[Elecraft] K3 battery power

[Eric Fitzgerald]

On Jul 20, 2010, at 9:00 PM, Wes Stewart wrote:

> Joe took the words right out of my mouth.
>
> Personally, I use an "unnecessary" boost regulator when on battery  
> power or a PS set to at least 14V otherwise.
>
> [snip]
> Unfortunately, this does not apply to transmit IMD.  Since the K3
> (like all other solid state transmitters) has a fixed ratio broad-
> band transformer between the final FETs and the 50 Ohm output.
>
> As the voltage falls and current increases, the amplifier impedance
> changes (decreases), the final amplifier operates into an increasing
> mismatch and the IMD becomes worse.  Keeping the voltage to the
> final amplifier as high as possible within its specification allows
> the lowest possible IMD and highest efficiency.
>
> 73,
>
>     ... Joe, W4TV
>

Interesting.  I run a K3 off a couple of pseudo deep cycle 12 volt  
batteries with an Iota smart charger hooked up.  I run mostly digital  
so IMD is important to me.  The Iota runs between 13.1 and 13.6 volts  
by my K3's meter.  Would the difference between that and 14 volts make  
a meaningful difference in the IMD ?  What brand and model booster  
provides 14 volts?  The MFJ promises 13.8.

TIA

73 de Eric, KG6MZS