I still have one of those boxes. They are a little bigger than that cubic foot and weigh in at ~70Lbs. also They are fetching $5000 and up depending on the plug ins. To do what Rod wants to do you would need a display frame an IF plug in and probably 2 RF plug ins. It would go from HF to 18GHz. To get the most from them you need some additional boxes, like tracking oscillators or noise generators. There are now several do it all boxes from HP and Tek and probabaly some much less expensive stuff for the communications serviceman from outfits like Sencore.  Good Luck Rod, but don't expect much for $500.  There are now a lot of kits for many good devices around, it's just finding them that's hard.