at88 site:www.edaboard.com

i made simple RF link and the receiver was simply a radio , the o/p signal of the radio (after removing the speaker) is the same as i/p signal to transmitter , the link operates at 88 MHZ , but the problem when i used PIC16f84a(Pin RB0) connected directlly to the o/p of radio and using TMR0 to measure the freq. of incoming signal (I tranmitt square wave) and i used LCD to show the values of TMR0 at each +ve & -ve edges of the square wave the values wasn't the same , although the CRO at RX shows the same signal as tramitter,

Where the problem come from , Can anyone help ?

Thanks