Not normal. Make sure the power supply voltage is stable and do the testing at 13.8v.
Vic 4X6GP > On 3 May 2016, at 5:10 AM, Bill Leonard N0CU <[email protected]> wrote: > > I recently got a new K3s/10 built up and running. This week I ran some tests > to get familiar with it and one test that surprised me was the high Tx IMD > levels. I first noticed that the two tone waveform on a Tek o'scope showed > flat topping starting at about 4.5 W. As the power level was increased the > flat topping got worse. I checked the spectrum with my HP spectrum analyzer > (on 14 MHz) and measured the following 3rd order IMD levels feeding a 1.1 > SWR: > > 1 W: -36 dBc > 4 W: -31 dBc > 4.5 W: -33 dBc > 6 W: -34 dBc > 8 W: -25 dBc > 10 W: -21 dBc > > It was interesting that as the power was increased from 4.5 to 6 watts, the > increased distortion didn't show up in the 3 rd order IMD, but rather the 5 > th and higher order products. > Since I am new to Elecraft radios, I don't know if this behavior is expected > or if there is something in my transmitter that needs to be checked out. > I have built up a number of amps over the years and I am used to seeing flat > topping start at, or a little below the maximum CW output power. My K3s puts > out about 12 W max, so I was expecting the flat topping to start at about 11 > W. > > Bill N0CU > > > > -- > View this message in context: > http://elecraft.365791.n2.nabble.com/High-Tx-IMD-with-new-K3s-10-tp7617100.html > Sent from the Elecraft mailing list archive at Nabble.com. > ______________________________________________________________ > 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]
