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Tuesday, September 29, 2015

Automatic TX/RX Antenna Switch


Sometimes it is necessary to use separate antennas for receive and transmit. For example you want to use an efficient vertical on 80m for transmit, but a directional beverage antenna for receive. The MFJ-1707 automatic antenna switch serves exactly this purpose. Just connect your transceiver, receive and transmit antenna as well as power - and off you go! The built-in HF sensor (HF vox) immediately switches from receive to transmit antenna. Instead of the HF vox a cable can be used for PTT keying. After releasig the PTT the switch reverts to the receive antenna after an adjustable delay time (hold time). This delay protects for example a very sensitive receive amplifier. An additional switching contact signals the state of the switch, useful for blocking other devices or. The MFJ-1707 automatic antenna switch can be used with any mode. Max. power is 200W SSB PEP. A 12V DC supply is required, you can use the normal power supply from your transceiver. Size of the switch: 101 × 66 × 38mm.