Re: "WRU nailed it. I missed it in the original posting. You're losing 1.7 volts in 8ft of that "#14 wire"."
That's why Walter is known as "wunder"! <<grinning>> I missed it, too :-( Mark ars: KE6BB -------- Original message -------- From: Kevin Stover <[email protected]> Date: 04/17/2016 4:18 PM (GMT-08:00) To: [email protected] Subject: Re: [Elecraft] KXPA Power Output WRU nailed it. I missed it in the original posting. You're losing 1.7 volts in 8ft of that "#14 wire". That's about as bad as it gets. Why didn't you use the power cable supplied with the amp? I believe it's #12. What kind of power supply is running the amp? It has to be 25 amps peak *minimum*, I'd say continuous. What else is being run on the same power supply? On 4/17/2016 4:19 PM, Walter Underwood wrote: >> On Apr 17, 2016, at 11:44 AM, Art Nienhouse <[email protected]> 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) -- R. Kevin Stover AC0H ARRL FISTS #11993 SKCC #215 NAQCC #3441 --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
