Smart Guides Guide to Selecting the Right Antenna

First up - you will need three pieces of equipment to improve your mobile signal: - an antenna - a cable and - a connector.

For more information, please visit our website.

Similar to your TV, mobile phones and wireless broadband modems connect to antennas.

1 - For increased signal, the best position for your antenna is as high as possible outside your car or house - this means you'll need cable to cover the distance from where you want to put the antenna, to where you want to use your or modem.

2 - You'll need something to connect your cable to your or modem - all good quality modems have an external antenna port, meaning all you'll need is a small adaptor cable called a patch lead to go from the big connector on the cable to the tiny connector on your modem.

Many phones have an external antenna port, most notably Telstra, Samsung, and Motorola brand phones. You'll just need to use a  cradle if your does not have an external antenna port.

If you don't like the idea of having to constantly tether your to a patch lead or cradle, you can connect your antenna to a smart repeater which will amplify and broadcast your antenna's signal throughout your house at full strength - this will give your mobile a full five bars.

There are four main factors that reduce mobile coverage:

• Distance from the cell tower

• Terrain

• Dense vegetation & buildings

• Your house

Distance

You're probably not too surprised to learn that mobile signal is reduced by distance (due to the Inverse-Square Law) from the cell tower, causing a gradual weakening of signal.

On flat terrain, most cell towers have a usable range of about 40km before you'll need to use an external antenna. With a good quality external antenna it's possible to receive signal as far as 120km.

Terrain

Radio waves diffract by nature - this means they can bend over hills and around structures/objects, so being able to see a cell tower is not the ‘be all and end all’ of obtaining signal.

If you've travelled through hilly areas, you've more than likely noticed you still have mobile reception, despite being in a small dip or behind a rise in terrain. It's large or sudden changes in terrain that will significantly impact coverage – in this type of scenario, height is the key success factor.

Vegetation

Dense sections of trees are notorious for diffusing signal - one or two trees will not impact signal strength too much - add more and more trees, and it's a little like 'death by a thousand cuts, with each tree absorbing and deflecting a small amount of signal.

The best way to mitigate this phenomenon is by increasing height to minimise the path that signal must pass through offending vegetation.

Building penetration

Mobile signal is reduced when passing through buildings, trees, water, and even the air we breathe. The worst offenders are thick and conductive materials such as concrete, metals and foil-based insulation – this is often why signal can be weak indoors despite a strong signal outside.

For a comprehensive look at all the factors involved, have a read through our Poor Coverage Explained guide.

OK let's get started 

Step 1 - What network am I on?

This seems a simple question to answer - and for some networks, like Telstra - it is. However, what we really want to determine, is what frequency the network operates on in your area.

While there are countless mobile network operators, there are only three mobile networks operating in Australia - Telstra, Optus, and Vodafone.

Use our Coverage Maps to determine what frequency your network is operating.

This table is a quick guide.

Australian Carrier Frequencies

Network Frequency

Step 2 - Where am I?

Different antennas are designed for different situations. So identify where you're trying to improve service - the house? car? boat? Are you in the one location, or are you moving around?

Rather than talking about antenna types and gains, this guide will work through the best antennas for your house, vehicles, and marine vessels.

The house or office

The best place to start is often by performing a quick self check. Walk around the house – is there a particular spot where signal is good? Walk outside the house or on to the street – does the signal improve?

Climbing up on your roof can give you an idea whether height is an important factor in improving signal. [The appropriate safety gear should be worn at all times when working at heights - getting a good signal is not worth a broken leg - eek!]

OK, now you need to work out where the nearest Telstra tower is, and how many towers are in the area. You can find this out by following our Guide to Locating a Tower.

If you're still not sure, book in for a Detailed Site Assessment where we can look after everything for you.

Indoor antennas

If you're on the move or don't have the room to mount a roof antenna, an indoor antenna is a convenient way to improve mobile service or wireless broadband speed.

While the much smaller dBi gain reduces strength, it allows indoor antennas to receive from many directions - with no need to fiddle around to find the optimal direction - they're perfect if you're moving around or don't know where the best cell tower is located.

