[Elecraft] How low (V) can the K3 go?

[Matt Zilmer]

The K3 / K3S is rated to meet its specs with a power source between 11 
and 15V.  The problem with operating at low voltages is that the TX IMD 
increases.  Distortion of any type is one of the enemies of data modes.  
Well, really, ALL modes.

I wouldn't operate the K3 / K3S much below 11.5V, personally.  A 
solution for battery operation when the source voltage is too low is a 
battery booster such as the N8XJK : 
http://stores.tgelectronics.org/the-new-n8xjk-boost-regulator/. These 
devices have a setting to go into an alarm state if the source voltage 
is too low (I set mine to 10.5V), and you can set the output for up to 
15VDC even with a source voltage as low as 9 VDC.  This will all work 
with a power supply as well.  You may want to beef up your supply 
cabling if you're seeing such a large voltage drop from source to K3.

If you're using a battery, read the specs to determine the lowest safe 
operating voltage.  Running a battery discharging below this minimum 
voltage will shorten its life (called overdischarge).

73!

matt W6NIA


On 9/16/2016 8:54 AM, Chris Kimball wrote:
> I'm running a test on my K3 with Olivia 8/500 data mode at 40 W output. The
> duty cycle is 1/3 transmit (4 min) and 2/3 receive.  A "LOW BAT" warning and
> beep occur occasionally during transmit, however, the ALC remains at about 4
> bars solid, one flickering.  The voltage during receive is more than 11 V,
> but during transmit it drops into the 9.x range sporadically.
>
> The test is into a dummy load and I have no way to judge the signal quality.
>
> When, at this power level, should I stop the test?  What's the best
> indication that the voltage is too low for a clean and usable signal?
>
> Chris
> NQ8Z
>
>
>
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-- 
Matt Zilmer, W6NIA
www.elecraft.com
Office: 831-763-4211 x125
Mobile: 909-730-6552
[Shiraz]