Re: [Elecraft] K3: Noise reduction tutorial/primer available?
Some of you were interested in what the Filters and such did on the K3 so I wrote this little bit of information up to help you out. I hope you find it useful. If you have any questions feel free to ask off the reflector. Thanks; In brief: Notch: The Notch has an Auto (for SSB use) and a manual setting for CW. This can be used to take out a tone (carrier) or other noise that is sitting in the middle or near your pass band area (the freq. you're listening to). It can also be used in CW mode to reduce the amount of noise you hear in the upper or lower part of the pass band area. Setting it up to do this takes SOME understanding of what a notch filter does, and how to adjust it. You may not hear any difference between having it on, and off depending on the noise, and on the settings that you have selected. Along with turning it on you also have to adjust the Freq. manually when using it in CW mode. Sometimes Notching out (CUTTING out) a selected signal can help with reception. For example if you are on CW and you have a lot of LOW end rumbling in headphones and you want to get rid of it, depending on your PITCH freq. you can turn on the NOTCH filter and set it to 300Hz for example. This will NOTCH out (cut out) all of the sound on and around the 300Hz freq. area. One thing you have to watch out for is setting the Notch freq in the menu to match, or come too close to your PITCH freq. If you do you will have essentially Notched out your Target freq that you're listening for. Not good. NR: The NR is used to reduce noise. As you've noticed it has settings as well. Settings 1-1 through 4-1 are normally used with CW, because of the long hallway effect that you've already experienced on SSB. Settings 5-1 through 8-4 are generally used with SSB because they don't tend to cause this kind of effect on the voices. You should always try to use the LEAST (or lowest) NR value you can IE 5-1 or 1-1... If it helps at 1-1 and is good enough, there is no need to process more than you need. Too much of ANYTHING is a bad thing. Even though it wasn't mentioned in the original question, the RF gain is another one of your BEST noise reducing tools you have... When used in conjunction with the NR filter, if you reduce your RF gain down to 4 or even 5 bars on the scale when the nose on 40 is 4 bars high (as you indicated it was) you will notice that your NR works exponentially better! This is because the DSP no longer has to process nearly as much noise along with signal. Don't worry, you will find that even when you turn the RF gain down on a signal that is S5 along with an S4 (4 bars) noise level you will NOT make the signal you're listening for go away. Just turn it down slowly as to hear when the person starts to get too low. If you start reducing their signal by more than the NR is reducing your noise level you know you've gone too far. You'll have to play around with this one some.. It's all about technique. Keep in mind that it may take 10 seconds or so before your NR starts to clean up the noise as you drop the RF gain, so try only dropping it as much as 1 bar less than the noise level at first, if you need to drop the RF gain lower then go ahead and then listen again for a few second more. NB: The NB generally works for Electrical noise and other pulsing type noises... You have already noticed that when you turn it on it can drop your S meter by as much as 1 S unit. With the proper settings (DSP/IF) you may be able to get that down to as much as 3 S units (bars) of noise reduction. However, keep in mind, with the reduction of noise with this method you will also have adverse affects on the signals you're trying to listen to. Such as a clicky sound on the CW tones, or flutter on a voice. Again, like the NR you always want to use as little as you can get away with. Starting with the lower numbers for DSP, and the Narrow modes for IF. Just for a starting spot, in my area I find that 2-5 with Med 2 seems to work very well at reducing the QRM/QRN. However, if I move it to 2-7, Med 2 I find that the noise level drops down 3 bars, but trying the have a QSO with a weak station is almost impossible. As well as the noise it tends to remove the sender as well. Try NOT to use your S meter as your gauge of where you should have your NB set to. For example, Turn off the IF NB, start with the DSP (because this seems to work best at removing noise) Next, Close your eyes and start to VERY slowly turn the DSP part of the NB starting at the lowest number (setting). LISTEN to when the noise is reduced to your satisfaction. It may take some going back and forth to get this right, or even hear a difference. When you are done, if you are not completely satisfied with the noise reduction continue this process using the IF part of the settings. Keep the DSP portion exactly where you found it to work best. When you find the best IF noise reduction you will have your
Re: [Elecraft] K3: Noise reduction tutorial/primer available?
