I now have a PCR1000 computer controlled receiver in the shack. It's a pretty nifty device, tuning 100 kHz to 1.3 GHz, and one that represents a trend I'd like to see more of. It is controlled entirely through an RS-232 serial interface (with the protocol not officially published, unfortunately), has an RF input, an audio output, and that's about it. The nifty thing is that all the building blocks within the receiver are independently configurable. If you, for some reason, wanted to use the 15 kHz IF filter and the USB demodulator, it will let you do this.
I kind of wish that someone would make a device like this with an ethernet interface, and send the audio via some useful protocol. I'd also like the ability to lock the receiver to an external phase/frequency reference (like my Z3801), but hey, those aren't really being demanded by consumers, yet. Pretty soon though, the omnipresent browser will serve as the front panel.
I understand that it is fairly well calibrated, so you can use it in a (scalar) reflectometer, for instance.
I've thought about using it to measure propagation using chirp beacons that are transmitted. ZL1BPU has a good description of G3PLX's chirp sounder project on his web site. They used a Motorola 56K EVM to do the processing, but I've been thinking that a sound card in a PC, and then some post processing, might work just as well.
I've scrounged around the web and found some useful links, including some claims for the protocol.
radio/pcr1000.htm - 7 Jan 2003 - Jim Lux
(radio home page) (Jim's home page)