There are a number of things that need to be for the RTF receiver to match your JR radio.
band= I assume your JR radio is 72 Mhz, your RTF receiver also has to be 72Mhz, some are 27Mhz
Channel= If they are the same band they have to be the exact same frequency within that band.("IF" they are the same band you may be able to change the crystal to match your channel if you can find a crystal that is compatable with your receiver)
Shift= JR uses positive shift as does Airtronics, Hitec and Futaba operate on negative shift, Your RTF is anyones guess.
The easiest fix is to replace the receiver with one that is compatable with your radio.