Antennas

External Antennas for 4G and 5G Routers

Every 4G and 5G router ships with stub antennas fitted directly to the SMA ports on the casing. In many installations – urban offices, well-sited cabins, properties close to a mast – these work perfectly well. In others, particularly inside steel-framed buildings, thick stone walls, basements, remote rural locations, or anywhere the router must be positioned away from windows, an external antenna makes a measurable and often significant difference.

This page explains when an external antenna is needed, what types are available, how to choose the right one, and how to avoid the common mistakes that reduce performance rather than improve it.

Do You Actually Need an External Antenna?

Before purchasing an antenna, work through this process. Antenna upgrades that are purchased without testing first frequently disappoint – not because the antenna is poor, but because the problem was something else entirely.

1. Baseline test with the supplied antennas in the intended location. Install the router where it will live in normal operation. Open the router’s diagnostic page and note the RSRP value – this is a far more reliable indicator of signal quality than the bar display. RSRP of -80 dBm or better is excellent; -80 to -100 dBm is usable; below -100 dBm is marginal and an external antenna will likely help. Run a speed test and record the result.
2. Try different positions within the same space. Signal varies considerably within a single room. A position near a window can outperform a central cabinet location by 10-15 dB – the equivalent of moving substantially closer to the mast. Try several positions, including elevated ones, before concluding the signal is poor.
3. Test outdoors on a dry day. Take the router outside, clear of the building envelope, and run the same tests. Building fabric – reinforced concrete, metal cladding, low-emissivity glass, and cavity wall insulation – can attenuate cellular signal by 10-25 dB or more. If outdoor RSRP and speed results are substantially better than indoor results, the building is the problem. An externally-mounted antenna replicates that outdoor performance inside the building, through a cable rather than through the walls.
4. Test each network in turn. If you have a multi-network SIM card, lock the router to each available network and run the same tests. Coverage and performance vary significantly by operator at any given location. EE tends to outperform in rural areas; Three is often strongest in dense urban environments. Choosing the right network is sometimes a more effective fix than adding an antenna.
5. Consider the direction of the nearest mast. Check coverage maps or use a signal mapping tool to identify the likely mast direction from your location. If signal is marginal, a directional antenna aimed at the mast will always outperform an omni-directional antenna – but only if you know which direction to point it.

Antenna Types

Omni-Directional Antennas

An omni-directional antenna radiates and receives signal equally in all horizontal directions. This makes it the right choice when the mast direction is unknown, when the device is mobile, or when signal is present from multiple directions and you want to capture all of it. Omni-directional antennas are available in wall-mount, mast-mount, magnetic-base, and standalone desk or bracket configurations.

Typical gain for an external omni-directional antenna is 3-5 dBi – a meaningful improvement over the 0-2 dBi of a standard stub antenna, but less than a directional antenna aimed correctly.

Directional and Panel Antennas

A directional antenna concentrates its gain in a specific direction, delivering significantly higher performance in that direction at the cost of reduced sensitivity in others. If you know where the nearest mast is – or can identify it from testing or coverage maps – a directional panel antenna aimed at the mast will outperform an omni-directional antenna of any comparable size.

Typical gain for a directional panel antenna is 7-12 dBi. A Yagi-style directional antenna can reach 12-15 dBi, making it the right choice for locations with very poor signal where maximum gain in a single direction is the priority.

MIMO Antennas

Modern 4G LTE and 5G routers use MIMO (Multiple Input Multiple Output) technology, which uses multiple antenna ports simultaneously to increase throughput. A router with two antenna ports (2×2 MIMO) connects two antenna elements; a router with four ports (4×4 MIMO) connects four. Connecting a single external antenna to one port while leaving others on stub antennas partially defeats the purpose of MIMO.

MIMO antennas contain multiple elements in a single housing, connected to the router via multiple cables. For maximum performance, always use a MIMO antenna that matches the number of antenna ports on your router, and connect all ports.

Vehicle-Mount Antennas

Antennas for vehicle installation must tolerate weathering, vibration, temperature cycling, and the physical stresses of road use. Roof-mount antennas with magnetic bases are common for testing and temporary installation; permanent installations use through-hole or adhesive-mount bases with sealed cable entry. Vehicle antennas are typically low-profile to reduce wind resistance and avoid catching on overhead obstacles.

For in-vehicle routers with multiple antenna ports, a single MIMO puck antenna covering all ports from a roof-mount position is generally the cleanest solution. See also: 4G router for vehicles.

Building-Mount and External Wall Antennas

For fixed installations where the antenna is mounted on the exterior of a building and cabled back to a router inside, a weather-rated wall-mount or mast-mount MIMO antenna is the standard solution. These are designed for permanent outdoor installation, typically with an IP67 weatherproofing rating, and connect to the indoor router via a coaxial cable run through the building fabric.

