Antennas for INSYS Routers – Selection, Installation and Optimisation

Antenna guide for routers from INSYS icom

The choice and installation of the antenna have a significant impact on how reliably a mobile or Wi-Fi router can establish and maintain its wireless connection. It is not just a matter of achieving the highest possible antenna gain. The frequency range, number of antenna paths, mounting location, ground-plane dependency, cable length and the networks actually in use must all be compatible.

This guide assists you in selecting and installing antennas for the MRX.neo, MOROS.neo, MRX, SCR, ECR and MIRO router series. It covers, in particular, LTE/4G, 5G, LTE450 and Wi-Fi.

The guide helps you select a suitable INSYS antenna, decide between a single antenna and MIMO, ensure professional installation, and subsequently assess and optimise the wireless connection. It also covers the selection of third-party antennas and the regulatory requirements that must be taken into account.

Please note the following when making your selection!

The best antenna is not necessarily the one with the highest gain or the most antenna paths. It must be suitable for the router, the intended networks, the installation location and the intended use.

Preliminary considerations regarding the correct antenna installation

1. Determine which radio services and networks to use

2. Determine the number of antenna paths

3. Determine the installation location and ambient conditions

4. Check installation options

Determine which radio services and networks to use

First, clarify which wireless services and cellular networks the installation is actually intended to use.

Please note the following for 5G or LTE450 applications!

A 5G-capable MRX.neo will generally also use LTE/4G. Similarly, a suitable LTE450 configuration may support other standard LTE bands in addition to LTE450. You should therefore not choose the antenna based solely on the router’s model name.

If you are using a multi-roaming SIM, you should also consider that different network operators’ networks may be used. You should therefore not unnecessarily optimise frequency coverage and antenna location exclusively for a single network operator. If necessary, check with your SIM provider to find out which roaming networks are available.

Do not use combination antennas!

On the MRX.neo, MOROS.neo and ECR Wi-Fi routers, mobile and Wi-Fi signals are transmitted via separate antennas. A combined mobile/Wi-Fi antenna must not be used for these configurations.

How important is it to know which frequencies (bands) are actually being used?

The frequency band that a cellular router actually uses at a given location is determined by the network, the radio coverage and the router itself, and may change during operation. The antenna should therefore always cover the frequency ranges relevant to the application.

Targeted optimisation for specific frequency bands is particularly useful when the radio coverage at the specific location is known and special or problematic reception conditions require it.

Determine the number of antenna paths

Check the specific router configuration to determine whether one, two or four cellular antenna paths are provided. For MIMO or diversity configurations with 2 or 4 antennas, please note the antenna paths and port assignments specified for the respective model.

For routers in the MRX.neo series with a 5G modem, a 4×4 MIMO configuration is provided for in standard 5G/LTE operation. A 2-antenna configuration is only possible for certain frequency bands and port combinations; a 1-antenna configuration is not recommended, except in isolated cases. Further information can be found here.

The MRcard PL450D has two cellular antenna ports. The second port is used for MIMO or Rx diversity.

Dual SIM Single Standby (DSSS) for the MRcard450D!

The two SIM holders fitted to the MRcard PL450D do not represent two independent cellular modems or two independent antenna systems: the card has only 1. The two SIM holders are required to operate the device with standard LTE SIM cards and the special SIM cards for LTE450. These do not operate in parallel, but rather as fallback/redundancy connections.

Whether the higher data rate made possible by MIMO is actually required for the application is a separate consideration. For further information, please see the section Single antenna, 2×2 MIMO or 4×4 MIMO?.

Determine the installation location and ambient conditions

A closed metal control cabinet can significantly attenuate cellular signals. You should therefore mount the cellular antenna outside the metal cabinet.

You should also check whether the antenna requires a metallic ground plane. A ground plane is a conductive reference surface which, in appropriately designed antennas, forms an integral part of the antenna system.

For Wi-Fi, the actual coverage area required is the decisive factor. If, for example, Wi-Fi is only needed for maintenance work in the immediate vicinity of the control cabinet, the Wi-Fi antenna does not necessarily have to be mounted in the same location as the mobile phone antenna.

