Rick, Check your compression and ALC settings. There's a specific setup/configuration for proper use AND test. Based on my reading you can cause a bad signal on ANY transmitter with the comp/alc settings miss-adjusted.
I'm sure someone here can better address the setup/configuration. jer -----Original Message----- From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Rick Stealey Sent: Tuesday, September 01, 2015 11:18 AM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] K3S IMD Questions I have been playing with a Flex 6300 here in my shack recently. I consider it a great piece of test equipment for analyzing signals in the shack as well as on the air. It does everything and more, as a spectrum analyzer, that my old HP141 analog setup did, except it doesn't have a tracking generator. My measurements are not completed and I am still experimenting, but here is what I've done so far. Phase noise, cw transmitted bandwidth, and 2 tone IMD tests. My two rigs are a K3/100 and an FT100D (how good, and how bad can you get!) Using a Flex 6300 as a spectrum analyzer, I fed a greatly attenuated signal into it, keeping the level just under 0 dbm, and assuming it is not generating imd of its own, but I haven't quantified that yet. Phase noise tests - I was interested in seeing if it could display the RELATIVE benefit of the new synthesizer on my K3, looking at phase noise. Here are PRELIMINARY RELATIVE results, without numbers, in order of phase noise level at 2 khz separation:An 8640B signal generator (known to have low phase noise)The K3 with original synthesizerThe FT100 After I install the new synthesizer I hope to be able to compare it to the original one. I verified the FFT spectrum analyzer (Flex 6300) can give an instant view of transmitted bandwith of the cw signal sending fast dots. MUCH easier and better than the old analog HP spectrum analyzer which had to sweep extremely slowly across the band with a narrow filter. With this setup you hold the key closed, and hit the control-print screen buttons on the keyboard and you have a beautiful picture ! Ain't technology great? 2-tone IMD measurements -The two tone test of the K3 showed something interesting, since it has both 10 watt and a 100 watt PAs installed. Starting with low power and cranking up the power control, you notice, of course, that the ten watt PA has worse IMD just before the big PA kicks in, in the 11-12 watt range. Then it is very clean (approximately -40 db for third order) at its best, and ok in the 30 watt range (where it would be set to run my 8877 amp) but then gets quite ugly above 65 watts. And I mean in the -20 db range at 100 watts. IF it was overloading the spectrum analyzer these tests would be invalid, so I need to verify that. As I said these tests are preliminary. I need a few more hours. In my humble opinion, running at full power, 100 watts barefoot, my K3 would be transmitting an unacceptably sloppy signal. Keeping it in the 65 watt range or under, or driving an amp would be better, provided your amp is clean. My 8877 amp is VERY clean. I don't know about a solid state amp. Some of the ugliest signals I have seen on the bands with the Flex panadapter in very limited observations have come from Expert 1500 watt amps (2 examples). The very best was an Anan 100 with a Ten Tec 1500 watt tube amp. The waterfall was a brick wall - NOTHING whatsoever outside the 3 khz bandwidth. Rick K2XT ______________________________________________________________ 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 Message delivered to je...@carolinaheli.com ______________________________________________________________ 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 Message delivered to arch...@mail-archive.com
