GSM antenna

Remote installations fitted with GSM/GPRS telemetry equipment often comes under attack by groups such as bored youths and local hooligans congregating in specific areas.

Locations with telemetry equipment include vending machines, bus stops fitted with RTPI (real time passenger information) equipment, utility boxes for acting as a local information gateway from homes back to service providers and remote weather stations for transmitting local weather to a centralised point. All have a critical requirement for ensuring products are built to last in their particular environment and wireless connectivity over a GSM or GPRS network is becoming a low cost way of interacting with remote sites.

Use a Low Profile Antenna
Although most GSM/GPRS antennas are vertically polarised, a growing trend of low profile antennas are being introduced to the market. These are designed to be fitted low down on the casing and secured via a through hole bolt which passes through a hole on the enclosure. This ensures the antenna cannot be removed without access to the inside of the enclosure and no cabling is visible. Good quality products such as the Siretta Antenna Tango 1 and Tango 2 series are designed with robust plastic enclosures to give adequate protection against all but the most sustained attack. These offer quad band GSM/GPRS cellular connectivity and often 3G and 2.4GHz operation as well. Siretta Antennas also produce a Tango 5 series which provides GPS (satellite tracking) capability as well.

Elevate the Antenna
GSM/GPRS communications operates on a line of site principle so it is a useful idea to raise the height of the antenna above ground level if possible. This gives the additional plus of keeping the antenna out of arms length whilst improving communication at the same time.

Cable in these types of installations can be routed up bus stop poles or underground to minimise other parts of the equipment being targeted. A good example of this is the Oscar 1 series by Siretta Antennas. This is supplied with a bracket for fixing to mounting poles sides of buildings and 5 metres cable which is sufficient for the majority of installations but can be extended if necessary.

For weak signal areas such as remote sites with perhaps one cell site in a locality, a Yagi antenna such as the 900MHz Oscar 3 from Siretta can be installed at a high point and pointed in the direction of the cell site.

Hide the Antenna
Providing the equipment is not inside a metal enclosure (RF signals do not transmit well inside these), internal antennas can be used. These are available with varying lengths of cable according to the distance between antenna mounting site and telemetry unit. If they are going inside equipment, a less rugged, non waterproof antenna could be used. Siretta Antennas produce a neat range of embedded antennas or adhesive antennas to fix inside enclosures.

The above pointers should be useful in overcoming objections often given by end customers who are concerned about longetivity and robustness of products in the field. Providing field trials are completed satisfactorily, they should provide a practical compromise to maintaining suitable signal levels whilst not being seen as weak spot to a design.

Many support calls are received from design engineers wishing to improve signal performance when designing, testing or rolling out telemetry products fitted with GSM or GPRS wireless modules or terminals. As our specialism is wireless communications, I wrote this article to assist engineers and installers in maximising the working range in their GSM / GPRS system. To do this, an assumption has been made initially that a suitable antenna and cable configuration has already been selected and qualified.

Although we are concentrating on the improvement of GSM/GPRS signal transmission and reception in embedded design applications, similar transmission / reception rules cover the majority of today's wireless M2M modules. These include 3G and ISM bands such as 433, 868 and 2400MHz. The latter frequency also covers Bluetooth, WiFi and ZigBee / IEEE802.15.4 standards.

A GSM or GPRS antenna propagates on 850, 900, 1800 & 1900MHz frequencies. The propagation rules on these frequencies mean that the wireless equipment radiates in a straight line, operating in a line of sight basis. Although radio signals do bounce off and travel through certain materials, using the line of sight practice should be the first rule to observe. Obvious to some, there needs to be particular emphasis on the fact that the antenna receives or transmits the signal, not the wireless module.

Obstructions placed between the base station and antenna will absorb the signal to varying degrees. For instance a sheet of paper between transmitting and receiving antennas in a GSM environment would have virtually no effect, however if an antenna was inside a building or metallic enclosure, it would have a more dramatic effect. Likewise, a geographic obstacle such as a hill between base and outstation would block a GSM/GPRS radio signal.

