[Elecraft] Power control on 50MHz

[Lyle Johnson]

> I would really, really like the option to disable this switching out of the
> 100W PA altogether. It seems to be an utterly pointless extra complication.

Part of the point is that the DAC used to create the signal at 15 kHz, 
which is upconverted, is using fewer bits at lower output levels.  While 
the gin scaling is very coarse, switching the HPA out at power levels 
which can be safely handled by the LPA improves the IMD of the signal 
being amplified by the Tx chain.  iI is partly for this reason that 
there is a switchable attenuator in the Tx chain as well.

73,

Lyle KK7P