Mobile Antenna Selection

You need to select the external donor antenna that will suit your requirements and there are 3 important factors to consider when selecting the CORRECT antenna which are in order of importance:

1. Gain
2. Strength and Durability
3. Removeable Whip

Options for Donor Antenna Gain:

 The collinear donor antennas that we supply for mobile/moving applications come in 3 versions.

• Fixed Whip on Standard Duty Spring - RFI CD Series Antennas - Perfect for highway use and mild dirt roads, comes with a standard duty spring base. These are a fixed whip antenna and cannot be removed from the base.
• Removable Whip on Medium Duty Spring - RFI CDR Series Antennas - Better suited to highway use with dirt roads thrown in and come with a medium duty spring base and removeable whip which unscrews off the base to store when not in use.
• Heavy Duty Mothership - RFI CDQ Series Antennas - Perfect for severely corrugated dirt roads, 4WDing/Off-roading and commercial/industrial use. These are really tough antennas which look the part and come with a heavy duty spring base and a RFI Quickfit® removeable whip which unscrews off the base to store when not in use.

We also stock the RFI CSM600 magnetic base antenna for applications where you want to take the unit between vehicles or structures. The magnetic base cellular LTE antenna is only recommended for highway/sealed roads use where the signal is scratchy such as 1 bar of service that you need to get that little bit of extra service but don't want to mount an antenna to your vehicle. The antenna gain is 2.5dBi to 4dBi so it is suited to shorter distances where service intermittently breaks up between mobile phone towers. This solution will improve the mobile phone service when there is a sniff of service outside.

So which Antenna do you get?

There is a highly informative and totally independent review/article on testing of some well known brands of Cel-Fi Go compatible antennas and which ones performed the best. This link is to an external website called "CHOICE" and we have absolutely no affilliation with the author or the website. click here for the article which we think is a worthy read.

This article clearly shows that the RFI antennas outperform other brands by over 10km and this is the exact reason why we believe in RFI Antennas to which we are an Authorised RFI Dealer in Capalaba Brisbane and a Capalaba QLD stockist of RFI antennas.

We believe RFI antennas are simply the best available on the market.

Stationary Building Fixed Antenna Selection

You need to select the external donor antenna that will suit your requirements and there are a few important factors to consider when selecting the CORRECT antenna:

1. Directional or Omni-Directrional Antenna
2. Antenna Gain
3. Antenna Types

1. Directional or Omni-Directional

An "Omni-Directional" antenna means that the antenna transmits and receives its signals in a 360 degree pattern. The signal radiates from the antenna just like dropping a stone in a pond and the ripple that is created is pushed out in a uniform 360 degree pattern. These antennas will collect any and all signals within the antenna frequency range that go past the antenna, which means that they also collect a lot of unwanted signals which is referred to as noise. Excess noise will reduce the quality of the signal and reduce the effectiveness of the system.

A "Directional" antenna is one that transmits and receives its signals in and from the direction that it is pointed. Directional antennas are used for a couple of reasons which are to maximise the signal strength and quality, and also to reduce the amount of unwanted signals (noise) from other sources such as other cell towers.

Both antennas have their place and we use both of them in different applications.

If there is fair to good cellular signal strength outside the building and the system is in a domestic installation, then an omni-directional antenna will be sufficient. The omni-directional antennas are easy to install and there is hardly any maintenance required once they are up in the air.

In areas where there is low signal strength outside, areas where there is lots of RF noise from other sources, long distances between the antenna and cell tower or commercial applications then we recommend a directional antenna to aim at the cell tower so that the signal strength and quality can be maximised whilst minimising the unwanted noise. These antennas are harder to install as they need to be pointed at the cell tower and tuned in to get the best signal strength, quality and reduced noise.

If you want to know more, read this Wikipedia article on Directional Antennas or this Wikipedia article on Omni-Directional Antennas.

2. Antenna Gain:

The lower the gain, the wider and more mushroom style the signal pattern is. Low gain antennas are suited to hilly / built up areas and shorter distances.

The higher the gain, the more directional and pin-pointed/flatter the signal pattern is. Higher gain antennas are suited to flatter country and longer distances and line of sight point to point applications.

3. Antenna Types:

1. Compact - These antennas are for applications where it is hard to mount an antenna somewhere outside the building or the larger antenna types are not wanted for visual appeal. The gain on these antennas is normally very low so the cell tower must be in close range with good signal outside.
2. Collinear -  These antennas are an omni-directional antenna, and our collinear donor antenna selection is normally in the form of a fixed whip style antenna just like you see on the bullbar of 4WD's.
3. LPDA - Log Periodic Dipole Array antennas are a wideband antenna which we use in the cellular spectrum of 700MHz to 3800MHz frequency range. At the time of writing this, this frequency range covers 3G, 4G and 5G systems. These are a high gain antenna, but not as high as the Yagi, and are suited to directional applications where there is a fair distance between the antenna and cell tower. See the Wikepedia article here.
4. Yagi - This is a narrowband antenna with high gain used for long distances and targeting a particular band within a narrow frequency range. Normally we use these to target band 28 on 4G and band 5 on 3G which fall in the 700MHz to 900MHz frequency range. See the Wikepedia article here.

So which antenna do you get for a mobile phone repeater?

Domestic Installations:

For a single cellular repeater system in suburbia where there is good signal outside and nothing inside the home, we normally recommend a 6.5dBi omni-directional colinear antenna mounted up on the roof on a short mast.

In areas where the cell towers are at a greater distance from the antenna and a directional antenna may not work because of hills being in the way, we recommend an 8.5dBi omni-directional colinear antenna mounted up on the roof on a short mast.

Rural Installations:

A lot of our rural clients are located many km's away from their closest cell tower and need to use a directional antenna with higher gain. The most common is an 11dBi LPDA directional antenna which we use a lot on cellular distributed antenna system installations that are a fair distance from the cell tower and we need to target the signal for optimal performance. 

Where the site is located a long way from the cell tower in flat country, we recommend a 15dBi Yagi high gain highly directional antenna. These antenna are narrowband and will only work on their specified frequency range so care is needed when specifying a Yagi antenna, but they perform very well in these applications. We have been know to improve mobile phone signals at properties that can't make phone calls with the phone continually dropping out due to poor phone signal, to seamless phone calls and around 30Mb/s data download speeds which is more than ample to stream movies.

Commercial Applications:

We recommend that you contact us for a commercial system so that we can have a chat to you about your requirements and what you want to achieve from the system. 

Otherwise taking all the above into account, we recommend an LPDA directional antenna with the gain dependent on the location. 

Mountain Country:

you will need to contact us for locations that are shaded from cell tower signals by mountains and large hills so that we can perform a site survey to ascertain if a cellular system is right for you. 

Note: This is a general guide to help our customers understand what may be required for their site. Each site and/or application is different and that's why we always recommend to conduct a site survey before specifying or installing an antenna system. If you are unsure or do not know much about antennas, then we recommend that you contact us and get professional advice for your application before you purchase any antennas or systems from us or anywhere else.