Don, Thanks for the references. Many of us were not on this reflector or even owned a K3 in 2009 so would not know. I am printing this off for future reference when I am ready to investigate NR/NB more thoroughly. 73, Ed - KL7UW --- Message: 8 Date: Fri, 09 Jul 2010 15:00:26 -0400 From: Don Wilhelm w3...@embarqmail.com Subject: Re: [Elecraft] K3: Noise reduction tutorial/primer available? To: w0...@aol.com Cc: Elecraft@mailman.qth.net Message-ID: 4c3771ca.1010...@embarqmail.com Content-Type: text/plain; charset=ISO-8859-1; format=flowed There was straight talk about NR from Lyle Johnson (who designed and implemented the algorithms) in his reflector posts of 8/25/09 and 8/27/09 as well as the information in the Firmware Release Notes for version 3.30 (avaliable using the K3 Utility Help pulldown). Page 25 of the K3 manual has a comprehensive description of the tools available - Reducing Interference and Noise section. The manual content is Wayne's work, so those who know most about those implementations have already spoken. I am not certain how much more authoritative information you are seeking. As far as explicit Here is how you use it - each individual case or instance of noise is different and will require different treatment. Each user will have to cycle through the settings available to see which works best - the result is a compromise, there is little that can move a signal out of the noise and provide a completely distortion-free and clear copy signal - copy will be improved, but just how much is improved and how much distortion is tolerable is a question each operator must answer. 73, Don W3FPR 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-QRT*, 432-100w, 1296-QRT*, 3400-fall 2010 DUBUS Magazine USA Rep dubus...@hotmail.com == *temp __ 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
[Elecraft] K3: Noise reduction tutorial/primer available?
Excellent thread, several fine responses. This is one for Wayne and/or Eric to weigh in upon with Elecraft concise, straight talk this is how to use the NB and NR. Over to you guys! __ 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
Re: [Elecraft] K3: Noise reduction tutorial/primer available?
There was straight talk about NR from Lyle Johnson (who designed and implemented the algorithms) in his reflector posts of 8/25/09 and 8/27/09 as well as the information in the Firmware Release Notes for version 3.30 (avaliable using the K3 Utility Help pulldown). Page 25 of the K3 manual has a comprehensive description of the tools available - Reducing Interference and Noise section. The manual content is Wayne's work, so those who know most about those implementations have already spoken. I am not certain how much more authoritative information you are seeking. As far as explicit Here is how you use it - each individual case or instance of noise is different and will require different treatment. Each user will have to cycle through the settings available to see which works best - the result is a compromise, there is little that can move a signal out of the noise and provide a completely distortion-free and clear copy signal - copy will be improved, but just how much is improved and how much distortion is tolerable is a question each operator must answer. 73, Don W3FPR w0...@aol.com wrote: Excellent thread, several fine responses. This is one for Wayne and/or Eric to weigh in upon with Elecraft concise, straight talk this is how to use the NB and NR. Over to you guys! __ 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
Re: [Elecraft] K3: Noise reduction tutorial/primer available?
On Jul 9, 2010, at 3:00 PM, Don Wilhelm wrote: I am not certain how much more authoritative information you are seeking. As far as explicit Here is how you use it - each individual case or instance of noise is different and will require different treatment. At least for myself, it would be useful to have a paragraph or two that could be titled K3 NB and NR for Dummies and might look something like this: Each operator and location will experience unique noise sources and conditions. In order to best use the NB and NR tools, a certain amount of experimenting is required. That being said, here are some general guidelines for using NB and NR tools under very generic situations. Each operator will have to play around with these settings for their own situation! NB: Lightning noise: (?) Power line noise: XYL is vacuuming the house: ? Plasma TV noise: NR: Unlike the NB system, the NR tools are for combating random noise of an unknown (or random) source. In this case, a starting place for using the tool might be easier based on mode rather than source: SSB: (my favorite is 5-1) CW: ??? DATA: OFF then again, this would be better in a WIKI than the official documentation... Take care Gary / k3wow __ 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
Re: [Elecraft] K3: Noise reduction tutorial/primer available?
