K2AV replied to AE6RH, who described a situation on 75m where it appears he was hearing the Hainan woodpecker & the K3's NB took it down by two S-units, following some previous posts about the K3's NB effectiveness on this type of impulse noise:
>NOTHING removes ALL noise. The K3 can pretty much nail key clicks. It also >completely kills whatever my neighbor beyond my neighbor does in cold >weather that I can see all the way up to VHF analog TV. I'll take those two >and smile about anything else only moderately reduced. > >I note at one point some had complained they couldn't eliminate some of the >(Chinese?) jamming signals. I would note that those signals were >specifically DESIGNED to resist elimination. Yes, no NB removes all the noise, but I doubt any manufacturer has such a determined user group that tries to explain anything untoward away. The best example of this is the K2's screwdriver scratch blanker. Now we are told a simple, repetitive impulse train somehow can be made not blankable, though perhaps K2AV is referring to something else. My other radios blanked the British over-the-horizon radar quite well. They also blanked the Chinese OTHR quite well, as long as the pulses don't seem mushed up (we're close enough here that we can hear the pulse & that pulse coming a little later, not off a target, I guess from the backscatter we also use sometimes to work people, all the OTHRs that use the amateur bands have the sort of umph for it). If I can't make out the pulses myself, the NB can't & therefore little if any blanking action with any NB. These were old radios, like IC-765 & TS-950S. Something about old NBs, I recall a bloke here once found the FTDX-400's (or something of that vintage) to have a combination of simplicity & performance that is probably worthy of copying outright as a replacement for the KNB2. However a predictable impulse noise train (like OTHR) is best blanked by feeding a noise gate with pulses of the same repetition rate, with pulse width & phase of the train adjustable by the operator. We did such a product at AEA something like a quarter century ago. A trivial task for a DSP radio like the K3, I would imagine. It is unfortunate that accuracy of the front panel clock or further blurring of the distinction between SSB & CW modes seems more important to the user community. Maybe as more & more countries fire up their OTHRs on the amateur bands & conditions return so that they can be heard over there, the community will change its tune. 73, ex-VR2BG/p. ______________________________________________________________ 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
