I didn't knew about this. I just want to confirm again, that I can put gosub kind of statements in the ISR, where it can point to labels outside the ISR?
That is not what I was trying to say.
Your code loops back to START: regularly, have a GOSUB in there that will take you to the routine that WAS in the ISR. Looks like that routine is for setting the LEDs and I bet your code will run fast enough that if the LEDs are set/changed through every loop it will be fine.

Some of the transmitters are transmitting a carrier wave all of the time when they are powered up. Could be "jamming" the receiver.


High PortC[x+3]
That is interesting... never tried that but I do not think it will work.
Maybe if the . is put in after C ???