For outdoor installation, the environmental conditions as well as the requirements for earth connection, equipotential bonding, and lightning and surge protection must also be taken into account. Outdoor installation generally requires a higher level of protection against the ingress of water and dust. This is indicated by the IP rating.

For some applications, special protection against vandalism may be necessary. This is indicated by the IK rating.

Is the cable connected to the antenna long enough, or might an extension cable be required? Longer cables have an attenuating effect on the radio signal. Further information on this can be found in the sections How to read an antenna’s technical specifications correctly and Antenna extensions.

Check installation options

Before installation and commissioning, please clarify the following points in particular:

• What is the intended orientation?

• Is a ground plane required?

• What are the recommended distances from metal and other antennas?

• How should the cables be routed?

• What bending radii are required?

• Which connectors are to be used?

• What is the port allocation?

If using an external antenna, additional electrical safety precautions must be taken into account. Information on this can be found in the section Installing antennas correctly.

Selecting the right antenna

This section presents the antennas offered by INSYS icom and compares them to help you select the right one for your application.

Using these antennas, which have been qualified by INSYS icom, not only ensures a wide range of applications but also guarantees compliance with regulatory requirements (e.g. the RED Directive).

Also refer to the overview of the antennas supplied by INSYS icom.

Selection matrix router > network > cellular antenna

With the MRcard PL450D, two identical single antennas can be used for LTE450. INSYS does not currently offer an integrated 2×2 MIMO antenna specifically for LTE450.

The Magnetic/screw/adhesive Antenna, item no. 10017462, does not cover the 700 MHz and 2600 MHz frequencies and is therefore not listed in the table above. It is particularly suitable for networks that predominantly use 800, 1800 and 2100 MHz. In Germany and many other countries, however, this means foregoing the important 700 MHz rural coverage as well as additional capacity in towns and cities, meaning that reception and data rates may be noticeably limited depending on the location.

With the MRcard MSI.5G, the two-antenna configuration depends on the band and port. If the bands in use are unknown or are subject to change, the standard four-antenna configuration should be used.

When using multi-roaming SIM cards, potential alternative operator networks should also be taken into account in terms of frequency coverage.

Selection matrix router > Wi-Fi antenna

Single antenna, 2×2 MIMO or 4×4 MIMO?

• only small data volumes are transmitted,

• there are no high data throughput requirements,

• cellular reception at the location is good and stable,

• brief interruptions or fluctuating transmission rates are not critical for the application or

• Installation space, the amount of cabling required or the costs involved may be a factor against installing additional antennas.

When is it best to use 2 or 4 antennas?

The situation is different when a high data rate or a particularly robust wireless connection is required. In such cases, additional antenna paths become more important.

With LTE, two antennas can be used for 2x2 MIMO (Multiple Input Multiple Output) or Rx diversity. With 5G, there are four antennas, and this is referred to as 4x4 MIMO. Put simply, this provides the modem with additional, ideally diverse, reception paths.

The benefits are particularly evident in more challenging radio conditions. This may be the case, for example

• inside or near large metal structures,

• in a densely built-up area with significant multi-path propagation,

• in locations with poor or highly variable reception,

• when a high level of connection stability is important or

• when large volumes of data are regularly transmitted (e.g. video transmission, remote maintenance on large systems with many network users).

Consider location and application together

The table below provides a summary overview:

Please pay attention to the location of the antenna!

Before installing additional antennas, the antenna location should also be considered. A single, well-positioned outdoor antenna may be more suitable for a particular application than several antennas at a heavily shielded or radio-technically unfavourable installation site. A full MIMO configuration therefore does not replace the careful selection of the antenna location.

Please note for LTE450!

The MRcard PL450D has two antenna connectors and supports LTE MIMO on the downlink and RxDiversity. However, particularly with LTE450, many applications are traditional utility and telecontrol applications involving comparatively small volumes of data. The main reason for using two antennas in such cases is therefore often not to increase the maximum data throughput, but to utilise an optimised reception path, as the large diameter of LTE450 cells tends to result in weak signals at remote locations.