One simple way of overcoming obstructions in a line of sight communications environment is to elevate the radiating antenna. Many of today's GSM/GPRS antennas are supplied with different lengths of cable and office or base station antennas are providing with cable lengths of up to 15 metres. This will give the installer a greater scope for installing the antenna as high above the ground as possible and preferably outside of a building towards the area with best cell site coverage.

It is worth noting that less cable equals less RF loss so when specifying cable lengths and antenna,

When specifying an office or base station antenna, the engineer needs to ensure that the antenna, cable and connector configuration is of 50 Ohm impedance and the cable length is optimised for the site. Co-axial cable has differing levels of RF loss depending on the type selected so it is advisable to have enough for the installation without too much surplus. Although installations vary from site to site, this can be overcome in the field by ensuring installers have carried out site surveys and have extension leads to allow for routing. These can be added or taken off at the discretion of the installing engineer. Similarly, care should be taken when fitting inter series RF adapters or link cables in line.

Regarding RF loss, the higher the operating frequency, the greater the loss. In the United Kingdom, 900 and 1800MHz frequencies are used. Vodafone and O2 generally operate on 900MHz and Orange and T Mobile generally operate on 1800MHz although some cell sites are now shared.

In addition to 900MHz systems offering a lower loss at the equipment and cable end, several other advantages also exist.

900MHz GSM/GPRS systems operate on 2 Watts whilst 1800MHz operates on 1 Watt. With a 2 Watt 900MHz system operating on twice the power, the working range will be significantly enhanced.

Additionally, 900MHz networks benefits the user by being able to transmit over a greater distance. Lower frequencies having longer wavelength distances between sequential crests of a sine wave mean they are able to travel further.

Whilst 1800MHz may be good in a city environment with the luxury of multiple cell sites, it will hamper performance when being installed around country locations with fewer cell sites within operational line of sight. Whilst this will provide an overall picture, this theory cannot take into account local factors such as a 1800MHz cellsite being 100 metres from a target location!

With most businesses designing and building GSM/GPRS equipment, airtime is usually selected after a commercial decision largely based on price. Engineering input should be listened to as to reasons why it is worth paying slightly more to ensure quality of service by recommending a 900MHz network is selected.

Whilst network selection is an important consideration, antenna and cable selection is critical to the success or failure of a product in the field. This is often overlooked resulting in the last part of a Bill of Material to be firmed up, lack of sufficient field testing and numerous on costs associated with a below par Quality of Service.

You may think that technology had developed so much that antennas were no longer needed on cell phones and other mobile electronic equipment. But in actual fact, electronics designers and manufactures built the GSM antennas on the inside of the electronic devices.

Why do they install the GSM antenna inside the device? Well for a start it's more ascetically pleasing. In the case of mobile phones and table computers, it's more convenient if the device is going to be carried around in a pocket or handbag to not have a perturbing antenna. Additionally external antennas on small electrical devices which are transported in pockets and handbags tend to get broken. A small antenna easily gets damaged or snapped off, so it makes sense to design in internally and offer the antenna some protection. After all, the antenna is an important part; if it can't send and receive data the device is redundant.

But most importantly, designers make electronic devices with internal antennas because they can. GSM antennas cove come on a long way since the first-generation technology, and GSM antennas no longer need to be external to provide the best reception.

GSM has over one billion users worldwide and is available in 190 countries. GSM supports voice and data communications, typical maximum data rate is 14.4 kbps. GSM Antennas transmit and receive this data.

GSM networks operate in a number of different carrier frequency ranges (separated into GSM frequency ranges for 2G and UMTS frequency bands for 3G), with most 2G GSM networks operating in the 900 MHz or 1800 MHz bands. Where these bands were already allocated, the 850 MHz and 1900 MHz bands were used instead (for example in Canada and the United States). In rare cases the 400 and 450 MHz frequency bands are assigned in some countries because they were previously used for first-generation systems.

Nowadays GSM products are operating at 900, 1800 and 1900 MHz (some people have also though of 800 and 450 MHz versions sometimes).

GSM technology has been the most prominent mobile phone technology in the world. Although there are other technologies that are competing with GSM, it has not budged in its dominance. GSM offered a lot of possibilities to the world of mobile phones like text messaging and even low speed internet access. Further improvements were made with the introduction of GPRS and EDGE that extended the capabilities of GSM networks. Multimedia messaging was added to its list of features allowing subscribers to send pictures, audio clips, and even short video clips to each other.

