Selection of ferrite cores

I'd like to use ferrite cores to put around the cable in order to reduce the current on the surface. The frequency range is around 800MHz ~ 2GHz.

Could someone please advise the spec of ferrite cores ?
Thanks for your kindly help.

what exactly are you trying to do, current on the surface is skin effect and i dont belive ferrite cores affect this, though honestly i would be interested to sit down and work through the math to try and find their effect.

To measure the antenna you have to choke the feeding cable or the cable would be one part of your antenna and it is not correct.

Can someone advise ferrite cores covered 800MHz ~ 2GHz ?

Thanks.

digkey part number 240-2131-ND. There are other types/sizes shown on the same catalog page.

Clamp two of them on the outside of the cable around λ/4 apart. Maybe another one at the far end.