If you've noticed your signal strength is usually stronger next to a window or doorway, then this is often the best place to put the antenna.

One of our most popular models is our 12dBi window mount antenna - its adhesive stick on mounting makes installation easy.

Roof antennas

Most issues with slow wireless broadband or bad reception are solved with a roof mounted antenna. If you've located your nearest cell tower, the next step is simple.

There are two main types of roof antennas - directional (Yagi) antennas and omnidirectional (collinear) antennas.

Directional, or Yagi antennas, are the most popular choice of antenna, as their high power provides the strongest increase of all antenna types.

The trade-off here is that they require aligning in the direction of the cell tower - the higher the dBi gain, the more precise you'll have to be.

In deciding between Yagi models, wider angled 12-14dBi antennas are more suited for hilly areas, while the 15-16dBi antennas are better for very long range connections, with less hills in the way.

Omnidirectional antennas are designed for areas around town or in the suburbs where there are often several cell towers within range. This antenna lets your mobile decide which tower offers the best signal. However, as omnidirectional antennas spread their power over a 360° range, they don't receive signals as strongly as their Yagi counterparts.

There are typically three Yagi antennas we recommend for different areas depending on their terrain type and distance:

• 12dBi LPDA Yagi: Short Distance (1-15km) or Nearby Hills (1-5km)

• 14dBi or 15dBi Yagi: Moderate Distance (15-30km)

• 16dBi Yagi: Long Distance (30-70km) or Flat Areas (hills > 15km away).

The car

Choosing an antenna for your vehicle usually isn't too complex. All car antennas receive signal from all directions, and follow the same principles as a UHF aerial.

The choice of antenna depends on the area you're travelling through. A higher gain means a stronger signal, however, when you increase an antenna's gain (i.e. its dBi), the angle it can receive from is reduced.

This means that high gain antennas are more suited to flatter areas, and moderate gain antennas (such as a 5-6dBi) are better suited to hilly areas.

Choosing an Australian made antenna is your best bet - brands such as RFI and ZCG Scalar are high quality and extremely durable, and they're specifically designed for the tough Australian environment. They have a more sophisticated internal design, allowing most models to operate on multiple mobile networks.

Around town

Built up areas often have several cell towers within a few kilometres, and are usually mounted on tall monopoles or on top of hills.

The antenna of choice for many fleet and commercial vehicles is the 5dB RFI CD or the 6.5dBi RFI CD (formally ).

General highway and travelling

If you're after a versatile antenna capable of functioning in a range of different terrains, the 6.5dBi RFI CDQ and 7.5dBi RFI CDQ (formally ) are the antennas of choice for all Australian networks.

Outback QLD & WA

For flat outback areas the clear choice is the ultra-high gain 9dBi RFI CDQ (formally )

We often hear of customers purchasing falsely advertised 9dBi antennas - as a general guide a 7dBi antenna should measure about 1.1m and a 9dBi antenna should measure about 2m in length.

The boat

Marine antennas are typically high gain omnidirectional antennas (6-9dBi), to allow maximum off shore range no matter which direction your vessel faces.

Selecting an appropriate antenna depends on the type of vessel you have, and how far off shore you plan on going.

As a simple rule of thumb: the higher the antenna gain, the further off shore you can go. 8 or 9dBi marine antennas can easily extend your range past 120km off the coast. However, because higher gain antennas have a smaller angle in which they can receive signal, smaller vessels that sway side-to-side, may be better with a slightly lower gain, (such as a 7.5dBi) antenna, to compensate for the motion.

In practice, this is generally not an issue for most vessels as the receiving angle is a 'half power' measure, which means that if your boat was to swing past the quoted angle, the received gain would be 3dB less (half the power in Watts) - the same as a lower gain antenna.

Here are some we recommend: - ZCG 8.1dBi Deck Mount Antenna - ZCG 8.1dBi Mast Mount Antenna

If you are looking for more details, kindly visit Relacart.

Antenna gain

The first step in understanding antenna gain is that your or modem's internal antenna gain is typically 15 to 0dBi. So any good quality external antenna usually provides immediate benefit regardless of stated gain.

