Directional Finding.


The purpose of this unit was to find the directional bearing of a transmitter whose signals were being picked up by the wireless interceptor lorries.

Directional finding (D/F) units were housed in either a 15cwt. Vehicle or 10cwt. Trailers each (SWS)
special wireless section had D/F units in each section.  The type of frequency's covered were,

1)    0.9 to 2 .05 Mc/s

  1.   1.7 to 4.0  Mc/s

  1.   3.5 to 7.3 Mc/s

  1.   7.0 to 14.4 Mc/s.


DF Receiver used in this work was a modified R 106 (HRO), accurate results were under the following conditions.

  1. When the station was within the ground wave of the transmitter.

  1. When the station was at such a distance that the sky - wave is received. But not at a too steep an angle usually this meant that the D/F station was at least 200 miles from the transmitter.


Also with this type of unit very little of the history in known but with the help of an ex member's of a D/F unit. Philip hopes to rebuild a D/F trailer in the very neat further but money and time will keep the trailer from bearing built within the foreseeable further. Along with the Bedford Interceptor these will be the only ones to be seen anywhere. Has all these units were dismantled very soon after World War II.