Although mobile phones are the dominant GSM user, other devices are being developed which also use GSM technology. As with all devices; being mobile means, being small. In most cases pocket sized is the ideal. Because of these trends, GSM antennas have become smaller and light weight so that they can fit inside a compact 'pocket sized' devices.

With no real competition to GSM, and with GSM developing more and faster ways in which we can send and receive data from one mobile device to the next, GSM antennas are a necessary staple of the wireless age.

The release of our compact Yagi antenna this month highlights the advantages of using well built, high gain antennas in remote environments where cellular connectivity is required. Designed for industrial use our high gain GSM/GPRS or 3G antennas ensure that a reliable cellular connection can be maintained even in remote locations.


Oscar 16 - 12dBi GSM/GPRS Yagi Antenna
Offering high gain cellular connectivity, Oscar 16 is ideal where maximum power can be directed at a lone cellsite in remote locations. A discrete size and including mounting bracket, Oscar 16 immediately adds impact and operates across 850/900/1800/1900MHz cellular networks.


Oscar 1 - 3.5dBi Wall Mount GSM/GPRS and 3G Antenna
Ruggedly constructed and designed for outdoor environments, Oscar 1 is a penta band, high performing, low cost way of increasing cellular signal. One of our top 5 sellers with installation engineers, Oscar 1 comes with a moulded 5 metre cable and either SMA or FME connectors.


Oscar 12 - 10dBi Omni Directional GSM/GPRS Antenna
Siretta Oscar 12 offers a robust, high gain antenna to operate on European GSM/GPRS and forthcoming 4G networks. Designed for external wall mount fixing, this antenna significantly improves cellular performance in fringe coverage areas.


SWGPRS023 - GSM/GPRS Signal Tester - great for cellular surveys!
Our Signal Testers use detachable antennas, allowing for third party antennas fitted with an SMA male connector to be used to carry out a survey. This makes the SWGPRS023 a great choice with installers and engineers to ensure their antenna is not only installed in the optimum location but also on the best available network.

GSM Stub Antennas are quite simply stubby antennas that work on the GSM network. GSM stub antennas are available with different mountings, such as right angle connectors and hinged mount, but despite their mounting types, all GSM Stubby antennas are essentially the same, GSM Antennas in the stubby short format.

Until recently, conventional commercial antennas in the worldwide market have been external ones, because they provide omni-directional radiation patterns for optimum coverage in all circumstances. In addition, stubby antennas are shorter, more robust and, arguably, more aesthetically appealing than the retractable antenna.

GSM uses a wide variety of antenna types. Indeed, as long as it is able to capture a GSM signal, almost any kind of antenna can potentially function as a GSM antenna. GSM stands for Global System for Mobile Communications, so as you might expect you can find GSM antennas on most electronic mobile devices. When you are designing a mobile device it is essential to factor in the type of antenna the device will use.

GSM Stub Antennas have the unique feature of being small and discrete. In an age where small is desirable the stubby antenna has been popular.

However, it's not just fashion that brought the stubby antenna into favour, small also is practical. When you are designing an electronic device that shares data with other technologies you will need to design in an appropriate antenna that will be able to transmit the data. GSM stub antennas are ideal for mobile devices such as phone, vehicles, tracking devices, animal collars and devices that will be on the move in use. Short, non-obtrusive stubby antennas are ideal for situations when radios are worn on user's belt because there isn't a long antenna that sticks into the wearer as they move. Stubby antennas are also ideal for mobile devices that will be carried around in a bag or tool box, because stubby antennas are durable and can withstand harsh treatment.

The GSM stubby antenna offer high performance with a minimum of size.

Designed for permanent installations such as walls of buildings or on masts, office mount antennas are physically larger and therefore tend to offer the best wireless performance. The size of the GSM antenna is usually proportioned to a better overall signal reception as the larger the size, the closer the antenna is to receiving the full signal wavelength. Products such as the Oscar 1 GSM antenna are used when maintaining a cellular link is critical such. For instance, when clients are looking for a continuous "Quality of Service".

The GPS antenna has to be installed in a location with direct view of the sky. For a concealed installation, the GPS antenna can be hidden in a place where it will not have any metal above it.

