[Elecraft] Re: AA primary cells: NiMH vs. Alkaline

[Wayne Burdick]

Phil Wheeler wrote:

> >Note that we recommend using 3-4 watts when running from internal
> >battery, because best PA collector efficiency at 9 to 10 volts occurs at
> >a lower power level than at 12-14 V.
> >
>
> I often use a battery pack which has 10 NiMH AAs in series.  Would a
> different power recommendation apply?

Best efficiency would be somewhat higher with 10 cells rather than 8,
but still, the lower the power output, the longer the batteries will
last. You can drop power during a QSO if you think it won't impact
readability. Wes Hayward is a big fan of the 0.5-watt level, although to
do that efficiently with a 5-watt class transmitter you'd have to bypass
the PA stage and run from the driver.


> Also, aside from the cost, would Lithium AAs work well for this
> application?  The thrust of the question is there are situations (e.g.,
> backpacking) where the weight savings and the low-temp characterisitics
> of Li cells can make them worth the cost.

The weight saved by using Lithiums would be at most a couple of ounces.
Since the rig, antenna, key, log, and batteries weigh upwards of 32
ounces, this probably isn't a good tradeoff. More likely someone trying
to reduce weight to a minimum would start with a completely stripped,
optimized monobander such as the Wilderness SST, *and* use lithium or
LiIon batteries. Such rigs routinely finish at the top of the heap in
the ARS "Spartan Sprints," proving that they're effective for
communication despite their lack of frills. (Non-Impartiality Alert: I
designed the SST  :)

Wayne