Raspberry Pi based remote SDR head

Simon PurplePlaNET simon at purpleplanet.org
Fri May 10 23:06:16 UTC 2013


Hi Alan, 

Where I live, the temperature extremes inside my attic are not so bad.   

If you look at devices such as the Kinetic SBS 3, you will see that Ethernet ports are becoming quite normal on SDR gear these days. This not only allows you to minimise the cable run to the antenna (important at 1090MHz) but also to use the device from anywhere with an adequate network connection to it. 

http://www.kinetic-avionics.com/ 

A 500 foot drum of RG-6 may only cost $32 at Home Depot, but you would need over 30,000 such drums to reach the closest Home Depot from my home. Quite an outlay when we already have the wealth of a global telecommunications industry at our fingertips and begging to be used!

My main reason for doing this however, is really to make a better radio than the RTL dongle provides on it's own. I am interested in front end filtering and an LNA and want to use the rPi to control this. You could still run 500' of lossy co-ax to the antenna if you wanted to... :-)

I could buy a Funcube Pro+ Dongle for £150 instead, but where is the fun in that? 

Simon


----- Original Message ----- 
From: "Alan Corey" <alancorey at yahoo.com> 
To: osmocom-sdr at lists.osmocom.org 
Sent: Friday, 10 May, 2013 03:39:55 GMT +00:00 GMT Britain, Ireland, Portugal 
Subject: Re: Raspberry Pi based remote SDR head 

To no one in particular: The usefulness of doing this escapes me. Sure you'd want to put the receiver up high, but in an attic?  There are all kinds of temperature extremes up there, from very hot most of the year to below freezing in colder climates in the winter. 

Something like a 1-transistor preamp feeding some RG-6 seems like a more practical solution.  You can buy 500 feet of RG-6 for about $32 at Home Depot and good low-noise transistors are available under $1.  You just need enough gain to offset the cable loss and RG-6 is pretty good. 

  Alan 
----- 
Radio Astronomy - the ultimate DX 

--- On Thu, 5/2/13, Simon PurplePlaNET <simon at purpleplanet.org> wrote: 



From: Simon PurplePlaNET <simon at purpleplanet.org> 
Subject: Raspberry Pi based remote SDR head 
To: osmocom-sdr at lists.osmocom.org 
Date: Thursday, May 2, 2013, 7:57 PM 


Hi folks, 

I've been messing around with rtl_tcp and an RTL2832 device on a Raspberry Pi and want to add a bank of front end filters and a LNA that can be controlled by the GPIO. 

I want to allow manual control of the signal path via a web page hosted on the Pi, but also want to be able to have the filters selected automatically based on the frequency that the RTL device is tuned to. 

I noticed that rtl_tcp helpfully echos the frequency changes to the console, so I wrote a simple shell script to gather this data and control the GPIO. 

Somebody may have already done this and there is probably a better way to achieve it but, if this would be of any use to you, please feel free to copy and use as you wish. 

http://www.purpleplanet.org/?q=rtl-robot 

Cheers, 

Simon 






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