Please note the following when using an MRX.neo 5G on unknown or changing cellular bands!

Use four antennas! Reducing the number to two requires knowledge of the bands in use and the correct connection configuration.

As a general rule, 2x2 MIMO does not automatically mean double the data throughput (nor does 4x4 MIMO mean four times the throughput). The practical benefits depend on many factors, including the cellular service contract, the cellular network, current network utilisation, the characteristics of the radio cell, the frequency band, local radio conditions and the behaviour of the application.

Use ready-made 2x2/4x4 MIMO antennas or 2/4 individual antennas?

In general, the use of ready-made, integrated 2x2 or 4x4 MIMO antennas is preferable to the use of several individual antennas.

For 2×2 MIMO, either an integrated 2×2 MIMO antenna or – where provided for in the relevant configuration – a pair of suitable individual antennas may be used. Where individual antennas are used, the same type of antenna and comparable cable routes should be employed. Guidance on installing multiple individual antennas can be found in the section Arranging multiple cellular antennas.

How to read an antenna’s technical specifications correctly

Frequency range

The antenna must cover the frequency bands that are actually to be used. Alternatively, in cellular communications, numbered band designations are used for this purpose.

If in doubt, check that the frequencies/bands supported by the router match those of the antenna and the bands used by the cellular network operator.

Terms such as 4G antenna or 5G router are used solely for classification purposes. The specified frequency ranges are decisive for technical selection.

When using multi-roaming SIM cards, the frequency bands of several operators’ networks may be relevant.

An overview of the networks used by cellular network operators can be found, for example, here: https://www.frequencycheck.com/countries/germany

To obtain data on a specific cell tower, we recommend using the website https://www.cellmapper.net.

The antennas supplied by INSYS icom generally support all frequencies used in practice, with the following exception: the Magnetic/screw/adhesive Antenna, item no. 10017462, does not cover the 700 MHz and 2600 MHz frequencies. It is particularly suitable for networks that predominantly use 800, 1800 and 2100 MHz. However, in Germany and many other countries, this means foregoing the important 700 MHz rural coverage as well as additional capacity in urban areas, meaning that reception and data rates may be noticeably limited depending on the location.

Antenna gain

Antenna gain is usually expressed in dBi. It is determined by the design and is generally frequency-dependent. A high value is not necessarily better. The frequency range, directivity, installation conditions and regulatory requirements must also be taken into account.

The antennas offered by INSYS icom have been selected on the basis of good performance and compliance with regulatory requirements.

Matching / VSWR

If an external antenna is used, its electrical characteristics must be compatible with the RF system. The impedance must be 50 ohms.

VSWR (Voltage Standing Wave Ratio) or return loss describe the antenna’s matching across the relevant frequency range. Check the VSWR across all frequency ranges that are actually intended for use. A VSWR of ≤ 2:1 is a good target value; lower values indicate better matching. With broadband mobile communications antennas, higher values may also occur in individual frequency ranges. You should therefore not evaluate just a single best value, but rather the trend across the required frequency bands.

These values have been tested for the antennas selected by INSYS.

Ground plane

Check whether the antenna requires a conductive or metallic reference surface, or whether it is designed to be independent of the ground. The installation specifications form part of the antenna selection process.

Cables and connectors

Cable attenuation increases with cable length and frequency, and weakens the radio signal arriving at the router. INSYS uses special, high-quality RF cables with very low attenuation in the antennas it supplies.

Please also check the exact RF connector. INSYS icom uses SMA connectors exclusively:

• SMA connectors for cellular antennas

• RP-SMA (Reverse Polarity) for the Wi-Fi antenna connectors

Environmental conditions

For outdoor installation, the protection code, temperature range and, where applicable, mechanical resistance (e.g. to vandalism) are particularly important.

Ingress Protection code: For outdoor installation in an exposed environment, select a suitable antenna with a protection code of at least IP65.

