There are many names for an indoor cell extender. It is commonly referred to as a Cell Booster, but it is actually a fully functional low power cell phone repeater. The industry refers to it as a mini, pico or SOHO repeater or cell extender. There are types of indoor and outdoor. There are different formats like CDMA, GSM, DSC, UMTS. There are also combinations of the aforementioned frequency formats and they are known as dual and even triple band repeaters. All repeaters should be considered the responsibility of the network operator. The network and frequency spectrum are their licensed property on which they provide specific services and for which the end user pays revenue. The quality of the equipment used in these networks is their responsibility, as well as providing coverage everywhere. Installations of any kind must be performed by a fully qualified network technician or designated contractor.
Should a residence or business not have indoor cell phone coverage, should you consult your preferred network operator whose services have been assigned before making such a decision? Only if this service is not available for any reason, the resident should consider installing an indoor cell extender.
• It should be remembered that this motto is an indoor repeater and has been designed to provide indoor signal coverage.
• Coverage within homes, shelters, warehouses, workshops, factories, shopping centers, basements, offices, tunnels, all fall into the category of interior coverage.
• These are systems that are not for repeating the signal at any distance outdoors, but with the use of multiple antennas and line amplifiers, large indoor or isolated arias can enjoy convergence.
• Although it is an indoor device, it must be installed by a qualified installer.
• Although cell amplifiers are available over the counter as a DIY kit, it is strictly recommended that you do not purchase one and try to install it yourself.
Before installing a cell extender, measure the RSSI (Received Signal Strength Indication). This is done by a trained installer who measures RSSI using a high quality portable mast, cable and antenna. This is installed and measurement is done using a handheld spectrum analyzer, handheld signal strength meter, or software used on a laptop or cell phone. The full signal can be indicated on your mobile phone, but there is no available coverage of the network you need to connect to, so it is also relevant to determine which signal from the carriers is being measured.
The RSSI depends on the provider; In other words, the network you connect to may fluctuate, improve, or deteriorate. The output power levels of BTS can be changed or an antenna can be turned a little in another direction, the network could erect another BTS (Base Transmission Station) or cell phone tower in the vicinity. A building or a bridge could have been built between the BTS and the home or business completely protecting it. Because high frequencies are dependent on LOS (line of sight), these factors can change and individuals can be drastically affected. All of these factors must be measured and recorded.
The RSSI measurement must be carried out at a height not lower than 7 meters from the ground. This is the minimum installation height of an outdoor antenna in a cell extender. The RSSI at ground level is irrelevant for this purpose. It is imperative that you have some sign at the installation site; if there is no signal, there is nothing to amplify. But just because there is no signal at ground level does not mean there is no signal, there could be a good signal just above the tree line.
What is to be achieved? These measures are reduced to determine what the external profit should be (donor or up / link). The number of BTS towers in the coverage area and their location is information necessary to select the correct type of antenna to communicate between the BTS and the repeater. This criterion is not included in DIY kits. The types of antennas, their radiation patterns, and their strength (gain) are not common knowledge to the layman. Once this is established, a link budget can be calculated and the correct cell extender recommended. This will ensure a cell extender that does what it is designed to do, that is, give you coverage indoors. An incorrect calculation and an unqualified installation will most likely lead to a system that oscillates, generates noise on the network, and provides very limited coverage.
Typical evaluation of signal strength The signal from a bar on your cell phone can be amplified to its maximum power with a cell phone extender. Signal strength is measured in dBm. Here is a rough guide that might help. Remember, this is what the user is experiencing at ground level. You can have the complete signal on a hill 100 meters from your house.
5 Bar = -40-80 dBm very good
4 Bar = -85 dBm good
3 Bar = -90 dBm usable
2 Bar = -95 dBm can break and drop calls
1 bar = -100dBm poor
Theoretically, using a Coiler TG900 27dBm Cell Extender with 60dB Gain and selected antennas, a -90dBm site can be amplified to -27dBm, which will provide coverage to a normal size home. It is common between 7 ~ 10 meter radius on the GSM900 frequency. Much larger coverage arias have been achieved regularly, but you tend to be very careful when drawing coverage when applying RF as it is not very predictable and many variations are applied.
