FHT/FFT analysis of RSSI output

[papadeltasierra]

Anyone tried using one of the Arduino FHT/FTT libraries and readRSSI() so analyse signals?  There's a very low 'baudrate' signal near me that I'd be interesting in watching and thought something like this might work.  To give you an idea of what it's up to...
- 433-ish MHz
- When the signal is there, there is a low frequency (about 15Hz) continuous signal (yes Hertz, not kiloHertz)
- There is on/off signalled by twin 37/74Hz signals
- It looks like around 48 bits of very low baud rate data being sent.
So I thought, sample readRSSI() at relatively lowrate (210Hz should be enough) and use FFT/FHT to identify the 15/37Hz signals to get 0/1 out.

Anyone done anything similar or am I going o be way off-piste with this one?

FYI, I'm wondering whether this is related to the local parking signs which look like they might be using 433MHz.

[Kilo95]

I will totally not be any help but please don't forget to keep us posted if you find out what it is.  I'd be interested to know

[Felix]

FFT or FHT or FTT? 
What do they stand for?
Fast fourier? Are you doing that on arduino? Really?
I would probably not even try. How can you trust the radio to give you accurate readings of the frequency when it doesn't even have a TCXO like a real instrument?