A single chip radio transceiver includes circuitry that enables received RF signals to be down-converted to baseband frequencies and baseband signals to be up-converted to RF signals prior to transmission without requiring conversion to an intermediate frequency. The circuitry includes a low noise amplifier, automatic frequency control circuitry for aligning the LO frequency with the frequency of the received RF signals, received signal strength indicators for adjusting frontal and rear amplification stages accordingly, and, finally, filtering circuitry to filter high and low frequency interfering signals, including DC offset. A radio frequency (RF) variable gain amplifier (VGA) includes a power amplifier in a direct conversion radio transceiver that includes a gain determination module that reduces an input gain level to the power amplifier to adjust the output power level of the power amplifier according to temperature indications to maintain reliable operation or power level indications to maintain a constant output power level.