Cable Types, Connectors, and Signal Loss

The cable connecting the antenna to the router is frequently the most overlooked part of an antenna installation – and the most common source of poor results after installation. Every metre of coaxial cable introduces signal loss, and the wrong cable type can negate the benefit of a good antenna entirely.

Coaxial Cable Types

The most common coaxial cable types used in cellular antenna installations are:

• RG58 – thin, flexible, low cost. Loss of approximately 1.0-1.5 dB per metre at LTE frequencies. Suitable for short runs only – up to 2-3 metres. Do not use for runs of 5 metres or more.
• RG174 – thinner and more flexible than RG58, typically used for short patch leads at the router end. Higher loss than RG58 – for short internal runs only.
• LMR-200 / Ultraflex 5 – semi-flexible, moderate loss (approximately 0.5 dB/metre at LTE). Good balance of flexibility and performance for runs up to 10 metres.
• LMR-400 / Ultraflex 10 – thicker, lower loss (approximately 0.2 dB/metre at LTE). Correct choice for runs of 10-20 metres. Less flexible; requires careful routing and a larger hole through the building fabric.

Connector Types

The three connector types most commonly encountered on 4G and 5G routers are:

• SMA (male/female) – the most common connector on industrial and commercial 4G routers. Screw-on, robust, suitable for permanent installations. SMA-male on the cable, SMA-female on the router.
• TS9 – small snap-on connector found on some compact and consumer-grade routers, particularly Huawei and ZTE devices. Not suitable for high-vibration environments. Requires an adapter for use with standard antenna cables.
• N-type – large screw-on connector designed for outdoor and high-power applications. Found on the weather-side end of many building-mount antennas. Requires an N-to-SMA adapter or pigtail at the router end.
• FME – small, lightweight connector found on some vehicle and compact antennas. Often used with a vehicle-mount antenna feeding a pigtail to an SMA connection at the router.

Always confirm the connector type on both the router ports and the antenna before ordering cable or adapters. Adapters introduce a small additional insertion loss but are unavoidable when connector types differ.

Antenna Recommendations by Application

CCTV and Remote Monitoring

CCTV installations typically use a private IP SIM card in a fixed router, mounted in an enclosure on or near the building. A wall-mount or pole-mount MIMO antenna with a 5-10 metre LMR-200 cable run is the standard approach. The antenna should be positioned on the exterior of the building at the highest practical point, oriented towards the nearest confirmed mast. See also: 4G router for CCTV.

Rural Broadband and Holiday Lets

Rural properties with thick stone, concrete, or metal-roof construction frequently see the largest improvement from external antennas. A directional panel antenna aimed at the nearest mast, with a 10-metre LMR-200 cable run from a roof or gable mounting point to the router inside, can transform a marginal connection into a reliable one. Where the mast direction is uncertain, an omni-directional MIMO antenna is a safer choice. See also: 4G router for holiday lets.

Energy Sites and BESS

BESS and remote substation installations typically use industrial routers inside electrical enclosures – environments that provide significant RF shielding. An external antenna mounted on the enclosure exterior or on a nearby pole, with a sealed cable entry through the enclosure wall, is standard practice for these installations. For sites requiring maximum resilience, two separate antennas on separate cable runs for each SIM are recommended. See also: 4G router for energy and BESS.

Construction Sites

Construction sites change character as the build progresses. A magnetic-mount MIMO antenna on the roof of a welfare unit or site cabin provides good coverage in the early stages and can be repositioned easily as the site develops. For permanent site office installations, a mast-mount omni-directional antenna is more appropriate. See also: 4G router for construction sites.

Vehicles and Fleet

Roof-mount MIMO puck antennas are the standard for HGVs, vans, and buses. These provide a low-profile, weatherproof solution covering all antenna ports on the in-vehicle router. Cable routing from the roof through the vehicle headlining to the router mount point uses low-loss thin coaxial cable or flat window-entry lead-throughs where a hole through the body is not practical. See also: 4G router for vehicles.

Antenna Installation: Common Mistakes

• Wrong cable grade for the run length. The most common problem. Always match cable grade to run length.
• Single antenna on a multi-port router. Partially defeats MIMO. Use a MIMO antenna covering all ports.
• Antenna positioned near metal structures. Metal objects within 30cm of the antenna degrade performance significantly. Position the antenna clear of metalwork.
• Connector not fully tightened. SMA connectors that are finger-tight but not spanner-tight introduce several dB of loss and can cause intermittent connection problems.
• Purchasing before testing. The test process above takes 20 minutes and frequently identifies that repositioning the router, not adding an antenna, is the solution.

Get Antenna Advice

Not sure which antenna is right for your application, router, and location? Tell us about your installation – the router model, the site type, the estimated cable run length, and the results of your signal tests if you have them. We will recommend the right antenna, cable grade, and connector configuration and can supply everything together as a complete installation kit.