IQ Recorder .raw file format

[Christopher Bridges]

Hi Folks,

Can someone tell me what the IQ recorder settings are please? I use a FCD Pro+, RTL, or USRP so this information is important.

Rate = rate/decimation (if used)? Endianness = little? Number of channels is 2? Data type = uint16?

I used soxi on the file and got:

Chris-MacBookAir:~ chrisbridges$ soxi gqrx_20160608_113307_137891100_192000_fc.raw 

soxi FAIL formats: bad input format for file `gqrx_20160608_113307_137891100_192000_fc.raw': sampling rate was not specified

It'd be great if gqrx should really add the header information automatically after the recorder stops too as this is my preferred sdr application. I'd rather not use sdr# or gnuradio for my recording needs.

73s Chris

[Alexandru Csete]

On Wed, Jun 8, 2016 at 1:52 PM, Christopher Bridges
<drcpb...@gmail.com> wrote:
> Hi Folks,
>
> Can someone tell me what the IQ recorder settings are please? I use a FCD
> Pro+, RTL, or USRP so this information is important.

Hi Chris,

It's just the raw samples in float complex format coming from the device driver.

>
> Rate = rate/decimation (if used)? Endianness = little? Number of channels is
> 2? Data type = uint16?

Rate is written in the file name (note that there is a bug in released
version when using decimation)
Endianness is whatever is native for the processor. I think most
processors are little endian now.
Single precision float, so 2 x 4 bytes / sample for IQ.

I think that is sufficient info to convert the data with sox or some
other tool, no?

>
> I used soxi on the file and got:
>
>
> Chris-MacBookAir:~ chrisbridges$ soxi
> gqrx_20160608_113307_137891100_192000_fc.raw
>
> soxi FAIL formats: bad input format for file
> `gqrx_20160608_113307_137891100_192000_fc.raw': sampling rate was not
> specified

That's normal since it is raw data without any particular format or metadata.

> It'd be great if gqrx should really add the header information automatically
> after the recorder stops too as this is my preferred sdr application. I'd
> rather not use sdr# or gnuradio for my recording needs.

That would require using a specific file format or container. While it
would be very nice to have, I don't have time to work on gqrx at the
moment.

Alex