FM repeater operation on the 2-metre band uses one frequency for transmission and one for reception. What is the standard difference between the transmit and receive frequencies (known as "offset")?

On the 2-metre amateur band (144 to 148 MHz), repeaters use a standard frequency offset of 600 kHz (or 0.6 MHz) between the transmit and receive frequencies. This allows the repeater to listen on one frequency and simultaneously retransmit on another without interfering with itself. This spacing is an established band plan standard. Depending on where the repeater's output frequency is located within the 2-metre band, this offset will be either a positive (+600 kHz) or negative (-600 kHz) shift. Other bands have completely different standard offsets, such as 5 MHz for the 70-centimetre band.