Radio direction finders

Claim 1

AN AUTOMATIC RADIO DIRECTION FINDER COMPRISING IN COMBINATION SUBSTANTIALLY NON-DIRECTIONAL MEANS FOR DERIVING A NON-DIRECTIONAL SIGNAL FROM AN INCOMING RADIO WAVE; DIRECTIONAL MEANS OF VARIABLE DIRECTIVITY FOR DERIVING FROM SAID INCOMING RADIO WAVE A DIRECTIONAL SIGNAL DEPENDENT ON THE MOMENTARY DIRECTIVITY OF SAID DIRECTIONAL MEANS; MEANS FOR TRANSLATING THE NON-DIRECTIONALLY AND DIRECTIONALLY RECEIVED SIGNALS INTO SIGNALS OF THE SAME RELATIVELY LOW FREQUENCY AND LYING WITHIN A RELATIVELY NARROW FREQUENCY BAND; MEANS FOR PERIODICALLY REVERSING THE PHASE OF ONE OF THE RESULTANT RELATIVELY LOW FREQUENCY SIGNALS THUS PRODUCED; MEANS FOR COMBINING THE PERIODICALLY PHASE REVERSED RELATIVELY LOW FREQUENCY SIGNALS WITH THE OTHER LOW FREQUENCY SIGNALS IN SUCH MANNER THAT, WHEN THE FORMER IS OF ONE PHASE THE TWO SIGNALS COMBINE ADDITIVELY AND WHEN IT IS OF THE OTHER PHASE THE SAID TWO SIGNALS COMBINE SUBTRACTIVELY; AND MEANS RESPONSIVE TO THE RESULT OF COMBINATION FOR VARYING THE DIRECTIVITY OF SAID DIRECTIONAL MEANS OF VARIABLE DIRECTIVITY.