Wideband Active Rod Antenna
The circuit employs a J309 Siliconix FET, which is known for its high-frequency performance, to drive a 2N5109 transistor configured as a wideband RF amplifier. This configuration is advantageous for applications requiring broad frequency response and efficient amplification of RF signals. The 2N5109 transistor is capable of handling higher power levels, making it suitable for RF amplification tasks.
A relay is integrated into the circuit to enable the bypassing of the amplifier during transmit mode. This feature is particularly useful in radio frequency applications where switching between receive and transmit modes is necessary. The relay can be controlled by a simple logic circuit or a microcontroller, allowing for seamless transitions between the two modes.
The active antenna element used is a 2-meter 5/8-wave whip antenna, which is effective for enhancing signal reception and transmission over the specified frequency range. This type of antenna is known for its good gain characteristics and is commonly used in various RF applications.
Power is supplied to the amplifier through the coaxial cable, which simplifies the design by allowing a single coax lead to handle both the RF signal and the DC power. This approach reduces the complexity of the wiring and minimizes potential points of failure.
To enhance the reliability of the circuit, a surge arrester (U1) is included to protect against electrostatic discharge (ESD). This component safeguards sensitive electronic parts from voltage spikes that can occur during static discharges, which is critical for maintaining the integrity and longevity of the RF amplifier circuit.
Overall, this RF amplifier configuration is well-suited for applications that require efficient signal amplification with minimal components and enhanced protection against electrical disturbances. A J309 Siliconix FET feeds a 2N5109 in a wideband RF amplifier configuration. A relay is used to bypass the amp lifier in the transmit mode (if desired). A 2-m 5/e-wave whip is used as the active antenna element. The amplifier is fed dc via the coax cable, which makes the use of only a single coax lead for both signal and power. U1 is a surge arrester for electrostatic discharge protection. 🔗 External reference
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