SX127x / RFM9x supports FSK - is it ever used?

The Semtech SX127x (and HopeRF RFM9x modules) supports both LoRa mode and FSK mode.

Is the FSK mode ever used with these modules?
If yes, for what?

Slightly off topic, but FSK mode is great for sending FSK RTTY when used in a high altitude balloon tracker.

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Do you mean FSK in general, or using these LoRa chips/modules?
Is it actually used with LoRaWAN?
Is it actually used with TTN?
(My own experience with FSK is limited to the cheap 433MHz modules used for weather stations, garage door openers etc. It does not seem logical to use a relatively expensive LoRa module for that.)

@LoRaTracker
Would you use something like a TTGO LoRa32 V2 board for that?

@matthijskooijman
I am aware that LMIC-Arduino requires DIO2 for FSK but when is FSK ever used?

It could make sense to use this mode for local firmware updates, not routing them over LoRaWAN network. Because with FSK you achive higher data rates.

A TTN node could change it’s radio mode to FSK when awaiting a firmware update. Then a local FSK connection, e.g. to a second master mode, would be established as firmware update link. Aber update the node would switch back to LoRa an TTN.

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The LoRa devices, as well as others such as the RFM22B, allow for relativly rapid frequency shifts, so you can generate FSK RTTY fairly easily. Or FM tones (need access to DIO2) which if you have a suitable receiver, a handheld or SDR, is a quick and simple way of checking a LoRa device is working.

FSK RTTY is used for balloon tracking quite often in the UK, all you need is an el-cheapo SDR to receive it, the range is slightly less than LoRa at SF12.

Cant say I have ever seen the FSK data mode in a LoRa device used.

As for FSK RTTY on an LoRa\ESP32 combination I dont see why not, the delays would need to be set to get the baud rate correct, but thats a once only task.

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FSK is used for LoRaWAN in EU868 …

https://www.thethingsnetwork.org/docs/lorawan/frequency-plans.html#eu863-870

Yes, it’s part of the specs but is actually being used?
Specs alone do not make this clear.

This guy is using it, albeit not for LoRaWan, to decode all kind of things he sees at 434 MHZ.
There is even some OOK in there.

Pim

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