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    A sensitive and reliable rf field strength meter is an invaluable instrument in amateur radio and in radio controlled model area. A field strength meter is used to align an antenna to get the best possible gain, to determine the transmitting range of radio controllers …

    Designing the rf field strength meter to be sensitive it is a requirement because there must be as many wavelengths as possible between the meter and the transmitter, the measurement can be done without using a stronger carrier signal and most of the radio controllers are of low power type.

    Considering these factors, a dual MOSFET is used as an RF amplifier in this circuit. The amplification can be adjusted by P1 and with S1 switch we can select three frequency ranges:
    L1 – 480 kHz to 2.4 MHz
    L2 – 2.4 MHz to 12 MHz
    L3 – 12 MHz to 40 MHz
    The antenna is made of 30 cm long metal rod.

    The rf field strength meter circuit schematic

    field strength meter circuit schematic

    Active components: 3N140, 3SK35, 3SK37

    attentionThis article was received from one of our visitors, please take into consideration that the presented information might not be correct. Also please contact us if you have any problems with the presented material.
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    3 Responses to "RF Field Strength Meter Circuit"

    1. euripedes de souza neves pp2bbd says: on May 25, 2012 at 5:11 pm

      muito bom, bom mesmo.

    2. euripedes de souza neves pp2bbd says: on May 25, 2012 at 5:12 pm

      fiz e deu tudo certo.

    3. Years done model flying and rf racing and never seen a. metre, i don’t see the use for it, but usefull to see the radiation between your gear and when using the real anti rf plates, watching the results, and now building a switch for an emi circuit measurement.

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