GSM, or Global System for Mobile Communication, is a system for transmitting mobile communication information. Global System for Mobile Communications is the most common type of cellular network worldwide, and they require GSM antennas. GMS antennas are antennas that are able to transmit and receive data from one antenna to another; this might be to a personal mobile device or from one machine to another machine.

Most modern mobile phones have an internal GSM antenna, usually contained in or near the bottom of the phone. A GSM antenna also can be found in a laptop, a netbook or a Universal Serial Bus (USB) device. In these cases, the antenna is meant only for data. It usually will use 3G technology to deliver quick wireless Internet service over a GSM network.

GSM also can be used to transfer data, for use in email or Web browsing on mobile phones. Many phones have a GSM antenna that is compatible with third-generation (3G) technology for much faster speeds.

GSM uses a wide variety of antenna types. Indeed, as long as it is able to capture a GSM signal, almost any kind of antenna can potentially function as a GSM antenna. However, a few primary types of GSM antennas are in use today, and a review of these types is a good place to start in learning more about how GSM works.

GSM antennas will be either directional or omni directional. Omni directional antennas, also known as helical antennas, can receive signals from any direction. Directional antennas usually have more gain, that is, more sensitivity to signal, than omni directional antennas. Directional antennas accomplish this greater sensitivity because they are able to focus their energy patterns onto a smaller area than omni directional antennas. However, to receive signal, directional antennas must be pointed in the specific direction from which the signal is emanating.

Monopole antennas consist of a small pole placed upon a planar piece of metal or a series of wires radiated out from the pole. Monopole antennas are omni directional in nature and have equal gain in all directions.

Although most GSM/GPRS antennas are vertically polarised, a growing trend of low profile antennas are being introduced to the market. These are designed to be fitted low down on the casing and secured via a through hole bolt which passes through a hole on the enclosure. This ensures the antenna cannot be removed without access to the inside of the enclosure and no cabling is visible.

In general, GSM antennas must be small in size. Most new electronic devices are getting smaller and more compact in their designs. Therefore GSM antennas need to be small enough to be able to fit inside these devices. In addition, the antenna should have a gain of about 8 dBi. To operate at GSM antennas, the antenna must be able to receive both the standard and the extended GSM bands, 880 MHz (megahertz) to 960 MHz.

GSM service can be used on a number of radio frequencies, depending on the region and technology used. Many modern phones with GSM antennas support a variety of these frequencies so that they can be used while travelling.

All antennas need to have their performance tested. Off the shelf antennas also need to be tuned, so you also play around with matching circuits, ground plane clearance and ground length.

T Bar GSM/GPRS/3G & 2.4GHz antenna

The Alpha 1 Antenna is designed for providing effective GSM / GPRS /3G & 2.4GHz performance in indoor applications, the Siretta 'T Bar' antenna is popular for in vehicle communications as both a versatile antenna for hands free car kits or in after market telemetry applications.

Optimised for use on all 4 GSM / GPRS frequencies, the Alpha 1 Antenna also offers 3G functionality for mobile broadband users as well as 2.4GHz ISM performance to accommodate users of Bluetooth, WLAN and Zigbee products.

2.1GHz (3G) 02dB gain quad band GSM and 2.1GHz (3G) and 2.4GHz 2500mm cable SMA Male internal T-bar antenna

Designed for providing effective GSM / GPRS / 3G and 2.4GHz performance in indoor applications, the Siretta "T Bar" antenna is popular for in vehicle communications as both a versatile antenna for hands free car kits or in after market telemetry applications .

Multi Band Antenna - Works on quad band GSM/GPRS, 3G and 2.4GHz networks
High grade mounting adhesive
2.5m cable
SMA male connector
Flexible moulding - can contour around different materials

The Alpha 1 Antenna is a simple cost effective solution for applications requiring a reliable wireless connection. An alternative Alpha 1 Series version with an FME female connector is also available under part code ANTA7250F0200AI1.

When you are designing an electronic device that shares data with other technologies you will need to design in an appropriate antenna that will be able to transmit the data. GSM antennas are ideal for mobile devices such as phone, vehicles, tracking devices, animal collars and devices that will be on the move in use.

