[Elecraft] K3: pwr out - does this sound right?

[Brian Alsop]

"And it's connectors" is quite true.  I did some back of the envelope 
calcs here and 60-75% of the voltage drop appears to be due to the 
connectors + power supply sag.

This conclusion was drawn from a least squares linear fit of the V vs I 
plot to obtain an effective R value.   Then the cable resistance was 
determined from wire cables.      I collected a number of them from 
people with different supplies, crimped and soldered PP's.  These 
effective resistance values seem to vary 50%-- perhaps a reflection of 
power supply sag.  We're talking total effective resistances in the 0.02 
to 0.04 ohm range.

Draw you own conclusion whether or not it would be desirable to have a 
lower resistance connector. 

The calc's do indicate for a 5' cable,  the difference between  using 10 
ga and 12 ga supply cable is negligible.

73 de Brian/K3KO

Dave G4AON wrote:

>Doug, I guess you are seeing the Voltage drop on the power lead and it's
>connectors. With my "not so old" Racal linear power supply, I obtained
>the following results from the metering on the K3:
>
>Zero out, 13.8V
>5 Watts out, 13.5V
>100 Watts out, 13.3V
>
>This was checked into a 50 Ohm load on both 80m and 20m
>
>73 Dave, G4AON
>K3/100 #80
>  
>