30dBm GSM Repeater /Line Amplifier/ Mobile Signal Repeater (GW-30LAG)

Product Overview

An in-building coverage system only delivers what survives the trip from the source to the antenna. Long feeder runs, power splitters and directional couplers each take a share of the signal, and in a large building those shares add up to the difference between a clear call and a dropped one. This 30 dBm GSM line amplifier makes up that loss: it takes the output of a base station (BTS) or a repeater, restores it to working level, and passes it on to the distribution network that feeds the indoor antennas.

Installers add it to a system that already has a signal source rather than using it on its own. A repeater can stay in one equipment room while the amplifier, placed further along the chain, puts back what the cabling has taken; together they cover a building that neither would cover comfortably alone. That is what makes a centralised mobile signal booster layout practical in a large property, where running a second repeater to every floor is neither inexpensive nor easy to maintain.

In an indoor cell phone signal booster system this is often the component left out of the first design and added when one floor tests weaker than the rest. It goes in at the point where the chain needs help, not at a fixed position, and the goal is straightforward: meet the field strength the coverage plan asks for at the antenna, rather than back in the equipment room.

Key Features

• 30 dBm of GSM output. The amplifier delivers 30 dBm in the GSM band, the power class used for in-building distribution runs where the source is healthy but the cable network between the source and the antennas is long.
• Built around distribution loss. Its design target is the system loss created by in-building distributing cable, power splitters and directional couplers, so the level arriving at the antenna stays close to what the coverage plan assumed.
• High linear design with ALC. Automatic level control holds the output steady when the incoming signal drifts, and the linear amplifier stage keeps interference back at the base station low. Those two behaviours are what keep a cell signal booster installation stable after commissioning rather than only on the day it was set up.
• A less expensive answer to a weak zone. Where the source is fine and the far end of the building is not, adding amplification to the existing chain usually costs less than commissioning another repeater, and it leaves the original installation untouched.
• Compact and low consumption. The case is small enough for a riser, a wall position or a communications cabinet, and the ribbed metal top works as the heatsink, so heat leaves through the housing surface instead of sitting inside the case.
• Works with the devices people carry. Voice, data and video on handsets and other cellular devices inside the covered area, with nothing to configure on the phone itself.
• Straightforward to install. A matched AC adapter, an installation kit and a printed manual come with the unit, so the work on site is a supply connection, a run from the source and a run into the distribution network.

Placement in the Signal Chain

A typical chain runs: donor antenna on the roof, repeater or base station output, line amplifier, power splitter, directional couplers, then the indoor service antennas. Everything after the source takes signal away. The amplifier is fitted where the accumulated loss would otherwise leave the last antennas starved, usually between the repeater output and the first splitter and sometimes further down a long riser run. In a small single-antenna mobile signal booster installation there is often nothing for it to do; in a multi-floor building it is the difference between even coverage and a strong corridor with dead offices behind it.

Placement is a design decision rather than a fixed rule. A two-way splitter divides what reaches it between two outputs, a four-way splitter divides it four ways, and a directional coupler taps a proportion of the line while passing the rest. Put the amplifier before those devices and every downstream antenna benefits; put it after them and you have amplified an already-divided signal. That is why the same unit can be exactly right in one building and unnecessary in the next, and why the loss budget rather than the floor area decides where it goes.

The other thing this stage buys is design freedom. With amplification available mid-chain, a project can run one centralised repeater and a longer feeder network instead of several smaller repeaters on different floors, which simplifies power, monitoring and maintenance and lets the coverage design follow the shape of the building. If a mobile phone signal booster is already installed and the upper floors still test weak, adding an amplifier at the right point is usually less disruptive than commissioning a second one, because the existing hardware, cabling and approvals stay as they are.

Specifications

Typical Installations

• Hotels. Guest floors are fed from one equipment room and the run to the last wing is long, so the level reaching the end-of-corridor antennas is what guests judge the hotel by. The amplifier goes in ahead of the floor splitters so the last rooms behave like the first ones.
• Offices. Open floors, meeting rooms and several splitter stages sit between the equipment room and the desks. One amplifier before the splitter network keeps the far side of the floor usable, which is the part a cell signal booster installation is usually judged on.
• Shopping malls. Wide floors under low ceilings need many small antennas rather than a few large ones, and every split costs level. Amplifying before the split means each antenna receives enough to radiate instead of the cable taking the budget.
• Basements and parking levels. These sit furthest from the donor side and are the first areas to fail. The amplifier is fitted before the run goes down, so what arrives at the basement antennas is still worth transmitting.
• Homes and apartment blocks. The same problem at a smaller scale: a repeater in one room and a feeder to the others. Fitting the amplifier keeps the second and third rooms from being decorative.
• Buildings with one central repeater. Where it is simpler to run a single feeder and amplify downstream than to add a second repeater, this is the component that makes that layout work in an indoor cell phone signal booster system.

