[Elecraft] K3 Voltage on TX

[Bob McGraw - K4TAX]

You don't happen to have anything else in line between the power supply 
and the K3 do you?  I've found those DC distribution panels sold by 
certain companies are contributors to significant voltage drop.  Your 
statement " With the radio connected directly to the PS.  I am now 
seeing 14.1 VDC and 12.0 VDC on TX." is a clue that the way you have 
things configured is not optimum.     In fact, anything in line between 
the power supply and radio can contribute to this.  Even fuses, 
switches, power connectors and such.  Any connection that is loose or 
terminal that is loose will be a voltage drop point.  They just add up.

My rule:  the radio connects direct to the power supply.  No exception.  
If you need DC for something else, connect it direct to the power supply 
as well.  I also use a dedicated ground conductor between the radio and 
DC supply ground.  The DC Negative is not considered to be adequate ground.

73
Bob, K4TAX
K3S s/n 10163

  

On 10/26/2015 12:05 PM, Rich wrote:
> Thanks to all.  I have check my PS and it does not fluctuate even a 
> tenth of a volt on TX.    With the radio connected directly to the PS. 
> I am now seeing 14.1 VDC and 12.0 VDC on TX.  So I need to look closer 
> at the wire gauge and connectors.  That is still about 2VDC drop.
>
> Thanks for the help
>
> rich
>
> On 10/26/2015 12:09 PM, Phil Wheeler wrote:
>> If the wire gauge is OK and the supply regulation is not at fault, 
>> give some attention to the connectors at each end of the cable, too. 
>> A drop of 2.8 Volts points to some sort of issue.
>>
>> 73, Phil W7OX