TFM’s Managing Director, Mark Fitton talks to one of our Network Engineers for his expert advice on antennas

Having a finance background, I like to understand what value our products and services add to our customers. One of those products is antennas, and believe me when I say there are a lot of options on the market, all offering different benefits and cost profiles.

Which antenna is the best?

To make this assessment, I talked it through with one or our resident tech gurus, Network Engineer Steve Townsend.

Mark: What exactly is an antenna, and what does it do?
Steve: In simple terms, the antenna is a critical part of a wireless modem that converts the radio signals into tiny electrical signals. These electrical signals get amplified, and then processed by the modem.

Mark: So, sounds like it’s important! What options are there for antennas?
Steve: Again, keeping it simple, the standard format of antennas is internal. If you look at your phone, tablet or 4G-enabled watch, you’ll see that the antenna is built into the device. This is also the case for consumer-grade mobile broadband routers. Now, internal antennas are great for portability and aesthetics – cast your mind back to the good old days when antennas were pointing out of the phone! But external antennas can give better options for fixed installations.

Mark: What advantages does an external antenna give?
Steve: First, by not having to engineer the antenna into the device, the designers aren’t constrained in the same way. This means the antenna can be designed with performance in mind, rather than compromising performance with fitting it into the housing. Second, if the router is housed in a building that shields radio waves from getting in – like a container made of metal or a building with thick walls – an external antenna could mean the antenna is housed outside of the structure. And of course, the antenna can be housed on a mast. Higher up, giving a better signal, and pointed in the direction of the mast.

Mark: How do we know if external antennas are better? Can we measure and quantify the performance increases?
Steve: With the Cradlepoint devices, the performance stats of the routers are logged regularly and uploaded into the cloud portal. That means we can then analyse and compare them – in a test scenario or in a customer device. These stats include the strength of the signal received, and the quality of the signal received. Both factors will influence the end-user experience, which is the ultimate goal of what we want to be optimising. Another benchmark is a speed test. There are other factors at play, but this can give a good indication of performance at a point in time. Certainly, if several measures are combined, that can give a good proxy for performance.

Mark: Sounds good, do you have any examples of this?
Steve: Absolutely! Several of our customers have metallic framed portacabins, which have terrible performance when the antenna is inside the structure. But housing it externally onto a pole has driven a 5-8x improvement in speeds. Another example is a building with extremely thick walls. This had similar issues with poor performance inside, but the Cradlepoint coupled with a well-placed external antenna has driven 8-10x improvement in speeds.

Mark: So, you’re saying that external antennas are the way to go?
Steve: Not necessarily. If the signal is strong where the end user is, or the connectivity speeds are not overly important, or there are only one or two users, then a low-end router with internal antenna would probably be a more cost effective solution. However, if there are greater demands on data and performance, then an enterprise-grade router often makes more sense. Of these, if there is sufficient signal indoors – for instance, if the router can be sited next to a window – then the ‘paddle’ antennas that plug directly into the router will generally work well and deliver comparable performance to a true external antenna. But if the signal inside is poor, then mounting the antenna externally, and being able to direct the antenna towards the mast, will be more beneficial. Also, a ‘directional’ antenna can have more gain than an ‘omni directional’ antenna, but only if it is pointing in the right direction. There’s a lot to consider!

Mark: Okay – I’ve learnt a lot, and we haven’t really covered anything technical.
Steve: Indeed, these are more practical points to consider when choosing a mobile connectivity set-up, especially when focussing on the antenna part of the solution. There is so much more to it, whether that’s looking at the specific performance metrics in more detail, going into the benefits of MIMO (multi-in-multi-out), or looking at carrier aggregation.

Mark: In a nutshell, what is MIMO and carrier aggregation?
Steve: Features built into modern modems that optimise the available bandwidth between the router and the mobile masts, which result in more stable connections and/or better speed performance. It’s important to consider both of these factors, as often people focus solely on speed because that’s easier to measure.

Mark: Last question – pricing?
Steve: The ‘paddle’ antennas cost around £12, and an external antenna with 5m of low-loss cable costs around £150, depending on the model. So, you potentially can get an 8-10x performance increase for a one-off investment of £150. Obviously only the customer can say if this is justified, but generally we see customers justifying the expense in areas far from a mast, in specialist buildings, or in densely populated areas.

Mark: Thanks Steve, for walking us through antennas!

If you’re reading this and would like to chat through your options, please contact us today!