I'm in the process of testing a GNU Radio transmitter. The
transmitter will be connected to a solid-state power amplifier
(SSPA) for near-Earth satellite communications. The SSPA
expects an input of 0dm from the USRP TX port.
The first step is thus to measure the power from the USRP.
To that end, the flowgraph generates a complex sinusoidal
signal with a unit magnitude. The UHD:USRP Sink block is set
to maximum gain (i.e. normalized gain of 1.0). Unfortunately,
the maximum power I can see from the spectrum analyzer is
around -6.93 dBm as shown below. To my understanding, the USRP
can transmit up to 20 dBm as reported in the "External
Connections" section at this Ettus link :
Could anyone explain why I can't achieve a 20 dBm (or
anything around it) power level?
Thanks in advance,