Hi. It would be really usefull to have software decoder for FSK message sent by emergency location beacons.
EPIRB on 406MHz. Looks like flipper could be really good device for this.
If someone would be interested in writing this kind of module? I would even donate it.
That’s a very interesting idea. The Flipper probably wouldn’t receive the signal from far. I wouldn’t want to rely on it to find someone in an emergency but it would be better then nothing. The file could probably be sent over Bluetooth to a phone with GPS or read to an emergency responder.
Hi. Idea is to have small portable unit for veryfication if EPIRB is correctly programmed (country code, hex id).
There is ready code on French web in C. I just compiled it on my laptop and works great. You just give wav file and it’s decoding message. Only work would be to port this C-code to flipper.
That sounds like a good use for the Flipper.
Sounds like. I attached document with RF signal and protocol description and also ready working program. I have modified this program also to display 15 digit HEX code and country name, also I translated it.
I can also provide some wav files with recorded aviation ELT’s and perform life tests - I have access to those units.
However I’m not programmed do I have no idea how to put it into flipper 
What’s the protocol for testing? Obviously you don’t want a test to look like an actual SOS.
ELT and other types of those beacons can transmit test frame or alert frame. Test is running when I push test button.
Protocol is the same, but initial bits indicate that frame is “test” or “alert”. This decoder I attached link will show what type of trasmition it is.
I have recorded some “wav” files with both signals, I can share them. They are properly decoded by attached software (http://jgsenlis.free.fr/).
I obtain all signals by using original emergency beacon but with dummy load instead antena (to prevent signal getting to satellite) and by handheld 406MHz Yaesu receiver. I recorded it just by audio program on my Mac.
I can also get dumps by Flipper but I’m not sure how to setup “RAW” to get it correctly. Modulation is Narrow FM (so standard, mono FM).
IEEE_AESM_Mladenov2021 (2).pdf (1.4 MB)
You can pair it with an External CC1101 module to improve the range.