Model Number : Dual VHF Radio Autoswitch. Max Marine Electronics Dual Marine VHF Antenna Autoswitch. This device needs 12V DC power to operate. Without power the antenna will be connected to VHF A, once power is supplied to it, the relay will default to VHF B. Afterwards, whichever radio was the last to transmit will remain “active” and stay connected to the antenna until the other radio begins to transmit.
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