An up-converter built into the receiver aerial input system. Receives from 7kHz to 2.2MHz and mixes this range with a 5MHz source coming from the Frequency Standard FSA.  The resultant highly accurate result of 5007kHz to 7200kHz is then fed to a standard HF receiver [switched to the FTA line] tuned as required, so that if, say, 16kHz was needed, the HF receiver would be tuned to 5016.0kHz.

Fitted widely throughout  the Fleet.

Click here FTA.pdf for a description, and here FTA[1].pdf for a picture.

 See also the COMIST/ICS scuttle on the TRANSMITTER matrix.