single voltage to control two TX/RX switches, schematic?

[neazoi]

Hello I need a circuit that can control the voltage electronically, so that a TX and an RX can be switched on/off alternativelly.
When the TX power is switched on the RX power is off and in reverse.
This has to be controled from a single control input voltage

The simplest possible solutions please.
Thanks a lot!

 

[barry]

What are TX and RX? A 1Megawatt radar transmitter? An RS-232 receiver? What voltages do you need to turn these TXs and RXs on 3.3VDC? 240VAC? We need a lot more information in order to answer your question.

 

[neazoi]

What are TX and RX? A 1Megawatt radar transmitter? An RS-232 receiver? What voltages do you need to turn these TXs and RXs on 3.3VDC? 240VAC? We need a lot more information in order to answer your question.

These are 12v voltages controlling <500mA currents, used on a QRP HF transceiver.

 

[barry]

Fine, so do you need to actually switch the power to the devices? One approach is to have an N-channel MOSFET between the common side of the device and ground. When the gate of the device is driven high, it gets power. You would add an inverter to one of the mosfets gates, so that one device is off when the other is on. Depending on your system, it might be better to drive the high-side of the devices rather than the ground side. In that case, you could use a P-channel MOSFET. What is the nature of your
"control input voltage"; that will determine the required circuitry. If it's 0-10 volts, that would be great.