Installation & Commissioning

1. Walk the route before anything is mounted, from the donor side through the repeater to the splitter, noting where the amplifier will sit, how the cable arrives and where the nearest AC outlet is.
2. Check the loss budget for the antenna you are most worried about, adding up cable, splitter and coupler loss between the source and that antenna, and confirm the 30 dBm output covers it with margin. If you would rather have the figures reviewed, send them over before the unit goes on the wall.
3. Fix the unit indoors, close to the splitter or at the point in the riser where the run changes direction, with air space around the ribbed housing and enough room to reach the connections.
4. Connect the source side first: repeater or BTS output into the amplifier input, keeping the jumper short and every connector properly terminated.
5. Connect the distribution side from the amplifier output into the splitter or coupler network, then check that each antenna feed is sound before powering anything up.
6. Power up with the supplied adapter and let the automatic level control settle. If the level cannot be brought into range, the input is either too weak or too strong and the placement needs revisiting rather than the gain being pushed.
7. Test with a handset at the farthest antenna. A call and a data session on a real phone is the check that matters, and the far antenna should now behave like the ones near the equipment room, which is the whole point of adding this stage to a mobile phone signal booster system.
8. Record the work: amplifier position, cable routes, the levels you measured and a copy of the manual, so the next technician starts from a known state instead of from memory.

Standard Package

Each unit ships as a working kit rather than a bare box. Inside are the AC 90–264 V to DC 9 V/5 A power adapter, an AC power cord in the standard you specify — EU, US, UK, SA or China — an installation kit and a printed user manual. The adapter's wide input range means the same unit travels to most markets; only the cord changes, which is why the cord standard is worth stating clearly at the time of order.

The front panel keeps the connections and controls together, with the DC input, the power switch and the indicator area on one face, so commissioning and later checks happen from one side of the unit. The ribbed top is the heatsink and should stay clear: do not stack paperwork, spare cable or tools on it, and leave a little air around the case, especially inside a closed cabinet.

On arrival, look over the carton for transit damage before signing, confirm the cord matches the standard you ordered, and make sure the installation kit and manual are present. If anything is missing or the case shows impact damage, photograph it and speak to your sales contact before the unit is mounted, because it is far easier to sort out before installation than after.

Ordering & Delivery

• Band and site details. Tell us the band you are amplifying, whether the source is a base station or a repeater, roughly how many antenna points sit downstream and what the building is used for. That is enough for us to confirm whether this 30 dBm GSM model fits your coverage plan or whether your network calls for a different amplifier.
• Cord standard. Confirm EU, US, UK, SA or China when you order so the right cord is packed; this is the one item that changes with destination.
• Quantity and site count. Let us know how many points in the chain need amplification and whether the order covers one building or several, so the packing and the schedule match the project.
• Lead time. Ask for the current lead time for your quantity and destination before you set an installation date; it is quoted per order rather than fixed in advance.
• Shipping and packing. Agree the shipping terms and the packing you need for transport, whether that is a single export carton or consolidated packing for a project, with your sales contact.
• Documentation. The user manual ships with every unit. If your project files need anything else, say so before the order is confirmed and we will tell you what can be provided with the shipment.
• Service. Ask how service and replacement are handled for your order so the arrangement is clear before the kit leaves us.
• Local approval. Repeater and amplifier deployment rules differ between markets. Check what your operator or regulator requires before installation day, and tell us early if your project needs specific paperwork.

Line Amplifier Comparison

Technical Support & Model Matching

Getting the right model matters more than anything else, so Greetwin builds technical support into every order. Tell us the band, the site and the coverage you need, and our engineers will match a model to it, check gain and output power against your installation, and say plainly when something will not fit. We also advise on antenna placement, cabling and commissioning, then stay with you through troubleshooting once the system is running. All of this is backed by our ISO 9001 certified production in Shenzhen, responsive after-sales service and spare parts.

FAQ