The K3 will actually continue to operate well below 11 V, which is rare for any 
desktop transceiver. It will automatically reduce maximum allowed transmit 
power output, to some degree, based on the supply voltage. This allows use from 
a depleted 12-V car battery, for example. Our objective is to keep you on the 
air even in less-than-ideal conditions.

But as you noted, higher supply voltages result in improved IMD performance. 
Low voltages should only be used when there's no other choice.

73,
Wayne
N6KR


On Sep 16, 2016, at 9:12 AM, Matt Zilmer <ma...@elecraft.com> wrote:

> 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
>> 
>> 
>> 
>> --
>> View this message in context: 
>> http://elecraft.365791.n2.nabble.com/How-low-V-can-the-K3-go-tp7622535.html
>> Sent from the Elecraft mailing list archive at Nabble.com.
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft@mailman.qth.net
>> 
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to mzil...@roadrunner.com
> 
> -- 
> Matt Zilmer, W6NIA
> www.elecraft.com
> Office: 831-763-4211 x125
> Mobile: 909-730-6552
> [Shiraz]
> 
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft@mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to n...@elecraft.com

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Reply via email to