This antenna must be grounded to a proper earth ground.
According to the National Electrical Code Sections 810-15s and 810-21, the grounding conductor shall be connected to the NEAREST accessible locations of the following:
A) The building / structure grounding electrode.
B) The grounded interior metal water piping system.
C) The power service accessible means external
to enclosure
D) The metallic power service raceway
E) The service equipment enclosure
F) The grounding electrode conductor
The important thing is to connect to ground at the nearest point.
The myth is that lightning follows the path of least resistance. It actually follows the path of least impedance. Coiling cables creates an air-wound transformer, which lowers the impedance. This means you are in fact making your radios a more appealing target for surges.
This radio exceeds International Standard IEC 61000-4-5 when properly grounded. for surges.
No lightning is not covered by warranty. If you follow the instructions, your chance of lightning damage are greatly reduced, but nothing can protect a radio from a direct lightning strike.