[Elecraft] K3 - Power cable voltage drop

[hawley, charles j jr]

I used to run my K3S with an auto turn on Rigrunner which I liked very much, convenient. But the voltage drop was concerning. I go direct now to the rig.

Chuck Jack Hawley 
KE9UW

Sent from my iPhone, cjack 

> On Dec 22, 2019, at 10:21 AM, Don Wilhelm <donwilh at embarqmail.com> wrote:
> 
> Tony,
> 
> While those figures with the 10 gauge wire are good, they would be better if you ran the K3 power directly from the power supply rather than from the power distribution strip.
> 
> Each connection will have some voltage drop, so in addition to increasing the wiring gauge, reducing the connection points will help just as much.
> 
> 73 Merry Christmas, or Happy Hanukkah whichever you choose to celebrate.
> Don W3FPR
> 
>> On 12/22/2019 10:47 AM, N2TK via Elecraft wrote:
>> I have been using an Astron SS-30M power supply for several years to feed
>> two K3's.
>> I use 12ga wire from the power supply to an MFJ-4012 power strip. From the
>> power strip I use 12ga wire to each K3. Total length from power supply to a
>> K3 was 8'. Each K3 is set for 100W on 30M into a dummy load.  The K3's were
>> tested one at a time. The power supply voltage went from 14.38 to 14.30 at
>> 100W.
>> Both K3's read the same on the K3's internal voltmeter - 14.1V in receive
>> and 12.7V at 100W setting on the K3's. The P3 read 107W out.
>> Changed the cable to 10ga wire direct from the power supply to each K3.
>> Length of each is 7'. Same test. Power supply voltage was still 14.39/14.30.
>> Voltage on each K3 was now 14.2v. Key down 13.6V. So, 0.6V drop in 7' of
>> 10ga wire.
>> P3 output was now 114W.
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