Mechanical strength: If the antenna is installed in a public area or any other freely accessible location, increased impact resistance may be advisable in addition to the IP code. The IK code describes resistance to defined mechanical impacts. For protection against vandalism, the following can be assumed: IK09 for areas generally at risk of vandalism; IK10 for areas with a high risk of vandalism. Please note that the IK code does not guarantee complete protection against vandalism; the method of installation, accessibility and protection of the antenna cable must also be taken into account.Mechanical strength: If the antenna is installed in a public area or any other freely accessible location, increased impact resistance may be advisable in addition to the IP code. The IK code describes resistance to defined mechanical impacts. For protection against vandalism, the following can be assumed: IK09 for areas generally at risk of vandalism; IK10 for areas with a high risk of vandalism. Please note that the IK code does not guarantee complete protection against vandalism; the method of installation, accessibility and protection of the antenna cable must also be taken into account.

Antenna extensions

INSYS offers the following antenna extensions:

Keep the extension cable as short as is practical. A longer cable may nevertheless be the better solution if it allows you to achieve a significantly more favourable antenna location.

Example of frequency-dependent cable attenuation

The following table shows typical values for a comparable H-155 cable as a guide. These are not guaranteed attenuation values for INSYS extension cables.

In MIMO systems, antenna paths that belong together should, where possible, be extended using the same type of cable and comparable cable lengths.

Please note that attenuation affects both the transmission and reception directions.

The attenuation values given are primarily intended to provide an indication of the attenuating effect of a cable. In practice, it is not advisable to calculate the influence of the cable using simple signal-level calculations, as other necessary factors in the specific situation are either unknown or dynamic.

In practice, it is advisable to assess the influence of the antenna cable directly in specific installation situations; see the section Assessing antenna extension for further details.

Choosing the right external antennas

INSYS accessory antennas are designed to suit the intended applications and router configurations. Of course, antennas from other manufacturers can also be used.

Checklist for third-party antennas

The information set out in the previous sections applies. When selecting an external antenna, please check the following in particular:

Keep cellular and Wi-Fi separate

For devices equipped with cellular and Wi-Fi functionality (e.g. MRX.neo, MOROS.neo and ECR), cellular and Wi-Fi signals must be transmitted via separate antennas. A combined cellular/Wi-Fi antenna must not be used.

Third-party MIMO antennas

An integrated 2×2 MIMO antenna provides two separate RF paths, whilst a 4×4 MIMO antenna provides four.

When selecting MIMO antennas, the individual antenna paths should be decoupled (isolated) from one another by at least 10 dB, preferably 15 dB or more.

If multiple routers are installed in an application (e.g. 2 routers for redundancy purposes), DO NOT use multi-MIMO antennas for this purpose (e.g. a dual 2×2 MIMO antenna to which 2 routers, each with 2×2 MIMO, can be connected).

Directional antennas for multi-roaming SIM cards

A directional antenna for cellular communications can be useful in difficult reception conditions. Its alignment will generally favour a specific base station and, consequently, a specific operator’s network where applicable.

If a multi-roaming SIM card is to enable the use of alternative operator networks, these should be taken into account when selecting the location and aligning the antenna. A directional antenna optimised for a single base station may compromise the desired network redundancy if alternative networks are served from other directions.

This does not necessarily rule out the use of a directional antenna. The decisive factor is which objective is more important for the specific installation: optimising a particular radio link or ensuring access to multiple networks.

Conformity and approvals

For radio equipment in the European Union, Directive 2014/53/EU of the European Parliament and of the Council of 16 April 2014 on the harmonisation of the laws of the Member States relating to the making available on the market of radio equipment (Radio Equipment Directive – RED) is particularly relevant. The current legal position applies.

This section is intended to provide technical guidance and does not replace a legal assessment of individual cases.

Why the antenna is relevant to conformity

The essential requirements of Directive 2014/53/EU include, in particular, the protection of health and safety, electromagnetic compatibility and the effective and efficient use of the radio spectrum.

The characteristics of the antenna system used may affect these requirements. The frequency range, suitable connector and mechanical mountability alone are therefore not sufficient to assess the regulatory suitability of a third-party antenna.

