Hi Larry, I assume you've tried playing with different settings of both the IF and DSP noise blankers. If not, by all means try it and use the least aggressive settings that make the situation tolerable.
I'm not sure how the DSP NB works, but the IF NB works by essentially shutting off the signal path in the IF stage for the duration of the noise pulse. For relatively infrequent pulses, these brief blank spots in the received signal aren't very noticeable to our ears. However, if the blanking action is frequent (either because of the nature of the noise or because the threshold is set too low), the blanker effectively becomes a mixer combining the desired signal at the IF frequency with the frequency of the noise pulses (and harmonics thereof, etc.) When this happens, you'll hear distortion and "intermod" just as you've described. I'm afraid it's the nature of the beast. Your best bet in the long run is to find and fix the source of the noise. A distant second best is backing off the NB settings to find a compromise between the noise and the intermod that's at least tolerable. 73 -- Joe KB8AP On Jun 12, 2010, at 2:34 PM, Larry Godek wrote: > I've got some local noise around here that sounds like a water > heater or sorts or something along that line. Anyway it's really > giving me fits on 6 meters. I ahve to run the NB almost all the > time and that distorts the signals and sometimes it doesn't even > clean up the noise. Doesn't matter if i use the preamp, attenuator, > Noise reduction or what. Plus when i turn the NB on i get all sorts > of crap from SSb signals 40 plus kc up in the band. If i turn the > NB off the SSb crud is gone. I operate mostly in the CW portion of > the band. When the NB is off i don't ahve this problem. Other than > finding the noise out there in the 0-90 degree quadrant anyone have > any idea as to whats going on? I'm really getting sick of the SSb > crud showing up when the NB is on down in the CW portion of the > band. I only have one antenna hooked to the radio. What else can i > tell you? > > Larry > W0OGH > > ______________________________________________________________ > 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
