3 X the sound frequency sounds like sound card over-drive, or simply exceeding the actual linear range of the sound card. On-board sound chips and cheep Chinese sound cards are particularly vulnerable to showing odd-order effects if you look way down. Those can sometimes be significantly improved by managing the range of input sound and line-in levels.
If you want to see a clean 100 dB range in audio devices, you will have to get a high-end audio card. The cheep stuff just doesn't go there. 73, Guy. On Mon, Feb 28, 2011 at 1:53 PM, kk7uq <disco...@waypt.com> wrote: > Hi Tom > > SNIP > ----------------------- > Been toying around with CW Skimmer, kinda an interesting program. > > Anyway, I'm receiving multiple "ghost image" CW decodes from the same > station while running Skimmer. They are 1 Kc or so apart from another. > Better stated, the same stations signal is being shown on the horizontal > waterfall numerous times. I have tried narrowing the K3's filters, reducing > sound card audio into Skimmer & toyed around with every other parameter > with > no success. > ------------------------ > > I have seen the same thing on strong signals displayed on CW Skimmer. On > DX > Skimmer, I can see the same signal at 3x the pitch frequency. I can not > see > it on the waterfall view of the spectrum from MixW which is running at the > same time. This particular signal was running 50 dB above noise level and > harmonics were not visible in either the MixW spectrum or waterfall > display. > > If I increase the audio output level from the interface to the point where > there is clipping in the audio coming from the interface, I can see the > signal at 2x, 3x and more on the skimmer waterfall, but can only see the 3x > signal on the MixW waterfall. > > Try reducing your audio drive into the soundcard input to be sure a strong > signal is not clipping there, and then see if the multiple copies go away. > CW Skimmer does it's own AGC so it can operate well with reduced audio > levels. > > 73, Clint KK7UQ > > > -- > View this message in context: > http://elecraft.365791.n2.nabble.com/Multiple-Ghost-Image-CW-Decodes-While-Using-CW-Skimmer-a-K3-tp6070469p6074435.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: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
