Antennas on devices are what I like to think of as the “last, last mile”. Whereas in a fixed line world the last mile may be the copper or fibre from the exchange to the premises, in the cellular world this could typically be thought of the local cell tower(s) providing service to a device. However that local cell tower is only part of the equation. How well the device can transmit and receive to that cell tower determines the performance and reliability of a service and the antenna attached to that device is a critical part of that. In this blog post I am going to take a closer look at antennas and explore how we can improve the service by paying attention to this one often overlooked component.
All wireless devices have an antenna of some sorts. Antennas come in many shapes and forms, and in some cases, such as in the typical mobile phone of today, the antenna is an unseen but critical part of the phone’s operation. The only time we think about the antenna is when we are looking at the signal bar on the phone’s screen. As you probably know, the antenna is what enables the radio circuitry of the device to transmit and receive signals, in other words, that means voice and data. In most cases, the antennas that are included with a device’s packaging are sufficient for service—but they are definitely provided with low cost in mind.
Sometimes, having a mediocre antenna on a device is like having bicycle wheels on a Porsche—no matter how high performing the system is, one mediocre component can have the power to limit the total performance of the system and therefore the user experience.
Note that I’m not advocating that every single one of your devices should be retrofitted with a giant antenna—in most cases the service will be sufficient. However, it’s important to know that the antenna is upgradeable and can be optimised can help you and your end user in challenging deployments. The field of antennas and RF engineering is also vast and in this post we are only touching the very tip of the iceberg!
So why upgrade?
Antenna performance can be measured in gain (expressed in decibels). Larger antennas generally pick up more signal, which means more gain. Having a stronger signal against background noise (SNR – Signal to Noise Ratio) means that the signal is clearer, and if the device can get the data “right” more often this means upper layer protocols, and applications don’t have to re-transmit data as often. While all these calculations happen hundreds of times a second, the net effect has a higher bandwidth effect for an application.
In plain and simple words, a properly selected antenna could give a site higher bandwidth and reliability!
Types of antennas
Antennas for our purposes can be thought of in two fields: omnidirectional and directional.
Directional – Useful in areas of poor signal, the directional antenna can be pointed towards a particular cell tower. This is best when the location is fixed and signal quality is poor with the included antenna. Consideration should be taken though, as if the tower the antenna is pointed at fails, the directional antenna will not have as strong a signal towards other cell towers which could provide service.
Omnidirectional – This means that the antenna will transmit and receive in all directions. While not having the focused power of a directional antenna these are useful where there is good signal coverage, or the device is mobile, for example a router on a WiFi-enabled bus.
Besides directional and omnidirectional, here are some other considerations for antennas.
MIMO (Multiple Input / Multiple Output) for enhanced LTE (4G) performance – allowing the device to send/receive data to multiple LTE base stations as once. This also means the device must have the capability.
Weatherproofing – These antennas are designed to be mounted outdoors, attached to the side of buildings or on poles etc. Some antennas are also weatherproof but slimline, for example if the application is the aforementioned bus Wi-Fi then it would be mounted on the roof of the bus.
High Gain – Antennas have a gain rating. The larger the number, the more signal the antenna can receive, however the tradeoff is usually in size.
Cabling – I’ll refrain from a last, last, LAST mile statement, but the cable is just as important as the antenna! Make sure the antenna is connected to the device with quality cable recommended by the vendor and also that the distance between the antenna and the device is within the cable specifications.
Location of the device
Could there be an alternative to a new antenna? Possibly. If your service is not performing up to scratch, the immediate environment around the device could also be reducing performance and you may be able to extract a better performance without resorting to a specialist antenna. For example, be suspicious of antennas near large metal objects, and other devices which generate a lot of RF noise, for example high voltage power cables or machinery.
One trick sometimes used, is that if the router location with its antennas is suboptimal, try moving the entire router elsewhere, and run the router back to the network with some good quality cable instead (bearing in mind the maximum length runs for Ethernet cable).
In conclusion, keep in mind that the antenna is the “last, last mile” in a solution and don’t discount it as another tool in your arsenal to provide the best possible service for a solution. Just remember that bigger isn’t always better and there are other factors such as location and antenna type to consider before spending your cash!
In the near future, Pangea will have a selective range of antennas which have been tested with our router range. If you want to know more about antennas, Pangea, Pre-Ethernet, or IoT and M2M solutions, please feel free to get in touch here.