Antenna gain and radiated power

To aid technical understanding, the relationship can be simplified as follows: radiated power ≈ transmitter power − line losses + antenna gain

This simplified relationship explains why antenna gain may be relevant from a regulatory perspective. A higher antenna gain is neither automatically technically superior nor automatically permitted for every router/antenna combination.

Product-specific limit values

The following product-specific specifications for maximum antenna gain, as published in the relevant product manuals, apply to the use of third-party Wi-Fi antennas:

For certain cellular configurations, the relevant limit values depend on the router and modem equipment. The necessary data can be provided by INSYS icom on request.

Protection of persons from electromagnetic fields

The protection of human health is one of the essential requirements of Directive 2014/53/EU. The antenna used may affect exposure to radio-frequency electromagnetic fields.

INSYS points out in the installation documentation that, in order to ensure CE-compliant radio operation with the antennas used, the exposure of persons to electromagnetic fields must be taken into account and verified. INSYS can only guarantee compliance with the relevant requirements if the antennas supplied by INSYS as accessories are used.

Please also observe the safety and installation instructions for the specific router. A general safety distance from people is deliberately not specified in this guide for all router and antenna configurations.

Customer liability in the event of a non-compliant antenna

INSYS assesses the conformity of its radio products within the scope of the configurations specified for the respective product. Conformity is ensured when using the antennas supplied by INSYS icom. If a different antenna is used, the technical and regulatory requirements relevant to the specific application must still be complied with.

Directive 2014/53/EU distinguishes between the manufacturer’s obligations and the proper installation and intended use of the radio equipment, which are the responsibility of the customer, system integrator or operator.

If radio equipment is modified in such a way that its conformity may be affected, a new regulatory assessment may be required.

When should INSYS be involved?

If it is not clear from the INSYS documentation whether a specific third-party antenna is suitable, this can be clarified with INSYS icom before use.

To do this, please have the following information to hand, if possible:

• Router type and radio equipment

• Antenna manufacturer and type

• Full antenna data sheet

• Cables and extensions used

Use outside the European Union

CE conformity does not automatically imply that the router/antenna combination is authorised for use in other countries.

For the intended location of use, check the approvals for the specific router model and the relevant information in the product manuals, as well as the requirements regarding frequency use, transmission power and antenna installation that apply in the destination country.

Installing antennas correctly

Selecting the installation location

Where possible, try out several antenna positions before carrying out the final installation. Solid structures, metal surfaces, machinery and metallised glazing can significantly attenuate radio signals.

A smartphone with a SIM card from the same network operator can be helpful for an initial assessment. The final assessment should be carried out using the intended router and antenna.

Specialised cellular/network testers can be used for professional or routine site surveys; for example, the relevant measurement solutions from ENQT.

When using multi-roaming SIM cards, you should not optimise the installation based solely on a single known base station if alternative operator networks form part of the coverage strategy.

Router in a metal control cabinet

Install the cellular antenna outside a closed metal cabinet.

In this case, an antenna extension may be worthwhile despite the additional cable attenuation if it allows for a significantly better antenna location.

The same logic does not automatically apply to Wi-Fi. If, for example, Wi-Fi is only intended to provide coverage for a single service workstation in front of the control cabinet, select the Wi-Fi antenna position to suit this local coverage area.

Building

In modern buildings, windows with a thin metallic coating are often fitted for energy efficiency reasons. However, this coating causes significant attenuation of radio signals, and the signal strength available inside the building may be too low.

In practice, the metallisation of the windows is not usually visible at the point of installation, but it can be detected with a simple test: if the cellular signal strength improves significantly when the windows are opened, metallisation is present.

In such cases, the use of an external antenna is very helpful.

Ground plane and metal surfaces

Before installation, check whether the antenna requires a metallic ground plane.

In the case of an antenna that relies on a ground plane, the conductive mounting surface forms an integral part of the intended antenna system. The general recommendation to keep a distance from metal surfaces therefore does not apply to this mounting surface.

