Using Antenna Trackers for FPV
What are Antenna Trackers ?
Antenna Trackers are hardware devices that receive a telemetry data stream from your on-board your plane. It tells your tracker where in the sky you plane is. Some of them use the GPS information from your OSD on altitude, GPS location etc and send the data down the audio channel of your VTX to your ground station. Others use the same data transmitted down the video stream instead. As yet, there are no universal antenna trackers, so you have to use the same brand on the plane as on the ground.
You can get units that don’t require a OSD and transmit the data for tracking. Units like the MyFlyDream ATT, or the Skylark. Their unit on board the plane can be used as an OSD, but you don’t have to, as long as it has a valid GPS signal and connected to a spare audio input on the VTX your good to go.
The tracker hardware on your ground station listens for the data on the audio channel, receives it and works out which way the plane is and how high from your location. Knowing its own position ( by setting home coordinates before flight ) it can then send a signal to two servos. The two servos are in part of your tracker rig.
The rig can move your antennas on 2 axis, left to right and up and down, or pan and tilt. The signals tell one servo how much to the right of left to pint the antennas ( Pan ) The other signal moves the antennas up and down ( tilt )
The reason for the tracker to to point high gain antennas at your plane at all time so the antennas can pick the signal up. As the plane moves around the sky the antenna tracker follows it.
Very cool stuff
So what systems are we looking at ?
Quiet a few manufacturers make the tracker senders and receivers. They can be bought in many forms. One such example is the :
This is an example of the tracker unit. This unit is part of your ground station. The unit is supplied by a 6 volt supply. It can be powered of a BEC. It has two servo outputs, one for panning the antenna and the other for tilting it. It has USB connectivity so you can upgrade the firmware. and works off a audio channel to receive its data. Priced around £70 its a extremely accurate and practical solution. To make this a complete tracking system though you have to have either a :
The EzOSD is an example of a OSD with full telemetry data output. It has on board GPS which it receives the positioning data from.It sends the data down an audio channel to the tracker. The data si received and decoded by the tracker which then calculates any movement for the servos to point the antenna directly at it.
Priced at around £150
Priced around £110. This is the option if you don’t want a visual display, want to keep weight to a minimum, or use a separate OSD altogether. The Tiny doesn`t produce a picture, it just sends the data to the tracker. Its equipped with its own GPS sensor so doesn’t need any other equipment other than a power supply to work.
Once you have your OSD or telemetry hardware to send the data, a tracker that receives it you need a antenna tracker “rig”.
Companies such as Servocity do the hardware that you can attach your servos to that you can then mount your antennas too. Which type you choose and how you mount them is a personal choice and the sky is the limits.
For a beginner system an antenna tracker system is not advised, its overkill and not really needed. But as us boys like toys certainly worth considering as you progress
With the ImmersionRC systems above its an involved process of making your own tracker by purchasing the parts, putting them together, calibrating and testing. But now other manufacturer have released all in one units that require a tripod and you to attach the antennas only.
The MyFlyDream ATT is one of the all in one units. It uses an OSD on board the plane called a Telefly OSD. You do not have to use the OSD functions if you prefer to use your ow
n OSD on board and you can use it as a telemetry transmitter only. Like the TinyTelemetry is sends its signal down the audio channel of the transmitted FPV link via the VTX. The tracker picks up the signal and then moves its pan and tilt to point at the plane. I use this system and find it brilliant. You can calibrate the hard iron settings, servo centers and travels to get pin point accuracy from it. It unfortunately in its stock form only then passes on the video signal to the rest of the system. You can however use the spare channel ( wire unused ) to pass your audio on though which requires a little DIY. The system uses a slip ring to provide continuous 360 degree pan, this is what the EZTracker can not do, it has to revert back to 0 degrees and resume from there. With the slip ring feature it also gets rid of the antenna trackers largest problem, wires getting caught up, it has no wires going from the rotating tracker to the ground station. The Skylark is a copy of the MyFlyDream so no need to go into that system any further.