UAC popup says "Publisher: Unknown"
I have my installer updated for Windows 7 and all appears OK so far. But when I run it the UAC popup box says "Publisher: Unknown" I guess I have to sign the installer with a code certificate or something like that.

These certificates appear to be expensive and what I support is free software for amateur radio operators, so I am not exactly happy to have to pay for something I give away.

Are there any 'cheap' ways of resolving this?