Date of Design : 1928

Frequency range: 60 - 170  kc/s

Where fitted: D/F OUTFIT SF

A7 is a very simple tuner fitted in conjunction with amplifier M9 for use with a horizontal frame aerial.  As can be seen from the equivalent diagram, the tuner merely places an LC circuit in series with the frame coil.  A separate heterodyne is always to be used for CW reception.