Lower frequency higher ui material would be easiest to wind a choke on.  I suggest 75 material, perhaps a FT75-240 core which is 2.4" outside diameter.  The website below has a calculator that one can use to determine the amount of choking inductance in uH for different core materials and core sizes.
73
Ed, KI6R

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On Fri, Aug 4, 2023 at 10:13 PM Andy - KU4XR via 600MRG <600mrg@mailman.qth.net> wrote:
Hello Gentlemen:

I am needing a toroid that will choke off 2.5 KW on 1390 KHz
on a phoneline in the TX building connected to a dial up
remote control unit.

What material is good for this , and sources to obtain it.

Thanks for suggestions: 73

Andy - KU4XR
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