[Elecraft] KXPA Power Output

[Walter Underwood]

> On Apr 17, 2016, at 11:44 AM, Art Nienhouse <ka9zap at gmail.com> wrote:
> 
> My rest voltage is 14.1 the key down voltage is 12.4 […]. the 14 gauge zip power cable is what comes with a 100watt Icom the length is 4 foot there is no loss here that I can see to cause this low power output.

And there is your problem. The KXPA100 specs say "100 watts at 13.8 V”. It won’t produce 100W at 12.4V.

A 1.7V drop under load is very large. The power supply and wiring cannot supply the required current without dropping the voltage.

Eight feet of 14 gauge wire will have 0.9V drop at 24A. The electricity has to travel over both conductors of the 4 foot wire, which is why we use 8 feet.

It looks like you have some additional problems beside the small power supply cable. Maybe there is resistance in the connectors (poor crimp? not seated?). Maybe the power supply won’t reliably supply 25A. Maybe the line voltage or house wiring has an issue.

I would recommend at least 10 gauge wire and keeping the cables short. PowerWerx offers some useful pre-built cables at good prices.

https://powerwerx.com/adapter-extension-cables

wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)