SDR is fun and the way of the future. I'd say we're getting close to a very low cost SDR that also brings together usability and excellent RX/TX and filtering capability. We're not there yet and so my Kenwood TS-2000 and Yaesu 857D and 817ND still kicks the butt of low cost SDR's.

You'll find as you set up the base station your focus quickly moves to antennas. And then you become obsessed with antennas.

Definitely get into amateur satellites. http://amsat.org/status/ Go get a cheap handheld arrow dual band antenna with built-in diplexer to get started. I use macdoppler and also Ham Radio Deluxe's Satellite module. They are Mac and Windows respectively - I use them both for different things. Mostly I use macdoppler to make the doppler corrections automatically on my Yaesu 817ND and I use HRD for my TS-2000.

Also, build yourself a HF monoband dipole antenna tuned to 14.3MHZ and then listen in to the ham band from 14.00 to 14.150 for digital/cw and from 14.150 to 14.300 for voice. It'll cost you about 20 bucks for the coax and a few bucks for the wire. You don't need a balun if you're using low enough power for TX.

If you want to be a bit naughty (this is HN afterall) google around and learn about FLTSATCOM 7 and 8. It's an old US milsat that is basically an open repeater. They're geosynchronous birds that are used for encrypted comms but Brazilian criminal gangs periodically use them for free communication. They build antennas out of spare parts and use down-converters/up-converters to deal with the 250mhz frequency which is outside normal VHF/UHF. With your SDR you can build your own cheap home depot antenna and listen in without a converter. Just do absolutely not broadcast because you'll get arrested - someone already has. You can sometimes pick up used special forces directional portable antennas for a reasonable price on ebay for 250mhz.

I'm a radio amateur, callsign WT1J. If you're into this stuff and find yourself able to TX on HF or satellite, drop me a line and we can set up a schedule.

Mark.