adding chokes to coax will not effect inductance of antenna..
if you wish to do well do as Chris says..but you can wind turns of coax around 31 and 43 etc rings..
see g3txq common mode chokes for good designs..the idea is to get high impedance to common mode on coax at frequencies you use..
so if you just listen 1.8-7mhz then use 31 type..if you use 1.8-30 then you need 31 and 43 types etc..
i really only use loops for 1.8-7 so i use many turns around ft240-31..overkill for rx as good for 1kw but works well..( oh its using ptfe coax.)
also doing same at rig end is good too..and even half way down coax if you can..
do same to power cables too if you really want to clean up smpsu noise etc in your rx..
my place looks like a ferrite ring shop!