Re: Gnuradio for Raspberry PI 4 and SDRPLay works well, but need documentation

[Chris Vine]

On Thu, 14 Nov 2019 14:11:22 +0000
Müller, Marcus (CEL) <address@hidden> wrote:
> Hi Glen,
> 
> first of all: This email nearly eluded my attention – you replied to a
> completely different topic, and that means email clients will sort your
> mail under the "Simulated Time?" thread. Simply don't reply to emails
> if you don't mean to actually reply.
> 
> Then: The SDRPlay block isn't part of GNU Radio itself – it comes from
> somewhere else, and I must admit I don't know from where. You'll
> probably have to download the SDRPlay driver package and look inside.
> 
> Problem with the SDRPlay driver is: It's closed source, and as such,
> they can't link software against GNU Radio (which is GPL), and then
> distribute it. If someone could reverse engineer that and write a GPL-
> compatible driver (and integrate it with soapy or with gr-osmosdr),
> that'd be very cool.

The original poster can get some information from installing soapy and
doing 'SoapySDRUtil --probe'.

But I wonder what gnuradio block the original poster is using with the
proprietary driver?  I couldn't make it out from the image he posted.  I
only know of three: (i) gr-osmosdr's built-in support for sdrplay, (ii)
gr-osmosdr's built-in support for soapy and so for the soapy-sdrplay
plugin, and (iii) gr-soapy's support for soapy and so also for the
soapy-sdrplay plugin.  If there is a fourth I would be interested to
know what it is.  The first doesn't work that well for me with the
current proprietary driver whereas the last two work fine (for me on
x86/64).

In any event, with reference to the original poster's comments about
selecting the wrong band pass filter, RSP1A only supports certain
bandpass filtering widths.  These can be examined with the soapy
probe above.  Generally you want the bandwidth to be somewhat less than
the sample rate (soapy's probe will also tell you what sample rates are
available).