The key here is quality. Quality is typically measured by electrical efficiency, pattern stability, and VSWR (Volting Standing Wave Ratio).

On the other hand, gain is how the antenna focuses the radiated power.

You might be thinking, why would anyone buy a 6dBi antenna when they can buy a 9dBi instead - and while it's true that a 9dBi has a higher gain, it doesn't always translate to better performance.

Different antenna sizes and types have differing three dimensional patterns in which they receive signal. This is referred to as an antenna ‘radiation pattern’, and is often measured in terms of vertical and horizontal beam width.

Beam width refers to the angle in which an antenna receives signal, and is measured in degrees from the horizontal axis.

In a perfect world, all antennas receive the same amount of signal from the surrounding atmosphere in the shape of a doughnut, where width represents physical distance, and height represents physical height.

Given that you've only got a certain amount of dough (signal) to make the doughnut, you can either make your doughnut tall and skinny or flat and wide (or somewhere in between). In terms of beam width, a tall doughnut has a larger vertical beam width, and a flat doughnut a small vertical beam width.

Different antenna types

Aside from differing in gain, antennas also differ in their type of build. Each different build offers a different set of advantages and disadvantages.

Omnidirectional antennas (Ground Independent)

These are the most common type of mobile /UHF/CB antenna - they have a 360-degree horizontal beam width, meaning they work in all directions.

This type of antenna does not require a ground plane to function, so it can be mounted with a small bracket on just about any surface and location.

Best performance is achieved by mounting the antenna as high as possible - to eliminate as much signal interference as possible.

Magnetic base antennas (Ground Dependent)

This is a type of omnidirectional antenna that must be mounted onto a metal surface.

Magnetic Base or Ground Dependent antennas are half the size of ground independent designs, because they use the metal surface they are connected to as the other half of the antenna.

This means that the size, shape and surface area of the metal object are very important in achieving the best possible result.

This ground plane follows the same principles as the antenna - a larger surface allows for a larger fraction of the wavelength.

Ideally a surface with a diameter greater than one wavelength (about 35cm for Telstra Next-G 850MHz) will perform best, smaller surfaces down to 9cm will produce acceptable results (quarter wave).

Magnetic base antennas also achieve a more compact design by incorporating one or more loading coils which help maintain resonance, improve the radiation pattern, and most of all make the antenna more flexible - these traits are important for vehicles with low clearance.

Magnetic antennas are ideal for vehicles; they also make great indoor household antennas when mounted on filing cabinets and windowsills. Their compact design means they're an ideal travelling companion.

Although designed for metal surfaces, this type of antenna can be used on any surface, but will produce a gain 3dB less than what is stated - for example, a 7dBi magnetic antenna on a wood surface produces a 4dBi gain.

Yagi antennas

The odd looking TV antenna on thousands of house roofs, is the most common example of a Yagi antenna.

As mentioned earlier, Yagi antennas trade their ability to work in all directions (omnidirectional) for an increased gain. This is achieved by putting an array of smaller 'director elements' in front of the actual connected element.

These director elements receive the incoming signal and re-radiate the signal until it reaches the driven element (the one connected to the cable).

Behind the driven element, is a slightly larger element known as a reflector - and it does as its name suggests - reflects the signal back to the driven element.

By increasing the number of director elements and length of the Yagi, we reduce the horizontal and vertical beam width - resulting in an increased gain.

For a 3dB (twice the power) increase in gain, we have to double the length of our Yagi. For these reasons, a Yagi will often max out at 16dBi (on 850MHz) before becoming impractical in length.

The Yagi 21dBi myth - don't let anyone tell you that there is such a thing - because there's not!

In order to accommodate 21dBi, the Yagi antenna would need to be over six metres in length and impractical to install - so they just don't make them!

Grid parabolic antennas

In comparison to the Yagi, Grid Parabolic antennas increase their gain by increasing their width.

This is sometimes a more practical option, as they do not require stabilising brackets or cross bars to hold the antenna safely in place.

This type of antenna works in the same manner as a satellite dish - the signal is reflected off the dish/grid and onto the small receiving element placed above the centre of the grid or dish.

