Can I bend the long whip so it stands vertically? Should I do it?
does the downward slope of the ground plane leave a problem
unaddressed?

Although the issue may be more aesthetic than functional, I inform you that I
have a magnetic mount (built by Kathrein) that has a swivel at the whip
connection point. So, even if the mount is slanting, you can adjust the swivel
so that the whip is perfectly vertical.

73

Tony I0JX
Rome, Italy