Why The National Electrical Code requires all grounding electrodes at a building, the AC service ground rod, the telephone and cable entry grounds, and any tower or antenna ground rods, to be bonded together into one grounding electrode system. If they are left separate, a lightning strike or fault can raise one rod to thousands of volts above another, and the difference appears across your equipment and its cables. Bonding with heavy wire or wide copper strap keeps everything at the same potential so surge current flows to earth instead of through your radios or through you.
Watch out Keeping the rods far apart is exactly backwards: separated, unbonded electrodes create the voltage difference that damages gear. Ground rods are not tuned or resonant, and sealing them from soil moisture would only degrade the earth connection.
One station, one ground: bond every rod together. Separate grounds means dangerous voltage differences.