Software Defined Radio
RFSpace
RFspace has a receiver SDR-14 good for 0-30 Mhz. It uses a USB 2.0 interface to the computer and has a Windows program. It's $1099.
He is also working on a software defined spectrum analyzer. 500-30 Mhz.
The software component called SpectraVue is available separately from MOEtronix
USRP/GNUradio
http://comsec.com/wiki?UniversalSoftwareRadioPeripheral
http://www.gnu.org/software/gnuradio/doc/exploring-gnuradio.html
http://www.ettus.com/ Ettus Research LLC - The source for the hardware
$700 for the basic board and enclosure
$100 - $275 for each RX/TX daughterboard
WaveCOM
4 inputs, three 50HZ-25MHz and one 52.5 MHz – 87.5 MHz
This system has an onboard DSP
Seems like a closed box when it comes to software. "Source code material is available only to government authorities or official bodies and needs signing of a special license contract."
WinRadio
WinRadio makes SDR receivers. roucghly $500 - $3000
As might be inferred from the name they require MS Windows on the host computer. They do have an SDK available so that you can write your own programs.
Links
http://www.dxzone.com/catalog/Technical_Reference/Software_Defined_Radio/
