Showing results: 31 - 33 of 33 items found.
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FIM-71 VHF -
Potomac Instruments, Inc.
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.
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FIM-72A UHF -
Potomac Instruments, Inc.
The Model FIM-72A 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-72A is suitable for practically all types of RF emission measurements in the 450 MHz to 960 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 meter dynamic range of either 20 dB or 60 dB. A dc analog voltage, proportional to meter indication, is provided for driving a chart recorder or similar device. A leveled output from the calibrating generator is available for measuring cable insertion loss, filter response, amplifier gain, VSWR, 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.
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HFDF -
National RF, Inc
National RF's Type HFDF active directional antenna system consists of a high gain RF amplifier coupled to a tunable Faraday shielded loop antenna. Several loop antenna assemblies are available to provide coverage of frequencies in the HF and low VHF spectrum. Due to the nature of a Faraday shielded loop, the antenna exhibits a sharp null through the diametric center of the loop. This null is used to determine the direction of incoming radio signals or to locate electrical noise being radiated from some source. The internal high gain amplifier is used to compensate for the inherent inefficiency of the actual loop at the operating frequency. Overall, the system dynamic response is about +6 dB as compared to the dynamic response of a dipole. To aid in the direction finding process on strong signals, an internal 30 DB attenuator is provided. As the loop antenna presents a bi-directional response, tri-angulation may be required to eliminate the ambiguous signal direction. The line of site of the incoming signal is determined by listening for a signal null on the receiver or by watching the receiver’s S-meter.
