In a first aspect, the invention includes a radio frequency photonic transceiver, comprising: a radio frequency receiver; a radio frequency photonic transmitter; and a switch between the input of the radio frequency photonic receiver and the output of the radio frequency photonic transmitter. In a second aspect, the invention includes an apparatus, comprising: a radio frequency photonic receiver; a radio frequency photonic transmitter; and a switch between the input of the radio frequency photonic receiver and the output of the radio frequency photonic transmitter. In a third aspect, the invention includes a radio frequency, photonic transceiver, comprising: means for generating a radio frequency modulated optical signal; a radio frequency photonic transmitter; and means for switching between the input of the radio frequency photonic receiver and the output of the radio frequency photonic transmitter. In a fourth aspect, the invention includes a method, comprising: generating a first optical signal; electro-optically generating a first radio frequency signal from the first optical signal; transmitting the first radio frequency signal; receiving a second radio frequency signal; and electro-optically modulating a second optical signal with the frequency of the second radio frequency signal. In a fifth aspect, the invention includes a zero-intermediate frequency radio frequency photonic transmitter-receiver unit. In a sixth aspect, the invention includes a radio frequency photonic transmitter-receiver unit including a direct conversion receiver with receiver output.