RE: TF & RF crystals Does anybody know the Country of origin for this terminology please????
nigal1. Typically a receiver crystal is 455 KC different than the transmitter frequency for single conversion receivers and 11.7 (approx) MHZ different than the transmitter crystal frequency for dual conversion receivers. Transmitter crystals are usually 1/3 or 1/5 of the frequency being transmitted (the transmitter usually multiplies the frequency of the crystal be either 3 or 5). That is why you can not use a receiver crystal as a transmitter crystal. Whether the receiver cystal is above or below the transmitted frequency is what determines whether the reciever is using positive or negative shift.