Hi,

I am facing one problem with my unit for go-kart lap timer.
RF frequencies acts as identification for karts passing finish line
I am using 27MHz band crystal based TX & RX for this purpose.

My observations with board:

If crystal of frequency 27.175MHz is placed in receiver & if any unshielded probe or wire is touched to the ground pin of controller running at 11.0592 MHz (present on same board), receiver acts like actual signals from corresponding transmitter are received & triggers the event of kart passing the finish line.

This is not happening with crystals of all other frequencies in the range of 26.975MHz to 27.255 MHz with spacing of 30KHz.

Is there any relation between these frequencies i.e. 11.0592 & 27.175 MHz
Or there could be some other reason for this misbehavior of unit.

Pls. any one can guide me in this case.

Hope to get reply

Thank you,
Kaiwalya