1. LOOP INPUT CIRCUITS BY, AISWARYA.PL

2. LOOP INPUT CIRCUITS: The loop antenna is an inductive in nature. The loop output is not generally used directly as an input to the receiver. A variety of circuits is used at the input of direction-finding receivers to obtain a voltage which larger than the loop voltage. The basic elements of a few of these circuits are shown n fig 2.3

4. In fig.2.3(a),the inductance of the loop is tuned out by a capacitor,the two together making a series tuned circuit. The series tuned circuit provides a certain amount of circuit magnification of the loop voltage eL. Fig 2.3(b) and 2.3(c) show developments of the same circuit to achieve a better balance than is possible with the first circuit.

5. One of the Important sources of antenna effect is the asymmetry of the loop antenna with respect to the ground. To minimize antenna effect,the centre of the loop is earthed and its output is thereby,balanced. Any residual antenna effect can be compensated by introducing a controllable voltage in phase with antenna voltage.

6. Balancing of the loop is made more effective and accurate by enclosing it in a elecrostatic field. Fig 2.3(d),A completely shielded loop will not pick up any signal but if any break is introduced,the peformance of the loop is rarely affected.