Selecting the right antennas is a critical step. An antenna must be compatible with the receiver specifications and meet device requirements. Our long-time partner, 2J Antennas, has prepared an overview of areas that you might find interesting in case you are looking for the right antenna for your project. This is an archive article published 04/15/. Some information may no longer be up to date and in line with the current state. Please contact us in case of interest.

1.Identify your needs

What is the mounting type that is suitable to meet your application requirements?
In order to select the most optimized antenna, begin the process by confirming if the antenna will be integrated:

• Internally, for example, mobile device
• Externally which often comes with housing for protection in outdoor application and installation

Our producer 2J Antennas offers a large selection for internal and external single and combination antenna mounting types.

Internal Single and Combination Antennas Mounting types

• ADHESIVE MOUNT FLEXIBLE
  Small form factor antennas with flexibility for curved installation in devices.

• ADHESIVE MOUNT RIGID
  This mounting type is ideal for flat surface installations, using an industrial-grade adhesive layer.

• SURFACE MOUNT CERAMIC
  Due to high-quality ceramic, this surface mount is ideal for a wide range of environments and is compatible with surface mount technique (SMT), allowing for easy PCB integration into small devices.
  
  
• SURFACE MOUNT FIBERGLASS
  Fiberglass material allows for the small antenna sizes while offering cost-effective solutions to device designers and is compatible with surface mount technique (SMT) installation.
  
  
• THRU-HOLE MOUNT CERAMIC
  The thru-hole mount is typically in the center of the antenna offering extra security for installation for in-device integration.

• SNAP-IN MOUNT MODULE
  Locks the antenna in place, prevents unwanted rotation and facilitates rapid antenna installation and replacement

• SCREW MOUNT MODULE
  Modular antennas that can be installed on PCB standoffs
  
  

External Single and Combination Antennas Mounting types

•  CONNECTOR MOUNT
  Typical for antennas that require direct PCB mounting solution on devices
  
  
• ADHESIVE MOUNT 
  Using a high-grade adhesive option makes it ideal for quick mounting applications
  
  
• SCREW MOUNT
  Advantage is a secure and permanent installation also in outdoor extreme conditions.
  
  
• MAGNETIC MOUNT
  Offers flexibility for temporary installation, strong enough for permanent installations
  
  
• WALL MOUNT
  Can be used for indoor or outdoor installations
  
  
• POLE MOUNT
  recommended for marine or construction applications.
  
  
• MAGNETIC/ADHESIVE MOUNT
  Offers flexibility for temporary installation, strong enough for permanent installations.
  
  
• WALL MOUNT
  Can be used for indoor or outdoor installations
  
  
• POLE MOUNT
  recommended for marine or construction applications
  
  
• MAGNETIC/ADHESIVE MOUNT
  Offers the option of magnetic or adhesive mounting for external installations, especially for non-magnetized metal surfaces
  
  
• WALL/ADHESIVE MOUNT
  Offers the option of wall or adhesive mounting for building wall installations
  
  
• VELCRO/ADHESIVE MOUNT
  a solution for temporary use of the antennas
  
  

Frequency and Wavelengt
What is the frequency and why is it so important? The wireless band designated for a device to operate through is called frequency. Antennas are designed to have a range of frequencies to operate within. As an example, if a device is tuned to use Band 17(700MHz), the corresponding antenna must operate within 704 and 746 MHz for transmission and reception.

Are you sure, you know what is the wavelength? The wavelength is the distance radio waves travel during one cycle. Designing an antenna quarter wavelength long will provide the best efficiency and deliver the highest signal quality.

Quarter wavelength is calculated with the following formula:
Quarter Wavelength(mm) = (75/ FreqMHz)*1,000

IMPORTANT: 4GLTE and 3G/2G antennas have the potential to be used in applications requiring ISM standards. 4GLTE range specification of 698-960MHz and 3G/2G from 824-960MHz, meaning the ISM 868MHz standards operate from 863-870MHz and are located within the 4GLTE and 3G/2G range. The same applies for ISM 915MHz standards that operate within 902-928MHz, or dual band 868/915MHz.

