, and choosing the wrong pair leaves a whole service absent indoors.

The CG100 keeps O2/Vodafone 4G plus a 2G circuit call but leaves the all-network 3G layer absent; the CD100 keeps 4G families but carries neither 3G fallback nor a dedicated call band. The CW100 sits between them for the household that wants 4G data plus a working 3G layer across EE, O2, Vodafone and Three where 4G fades, with the same 45/50 dB gain, ≥10 dBm output, 10 users and 100 m².

Troubleshooting: Oscillation, No Signal and the LED Read-Out

Oscillation: looped field and flickering LED

The symptom is a flickering or climbing LED, a reading strong beside the whip but a step away falling, and dropped sessions despite power. Causes are a BS/MS port swap, the whip too close to the omni feed, or insufficient 10 m isolation letting the chassis feed itself. Fix the ports, increase the separation, move the whip to the opposite room, and let gain settle rather than driving into the loop.

No signal at all: dark LED and loose leads

A dark LED with the adapter live points to a loose BS connector, a blown adapter fuse, or the omni mounted where no donor exists. Reseat both connectors, try another socket, verify the phone reads bars outside first; if the phone reads zero on the roof, the booster cannot recover a block absent from the tower.

Weak far corner, dead valley and mains noise

A lighter far corner comes from the whip offset toward one wall; move it central, or split to a second antenna only on a strong donor. A dead valley below the decode floor needs the Yagi or a fixed system rather than another whip indoors. Hum following the mains points to the coax running beside the power loom; separate the feed and re-check.

Article Keywords

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