Frequently Asked QuestionsDiscover answers to commonly asked questions

The material for the ground plane should be electrically conductive. A metal surface such as iron or aluminum is the usual choice.

It should have a smooth, flat surface so that the radio waves are not scattered randomly from it.

Please note that with time, many metals corrode and can end up with a pitted surface. In such circumstances it is usual to paint the ground plane to protect it.

Some Siretta antennas, because of their construction, require a ground plane beneath them to achieve their data sheet specifications. A ground plane means that the antenna needs to be placed on a surface that will reflect the radio signals. The data sheet often specifies the size needed, which should be read as a minimum size. If a ground plane is needed but not specified, then it should extend at least ¼ of the antenna’s wavelength from the antenna in all directions on the plane on which the antenna is mounted.

The key aspects of these technologies are that the user is likely to control and operate both ends of the radio link and the distances are typically 1 to 10s of meters. Because the distances involved are small, the radio network is likely to be in a home or a building. The radiation pattern of both antennas needs to be considered if the link distance of the radio standard being used is long.

The full three-dimensional model of the antenna’s radiation field may need to be considered as the radio links created may be both above and below the antenna, as well as on the same level.

Polarization also needs to be considered. Where the radio link is a short distance, there are unlikely to be many reflected radio signals and so the polarity of the signal leaving the transmitter is likely to be the same as that arriving on the receiving antenna.

While almost all antennas are vertical polarization, that is vertical polarization with respect to the XYZ orientation diagram provided in the data sheet.

An antenna mounted at a different angle will have a correspondingly angled polarization that ideally needs to be matched at the antenna at the other end of the link.

Because of the large distances between your antenna and the antenna on the cell tower, there are likely to be many reflected signal paths between the transmitter and receiver.

This means that placement and orientation of the antenna can be somewhat of a trial-and-error process.

We recommend Siretta’s SNYPER Signal Analyser range for cellular installations. The SNYPER is a device that measures the received signal strength of every cell in range of the tester which can be used to pick the best operator as well as the bands of operation used on the site.

At the point of installation, the antenna may be connected to the SNYPER in LiveSCAN mode, which allows the received signal strength to be measured in real time.

The antenna can then be moved around to find the best position for optimal reception. This is especially useful for setting up high gain directional antennas, where micro-adjustments in positioning can make all the difference.

GNSS Satellites always transmit right hand circular polarized radio signals.

Therefore, GNSS antennas should always be mounted with the X and Y planes horizontal and the Z planes vertical. Because GNSS uses right hand circular polarization, the antenna can be freely rotated on the XY plane if it supports right hand circular polarization (check out our datasheets for the XYZ orientation of the antenna you are using)