Hi, Robin! Do you have a cheap lamp dimmer (the type that works with incandescent lamps only)? Most of them emit a terrible buzz when set to half-brilliance. The KNB2 is excellent for removing that noise.
You are absolutely correct: the KNB2 requires a train of evenly spaced pulses, such as those produced by a lamp dimmer, unshielded auto ignition, etc. It can't do much for random noise since it "anticipates" the timing of the pulses is even. When the pulse interval varies widely, it gets the timing wrong and blanks at the wrong instant. Also, sometimes annoying noise is too low in level for the circuit to trigger, even in low threshold position. I have discovered that on 80 meters particularly. Turning on the Preamp, even though it's not otherwise needed, will often make the noise disappear by bringing its level up to where the noise blanker is being triggered properly. Ron AC7AC -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Robin Kiszka-Kanowitz Sent: Monday, December 26, 2005 10:54 AM To: elecraft@mailman.qth.net Subject: [Elecraft] How can the KNB2 be tested? Hi, I have also recently built this unit and the only way I could test it was by scratching the antenna input with a metal object. I can hear that it removes the 'clicks' out of the peaks, but I have not been able to test it against real pulse noise. Whatever else I have tried hasn't seemed to make a difference, then again, it may not have been pulsed noise. 73 Robin OZ6ABM _______________________________________________ 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
