[Xastir] Off-topic: Rx eight freq. at once via RTL SDR: Send to Icecast

[Curt Mills]

Looks like the latest version allows mixing between channels too. Released
a couple of weeks ago.

https://github.com/szpajder/RTLSDR-Airband/releases

On Thu, Jan 19, 2017 at 10:44 AM, Curt Mills <curt.we7u at gmail.com> wrote:

> I started with "rtl_fm", piping to "lame" and then to "ezstream". That
> gave me one audio channel to send to the Icecast server. "rtl_fm" has
> another mode where you can give it multiple frequencies and it scans
> between them, still only one audio channel.  http://kmkeen.com/rtl-demod-
> guide/
>
> Correction from previous message: Now that I look at the sources, it looks
> like it was "rtl_fm.c" in the "rtl-sdr" package that had to be patched for
> the zero-samples-on-squelch rather than the method I'm using now. The patch
> allows the audio stream to continue when the "radio" gets squelched.
> Without it the stream keeps stopping and have to connect again with your
> audio client, which is untenable.
>
> What I'm doing now: Running RTLSDR-Airband against one RTL SDR, decoding 8
> different FM frequencies all at once (or 8 AM frequencies, such as
> aircraft), creating 8 audio streams, and sending all 8 streams to Icecast
> concurrently. So you can have multiple users connected to Icecast listening
> to whichever frequencies they like. You should be able to do ALL of this
> including some limited number of users connected to Icecast with an Rpi 3.
> I hear only one frequency corresponding to the audio stream URL I select
> from the audio client on my phone/tablet/laptop, but other users can be
> listening to any of the channels at the same time, up to however many users
> Icecast and your server can handle. If you use an external service instead
> of Icecast locally and feed the 8 streams to that service, you can have an
> unlimited number of people listening at once.
>
>
> On Thu, Jan 19, 2017 at 10:04 AM, Dana Rawding <dana at twc-inc.net> wrote:
>
>> I’m interested to hear more!  I’ve been doing something similar using
>> gqrx and a RTL-SDR receiver to scan the frequencies I’m interested in.  I
>> pipe it out to vlc with the following:
>> cvlc --demux=rawaud --rawaud-channels=1 --rawaud-samplerate=48000
>> udp://@:7355 --sout '#standard{access=http,mux=ogg,dst=192.168.X.X:8888}’
>>
>> It sounds like you have a much more elegant solution.  If two frequencies
>> are active at once do you hear both?  The way I do it works like a
>> traditional scanner but I think your method is more like an ACARS scanner
>> which listens to multiple frequencies at once.  I’m also interested in how
>> you are able to do 8 freqs as the best I’ve been able to do is 4.  Are your
>> frequencies are relatively close together?  For instance using this method
>> I’m able to listen to multiple freqs from 130 to 132 but I can’t pick up
>> the channels in 136 because the sdr doesn’t have enough bandwidth.
>>
>> Dana
>> N1OFZ
>>
>>
>> > On Jan 19, 2017, at 11:43 AM, Curt Mills <curt.we7u at gmail.com> wrote:
>> >
>> > So... Ken, N7IPB, and I redid the scheme and can now receive eight AM
>> -or- FM frequencies at once per RTL SDR receiver, using one piece of
>> software instead of a pipeline of commands. There are also free audio
>> servers where you can send these streams so you don't have to run your own
>> Icecast server either.
>>
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>>
>
>
>
> --
> Curt, WE7U
> http://we7u.wetnet.net
> http://www.sarguydigital.com
>



-- 
Curt, WE7U
http://we7u.wetnet.net
http://www.sarguydigital.com