The mounting and location of the GSM antenna is much less critical than you might imagine. The most important issue to consider is potential interference with other equipment, such as in-car entertainment systems.

If you are looking to use external GSM antennas in your design the best location is to mount the antenna on the highest point. Avoid locating the GSM antenna close to other electrical equipment to reduce the chance of GSM interference. The GSM antenna should not be shielded by metals. The GSM antenna must be able to receive GSM network coverage. You can check the signal strength using a signal strength testing unit. For designs where it's necessary for the antenna not to be seen, internal antennas would be the best solution.

Avoid touching the antenna area unnecessarily while the antenna is transmitting or receiving. Contact with antennas affects the communication quality and may cause a higher power level during operation and may reduce the battery life.

The internal flexi Antenna is a small rectangular Penta-band GSM antenna that can be easily integrated into OEM designs. It has been optimised for the GSM network operating on GSM, CDMA, PCS, DCS and UMTS networks making it suitable for global deployment. It also has the benefit of featuring omni-directional gain across all bands ensuring good reception and transmission.

The XDA Orbit is a small Pocket PC and the fact that it hides GSM, Bluetooth, Wi-Fi, FM radio and a GSM antenna inside its casing is a marvel. Superb battery life and the CoPilot software make it a good all-round device.

The Nautilarm V2 can be supplied as a complete kit including control unit, wired high stability quad PIR sensor, GSM Antenna, Remote Arm/Disarm key fob, Siren, Batteries, Wiring kit, External Status LED, Screwdriver and mounting hardware or you can buy the parts you need separately. The system is expandable with our range of wired and wire free alarm sensors. We recommend the use of our high stability quad PIR sensor because we have found it to be the only reliable motion sensor for use in boats.

The GXS6624 is an external antenna that is suitable for use with GSM Gateways, Premicells, Fixed Cellular Terminals and 3G Routers. The GXS6624 is a GSM Antenna and 3G Antenna with 5m long cable with an SMA antenna connector.

Omni Directional Antenna for use with GSM and 3G Applications. This antenna is suitable for use with our standard Fixed Cellular Terminals as well as the latest 3G GSM Gateway and 3G / UMTS Routers including the Ericsson W25 and Teltonika RUT100 3G Router.

The breadth of products using GSM or GPRS communications is widespread and as such a range of GSM antennas are available on the market according to the requirements of the product. There are 6 mounting types of GSM antennas if you want to know what they are, then this article is for you.

To first explain what a GSM antenna is, we need to cover what an antenna does, so we hope you bear with us as the next paragraph is as technical as it gets!

An antenna or aerial is a conducting device which coverts radio waves into an electromagnetic signal and vice versa. It is essential for a radio or wireless module to have an antenna to operate. Built using electrically conducting materials such as metallic or copper track, antennas are tuned to transmit or receive signals by building the antenna to a specific length in order to receive an electromagnetic wavelength. It then sends this signal to the radio. The electromagnetic wavelength carries different frequencies (measured in Hertz-Hz) depending on the antenna length.

GSM frequencies (also referred to as cellular) is a global digital communications standard which operates on 850, 900, 1800 or 1900MHz. The operating frequencies vary depending on which geographic region the user is in. For instance, 900 and 1800MHz are the two operating frequencies in Europe and Africa.

GSM technology is commonly used on wireless M2M and telemetry equipment because it allows users to communicate globally with another GSM enabled device in range of a GSM network. GPRS is an additional service - often available on the GSM network. It uses a dedicated data transmission link depending on the bandwidth available. As it uses the same carrier frequencies as GSM, a GSM antenna referred to in this article will operate with a GPRS enabled module.

Certain antennas outperform others despite them being tuned to the same frequency. For instance, a television aerial mounted on top of a TV set will not perform as well as an externally mounted Yagi antenna pointing in the direction of the nearest TV transmitter mast. The same is true of GSM antennas - some perform better than others, so we have outlined the various mounting types below to allow the identification of the best type for an application:

Magnetic mount

GSM antennas with magnetic mount bases are good for temporary installations where they are likely to be fixed to a metallic base. These are commonly used with telemetry or test equipment, as prototypes or externally mounted on vehicles. A popular type such as the Mike 1 antenna from Siretta Antennas is commonly used for all these purposes. They are usually supplied with 2-3 metres cable and different types of connector depending on the requirements of the wireless module.

