Switching On and Off the Power Amplifier in python

Hi all,
I am trying to perform On Off Keying and I figured out that the
way
actual chips (TI-Chipcon 1000) do it is by turning on and off the power
amplifier.
I found out that when I just modify the transmit constellation and use
benchmark_tx.py the received power does not go down to 0 when the
transmitted symbol is 0+0i. As pointed out by some of you, I found that
the
stream of symbols have a DC component which results in a beat frequency
at
the receiver.
My question now is, can I just shutdown and power up the (transmit)
power
amplifier depending on the transmitted symbol to perform On Off Keying.
I
think, I will not have the DC problem then because the power amplifier
would
now see only one symbol either 1 or 0 instead of a stream of symbols
which
have a DC component. In my understanding, the code currently sets
auto_tr to
true meaning that whenever it is not transmitting/ done transmitting a
packet it goes to the receive state and so the power amplifier is off.

Is it possible to set the power amplifier On/OFF in Python ? Where can I
find the code that performs this or is relevant to this?

Thanks,
Sri