[Discuss-gnuradio] Random behavior?

[Jakub Moskal]

Hi,

We are experimenting with two USRP1's (each with RFX2400) and noticed
some strange behavior. We use the
/usr/local/share/gnuradio/examples/digital/benchmark_rx[tx].py. We run
it once and the number of corrupted/lost packets is rather small, say
0-2%. Without modifying any default values of parameters, or touching
the USRP's, we start it again and the number goes up to, say 40%. We
run it again and the number of lost packets is about 90% and those
that make it through are mostly corrupted. It doesn't always occur in
this pattern, sometimes we get good ratio for a few runs of the
benchmark and then it goes down again. Sometimes it no packets are
received at all. All within the same parameters and physical positions
of the radios. We tried different values of Tx amplitude and Rx gain,
but radios keep behaving in this way. We attached the FFT sink on the
receiver side and see that the signal is coming in, but packets are
still mostly lost after a few runs, sometimes even after the first
run.

What could be the reason for this behavior? What is the optimal setup
for two USRP's -- in terms of physical distance and values of
parameters?

Thanks,
Jakub