Fwd: GNU Radio help

GNU Radio
1

  1. attached is the GRC file for “FILE TRANSFER USING USRP AND GNU
    RADIO”.

  2. the flow graph works fine when done with loop back from modulator to
    demodulator. but it does not work when connected with USRP. both receive
    and trans paths are on different machines.

  3. file received is always zero bytes. i could not find the reason why.

will you please help…

thank you…

2

Hi Vaibhav Rayanade,

your rx sees zero bytes, meaning that the packet decoder does not see
any valid packets.
That basivally means it can’t decode anything… this can imply a lot of
things that happened between
the tx and the rx USRP, including:

  • path loss,
  • clipping due to high gain,
  • frequency offset between LOs of tx and rx USRP,
  • wrong antenna for carrier frequency (125 MHz is kind of low…
    1/2\lambda is 1.2m),
  • wrong frequency for daughterboard (only mixing daughterboard
    supporting 125MHz rx+tx is wbx to my knowledge, you have one of these?),
  • evil multipath, path loss, all kinds of fading, and all the other
    effects you expect on an RF channel.

Greetings
Marcus