TX module heating up ????

[mackrackit]

The USART TX pin idles high, so a simple inverter circuit should be all you need to hold the RF transmitters data in pin low during idle periods.

Attachment 4465

Then an inverter will be needed on the receiver side also ???

I still think since you are basically building a transceiver you will want a way to turn the transmitter off when not in use. Does the module have an enable pin?

[Bruce]

Then an inverter will be needed on the receiver side also ???

Yes. The same circuit would be needed at the receiving end as well. Assuming the receivers data output idles low, which most do, then it holds the receiving PICs USART data input pin at logic 1, which is the idle input logic for the USART RX pin.

I still think since you are basically building a transceiver you will want a way to turn the transmitter off when not in use. Does the module have an enable pin?

If he's trying to build a transceiver using separate TX/RX modules on both ends, for sure. If you don't shut down the local receiver when transmitting, it takes longer for the receivers front-end to settle & recover from the strong local signal.