IC cable to address RF coming from nearby FM station

Am I reading this wrong or are you running an 18 foot tonearm cable to your phono stage? That would not be the way to do it. You want a short phono cable and a long cable from your phono  stage to your preamp.

@converge i’m assuming you’re replacing the interconnects between your phono stage and preamp/integrated?

I don’t think that’s the source of your problem. The root cause is most likely your phono stage, that would be the unit picking up the RF. 
Can you list your components - turntable, arm, tonearm cables, cartridge and your phono stage? What cables are connecting the arm to phono? There are phono stages, like Schiit Mani for example, that are susceptible to picking up nearby radio stations. Could be that…

Phonostages can be the root cause of RFI. Changing phono cables can sometimes cure this problem, relocating the unit may also be a solution.