Figure 1 shows the multimeter resistance profile as directed by a simple field strength meter circuit, high sensitivity, but without any change of meter.

Coil L, capacitor C1 form frequency selection circuit, and its magnitude as the signal frequency may be tested; field effect transistor can be used 3DJ6 and so on. Before measuring, the multimeter set R × 100Ω file, FET D terminal of the multimeter to the black jack table pen, the circuit ground connection jack red table pen multimeter, adjust the potentiometer W, so that the meter indicates infinity. Measurement, the meter indicates the resistance value of the smaller, indicating that the greater the field strength of the signal; the other hand, the field strength is smaller.
The circuit can be easily used to adjust a variety of small transmitters.