The modem was configured at 5MHz increments from 5100MHz to 5900MHz, which should result in a sweep from 3100MHz to 3900MHz. The bandwidth was 20MHz and power was default. The horizontal scale above is 90MHz / graticule.
For the following graph, the last bandpass filter in the transmitter chain was removed. Measurement power level was +20dBm.
In the following graph, both transmit bandpass filters were bypassed. Measurement power level was +20dBm. In order to see all the harmonics without filters a wider measurement spectrum was recorded: from 2GHz to 6GHz.Ignore the noise floor step at about 5.8GHz - that's an instrument (HP 8566A) artifact, not a component of the card's signal.