Re: [Elecraft] Noise blanker [was: K2 battleplan?]
Thanks for all the very helpful replies regarding the noise blanker! Mike AB3AP Ron D'Eau Claire wrote on 04/30/05 11:37 ET: Mike AB3AP wrote: I've noticed the majority of K2s seem to be built with the NB. [...] - The noise blanker is designed to suppress noise consisting of a train of high-intensity pulses with a regular interval between them. [...] ___ 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
Re: [Elecraft] Noise blanker [was: K2 battleplan?]
Jim: I found that nothing worked here until I RTFM and changed the NB threshold from High to Low. This whacked the horrendous track-light noise when my family has the audacity to use the family room when I am on 40 meters. ;-) Have you changed that setting? I really am going to fix these track lights, real soon now. Bob N4HY Jim Brown wrote: On Sat, 30 Apr 2005 16:42:19 -0700, Darrell Bellerive wrote: Have you considered the mods for the noise blanker: http://www.qsl.net/ve3mcf/elecraft_reflect/KNB2_Mods.txt That mod does NOT work for me. I own two KNB2's. One I built, one came in a K2 that I bought used, and had that mod. It simply didn't work at all. I've restored it to stock, and now it works fine. Jim K9YC _ ___ 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
Re: [Elecraft] Noise blanker [was: K2 battleplan?]
Hisashi T Fujinaka wrote: In my location, the K2 was unusable without the KNB2, so I'd get it in step 1. But as they say, YMMV. I've noticed the majority of K2s seem to be built with the NB. I don't have it, and since I don't seem to be having any man-made noise problems I've been wondering when where the NB is useful. Is it mainly for presumably noisier urban and suburban areas? Without it would something like Spectrogram show continual spikes at certain frequencies? And finally, would the DSP board have any substantial effect on the sort of man-made noise the NB addresses? Thanks! Curiously yours, Mike AB3AP ___ 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
RE: [Elecraft] Noise blanker [was: K2 battleplan?]
Mike AB3AP wrote: I've noticed the majority of K2s seem to be built with the NB. I don't have it, and since I don't seem to be having any man-made noise problems I've been wondering when where the NB is useful. Is it mainly for presumably noisier urban and suburban areas? Without it would something like Spectrogram show continual spikes at certain frequencies? And finally, would the DSP board have any substantial effect on the sort of man-made noise the NB addresses? Thanks! - The noise blanker is designed to suppress noise consisting of a train of high-intensity pulses with a regular interval between them. Good examples are the raucous buzz most cheap incandescent lamp dimmers produce or the staccato pops produced by poorly-shielded automobile ignition systems, especially on the higher frequencies. If the noise does not have pulses that occur with very fast rise times and at regular intervals, the noise blanker won't be able to identify it from regular QRN or it won't able properly time the action to suppress the pulses. It does a wonderful job on the proper sort of noise but, like all such noise blankers, it does it at some expense in performance. The blanker actually shuts off the i.f. strip for the duration of each pulse. Instead of a train of loud pops coming through the second detector and down the audio channel, you have a chain of 'holes' where there is no output. The problem is that process of switching the i.f. strip on and off quickly also turns the i.f. into an unintentional frequency mixer. With the noise blanker on, strong signals can mix with each other in the i.f. producing spurious artifacts that sound like everything from normal QRN to actual spurious signals on the band. That's why the noise blanker has an on/off switch. The noise blanker should only be turned on when it's needed. I don't have the DSP unit in my K2 so I can't compare them. The sorts of noise the noise blanker is designed to produce are more likely to be encountered in a urban environment, although sources capable of drowning out the bands might also be in your own home. The noise from cheap lamp dimmers usually doesn't travel very far, for example. The troublesome ones are usually very close by. 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
RE: [Elecraft] Noise blanker [was: K2 battleplan?]
