RE: [Discuss-gnuradio] radio front end ?

[Ettus, Matt]

> get signal samples? I did a web search for radios that output their IF
> signal and found several. Most of them cost $$$$. I found a 
> couple that were
> digital and output the digital IF samples. Those were very 
> costly. 

Unless its USB, PCI or Ethernet, these are probably the most difficult to
deal with

I found a
> few others that output their analog IF signal. If you were to 
> take one of
> those and then sample the IF would that work ok?

This is the easier option, if you can sample fast enough for the IF.  

The basic system is a downconverter (LNA, mixer, and LO) and a soundcard.
You could use a TV tuner to cover 50 to 900MHz, and then a fixed LO to
convert to baseband.  The fixed LO would be at 5.75 MHz, so it could be done
with 7400 or 4000 series logic parts, and it would be easy to get
quadrature.  With audiophile sub $300 soundcards, you can sample/output 4
channels (I/Q on 2 antenna polarizations?) at 96kHz.  That gives you 90kHz
of bandwidth from 50 to 900 MHz, which is plenty for some serious SDR.
Total cost is less than $500.

Those of us that have the microtune AD board (~$1200, 20 MS/s 4 ch), are
using a cable TV tuner.  It downconverts anything from 50 to 900MHz to a 6
MHz wide channel at 5.75 MHz.

Matt
N2MJI