QX7S wireless (bluetooth) trainer mode has notchy output

Hardware help and support for the FrSky Taranis
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krby
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QX7S wireless (bluetooth) trainer mode has notchy output

Post by krby » Sun Jun 24, 2018 8:53 pm

I just discovered this this morning, but someone posted a nice YouTube video of the behavior here:
https://www.youtube.com/watch?v=kN-HY5viLrw

For me, when using a pair of QX7S TXs in master/slave BT trainer mode, the servos on the model move in a jerky or notchy fashion. I don't see this when the master is controlling (or when the slave is controlling over a wired trainer connection).

Just guessing, but it feels like the resolution of the BT trainer connection is much lower than wired. I didn't change the PPM settings under the BT slave menu item, so they're still at Ch1-8, 22.5, 300u, and -.

Any help is appreciated.

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Kilrah
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Re: QX7S wireless (bluetooth) trainer mode has notchy output

Post by Kilrah » Sun Jun 24, 2018 9:31 pm

That's known and is just how it is. BT LE is too slow, wasn't a good choice for this purpose and is mostly useless as a result.

krby
Posts: 33
Joined: Thu Jan 16, 2014 1:17 am
Country: United States
Location: Northern California

Re: QX7S wireless (bluetooth) trainer mode has notchy output

Post by krby » Sun Jun 24, 2018 10:19 pm

Kilrah wrote:
Sun Jun 24, 2018 9:31 pm
BT LE is too slow

Thanks for the quick reply.
So the resolution of each channel is the same, but the protocol itself is just sending fewer frames per second?

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Kilrah
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Re: QX7S wireless (bluetooth) trainer mode has notchy output

Post by Kilrah » Sun Jun 24, 2018 10:30 pm

Yep.

It may or may not be possible to do better. OpenTX implemented the Bluetooth protocol so that it would be compatible with FrSky's own implementation in their Horus firmware without trying different approaches.

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