Gary, Have you read column 2 of page 25 in the manual? What it says is very close to what you have requested - except for explicitly stating that 'some experimentation is required'. It does say which noise sources the IF Noise Blanker is better suited for, and which the DSP Noise Blanker attacks more readily. Further down, it states that the more aggressive NR settings will make the signal sound hollow. I don't know just how much more information would be meaningful. There is no one setting that works best for any one type of noise all the time - how far the noise source is from your antenna and how it propagates are additional variables. A recipe for any particular situation could become quite complex. To be a valid chart the noise characteristics would have to be expressed in terms of the rise time, duration, and fall times of the noise present *at* the K3 input (not at the source of noise). It makes no sense to me to attach the antenna feedline to a spectrum analyzer to determine the characteristics of the noise before selecting which one to use on the K3. I think it much easier just to try the various settings (given the guidelines already in the manual) and find which one sounds best to your ears at that particular time - most likely the best will be different tomorrow because the signal affects the best choice as well as the noise type, and the signal will change with propagation changes too. 73, Don W3FPR Gary Dezern wrote: At least for myself, it would be useful to have a paragraph or two that could be titled K3 NB and NR for Dummies and might look something like this: Each operator and location will experience unique noise sources and conditions. In order to best use the NB and NR tools, a certain amount of experimenting is required. That being said, here are some general guidelines for using NB and NR tools under very generic situations. Each operator will have to play around with these settings for their own situation! NB: Lightning noise: (?) Power line noise: XYL is vacuuming the house: ? Plasma TV noise: NR: Unlike the NB system, the NR tools are for combating random noise of an unknown (or random) source. In this case, a starting place for using the tool might be easier based on mode rather than source: SSB: (my favorite is 5-1) CW: ??? DATA: OFF __ 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
[Elecraft] K3: Noise reduction tutorial/primer available?
Hi, I've been searching for some operating tips on how to strategically employ the following K3 controls: - NOTCH - NR - NB - WIDTH - SHIFT As good as the manual is, I still feel like I don't understand how these really work and when I should use them to get the best possible results. To date, I've been randomly turning them on and off, adjusting their various settings to see what they do. But I'm hoping some of the experts here can explain how and when they like to use each of these controls. I have been using my K3 for about 4 months. Lately, 40m has been a little more noisy for me (about 4 bars of noise). I suspect its QRN, but there may be some QRM as well. Activating the noise blanker (NB) will usually drop the noise by 1 S unit. Recently, I've been fiddling with the NR settings to improve the signal quality (this was very helpful on last night's 3905 40m SSB net - the noise without NR on was just horrible). I don't understand what the different NR settings are doing, as you move from 1-1 thru 3-7. Going from 1-1 to 1-4, it sounds like the person on the other end is moving farther down a long hallway - the signal gets more faint, disappearing into a surrounding quietness. 2-1 and 3-1 sound very similar to 1-1. And, I don't understand what NAR1,NAR2,NAR3 through WIDE1, WIDE2, WIDE3 settings on the NR feature are doing for me. I don't notice much difference no matter what I select with those. What about NOTCH? I don't seem to notice any difference whether it is engaged or not. Finally, I can sometimes use the WIDTH control to reduce interference from nearby signals, but if someone is booming in 2 kHz away, I can't seem to shut them out. Anything else I can do here? I am not sure what SHIFT is used for, perhaps this can be utilized? I have the 2.7kHz, 1.8 kHz and 400 Hz filters installed. Thanks for helping a newbie! 73 de Jeff, W6UX __ 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
Re: [Elecraft] K3: Noise reduction tutorial/primer available?
