Gary, The 8 watts that Ralf mentions is correct, but according to the KX3 specifications (Owner's Manual rev. B4, Pg 51), that is possible when using a 13.8 VDC power source. Although I haven't used one for some time, I would be surprised if an SLA battery voltage is that high during transmit. On 15m, It should be able to provide 10w PEP, but only with a 13.8v power supply. Reduce the power setting a few watts, and you may eliminate the problem.
The KX3 works differently than the rigs most of us have used (other than Elecraft rigs). When you set the power control to an output power, you are not adjusting the drive into the finals, but instead, you are telling the microprocessor that you want that much power out. The microprocessor then controls drive to the finals to get that output power. As the battery voltage drops, the KX3 microprocessor increases the current level (drive current) to get the requested power out. It is a closed loop system. Since P = E x I, the current must be increased as the voltage goes down to keep P constant at the value you requested. At some point, the KX3 current monitoring notes that too much current is being drawn, reduces the power output to protect itself, and displays the HI CURR message. This has been discussed at great length in the Yahoo KX3 group. Not sure if it has on the Elecraft list. I believe someone there put a table together that shows possible out possible vs. power supply voltage. If I can find it I will reproduce it here, with the proper credit, of course. Mark KE6BB From: Ralf Wilhelm<r...@super-deutschland.net> Sent: Fri, Dec 13, 2013 at 2:24 AM To: Gary Hawkins <g...@hawkins-zhu.com> CC: elecraft@mailman.qth.net <elecraft@mailman.qth.net> Subject: Re: [Elecraft] [KX3] Hi Curr Warning Hi Gary,The maximum specified output power of the KX3 is 8 Watts on 12, 10 and 6 meters (I think so).This would explain folding back on 10 but not on 15 meters and certainly does not explain the "display issue".GreetingsRalf,DL6OAPAm 13.12.2013 um 01:36 schrieb Gary Hawkins <g...@hawkins-zhu.com>:> On my last two SOTA outings I've experienced HI CURR warning with the KX3. I've read this is associated with low battery voltage or low antenna impedance. I think at one time there was also a software bug associated with specific settings that was fixed with a firmware release.> > My setup consists of KX3, with ATU, 1/4 wavelength vertical cut for 20m. SLA battery, well charged, operating above 12V under load. Antenna fed from 50ft co-axial cable, 30ft counterpoise connected to ground of KX3. TX power set to 10W> > Both times I was operating on 15 or 10m. ATU was tuned, showing 1:1.0 match.> > Does anybody have any idea what is causing the HI CURR warning?> > After it happens, TX power reduces to 5W. CMP and ALC bars display - no matter what I do I can't get these indicators to go in favor of SWR and RF. Even if I power off the KX3 it still comes up in this display mode. Finally, for no apparent reason, after five to ten minutes it then seems to switch back to SWR and RF display.> > Looking forward to your input,> > Gary> KK6GXD> ______________________________________________________________> Elecraft mailing list> Home: http://mailman.qth.net/mailman/listinfo/elecraft> Help: http://mailman.qth.net/mmfaq.htm> Post: mailto:Elecraft@mailman.qth.net> > This list hosted by: http://www.qsl.net> Please help support this email list: http://www.qsl.net/donate.html______________________________________________________________Elecraft mailing listHome: http://mailman.qth.net/mailman/listinfo/elecraftHelp: http://mailman.qth.net/mmfaq.htmPost: mailto:elecr...@mailman.qth.netThis list hosted by: http://www.qsl.netPlease help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
