Re: help request with simple live mic tx

Many thanks Marcus and Cristophe for your answers.

I keep on working, I appreciate your help very much.

All best

stefano

Il 30/03/2021 20:01, Marcus Müller ha scritto:
> Hi Stefano,
>
> no need to thank me for patience, you're doing cool stuff! (but
> please, always keep the mailing list in CC:, as there are multiple
> people who can help you!)
>
> The aO means "audio device is overflowing", which means you're not
> getting the data away from the audio source quickly enough. I'm at a
> different computer without GNU Radio on it right now, so I can't check
> your file, but:
>
> 1. Make sure your audio source is set to a sampling rate it actually
> supports. In my experience, 48000 and 44100 Hz are good bets.
> 2. Make sure your RF transmitter (i.e. your HackRF) is set to a
> sampling rate it actually supports
> 3. Make sure all decimating / interpolating steps between these to
> work out.
>
> For example: if your audio sampling rate is 48000, and your HackRF
> rate is 960000 Hz (I don't know whether that is supported!), then you
> need to achieve an interpolation by 20 in between. Now, it could be
> that you have an FM modulator with an audio rate = 48000 and output
> (quadrature) rate = 96000, then you need another interpolation by 10
> (using a "rational resampler" block).
>
> Hope this helps!
> Marcus
>
> On 3/30/21 1:29 PM, Stefano Zorzanello wrote:
>> thank you very much Marcus, I'm working on it, I just have copied the
>> file, but the original link is this
>> http://gareth.codes/hackrf-transmit/
>> <http://gareth.codes/hackrf-transmit/>
>>
>> and I was just trying to substitute the .wav file with an input
>> mic... I keep on working... but anyway, once cut the [short to float]
>> I get the following lines:
>>
>> Generating: '/home/pi/Desktop/SDR STUFF/top_block.py'
>>
>> Executing: /usr/bin/python3 -u /home/pi/Desktop/SDR STUFF/top_block.py
>>
>> libEGL warning: DRI2: failed to authenticate
>> qt5ct: using qt5ct plugin
>> gr-osmosdr 0.2.0.0 (0.2.0) gnuradio 3.8.2.0
>> built-in sink types: uhd hackrf soapy redpitaya file
>> [INFO] [UHD] linux; GNU C++ version 8.3.0; Boost_106700;
>> UHD_3.15.0.0-0-7a3f1516
>> Using HackRF One with firmware 2017.02.1
>> gr::log :INFO: audio source - Audio source arch: alsa
>> len(interp_taps) = 952
>> aOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaOaO
>>
>> >>> Done
>>
>> what should I change on the graph?
>>
>> Thank you very much for your patience.
>>
>> Stefano
>>
>>
>>
>>
>> Il 30/03/2021 08:23, Marcus Müller ha scritto:
>>> Why are you doing short to float, if the output of the audio source
>>> is already float?
>>>
>>>
>>> On 30.03.21 01:47, Stefano Zorzanello wrote:
>>>> Dear list,
>>>>
>>>> as a newbie I ask you for your help with the attached file. For a
>>>> sound-installation
>>>> purpose I'd like to transmit a weak signal, which is generated
>>>> live, over a particular FM
>>>> frequency. In my attempt based on a grc file found here
>>>> https://wiki.gnuradio.org/index.php/Simulation_example:_AM_transmitter_and_receiver
>>>>
>>>> <https://wiki.gnuradio.org/index.php/Simulation_example:_AM_transmitter_and_receiver>
>>>> I
>>>> get errors even if I change the vector lenght to 2 of [short to
>>>> float] and [multiply
>>>> const] blocks, and I don't know what values to change in order to
>>>> make it work.
>>>>
>>>> Any help is greatly appreciated,
>>>>
>>>> thank you
>>>>
>>>> stefano
>>>>
>>>> system:
>>>>
>>>> HackRF one
>>>>
>>>> Raspberrypi + usb card for input
>>>>
>>>> GRC 3.8.2.0
>>>>
>>>>
>>>>