Ignition keys and reader coils

[twoqu]

Hi!
I understand the key has some sort of electronic "pill" in it and this in conjunction with the reader coil in the ignition barrel transmits a radio signal at a particular frequency which the immobolizer picks up.
If thats accurate, what detiorates so that the signal becomes weak. Is it the reader coil? If so, whats the fix?
Thanks

[audiman]

It is usually the coil that fails. and the cure then is to replace it. This shouldnt need any re-programming of keys etc etc