How do you scan for outlying wireless frequencies?

When I'm in Wireless Workbench, I can hook up my QLX and ULX receivers that have a network port and scan for the frequencies that they are designed to work within i.e 470-534mhz. However, when you have something like security radios that are in frequency ranges that aren't covered by these receivers like the 400, 170mhz, or 900mhz ranges, how do you scan those areas to make sure those frequencies won't clash with your wireless mics? I've seen the Shure Axient AD600 that scans from 170-2ghz but it costs $5,500. Is that my only option?