For example, the following applies to INSYS icom antennas:

• Magnetic Antenna, item no. 10019504: requires a metal surface

• Magnetic Antenna, item no. 10026503: a metal surface measuring at least 30 × 30 cm is required

• Magnetic/screw/adhesive Antenna, Item No. 10017462: suitable for any surface

• Roof Mount Antenna, item no. 10022309: suitable for any surface

In the case of surface-independent antennas, nearby conductive surfaces may nevertheless affect the radiation pattern. Where there are no product-specific guidelines, a distance of approximately 30 cm from conductive surfaces can be used as a practical guideline.

Please refer to the technical documentation for the antenna!

Product-specific installation instructions take precedence over general spacing rules.

Aligning the antenna

Cellular network operators typically align their base station antennas vertically. Rod-shaped cellular antennas are therefore generally aligned vertically. For other antenna designs, the relevant product specifications must be followed.

A directional antenna should be aligned on the basis of the actual measured reception values and not solely by visually targeting a presumed base station.

When using multi-roaming SIM cards, it should also be borne in mind that alternative operator networks may be served from different base station locations.

Positioning multiple cellular antennas

If several individual antennas are used for MIMO or Rx diversity, they should, where possible, be of the same type and have comparable connecting cables.

The aim of this arrangement is to ensure that the antenna paths receive signals that are as different as possible, or that are as uncorrelated as possible. This can be achieved through spatial separation (spatial diversity) and through different polarisation (polarisation diversity).

You should therefore not install separate individual antennas directly next to one another. As a practical minimum guideline, a distance of approximately a quarter of the wavelength (λ/4) of the lowest cellular frequency used can be applied. At 800 MHz, this corresponds to approximately 9 cm; at 700 MHz, approximately 11 cm; and at 450 MHz, approximately 17 cm. A greater distance can further reduce mutual coupling and the correlation of the reception paths, i.e. further improve the RF situation.

Depending on the type of antenna, positioning the two antennas at different angles – for example, at an angle of approximately 90° to one another – can also improve the MIMO or diversity characteristics. However, such an arrangement does not, as a general rule, replace the need for physical separation, and is not necessary or appropriate for every antenna design.

You should therefore give priority to following the antenna manufacturer’s installation and alignment instructions. If no specific instructions are provided, ensuring that the individual antennas are sufficiently spaced apart is the simplest general measure.

In the case of integrated 2×2 or 4×4 MIMO antennas, the arrangement and orientation of the individual antenna elements are already determined by the design. Install these antennas in accordance with the manufacturer’s specifications.

In the case of a local network station, for example, it may initially be more important that the antenna is mounted at a location favourable for radio transmission outside the metal station building. For the MRcard PL450D, two identical LTE450 single antennas can be used and mounted, for example, at diagonally offset positions on the station, both aligned vertically.

Separate cellular radio and Wi-Fi spatially

For devices equipped with cellular and Wi-Fi functionality (e.g. MRX.neo, MOROS.neo and ECR), cellular and Wi-Fi signals must be routed via separate antennas. A combined cellular/Wi-Fi antenna must not be used.

Unless otherwise specified for a particular product, these instructions recommend a distance of approximately 30 cm as a practical guideline.

This rule applies to antennas for different radio services, namely mobile networks and Wi-Fi.

Routing the antenna cable

Avoid kinks, crushing, tensile stress on the connector, unnecessary adaptors and unnecessarily long cable routes.

Observe the product-specific minimum bend radius. If no value is specified, approximately ten times the cable diameter can be used as a general practical guide.

Extensions for MIMO

Keep antenna extension cables as short as is practical. The gain achieved through a better antenna location may justify additional cable attenuation; this should be verified by measurement.

In MIMO systems, antenna paths belonging to the same set should, where possible, use the same cable type and have comparable cable lengths.

A 2×2 MIMO antenna has two RF paths, whilst a 4×4 MIMO antenna has four. Accordingly, all paths used must be taken into account when routing the cables.

Connectors and cable glands

Check the exact RF connector. SMA connectors are used for the cellular connectors discussed here; Wi-Fi connectors use RP-SMA.