Adhesive mount

Sometimes GSM antennas can only be mounted on non metallic surfaces such as the inside of a glass windscreen or plastic surface. These are usually supplied with adhesive strips - the grade of the adhesive depending on the application. Similar to the magnetic type, cables and connectors are supplied and can be tailored to the requirements of the wireless M2M equipment.

Direct mount

Much like the antenna on a WiFi access point, direct connect GSM/GPRS antennas are available to connect directly to a terminal piece of equipment. Commonly using an SMA connector, they are the lowest cost external antenna. For instance, Delta 2 from Siretta Antennas has a right angled connector allowing a fast and convenient connection.

Office / Base Station mount

Designed for permanent installations such as walls of buildings or on masts, office mount antennas are physically larger and therefore tend to offer the best wireless performance. The size of the antenna is usually proportioned to a better overall signal reception as the larger the size, the closer the antenna is to receiving the full signal wavelength. Products such as the Oscar 1 GSM antenna are used when maintaining a cellular link is critical such. For instance, when clients are looking for a continuous "Quality of Service".

Through hole mount

These types of GSM or GPRS antennas are supplied with a fixing bolt on the base. These are mounted by drilling a mounting hole into the surface the antenna is going on to enable the fixing bolt to pass through. It is secured via a retaining nut. The cable is usually passed through the middle of the fixing bolt. Search online for Tango 2 GSM antenna and you will find some good examples.

Many of these antennas are low profile in design which means they do not look like an antenna. They are popular on high vehicles or vandal prone areas.

Embedded Antennas

These types of antennas are usually specified when designing equipment, such as a wireless communications box as they are built to fit in the box with the other electronics. There are 2 widespread designs available. The first is designed to mount directly onto a PCB however this method usually requires additional circuitry to get optimum results. The other is a copper track on a separate PCB which is fed to the radio or wireless module via a cable. A good example can be found by searching online for Echo 1 GSM antenna. This method is low cost but should be designed in by a qualified engineer as other considerations such as EMC testing needs to be properly understood.

The range of GSM antennas is vast however we hope that explaining the 6 mounting types helped pigeon hole the options available. Within each option the product variations will be huge. The selection thereafter will depend on the product requirements and performance expected.

About the Author.

David Taylor, is the Business Manager of Siretta Antennas Ltd - a specialist supplier of antennas, cable and connectors serving the Wireless M2M and telemetry markets.

Siretta Antennas, an operating division of Sequoia Technology Group Ltd, are a technology solutions company based in Reading, United Kingdom. Siretta design, manufacture and source industrial antennas, RF cable assemblies, connectors and RF test equipment supplying to customers throughout the world.

A GSM antenna is a conducting device which coverts radio waves into an electromagnetic signal and vice versa. GSM antennas enable the electronic device that the antenna is attached to, to send and receive radio waves and data. GSM antennas are essential for a radio or wireless module, and devices containing wireless modules.

GSM antennas are found in wireless machine-to-machine devices. GSM antennas make it possible to communicate with other GSM enabled device in range of a GSM network.

GSM antennas offer a quick and easy way to send and receive data via an antenna.

Low profile cellular telemetry GSM antennas are designed for all types of radio wireless systems. The covert low profile antenna element is sealed with a rubber enclosure and can be easily integrated into any application.

Some GSM antennas give better performance than other GSM antennas. So when you are looking to buy a GSM antenna, take a look at their reliability and performance to avoid disappointment.

Siretta Antennas have been producing and souring antennas and cable assemblies for over 10 years. We supply Antennas and Cables globally to many of the worlds leading organisations.

Whether you require an off the shelf or custom solution, Siretta has a wide portfolio of Antenna's and RF cable assemblies to fit your application.

Our extensive knowledge and experience in the wireless market allows us to support a wide range of customer applications, focusing on frequencies typically within 300 MHz - 5.8 GHz range. These encompass the VHF, ISM, GSM / GPRS / 3G and GPS frequencies as well as industrial WLAN and VHF / UHF antenna solutions.

Siretta is a division of the Sequoia Technology Group