It's all about the source of the noise. My KNB2 has made it possible for me to operate where I'd otherwise have noise pegging the "S-Meter".
The KNB2 removes repetitive high-amplitude pulse noise such as that produced by automobile ignition systems, cheap lamp dimmers, etc., that cause a loud "buzzzzz" in the audio. It senses the noise pulses and literally turns the signal path off for a very brief period when the next pulse arrives. Other kinds of noise, such as hash from d-c motor commutators or band noise aren't affected by the KNB2. Since large trucks such as you described are invariably diesel powered and so have no ignition system, the most likely source of that noise were the commutators in the d-c motors they use. That produces a hash much like heavy band QRN. The only way to reduce that noise that I've seen yet is a system to digitally process the signal, picking out the noise elements with a sophisticate algorithm. The Elecraft KDSP2 offers that ability. I don't have the KDSP2 in my K2 but the comments from users posted here no the reflector suggest that it's "denoiser" function works quite well. Ron AC7AC -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Fred (FL) Sent: Sunday, March 11, 2007 6:43 AM To: elecraft@mailman.qth.net Subject: RE: [Elecraft] Question from a newbie I built my K2 #54xx in May 06. Built the KNB2 Noise Blanker. Then found it never really seemed to work on any noise! One day, 4 cement trucks & 2 large pickups sat like 30 feet from my shack - all running, all working. The KNB2 did nothing to remove any of that man-made noise. Also it doesn't work on any band noise - that I ever found. I even got a 2nd KNB2, from Elecraft - and it didn't work either? The K2 itself - after build - operated true to all specs, calibrations, & alignments beautifully. I've since felt, the KNB2 is a design job left to be re-done, by some Elecraft designer, when they get around to it. The IC-7000's Noise Reduction and Noise Blanker circuitry - amazingly almost always reduces most band noises, real or imaginary, dramatically. Maybe in the K3? Fred N3CSY ____________________________________________________________________________ ________ 8:00? 8:25? 8:40? Find a flick in no time with the Yahoo! Search movie showtime shortcut. http://tools.search.yahoo.com/shortcuts/#news _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
