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Date: Wed, 19 Mar 2014 00:18:37 +0100
From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= <schaefer@iup.uni-heidelberg.de>
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Subject: Re: LF: Bluetooth instead?
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Hi Jacek,

Thanks for the advice.
Well, before starting with linux, i think i would prefer to lay a 2km 
long cable through the city :-) All my systems are windows based and wok 
well since my first own PC in 2000 (windows-linux can be a discussion 
almost as funny as cw-digimodes :-) ).

Apart from this, my motivation is to run a battery fed MF/LF receiver in 
the forest which sends its data via a 2.4 GHz link to the shack and is 
there converted into audio frequencies again. So, *on the far end, there 
is no PC and no internet!* And it MUST be a low power device, allowing 
to run several days with a single battery charge, at least 24*7 hours or 
better 24*14 hours.

I'm starting to think about spending more time to learn how this can be 
done. Maybe with a high integrated RF module and an ADC as the main 
special parts. I have to read about it and ask some programmers here...

73, Stefan/DK7FC


Am 18.03.2014 23:42, schrieb Jacek Lipkowski:
> Stefan,
>
> Maybe use a linux platform? Like a raspberry pi, or an old HP 
> thinclient (you can get them very cheap from auction sites). Under 
> linux you can connect any sound card that satisfies your requirements 
> for S/N, sampling rate etc (probably the internal sound card would be 
> ok for the simple stuff, but an external usb card would be better).
>
> This can be connected via wifi. The simplest way to stream would be 
> probably to have a pulseaudio server running on the thin client 
> (pulseaudio comes stock with most linux distributions, so probably you 
> wouldn't event have to compile anything from scratch). You can stream 
> using tcp or rtp (and some other protocols too). On the client side 
> you would also need pulseaudio, and the input should appear as a local 
> sound card to most applications. Pulseaudio has been ported to various 
> linux/unix (macos x included)/windows systems, so software choice 
> would not be a problem. You could also stream via the internet (tcp 
> tunneled in ssl or ssh, or rtp via vpn would be my choice), so that 
> you don't need to set up long range wifi links.
>
> This is a bit more complex than using a bluetooth headset, and 
> requires more power, but is still much simpler than building all of 
> the hardware yourself. The thin client can have much more logic than a 
> simple audio server, it can generate spectrograms by itself etc.
>
> This was probably proposed by others, but i didn't see pulseaudio 
> mentioned anywhere.
>
> VY 73
>
> Jacek / SQ5BPF
>
>

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Hi Jacek, <br>
<br>
Thanks for the advice. <br>
Well, before starting with linux, i think i would prefer to lay a 2km
long cable through the city :-) All my systems are windows based and
wok well since my first own PC in 2000 (windows-linux can be a
discussion almost as funny as cw-digimodes :-) ).<br>
<br>
Apart from this, my motivation is to run a battery fed MF/LF receiver
in the forest which sends its data via a 2.4 GHz link to the shack and
is there converted into audio frequencies again. So, <b>on the far
end, there is no PC and no internet!</b> And it MUST be a low power
device, allowing to run several days with a single battery charge, at
least 24*7 hours or better 24*14 hours.<br>
<br>
I'm starting to think about spending more time to learn how this can be
done. Maybe with a high integrated RF module and an ADC as the main
special parts. I have to read about it and ask some programmers here...<br>
<br>
73, Stefan/DK7FC<br>
<br>
<br>
Am 18.03.2014 23:42, schrieb Jacek Lipkowski:
<blockquote
 cite="mid:Pine.LNX.4.64.1403182323120.823@paranoid.lipkowski.org"
 type="cite">Stefan,
  <br>
  <br>
Maybe use a linux platform? Like a raspberry pi, or an old HP
thinclient (you can get them very cheap from auction sites). Under
linux you can connect any sound card that satisfies your requirements
for S/N, sampling rate etc (probably the internal sound card would be
ok for the simple stuff, but an external usb card would be better).
  <br>
  <br>
This can be connected via wifi. The simplest way to stream would be
probably to have a pulseaudio server running on the thin client
(pulseaudio comes stock with most linux distributions, so probably you
wouldn't event have to compile anything from scratch). You can stream
using tcp or rtp (and some other protocols too). On the client side you
would also need pulseaudio, and the input should appear as a local
sound card to most applications. Pulseaudio has been ported to various
linux/unix (macos x included)/windows systems, so software choice would
not be a problem. You could also stream via the internet (tcp tunneled
in ssl or ssh, or rtp via vpn would be my choice), so that you don't
need to set up long range wifi links.
  <br>
  <br>
This is a bit more complex than using a bluetooth headset, and requires
more power, but is still much simpler than building all of the hardware
yourself. The thin client can have much more logic than a simple audio
server, it can generate spectrograms by itself etc.
  <br>
  <br>
This was probably proposed by others, but i didn't see pulseaudio
mentioned anywhere.
  <br>
  <br>
VY 73
  <br>
  <br>
Jacek / SQ5BPF
  <br>
  <br>
  <br>
</blockquote>
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