I'm new to radio and SDR but, as a hobby project, I'm trying to decode a 2FSK radio signal received by an RTL-SDR that I sent using an SI4463 transmitter.

here is the Gnu Radio Blocks I'm using

The record file contains 3 packets, but I'm able to recover only one packet. Is there mistakes I've made in the GNUradio blocks?

  • $\begingroup$ might be an SNR issue. also, make sure you're actually using (boxcar-window) FSK, and not GFSK or GMSK (which are, for good reason, the more popular choices when using ICs like the Si4463) $\endgroup$ Jan 2, 2019 at 11:55
  • 1
    $\begingroup$ Also, I don't see any phase recovery here – how are you sure that something you received hasn't been shifted 180° on the air, so that all bits are inverted? $\endgroup$ Jan 2, 2019 at 11:56
  • $\begingroup$ oh and another hint: Switch your "Options" block from "WX GUI" to "Qt" and use the "Qt Frequency sink" instead of the "WX FFT sink", the "Qt Time sink" instead of the "WX GUI Scope" and so on; GNU Radio is no longer maintaining the WX GUI component, and the Qt GUI stuff is much faster (hint: try the middle-mouse-button menu by clicking on a Qt Graph). $\endgroup$ Jan 2, 2019 at 12:05
  • $\begingroup$ Thanks @MarcusMüller for your feedbacks. Yes I specified 2FSK in the parameters of WDS software. But How can I recovere the phase ? is there any GnuRadio block for it ? $\endgroup$
    – Zskdan
    Jan 29, 2019 at 14:30


You must log in to answer this question.

Browse other questions tagged .