Re: [Discuss-gnuradio] bladeRF - gr-osmosdr - gqrx - bandwidth?

[Ralph A. Schmid, dk5ras]

Hi,

> Hi Brian,
> 
> I didn't think of these cases - they make sense.
> I have added an option to set the bandwidth in the I/O configuration
dialog. It is

Great!

> available in the git repository. I could test it with hackrf anbd I hope
somebody
> else can test it with the bladerf.
> Currently it does no checking - just passes the value directly to
gr-osmosdr.

Just as an example, we have here three LTE carriers, and even with a few cm
of wire as antenna it is almost impossible to determine the three signals
here. It all mixes to a mush of signals. They are located as neighbor
channels, 10 MHz spacing (796/806/816 MHz), 9 MHz bandwidth each. Also the
GSM bands are full of real and fake carriers what becomes visible when you
have a look at the band ends and see signals "off limits" that simply are
not there. With the USRP1 / WBX I only can see a part of this spectrum at a
time, but almost without such aliasing artifacts. 

Otherwise, I like the little thing, seems reasonably sensitive even at high
frequencies (checked this with watching LTE2600 signals), just the lower
limit of 300 MHz is a bit ugly, down to 50 would be great :) Frequency is
off 2ppm, not good enough for hopefully (soon?) coming openbts support, but
I guess some recalibration can fix it.

While writing this, I downloaded and compiled it. The filter itself works
great, I can see it from the noise floor, just the images are not gone,
seems that the RX simply is not as good as other SDRs. Anyway this is only a
quick shot, I will test it more thoroughly these days, with different
combinations of sampling rate and filter limits.

> Alex

Ralph.