I have had at least 4 close calls (is there a definition?) in the last few weeks flying between two cities in the Minneapoli area. I have the TIS-B traffic sytem that alerts me when traffic is near within 6 NM and verbally warns me within 2 NM. In each case it is apparent the other plane didn't have a clue I was there, probably since most planes do not have this sytem. Unfortunately it only works within about 40-50 miles of class B airspace. It make me wonder how many close calls exist that pilots are not even aware of. Without a diversion of the fligh path a coule of these may have been tragic. I tried flying at odd altitude but with the last close call we apparently both had the same idea. Systems for certiied aircraft that work everywhere in interogating the transponders of other aircraft cost about $13,000, but considering my life this is at stake, this is starting to look cheap. Anyone else experiencing this issue too many times or just unaware?
