Hi Wayne, I measured with the built-in meter. Sorry, I don't have a dummy load, so I cannot test that. Next time I will connect two of the same sealed lead acid batteries in parallel and see if something changes. No problem to use two.
Thank you for the explanation. At least I can be sure that nothing is wrong with my KX3. 73, Arno -----Original Message----- From: Wayne Burdick [mailto:n...@elecraft.com] Sent: Monday, August 05, 2013 17:02 To: Arno Dienhart Cc: elecraft@mailman.qth.net Subject: Re: [Elecraft] KX3 power reverts from 10W back to 5W Hi Arno, The KX3 requires 11.0 volts minimum on key-down for power output levels of greater than 5 W. We do this to ensure low IMD in SSB transmit mode, but it's good practice in general because most 12-V batteries can be damaged quickly if you let the voltage go much below 11.0 with a heavy load applied. When you measured the voltage on key-down, were you using a voltmeter at the battery, or the one in the radio? You could have been dropping some voltage across the power supply wires (+ and - leads probably about the same), or in the KX3's DC input circuitry (reverse-polarity diode, current sense resistor, etc.). So even if you read 11.7 V, it's possible that you briefly dipped below that 11.0 threshold. Try running it into a dummy load, using the same battery. What is the voltage on key-down? (Make sure to bypass the ATU or tune it into the dummy load for this test.) 73, Wayne N6KR On Aug 5, 2013, at 2:49 PM, Arno Dienhart <a...@broadweave.net> wrote: > So I had set up in the park, with a charged 12V 17Ah battery > connected. It was a hot day but I was in the shade. > > > > Every time I set power level to 10W and keyed the TX, it reverted back > to 5W instantly. Why? > > > > The Volt meter showed 12.3 V at RX and dropped to 11.7V at TX. Was > that the reason (getting below 12V)? > > Was the PA getting too hot? It never went below 5W. > > > > Thanks for any tips, > > > > 73, > > > > Arno > > ______________________________________________________________ > 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 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