To ensure proper compatibility, please contact our SOS electronic sales department. For further analysis, we will contact directly the producer, 2J antennas.            

Fig.1, Examples of 1/4 wavelength; Frequency / Length graph

Standards & Bands
In our portfolio you can find 2J antennas that operate within many global standards. As example, our 4G LTE antennas are compatible with Cat-M, Cat-X, Cat-NB, NB-IoT and also SigFox and LoRa, known as LPWA market. The same analogy can apply often to other frequencies. As an example, WIFI antennas can be used for SigFox or LoRa in the 2.4 GHz spectrum. 

GNSS antennas are available with pre-filter, mid-filter or no-filter to meet the customers' different requirements.
The pre-filter offers the highest resistance and best reception and therefore is standard on all GNSS antennas. It is important to compare active gain and noise on the amplifier of GNSS antennas. 

Antenna standards from portfolio:

• 5GNR/4GLTE/FirstNet/CBRS/LPWA/3G/2G
• 4GLTE/FirstNet/NB-IoT/Cat-X-Mx-NBx/LPWA
• 3G/2G
• 2.4-5.0GHz WiFi/Bluetooth/ISM
• IRIDIUM
• GPS/GLONASS/BeiDou/QZSS/Galileo
• 433/868/915MHz/LPWA/Sigfox/LoRa /RFID/ZigBee/ISM
• TETRA/UHF/PMR/LMR
• 169MHz/ERMES/VHF
• DECAWAVE
• DSRC/C-V2X
• ORBCOMM 
• AIS
• DAB
• HDTV/DVBT
• AM/FM 

Fig.2, Frequency showing Standards Graph

2.Terms Explanation

To make the choice easier, we have highlighted some of the key points that require closer attention. The most effective way is to compare the favourite antenna to other products. However, do you clearly understand the parameters in which the antennas are tested and measured to achieve the most reliable performance results?

Testing Parameters
Testing parameters and methods can vary from manufacturer to manufacturer. Testing methods should always be fully disclosed such as free space, metal plate, plastic plate, glass, etc. Installing antennas outside of testing parameters will result in undesired antenna performance.
For example, if a screw mount antenna is measured in free space showing optimal performance results and is installed on a metal surface in the customer device, the antenna will not operate as expected. 2J Antennas will always disclose the complete measurement conditions to assure our customers get the most accurate data making the in-device integration of an antenna successful. In order to make a smart product selection between two manufacturers, we encourage that all testing should be completed with a standard length and high-quality cable in order to optimize antenna performance results. No alterations during testing such as shorter or no cables should be performed. This will result in inaccurate efficiency, peak gain and average gain results.

Return Loss
The return loss is measured in decibels (dB) and represents how much energy is transferred from the device to the antenna. It can help to can help to estimate the bandwidth and operating frequencies.
The lower the measurement the better. For a 50 Ohm system, it is recommended to have a minimum of -5dB or better measurement.

VSWR
Voltage Standing Wave Ratio (VSWR) is used to measure how much energy is transferred from the device to the antenna but with a different mathematical scale than the one used for Return Loss.
The lower the measurement the better, meaning closer to a 50 Ohm system and it is recommended to have a maximum of 3.5 VSWR. Please review the table below to learn more about the relationship between Return Loss and VSWR as well as other RF parameters and values.

Table 1, Return Loss to VSWR Conversion Table, and more RF parameters.

BandwidthBandwidth is a range of frequencies. A short frequency range is a narrow band and wider frequency range is categorized as a wideband. It is important to select the right antenna with the matching bandwidth as narrowband and wideband are not interchangeable.

Efficiency
Antenna efficiency (radiation efficiency) is the most important parameter of an antenna in mobile communications. It is a measure of the electrical efficiency in which a radio antenna converts the radio frequency power received into radiated power. In other words means how much energy is radiated from the antenna to the air, how good is the antenna to radiate the energy.
(100% means all energy radiated, 50% means half energy radiated, the minimum recommended is 25% but in some cases can go down to 10%, but the higher the better).

