It’s true. Antenna pass-thru for in-vehicle computing devices is officially passé (Vision Paper PDF). Even with a stellar installer and an external antenna (think rabbit ears for the vehicle), you’re limiting your mobile capabilities. Applying 1990’s technology yields little in-vehicle benefit now that LTE is designed to benefit from internal MIMO antennas.
Your field workers need tools when on-site. Many of these tools are electronic: computers, cameras, GPS, and voice recorders to name a few. All need connectivity to share their data. The catch: Antenna pass-thru only supports one device at a time, and only when it’s docked. This basically eliminates the device’s mobility capability and makes it a "wired" in-vehicle, possibly portable, computer or accessory. Here at Motion, our mission is to integrate the vitally important functions for the mobile workflows of an organization into a single mobile solution that remains viable from the office, to the vehicle, and into the field without needing a computing “wingman.” Devices such as voice recorders, cameras, GPS, and others are now part of our mobile products, but their value (always with you in one device) is lost if tethered by an external antenna.
Antenna pass-thru only supports one device at a time, and only when it’s docked. This basically eliminates the device’s mobility capability and makes it a “wired’ in-vehicle, possibly portable, computer or accessory.
Mobility is the productivity enhancer of our times. Work happens where people live and work, which is not the same as where a truck can park. I guess if all field work was servicing parking meters and drive-up windows, that would be fine.The reality is that the truck brings the field worker near the scene, not to it. Mobile devices – lightweight, durable, and with ubiquitous connectivity – enable work to happen where the work is. But antenna pass-thru is ultimately a tether keeping you far from the work, and it diminishes the ability of the device to stay connected when undocked. Why? Because the very design that allows for an external antenna degrades the ability to stay connected when no external antenna is attached. If your cell phone has a connection, then your Tablet PC should too. It shouldn’t need a separate external antenna to secure a signal. They are both talking to the same towers with the same internal radio protocols.
So why do so many trucks use external antenna? Because they used to need it, just like you used to have rabbit ears on TVs. We’ve moved on with TV tech, and so have mobile computers. Modern tablets don’t need external antennas *IF* designed right.
There is another significant hitch with antenna pass-thru: Loss of LTE performance. All carriers require radios submitted for certification to have two antennas. They function simultaneously to deliver two key benefits: a better chance of connecting if there is a weak signal, and double the bandwidth. With one external antenna, the predominate method supported, you lose signal selectivity in areas with weak signals. And you lose half the available bandwidth all the time. That is why if a manufacturer submitted a device for LTE certification with only one antenna, whether it’d be a tablet, a smartphone or a hotspot, it would be rejected.
Antenna pass-thru isn’t a good idea. It isn’t even a “can’t hurt” idea. It does hurt – with the steep price being less productivity, since your tablet is not truly mobile, and less bandwidth when mounted in a vehicle. As our Canadian country manager Scott Ball says, “When was the last time you saw a cell phone with an external antenna?” It’s all the same radio waves folks.