The noise blanker works extremely well on repetitious, high-amplitude pulse type noise such as that put out by cheap lamp dimmers, auto ignition, etc. The dimmers are more of a nemesis on the lower frequency bands were auto ignition is more of a problem on the higher frequency bands.
Basically, the blanker works by noting the interval of a train of pulses and then turning off (blanking) the signal path for an instant when the each pulse occurs. That effectively makes the pulses disappear. Having used my K2 in areas where I could not get away from those cheap lamp dimmers, it made the difference between hearing a roar of S9+ noise to having the background drop to an S1 or S2 level of typical band QRN. The blanker can't do much of anything if the noise does not consist of a train of high-amplitude pulses. Typical noises it can't handle are the hash from motor commutators, the frying sounds one sometimes gets from leaky power line insulators, etc. But it's FB on "popping" arcs that sometimes occur on power lines and anything else that is high-amplitude and repetitious. Even so, there is a downside to any noise blanker. It is punching holes in the signal path. They are too short to hear, so the noise just goes away. But that action of switching the I.F. signal path off then on again produces frequency "mixing", just like any frequency converter or "mixer". As a result, various frequencies in the I.F. path might produce mixing products that appear as spurious signals or other noise! That's why Elecraft recommends you turn the blanker OFF when you don't need it. Ron AC7AC _______________________________________________ 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
