MFJ-1708B – Transmit/Receive RF Sensing Switch, HF/VHF, SO239


The MFJ-1708B Transmit/Receive RF Sensing Switch is the perfect solution to seamlessly switch your antenna from receiver to transmitter. Equipped with a reliable relay, this switch efficiently shortens your receiver to the ground during transmission.

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Whether you prefer RF sensing with an adjustable delay or using the PTT line, this switch has got you covered. It even offers selectable open/short mute options for added convenience.

Featuring impressive SWR characteristics up to 450 MHz, the MFJ-1708B ensures optimal performance for a wide range of frequencies. Its adjustable receive delay, ranging from 50 ms to 4 seconds, allows you to fine-tune the switching timing to your preferences.

With excellent isolation between the transmit and receive ports, this switch guarantees seamless transmission without any interference. Additionally, it provides a control line input for radios that have a key line output, enabling easy integration with your existing setup.

The MFJ-1708B also offers a power-off bypass setting, allowing you to connect your transmitter directly to the antenna when the switch is powered off. This feature ensures uninterrupted communication, even during power outages or switch malfunctions.

To protect your receiver from any potential transmit RF spikes, this switch includes a receiver protection circuit. This circuit effectively limits any spikes, ensuring that your equipment remains safe and undamaged.

Furthermore, the MFJ-1708B includes a mute output, which can be set to either ground or open to mute. This customizable mute option allows you to control the audio output according to your needs.

For radios lacking a keying output during transmission, the RF sensing capability of this switch is particularly useful. It accurately senses when your radio is transmitting, ensuring precise and reliable switching without the need for a separate keying output.

Upgrade your antenna switching experience with the MFJ-1708B Transmit/Receive RF Sensing Switch. With its advanced features, exceptional performance, and robust design, this switch is an indispensable tool for any HF/VHF setup.

Additional information

Weight0.7 kg