I have a K2 with NB and the NB is very effective in the urban/suburban area I live it with lots of noise. But I did not get the NB for my K1 which is only used in the field where it is so quiet I sometimes think my radio has died. I'd say, get it without the NB and add it later if the noise in your operating environment is intolerable. Eric KE6US -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Mike Markowski Sent: Saturday, April 30, 2005 8:11 AM To: Elecraft Main Group Subject: Re: [Elecraft] Noise blanker [was: K2 battleplan?] Hisashi T Fujinaka wrote: In my location, the K2 was unusable without the KNB2, so I'd get it in step 1. But as they say, YMMV. I've noticed the majority of K2s seem to be built with the NB. I don't have it, and since I don't seem to be having any man-made noise problems I've been wondering when where the NB is useful. Is it mainly for presumably noisier urban and suburban areas? Without it would something like Spectrogram show continual spikes at certain frequencies? And finally, would the DSP board have any substantial effect on the sort of man-made noise the NB addresses? Thanks! Curiously yours, Mike AB3AP ___ 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
Re: [Elecraft] Noise blanker [was: K2 battleplan?]
In a message dated 30/04/05 16:12:07 GMT Daylight Time, [EMAIL PROTECTED] writes: I've noticed the majority of K2s seem to be built with the NB. I don't have it, and since I don't seem to be having any man-made noise problems I've been wondering when where the NB is useful. Is it mainly for presumably noisier urban and suburban areas? Without it would something like Spectrogram show continual spikes at certain frequencies? And finally, would the DSP board have any substantial effect on the sort of man-made noise the NB addresses? Reply: -- At first I thought the KNB2 noise blanker in my K2 was not working as it had no effect on the normal type of noise received at my QTH. Then after quite a few months found that the NB did indeed work and very well, but only on impulsive noise with sharp rise times like automobile ignition interference. Seems that the KNB2 is a lot more selective in what it will suppress. My old faithful Yaesu FT-480R 2m multimode on the other hand is not as choosy and will work over a wider range of noise types. The FT-480R if anything is rather simpler in the NB circuit design than the KNB2. The FT-480R picks up the RX wide band input half way through the two roofing filters that provide initial bandwidth control after the first mixer. It uses a relatively high gain IF section controlled with AGC to feed a detector circuit that gates G2 in the 2nd mixer MOSFET. It does work exceptionally well though, removing a variety of noise types. If the KNB2 worked to the same degree I would be very happy. The incidence of the type of interference that the KNB2 will gate out is seldom experienced at my QTH, so it gets very little use. In retrospect could have saved a some money by leaving the KNB2 out in my K2, though as has been pointed out in other postings there are some QTH where this noise blanker is really useful. Only hope that eventually some future mod or redesign of this module may be of benefit with the type of noise I suffer from. As regards use of the DSP2, I do not have one in my K2, but do have an external Timewave DSP-9+ available. The DSP-9 works I would guess in a similar way to the DSP2 in that it is in the audio chain. Impulsive noise is not removed by this device in noise reduction mode (NRr), though longer term noise that the normal noise blanker will not touch is suppressed in amplitude during it's duration. I would guess the audible effect is in a way similar to what used to happen with ANL circuits in the AM days. The DSP-9 and would presume other audio DSP devices have a longer delay in response time and so prevent any chance of removing sharp rise time noise. Though it may be looked on as heresy by the K2 CW fraternity, in the Timewave DSP-9+ SSB mode, morse can be almost completely eradicated by the action of noise reduction on tone (NRt). When going over to CW with an external DSP device, the user has to be careful that this NRt facility is switched off, otherwise little morse is heard. Bob, G3VVT K2 #4168 ___ 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
Re: [Elecraft] Noise blanker [was: K2 battleplan?]
On April 30, 2005 4:31 pm, [EMAIL PROTECTED] wrote: Only hope that eventually some future mod or redesign of this module may be of benefit with the type of noise I suffer from. Bob, G3VVT K2 #4168 Have you considered the mods for the noise blanker: http://www.qsl.net/ve3mcf/elecraft_reflect/KNB2_Mods.txt -- Darrell Bellerive Amateur Radio Stations: VA7TO, VE7CLA Grand Forks, British Columbia, Canada ___ 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
