14-20dB gain simple active antenna circuit diagram


Posted on Feb 6, 2014

A very simple active antenna can be designed using this electronic circuit diagram. This active antenna is based on transistors and other few common electronic components. Because in practice of frequency short-wave reception, the general rule is that if the used antenna is longer, the stronger the received signal will be we need in some cases


14-20dB gain simple active antenna circuit diagram
Click here to download the full size of the above Circuit.

( when we can not built a big antenna, because of some factors ). Antennas that are much shorter than 1/4 wavelength present a very small and highly relative impedance that is dependent on the received frequency. It is difficult to match impedances over a decade of frequency coverage. For this RF circuit a gain of 20dB is typical from 1-18 MHz, decreasing to 14dB at 30MHz. For this active antenna circuit many different types of JFET`s may be used, such as the MPF102, NTE451, ECG451 or 2N4416 and 2N3904 or 2N2222 transistor works well for Q2, Q3, and Q4. Transistor Q4 transform Q3`s relatively moderate output impedance into a low impedance, thereby providing sufficient drive for a receiver`s 50-ohm antenna-input impedance.




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Flashing Lamps
    12-Bit-da-conversion-system
    Start-and-run-motor-circuit
    5W-150mhz-amplifier
    arduino Selecting the right relay
    computer-internet-software
    4W Fluorescent lamp driver
    fade fade out led circuit car interior lighting
    Touch Controlled Musical Door Bell
    Visual System Simulator circuit
    General Hobbyist Circuits
    Crystal Oscillator
    With NE555 make double touch light switch 1
    A volt DC power supply circuit
    Before power is in the release state holding brake circuit
    TC35I use wireless data transmission and GSM communication module circuit design schematics



    Top