Peak Gain  
The most crucial parameter in mobile communication is antenna efficiency followed by peak gain.
Antenna gain is the measurement of an antenna's ability to direct or concentrate radio frequency energy in a particular direction or pattern. This is typically measured in dBi (Decibels relative to an isotropic radiator). Efficiency measures how much energy is in the air radiating in all directions, while peak gain is only measured in a single direction. While in fixed communication the most important parameter is the peak gain, since all the energy must be concentrated in one single direction.
This value comes from a single point in the radiation pattern being the maximum point in the 3D sphere.

Average Gain
Similar to efficiency, the average gain is represented with a different mathematical scale (dB) and takes into consideration any mismatch losses. 100% is 0 dB which is maximum radiated energy, 50% is -3 dB which is half of the radiated energy, etc. Please see below table for the relationship between efficiency and average gain:

    Table 2, Efficiency/ Average Gain Table

Radiation Patterns
The radiation pattern of an antenna is the strength of radio waves transmitted by the antenna traveling in different directions and angles.
Omnidirectional antennas offer a 360-degree doughnut-shaped radiation pattern that is uniformly distributed in all directions and are ideal for connecting devices that are on the same plane and to either side of each other.
Hemispherical antennas distribute their radiation over a hemisphere (half of the space).
Directional antennas radiate into one targeted direction allowing for longer transmission distances with less interference. 

The picture shows how the energy is being radiated to the air in 3 dimensional or 2 dimensional pattern. In 2D graph pattern, the horizontal and vertical planes are shown. Fig.3.

Fig.3, Radiation Pattern 3D and 2D Graph

Polarization
Polarization is the orientation of the electric field of an electromagnetic wave. The two most common polarizations are linear and circular.
With linear polarization, the electric field vector stays in the same plane were in with circular polarization, the electric field vector is rotating with circular motion completing a full turn for each RF cycle. This rotation can be completed right-hand (RHCP) or left-hand (LHCP).
Measurement and changes of polarization are determined in which the wave transmits through the environment from the transmitting to the receiving antenna.

3.Specification

Ground Plane
A ground plane is a surface area or metal that acts as a conductor and reflects the radio waves from other antenna components. The shape, size and the required clear area of the ground plane play an important role in determining radiation characteristics and gain.

Our portfolio of 2J Antennas offers both, ground plane dependent and ground plane independent antennas.
Low-frequency antennas such as broadcast antennas accept large conducting masses such as the earth or ocean as a sufficient ground plane. For very high frequency (VHF) and ultra-high frequency (UHF) antennas, the ground plane can be smaller and a metal disk, screen or wire is used as a ground plane. In automotive, marine and air equipment metal housing (car / airplane / boat) can serve as a sufficient ground plane.
As a general rule, the conduction surface must be at least a quarter of the wavelength of the radio waves in diameter and in ideal condition the bigger the ground plane the better control of the electrical performance is achieved.

Maximum Input Power
The Maximum Input Power is the maximum amount of power (in Watts) that can be transmitted to one antenna port without damaging it while maintaining performance.

Cable and Connector Types
The correct selection of RF cable and connector types is critical to proper antenna function. The connector serves as a mechanical connection between the antenna and RF system and the cable is the transmission line for radio frequency signals connecting transmitters and receivers. The cable lengths impact signal quality and strength.
Selecting a high-quality cable and connector that is compatible with the antenna will ensure optimal antenna performance. When considering a product, it is important to determine the correct connector gender, polarity and geometry as well as the cable length prior to a quote request.

We are very happy that you are interested in antennas. Read the sequel as well: 

2J Antennas is our longstanding partner in the field of antennas. Their valuable experience is a great asset for us as a project-oriented distributor. Many of our customers' projects have been built taking advantage of their wide range portfolio, as well as custom-made solutions from their professionals.

If you are looking for the perfect antenna, please contact us. We will be glad to help you with the selection at .

Source: 2J Antennas

slash Do not miss these articles

Do you like our articles? Do not miss any of them! You do not have to worry about anything, we will arrange delivery to you.

For more information, please visit antenna power distribution system.