LinHT – GRF5604 RF amplifier tests – part II

After receiving a new 10W 40dB attenuator, I decided to give the GRF5604 a spin again. I connected it to my LinHT prototype (Revision A hardware, for the record) and supplied with 5.1V. I’ve set the SX1255’s DAC gain to 0dB and mixer gain to -13.5dB, to prevent the power amplifier from saturating.

Here’s a spectrum plot showing harmonics with the fundamental at 36dBm (M17 signal at 433.475MHz):

Harmonics are below -60dBc, which I would call a good result (the output filter is a MiniCircuits LFCN-490+). The peak to the left is the PLL reference leakthrough (32MHz).

Stay tuned for more news.