Welcome new member!
I agree with CDN guy... paper money is a hobby that just keeps on growing. This is evident at any coin show where there's hardly a dealer who doesn't have a showcase of great notes for sale. Even the Canadian Coin News is beginning to put articles in about notes (with articles by Kari McCormick) and others. You will also see dealers offering catalogue and above for notes. National auctions often show high grade old notes outperform coins (and sell beyond expectations).
Despite the large quantities of radars you see, it is unlikely that their market value will drop. The only notes that may appreciate slightly are the more common, run of the mill notes. You are wise to get into radars and would do well to think about collecting special serial numbers (low numbers, repeaters, ascending solid and 2 digit, errors) and replacements (which now a days are special serial number ranges since that is the only way one can tell a replacement from an ordinary note). The common notes are collected by novice collectors (or dabblers) but should be collected in AU to UNC condition. Eventually, many novice collectors want to become more avid collectors and the only way to do that is to seek the truly rare, and interesting serial numbers. Rare prefixes, change-over (when a signature or printing date is changed in a specific prefix) are also notes you will want to seek. Once a collector has some experience and decides to get more into it, he/she either seeks all the prefixes, (a prefix collector), or decides to collect the more rare/scarce Dominion, Charter, and oher seldom sold notes (in any grade). That's when the hobby becomes a bit more than a hobby (lets say a passion!)....and well... I'll turn this thread over to those who can attest to that level of collecting...
Anyway.... Welcome to the forum and good luck hunting for those special notes!
James