Robot Mower External Antenna
This guide is intended to help owners of robotic mowers understand how to extend the base station / mower signal range, by fitting a robot mower external antenna. Actually, the antenna only needs to be fitted on the base station, as the device itself just needs to receive the signal. Other articles have covered the placement of the charging (base) station, and installation of the boundary wire. These topics are also important for a successful installation.
The base station communicates with the mower through a signal transmitted through the boundary wire. But the mower is not always in range of the boundary wire, so the installation also relies on a weak radio signal from the base station to the mower, a bit like the signal between a cordless phone handset and its cradle. Similarly, there is a limited range to this signal, about 50m maximum, under good conditions.
But there must be a direct line of sight between the base station and the mower for this to work properly. If structures or topography get in the way, the signal range may be reduced, or blocked altogether. Also, very importantly, this signal is relevant only when it is needed, which is upon starting the mower, or if it gets into a situation of difficulty where it has to extricate itself. Once the mower has started, and is running inside the boundary wire, the signal is less relevant.
Every Yard Is Different
Signal is good up to 50 metres, in ideal conditions
The Signal Is Important
- When it is being turned on away from the base station
- When it experiences an exceptional fault (eg. out of bounds, current overload, etc…)
My Yard Has Trees And Flower Beds
My Yard Is Uneven
Why An External Antenna?
The internal RF antenna within the base station is, by necessity, very close to the ground. As can be seen above, having an antenna that is close to the ground is sometimes not optimal.
In environments where the ground undulates, or has various levels, It is useful to be able to raise the base station antenna to a point where the signal may reach all areas of the yard.
That’s where an external antenna comes in. Further, the signal may be improved because the eternal antenna may have more gain than the basic wire provided within the base station
Fitting The Antenna
Modifying The Base Station
Once the coaxial cable, with a small SMA connector on the end, is attached to the main PCB, it is then necessary to pass it through the base station enclosure.
This can be easily achieved by drilling a small hole at the back of the enclosure, beside the boundary wire connectors, and passing the aerial SMA connector through the hole (as pictured, internally, and externally).
This hole will be sheltered by the same extrusion that shelters the power cable connector and boundary wire cable connectors.
What Size Antenna?
- 5dBi (12cm long). This antenna improved signal strength out to about 60 metres.
- 7dBi (14cm long). This antenna improved signal strength out to about 70 metres.
- 12dBi (27cm long). This antenna did not improve signal strength (it may have been faulty).
Robotic Mowers conventionally use a Radio Frequency signal from the base station to the mower, as an element of control of the mowing installation.
In some circumstances, such as where there are structures separating mowing areas, or undulations in the topography, the standard fittings of an antenna internalised in the base station may not be optimal.
It is possible to fit an external antenna to the base station in order to extend the range of the signal, and/or cater for obstacles, or undulations in the yard.
We have found through testing that a 7dBi antenna is optimal to extend the range of the signal. The antenna may also be placed in an elevated position to adjust for changes in levels of the yard..
Do You Want to Find Out More?
If you would like us to discuss the suitability of our devices to your situation, please just fill out the enquiry form below. Alternatively, if you would prefer to speak to us first, please call us on 1 3000 ROBOT. (1 3000 76268)