I used Mix 31 clamp on Ferrites for LM400 or my RG-213 cable. This is the thicker coax. You might need to trim off the outside plastic around the ends for it to fit. This can be done with a pair of wire clippers.
I used the round torroid cable cores for my AC or DC cables. Basically anything that gets plugged into the wall or has a transformer, I put these inline.
Torroid Cores : Mouser Part 623-2631803802
Clamp on Cores : Mouser Part 623-0431167281
You can easily wrap a thick computer power supply cable around this at least 7 times, maybe more. I secure each end (entry and exit) with a zip tie.
2 3/8in outer diameter
1 1/2in inner diameter
These are to clamp on coax. The inner diameter is just big enough to fit around LMR-400, RG-213 or RG-6.
I'm sure you could maybe double up on RG-8 or RG-8x.
Inside ferrite is 1 1/4in tall
Inner diameter is 3/8 across
Depending on how thick your LMR400 or RG213 jacket is, you might need to trim it. The left ferrite is not trimmed, the right is.
Palomar Engineers has a good article on choosing the right choke for your application.
I've typically found doing a little research and purchasing your ferrites or torroids online from an electronics retailer, you can save quite a bit of $$.