Lightning wants earth ground. It will take a destructive path
through rotor, pre-amp, or receiver IF you don't provide an
electrically shorter path. One technique involves a lightning rod above
the antenna and connected to earth. Another puts electrical bypasses
around things such as the rotor. There is no way to stop or block
lightning. For example, any post that suggests fuses for protection
means basic concepts - as even demonstrated by Franklin in 1752 - were
not learned. There is nothing (ie a fuse) that will stop or block such
transients. And yet that is how so many ineffective surge protectors
are promoted.

Most essential to protecting a tower, et al is earth ground. The
system component little seen is THE most critical component of a tower
protection system. An industry professional demonstrates the concept.
In this case, tower and building are treated as separate structures;
each must have its own single point earthing. Any connection to either
structure must first connect to its single point ground. To make both
structure's earth ground even better, both earth grounds are
interconnected:
http://www.erico.com/public/library/...es/tncr002.pdf

Having first established this most critical 'system' component, we
then move up the tower to bypass anything that may be damaged when
lightning makes an electrical connection to earth. Bypass so that
lightning will see that earth ground by a non-destructive path.

Same principle used on the tower must also be used in a building.
That means connection from tower to building must connect (every wire
in every cable) short to the building's single point earth ground
before entering building. This connection made by hardwire (ie coax
cable) or via an arrestor. Notice what an arrestor does not
accomplish. It does not provide protection. A arrestor's function is
simply to make an electrical connection short to earth. Note the
repeated reference 'short'. All incoming wires (from tower, AC
electric, phone) must enter at a common service entrance so that all
are earthed short to same single point earth ground.

Another has demonstrated the concept:
http://www.knology.net/~res0958z/

Earthing does not make your location more attractive. If lightning
needs that connection to earth, then lightning is going to strike. So
which electrical path do you want lightning too take? Franklin
demonstrated it in 1752. Lightning sought a conductive material to
earth ground - wooden church steeple. Notice how non-conductive
materials are now considered conductive. Franklin provided lightning
with an electrically shorter path to earth. His lightning rod was only
as effective as its earth ground. Your protection does same thing as
demonstrated in the above URLs.

wrote:
How would one make any part of the tower higher than the antenna? When
a rotor is used, which I need to use due to the distance involved,
there is no feasable way of having any rod stick higher than the
antenna. Also, if grounding the tower makes it more attractive to
lightning, why are tv antennas on roof tripods usually grounded? Thanks