[Amps] HLA-150? Nevermind.

[Steve Thompson]

Steve Katz wrote:
> Along the same line, different amp:
> 
> Tom, have you tested any of the Mirage VHF amps?
> 
> I have a few which don't seem to do well.  Never tried to specifically
> measure IMD, but they're not anything close to linear once operated at maybe
> 50% of rated output power.  1 dB compression occurs at maybe just over 50%
> rated output, and at 100% rated output they're in heavy compression (CW
> signal, 14Vdc power).  Not just one, but a few different models....
The transistors used in these sorts of amps are usually designed for VHF 
mobile radio use - class C, heavily into saturation for high efficiency 
at the rated power, inherent current limiting for high VSWR tolerance. 
These are things that kill linear operation, the 50% output you see at 
1dB compression is about the best they can do. Moving to 28 or 50V makes 
a world of difference.

Steve