Re: [Discuss-gnuradio] Funcube dongle issues and a solution

[Alexandru Csete]

On Thu, Jun 7, 2012 at 11:13 AM, Gasper Zejn <address@hidden> wrote:
>
> a bit more on my setup: I'm using funcube as a source, tuned to 868.48M, LNA
> gain 20dB, mixer gain 12dB, connected to simple squelch (threshold=-40dB,
> alpha=1) and on to quadrature demodulation block. This block then outputs
> clearly visible binary signal when funcube is initialized properly.
>
> The observed signal is rated at 20kbit, so it's a bit on the upper limit of
> what Funcube can do, but it's still possible to get a decent read. It's a
> burst of bits every 5s from a power meter[1][2], and the first part is a lead-
> in and stays the same even if readings change.
>
> Somewhere in the funcube source block there is obviously something wrong with
> initialization. Running qthid after starting flow changes something in funcube
> that makes it output correct signal. Using this and the fact, that the lead-in
> stays the same, it seems the "corrupt" signal (viewed in scope) is sometimes a
> derivative of the expected signal - most of the time on zero, with spikes up
> and down on transitions, with timing corresponding to transitions in expected
> signal.

Do you have the same frequency correction value in both qthid and the
FCD source? If yes, what is the value?

Alex