Potomac FIM-71

FIM71 Field Intensity Meter The Model FIM-71 is a portable, laboratory quality Field Strength Meter designed for rigorous field applications. Combining a calibrated half-wave dipole antenna and a highly accurate tuned voltmeter with a range of 140 dB, the FIM-71 is suitable for practically all types of RF emission measurements in the 45 MHz to 225 MHz spectrum. The operator can switch select wide or narrow bandwidth, peak or average value of TV or pulse modulated signals, AM or FM demodulation, and a meter dynamic range of either 20 dB or 60 dB. A dc analog output voltage, proportional to the meter indication, is provided for driving a chart recorder. A leveled output from the calibrating oscillator is available for measuring cable insertion loss, filter response, amplifier gain, and other signal ratio measurements. The 4-1/2 inch, taut band, mirrored scale meter is calibrated in volts and dB for precise measurements in field or laboratory environments. The tuned voltmeter is a single conversion, super-heterodyne receiver with carefully tailored sensitivity, gain, and linearity characteristics. The RF input is double tuned and designed for minimum VSWR and maximum out-of-band signal rejection. Uniform gain, independent of IF bandwidth, is provided by temperature compensated RF & IF amplifiers utilizing a combination of MOSFET, J-FET, bipolar, and monolithic integrated circuit devices. The linear detector is followed by a logarithmic shaping circuit which drives the meter in the LIN (20 dB) mode. In the LOG mode the meter indication (in dB) varies linearly over a one-thousand-to-one range of input levels.

Potomac FIM-71 datasheet & specifications