vswr amplifier output

Any experience with Amplifier Research amplifiers into large mismatch loads? I find that the output will vary a few dB from a near open to near short. Any amplifiers out there that won't vary at all?

The output of any RF amplifier will vary with load due to the mismatch loss:

Mismatch Loss [dB] = 10*LOG(1-Γ^2)

Where Γ is the reflection coefficient:

Γ = (VSWR-1)/(VSWR+1)