[Amps] HV MOSFETs for RF

[Catherine James]

This is one reason hams are always challenged in the amplifier area.  The commercial
users are heavily focused on FM, with its 100% duty cycle but lack of any requirement for linearity.

The modes hams use tend to either be 100% duty cycle and nonlinear, but work well at low power
(FM, PSK31, JT modes), or benefit strong from high power and have a lower duty cycle, but have
a requirement that they be linear (SSB).

So the people who most want and need ham amps are SSB users, and they have little
interest in anything that is nonlinear.  If a component works well at high power in nonlinear
operation but has to be significantly de-rated to get acceptable IMD, it's unlikely to be a
good fit for ham SSB usage.  Advances in the radio art that are highly efficient but fundamentally
nonlinear are of little benefit to most hams.

Does anyone outside of ham radio care about modulation modes that require excellent linearity?

73,
Cathy
N5WVR


John Lyles <jtml at losalamos.com> wrote:

> Up to now, most of the innovation posted on line has been using nonlinear classes 
> like E for homebrew AM transmitters (another topic!) and the hams there 
> have made great strides with kW level designs.

> But building linear (or Kahn EER/Linc) amplifiers and getting around the laws of physics (very 
> low Z due to low voltages) with the newer devices is the way to look forward.