Ferrite torus on grounding conductor ?

[Externet]

Regards.
On an old HF amateur radio installation, now dismantled, not in use since the seventies, the wire connecting from the transceiver to the buried grounding rod had a sustantial toroidal ferrite on it. The grounding wire just passing inside, no multiple turns.
Curious of what is such use for ? What would be the purpose/effect of having a ferrite toroid O about 50mm outside diametre, 10 mm thick, 30mm inside diametre at the grounding rod connection ?

VerticalHFwhipantenna----------------RG8coaxial--------------------PL259transceiverchassis---------------groundingwire----------------O----------------earthingrod

 

[biff44]

well, we use ferrite beads when we want to present a higher impedance to RF signals.
for some reason, they did not want all of the RF signals grounded to that metal earth rod. A ferrite bead, properly designed, might make the earth ground look more like a 70 ohm impedance to ground.