Although SMA and RP-SMA have a similar design, they must not be confused. In addition to the thread, check the design of the centre contact in particular.

Avoid unnecessary chains of adaptors.

In the case of cable glands, the bend radius, edge protection, strain relief, mechanical protection and the required protection code must also be taken into account.

Please note the following regarding cable entries!

The protection code of an antenna does not automatically determine the protection code of a subsequently fitted cable gland.

Outdoor antennas and protective conductors

When using an outdoor antenna, the shielding of the antenna system must be connected to the protective conductor.

This measure is distinct from any necessary equipotential bonding, as well as lightning and surge protection, and does not replace a comprehensive protection system.

Equipotential bonding, lightning and surge protection

An antenna cable coming from outside forms a conductive connection to the installation and must be taken into account when planning the equipotential bonding and, where applicable, the lightning and surge protection.

If the building is fitted with an external lightning protection system, the antenna installation must be incorporated into the protection scheme. Depending on the installation location, particular attention must be paid to the protection zone, air-termination devices and the required separation distances.

In this regard, DIN EN IEC 62305-3 (VDE 0185-305-3), Lightning protection – Part 3: Protection of structures and persons, in its current edition, is particularly relevant.

To protect electrical and electronic systems against electromagnetic lightning pulses, particular attention must be paid to equipotential bonding, cable routing, shielding and, where necessary, a coordinated system of surge protection devices. These measures are dealt with in particular in DIN EN IEC 62305-4 (VDE 0185-305-4), Lightning protection – Part 4: Electrical and electronic systems in buildings. The latest edition applies.

Whether surge protection is required for the coaxial cable, and if so, what type, depends on the protection strategy for the specific installation. Among other things, the protection device must be suitable for the frequency range used and the electrical stresses on the cable. Please refer to the products offered by our partner DEHN.

Please note the following when planning lightning protection!

The planning and installation of equipotential bonding, lightning protection and surge protection must be carried out by qualified specialists in accordance with the specific installation. This antenna guide is not a substitute for lightning protection planning.

Check and optimise reception

Once the installation is complete, the reception should be checked using the measurements provided by the router. Individual measurements are less meaningful than a systematic comparison carried out under conditions that are as consistent as possible.

Assessing cellular reception using RSRP and RSRQ

Do not use the signal strength value to assess the quality of the wireless signal.

RSRP, RSRQ and SINR are particularly relevant for LTE and 5G.

RSRP (Reference Signal Received Power) describes the reception level of the LTE reference signals and is expressed in dBm.

RSRQ (Reference Signal Received Quality) describes the quality of the LTE reference signals and is expressed in dB.

SINR (Signal-to-Noise Ratio) describes the ratio of the useful signal to interference and noise.

These metrics are used in 4G and 5G-capable routers.

In addition, the signal indicator is available. It combines the RSRP and RSRQ values and can be used in practice as a quick overall assessment; for a detailed analysis, the specific RSRP and RSRQ values, as well as the cellular standard, band and, where applicable, cell ID, should also be taken into account.

Details on how to interpret the values can be found under Signal indicator.

Please note the following when comparing reception parameters!

Comparability is only possible if different measurements are taken within the same radio cell (where the Cell ID and Location ID parameters are the same). It may happen that, by using a different antenna, the router connects to a different radio cell, and the first radio cell can no longer be reached due to changes in signal characteristics. Please take this into account when evaluating your results.

Assessing Wi-Fi reception

With Wi-Fi, the signal strength on the relevant Wi-Fi channel, expressed in dBm, can be used for comparative measurements.

The closer a negative dBm value is to 0, the stronger the received signal.

The following values can be used as a general practical guide:

Please note regarding the Wi-Fi signal strength!

These figures are general Wi-Fi guidelines and not INSYS-specific thresholds. The actual signal strength required depends, amongst other things, on the Wi-Fi client, data rate, modulation scheme, interference, channel occupancy and application.

Test the Wi-Fi in the areas where the clients are actually used. For example, a Wi-Fi network intended solely for maintenance work in front of a control cabinet does not need to be optimised to provide comprehensive coverage throughout the entire building.

