
A Primer on Cheap Software Defined Radios - yuvadam
http://blog.y3xz.com/blog/2012/12/02/a-primer-on-cheap-software-defined-radios/
======
rachelbythebay
It's too bad the author gave up on a Mac install. If all you need is the low
level fundamental C++ libraries of GNU Radio, it can be done without
installing dozens of support libraries. It's when you try to get all of the
Python and graphic stuff happening that it gets really complicated.

A Mac Mini with one of these $20 sticks is a decent little system for working
on this stuff. It has enough horsepower, is totally quiet, doesn't take up
much room, and only uses about 20 watts during ordinary receiving tasks.

I took notes on how I made this work on my Mac here:
<http://rachelbythebay.com/w/2012/09/19/brute/>

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keenerd
Feel free to ask any questions about the rtl-sdr project. I've been watching
it since it started and have since gotten a handful of commits into the
project.

Some key things that were not mentioned. There is the GQRX frontend and the
SDR# frontend. Both are fairly straightforward to set up and use.

Also not mentioned were the hardware differences (r820t vs e4000 vs fc0013).
To get decent signals you need to add a bit of filtering to the USB power
supply. And of course antennas, but that topic needs an entire book.

I've been working on a very simple sdr stack (currently merged in rtlsdr as
rtl_fm) that is meant to provide a sox-like experience. It is also stupidly
fast, enough so that even a little RaspberryPi can easily do pager decoding or
police scanning.

~~~
yuvadam
I'd love to read more on USB filtering. Could you point me to any resources?

~~~
keenerd
Ferrite clips/donuts are recommended and easy to install. Put capacitors in
parallel with the power, exact values vary. If you are feeling really
ambitions, add ferrites in series with the power lines or give the dongle a
solid metal enclosure.

The simplest is using a usb extension cable, the computer itself generates
large amounts of broadband noise.

<http://electronics.stackexchange.com/questions/25951/>

<http://electronics.stackexchange.com/questions/36040/>

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rwmj
The $15 USB dongle (actually $20) is this one right? [https://dx.com/p/mini-
dvb-t-digital-tv-usb-2-0-dongle-with-f...](https://dx.com/p/mini-dvb-t-
digital-tv-usb-2-0-dongle-with-fm-dab-remote-controller-844092096) Or is there
a recommended hackable dongle?

~~~
rachelbythebay
Check out the sidebar here: <http://www.reddit.com/r/RTLSDR/> Note "tuner
compatibility list".

~~~
th0ma5
and be sure to check out rachelbythebay's awesome projects about logging
emergency communications, very impressive.

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grendelt
I actually just finished assembling a SoftRock SDR ham radio receiver.
<http://imgur.com/a/K9SIg>

The kit is $21 shipped from FiveDash.com

Build notes: <http://www.wb5rvz.com/sdr/sr_lite_ii/>

Some may wince at the idea of assembling a kit (esp one with SMT parts), but
if you're not scared by those factors, check them out. No ham license needed,
though if you use the stock crystal for the LO, you better brush up on your
Morse Code! (I suggest using the 28.59MHz xtal)

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DanielBMarkham
Somewhar off-topic, but interesting: you can buy some really complicated-
looking radio gear. For those of you out there who love stuff with a lot of
switches, check out this ICOM radio.

<http://www.universal-radio.com/catalog/widerxvr/0095.html>

I have no idea what it does -- I'm assuming it's very similar to my son's ham
radio -- but it sure looks cool. Hobbies this complex have always been
intriguing to me.

~~~
empthought
The coolest thing about the hobby is that it scales to all sorts of different
interests and spending levels. Compare this to
<[http://smallwonderlabs.com/Rockmite.htm>](http://smallwonderlabs.com/Rockmite.htm>).
Sure, it has no buttons at all, but you build it yourself and you can still
have a wireless conversation with someone half a world away.

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pervices_b
Hi everyone,

I wanted to let you know that Per Vices has an SDR for sale right now, and has
a frequency range from DC - 4GHz.

Check it out: www.pervices.com

