Here is a very basic that you can build on.
Transmit snippet
Code:
TRAIN	VAR BYTE

TRAIN=$55
SEROUT PORTC.4,T2400,[TRAIN,TRAIN,TRAIN,TRAIN,TRAIN,9,3]
The $55 will "condition" the receiver to a mid point. Then 9 and 3 are sent.

Receive snippet
Code:
SERIN PORTC.4,T2400,[9],net
Waits for 9 and puts the next character in var net.

Get this working and then if needed add whatever encoding or chksum or bells or...

Is that coil the antenna? Looks a little long for you frequency. About 6.5 inches for 433mhz. That is wire length. not coil length. But if it works with the hardware encoder...