[Elecraft] Data mode and filters

[Joe Subich, W4TV]

On 2015-05-11 12:39 PM, Jim Brown wrote:
> That's true ONLY at full power. What matters a LOT more is IMD at
> the lower power levels required to drive power amps to legal limit.
> At reduced power levels IMD in the K3 is reduced significantly, while
> the IMD in the other rigs I've tested do NOT.

Considering that a great many stations operate at the 100 - 150W level
*with no amplifier*, moving to 48V final amplifiers capable of -37 dB
or better IMD is *very* important.  Continued insistence on PAs that
operate on a lead-acid battery for home stations at the 100W level
is a blind spot.

At least choose devices that will operate at either 12/24 or 12/48V
and design the transformers so that the PA can operate at 200W with
48 V and 25W at 12V with excellent IMD.  Those that refuse to use
reasonable dual voltage power supplies can still limp along with
their back-pack compatible battery supplies but those who prefer to
operate at the traditional 100W "barefoot" level can do so with clean
signals that befit the rest of the K3 design.

73,

   ... Joe, W4TV