Has anyone used the RFD868ux or RFD900ux with the Cube Orange? If so, could you help me figure out how you handled the power supply? Should I use the 10-pin cable included in the box to power it through both the Cube Orange and an external 5V source, or should I avoid putting this load on the Cube Orange altogether? If you have used this setup, what were your solutions regarding this issue?
Avoid putting the load on the FC. Use a dedicated BEC.
Has CubePilot ever stated the reason for that? Telem1 on the standard carrier board was supposed to support telemetry radios.
Not all telemetry radios are built the same. RFD uses more power than other telemetry radios.
They say to never power any telemetry radio
Powering Telemetry Radios Externally | CubePilot but they provided no reasons for such drastic measures.
Radios do not draw constant current, they draw high current peaks and produce high EMI.
Want reliability: use a BEC
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Apparently, I have to provide 5V from both the telemetry 5V pin and the power supply cable. I’m actually a bit confused about this part.I did a flight today without cutting the 5V wire of the telemetry cable. I drew 5V from both the telemetry port and supplied 5V from an external power supply via the power cable. Everything went fine during the flight, but would it be better if I supplied 5V to both the telemetry port VCC wire and the power cable?
I think you are referring to pin 2, which is the 5V external supply going to the 2-pin connector (lower right corner of your picture), and pin 5, which is the 5V supply wire on the 6-pin connector (lower left in your pic).
The tiny jumper on the modem allows you to choose which of the two pins are used for power.
For your application, you should have only the external power supply connected to a BEC on pin 2 and the jumper connecting pins 1 and 2 of the jumper pins.
With the 6-pin connector plugged into the telemetry port, pin 5 will have power from your Cubepilot Orange, but that 5V won’t go into the modem with the jumper configured as above.
In other words, you won’t have to cut any wires or unpin any connectors.
You never want to connect more than one source of power together without adequate protections (e.g., diodes).
ETA to add pic…
You likely already had the jumper in the right spot, but you should verify this.
You don’t want your Cubepilot to be the power source for the modem.
Thanks for the answer, it solved my problem!
In case you are reluctant to cut a perfectly good wire, you can instead remove the crimped end from the plastic housing. I do this myself when needed. I cover the bare metal connector with some heat shrink tubing to prevent shorts. This way I don’t permanently alter the connector.
As you are likely aware, it can be a problem to connect two different power sources in parallel. Many voltage regulator circuits will overheat when connected in parallel.
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