Systematically compare antenna positions

Where possible, compare different antenna positions or orientations under the same conditions:

1. Establish a stable cellular connection.

2. Record RSRP, RSRQ, SINR and signal indicator.

3. Please also record the network operator currently in use, the cellular technology, the frequency band and the network cell.

4. When you carry out a performance test (e.g. using https://www.telekom.de/shop/tarife/speedtest), record the download and upload speeds achieved, as well as the latency times and the destination server used.

5. Change only one parameter, such as the position or orientation of the antenna, or the antenna itself.

6. Wait until the connection has stabilised again – this usually takes at least 30 seconds.

7. Please collect the values again.

8. Repeat the measurement if necessary.

With a multi-roaming SIM, the network operator currently in use is particularly important. If the router switches between two network operators between measurements, you are no longer comparing just two antenna positions.

The same applies when switching between frequency bands or network cells.

If, however, the aim is to specifically investigate the network redundancy of a multi-roaming SIM installation, the availability of the intended alternative networks can form part of the test.

The procedure is the same for Wi-Fi.

Assess antenna extension

Do not just assess the attenuation of the additional cable, but the entire installation.

A useful comparison, for example, is:

Starting position → measure → new antenna location → connect the extension → measure again

An antenna extension can lead to a better connection despite its cable attenuation if it allows for a significantly more favourable antenna location.

However, do not infer a supposedly still permissible additional cable length from an RSRP difference. The antenna cable affects both the receive and transmit paths.

Is the RSRP good, but the RSRQ and/or SINR poorer?

A comparatively good RSRP, combined with a poorer RSRQ or low SINR, may indicate that the connection is not limited by the reception level alone. The useful signal may be sufficiently strong, but at the same time be affected by interference or noise.

Possible factors include, for example, interference, multipath propagation or the current radio conditions within the network cell being used. A low or negative SINR is a clear indication that the useful signal is barely standing out against interference and noise.

In this case, you should, in particular, try a different antenna position or orientation and, if necessary, carry out measurements at different times. You should also check whether the network operator, frequency band or network cell has changed between measurements.

An antenna with higher gain does not automatically result in a better connection under such conditions. It is not only the highest possible reception level that is crucial, but also sufficient signal quality.

Performance tests

RSRP, RSRQ and SINR describe the radio connection, but do not directly answer the question of what data rate an application actually achieves. A performance test can therefore be carried out as a supplementary measure, for example using a browser-based speed test (e.g. at https://www.telekom.de/shop/tarife/speedtest). This provides real-world figures for download, upload and latency.

However, a speed test does not measure solely the quality of the antenna or the installation. The achievable data rate depends, amongst other things, on the cellular standard and frequency band used, the available channel bandwidth, the load on the cellular base station, the network configuration and the transmission path to the test server. Even with the same antenna, the results can therefore vary significantly between two measurements.

Why doesn’t a “better” antenna always provide a higher Mbit/s speed?

A better antenna does not necessarily result in a higher data rate. For example, a wireless connection may already be established using the existing antenna, in which case the antenna is not the limiting factor. An improvement in the RSRP does not, therefore, automatically lead to a higher throughput.

Nor is a higher antenna gain alone a reliable measure of expected performance. For data transmission, signal quality and the conditions within the network cell are particularly relevant, in addition to the reception level.

With MIMO, it is also the case that multiple antenna paths do not automatically result in a higher data rate under all radio conditions. The actual usable MIMO benefit depends, amongst other things, on the radio conditions and the transmission. A single speed test is therefore not suitable for drawing direct conclusions about the quality of a single-antenna (SISO), 2×2 MIMO or 4×4 MIMO antenna based on a higher or lower measured value.

Please note the following when evaluating a speed test!

An antenna is not necessarily better simply because a single speed test shows a higher data rate. Improved or more stable reception, fewer connection drops or a higher connection margin during long-term operation can be just as relevant for industrial applications.

Troubleshooting

The following table provides a quick guide to troubleshooting. Where possible, change only one parameter at a time and then compare the results again.