The ideal situation would be to use the same grounding point. If you can't, then use another rod, as close as possible to the other rod.
Just to clear the air on the whole thing. Grounding your station will do nothing with a direct strike. That is not what the grounding is used for. Is used to discharge static build-up, which will hopefully prevent a strike to the grounded equipment. If it receives a direct hit, grounded or not, it and anything directly attached to it is burnt toast.
Bob
Drive a new rod if you must, but all grounding systems must be connected together per the "National Electrical Code".
250.58 -Common Grounding Electrode.
Where an ac system
is connected to a grounding electrode in or at a building
or structure, the same electrode shall be used to ground
conductor enclosures and equipment in or on that building
or structure. Where separate services, feeders, or branch
circuits supply a building and are required to be connected
to a grounding electrode(s), the same grounding electrode(
s) shall be used.
Two or more grounding electrodes that are bonded together
shall be considered as a single grounding electrode
system in this sense.
250.60 Use of Air Terminals. Air terminal conductors and
driven pipes, rods, or plate electrodes used for grounding
air terminals shall not be used in lieu of the grounding
electrodes required by 250.50 for grounding wiring systems
and equipment. This provision shall not prohibit the required
bonding together of grounding electrodes of different
systems.
FPN No. 1: See 250.106 for spacing from air terminals.
See 800.100(D), 810.21(J), and 820.100(D) for bonding of
electrodes.
FPN No. 2: Bonding together of all separate grounding
electrodes will limit potential differences between them and
between their associated wiring systems.
Run a piece of #6 copper between the two systems and your new rod should be a minimum of 6' from the old one. Ideally it should be at least twice the length of the rods apart - 16' for 8' rods.
You might think this is overkill until you have a lightning strike and the insurance company comes out to settle your claim. I worked with person who was a maintenance man in several factories for over 30 years. He cleaned his oil burner and several months later had a fire because of the furnace. The insurance company fought his claim for over 2 years because he wasn't a qualified oil burner technician.
Jim