Is it a usable signal? There are weak signals, poor quality signals, noisy signals, reflected signals, etc. The parable applies “garbage in, amplified garbage out.” The better the RSSI before amplification, the better the coverage and quality of the amplified signal. By reflected signal we mean that the signal bounces off a stationary object such as a mountain cliff or a building such as a silo, etc. These signals are not always stable. Often this signal varies in intensity. The reflected signal can be amplified, but the repeater will not necessarily stabilize the variable signal.
What network operator signal is being amplified? Network operators in SA often use the same infrastructure, but many high country sites host only one BTS operator. Therefore, it is necessary to ensure that the corresponding base station provides the service of the operator to which it is subscribed. The broadband GSM repeater amplifies the entire GSM900 frequency spectrum and the signal of the other operator is also amplified. This may mean that the user could have an excellent signal from operator 2 but a weak signal from operator 1. Service providers / network operators use band-selective transmitters and receivers (BTS) to control billing for their own customers and their customers. additional services. This means only that the operator’s dedicated channels in the frequency spectrum will be improved and not their oppositions. This also helps them identify who is responsible when a problem arises.
What services are amplified? By services we mean:
• GSM900 (Global System for Mobile Communications) – voice, GPRS and 2G (2nd generation) in SA
• GSM1800 or DCS (Digital Cellular Service) used for EDGE (Enhanced Data Rates for Global Evolution): high-density data and arias for voice in SA
• UMTS2200 (Universal Mobile Telecommunications System) commonly uses W -CDMA (Broadband Code Division Multiple Access), for 3G (3rd Generation) or HSDPA (High Speed Downlink Packet Access)
Because each of these technologies runs on a specific frequency bandwidth, you need a repeater for that bandwidth or a combined repeater designed for two or more bandwidths to enhance each format. GSM900 on the 900MHz frequency, DCS on 1800MHz and UMTS on the 2.1GHz frequency. South Africa operates a three-band network in its main suburban areas where all three services are available. In rural areas and smaller suburbs, a dual band network (GSM900 and DCS) or a single band GSM900 and GPRS network should be available. The UMTS cell extender cannot amplify 3G if the local BTS is not a UMTS operator, even if the end user’s mobile is 3G enabled. You will have to be satisfied with GPRS or Edge.
Why aren’t all signals available in all arias? There is no network available. A network is deployed according to a network plan. Services for arias are planned and delivered according to the potential market. The network operator is a company in which all shareholders demand the best dividends from their. A BTS will not be established to provide these end-user services for one or two farmers with the potential to generate R6000pm calls / sms made by themselves and their workers. When there is a substantial population of an aria, a market is created for network services and coverage will be provided accordingly.
There is no coverage even though the network is available due to distance. The approximate distance a frequency travels when generated at the prescribed power level. (power ratio in dBm in decibels) What is not commonly understood is that different frequencies have different wavelengths and are transmitted at different power levels as determined by the governing broadcaster. The power level is determined due to the danger of radio frequency (RF) radiation. 1800MHz is already a low microwave frequency and 2.1 GHz is close to the 2.4GHz frequency that most microwave ovens operate on. If this frequency is indiscriminately amplified, a real health hazard will be unavoidable. If it falls outside of this radius, you will experience a weak signal.
There is no coverage even though the network is available due to obstacles.
• A second point that is not commonly known is that the higher the frequency (the narrower the wavelength), the more difficult the penetration of obstacles, such as trees, buildings, steel structures such as roofs and hills, etc.
An indication of thumb sucking over an obstacle-free field (LOS or site line)
• GSM900 (900MHz) transmitted from a BTS must give a coverage distance / radius of 16 km
• DCS1800 (1800MHz) transmitted from a BTS must give a coverage distance / radius of 7 km
• UMTS (2200MHz) transmitted from a BTS must give a coverage distance / radius of 3 km.
3G and HSDPA have many challenges in city centers due to penetration. For example, Accompany could have excellent 3G connectivity; then a bridge, a building or the Gautrain aerial rail is constructed through the suburb of the city between the BTS and its receiving point, and that is the end of the 3G signal. It is only necessary to move the offices down the corridor to lose a 3G signal and this is due to penetration phenomena.
What should be clear is that it is not an easy task to cover everyone in a diverse country like South Africa. It is even more challenging to provide all available service with cell phone technology that introduces new formats and media such as “push technology” and video conferencing. It’s not just about the phone, it’s about the signal.
If you need help, don’t talk to just anyone. Talk to the right people.