I can help with some of these (though I'm clueless on the NB...) It helps if you visualize the passband of the receiver as a small part of the entire RF spectrum that the radio lets into your speaker (or headphone.) This would be similar to a movable and resizable window on your house - so you can move the window to different places on your house to see different things outside (or make it larger/smaller to see more at once or less at once.) This window analogy, being visual, makes things easier to visualize... Notch: This is like blocking out just a tiny portion of your window. For me, it's most useful for those times that a LID decides to spend an hour tuning up and their tuning carrier is right in the middle of my window. In SSB, the K3 will (by default) use auto-notch - so it'll look for a carrier within your passband (window) and automatically block it out. The best analogy I can come up with would be that the sun is shining directly into your window, so you put your hand between your eyes and the sun. Thats a notch filter. Width: Simply, this is the size of your window. Usually, you only want to see one thing at a time, and for SSB, that width is 2.7. However, when stations are too close together, you can make that window smaller so that adjacent stations aren't interfering with your view. (If that adjacent station is putting out splatter or a really wide signal, this might not help...) I usually end up shifting (see below) when messing with the width. Shift: This is just moving your window around on your house. If you look out your window and there is a naked guy that you don't want to see on the left side of the window, you can just move the window a bit to the right. Of course, now you might be seeing something undesirable on the right side... Ideally, a combination of shifting the window and making it narrower (width) will let you see only what you want to see. NB: No idea how this works on the K3. The documentation suggests the NAR/MED/WID if settings are useful for some types of noise and the DSP settings are useful for other types of noise - but I haven't seen anything that narrows it down more than that. NR (noise reduction) is a mechanism of pushing the audio through a DSP (computer program) to try and clean it up. My understanding is that the DSP works by analyzing the audio and only letting through audio that forms certain patterns (such as speech) as opposed to completely random audio. The different settings for NR use slightly different mechanisms to try and clean thing up, some more aggressive than others. The more aggressive mechanisms tend to be more destructive to the audio which gives it that hollow or echoing sound. Take care Gary / k3wow On Jul 8, 2010, at 1:34 PM, Jeff Hall (W6UX) wrote: Hi, I've been searching for some operating tips on how to strategically employ the following K3 controls: - NOTCH - NR - NB - WIDTH - SHIFT As good as the manual is, I still feel like I don't understand how these really work and when I should use them to get the best possible results. To date, I've been randomly turning them on and off, adjusting their various settings to see what they do. But I'm hoping some of the experts here can explain how and when they like to use each of these controls. I have been using my K3 for about 4 months. Lately, 40m has been a little more noisy for me (about 4 bars of noise). I suspect its QRN, but there may be some QRM as well. Activating the noise blanker (NB) will usually drop the noise by 1 S unit. Recently, I've been fiddling with the NR settings to improve the signal quality (this was very helpful on last night's 3905 40m SSB net - the noise without NR on was just horrible). I don't understand what the different NR settings are doing, as you move from 1-1 thru 3-7. Going from 1-1 to 1-4, it sounds like the person on the other end is moving farther down a long hallway - the signal gets more faint, disappearing into a surrounding quietness. 2-1 and 3-1 sound very similar to 1-1. And, I don't understand what NAR1,NAR2,NAR3 through WIDE1, WIDE2, WIDE3 settings on the NR feature are doing for me. I don't notice much difference no matter what I select with those. What about NOTCH? I don't seem to notice any difference whether it is engaged or not. Finally, I can sometimes use the WIDTH control to reduce interference from nearby signals, but if someone is booming in 2 kHz away, I can't seem to shut them out. Anything else I can do here? I am not sure what SHIFT is used for, perhaps this can be utilized? I have the 2.7kHz, 1.8 kHz and 400 Hz filters installed. Thanks for helping a newbie! 73 de Jeff, W6UX __ 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
Re: [Elecraft] K3: Noise reduction tutorial/primer available?
Thanks Gary and The Smiths (great 80s band, BTW!) for those very helpful pointers! Can't wait to try those techniques out tonight! 73 de Jeff, W6UX __ 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
Re: [Elecraft] K3: Noise reduction tutorial/primer available?
Jeff, I see you have gotten a few helpful answers. Let me add something to your questions about shift and width. The shift and width are mostly helpful for CW and possibly DATA modes - the SHIFT centers your receive passband. A rough estimate of the passband is shown in the lower left graphic on the LCD display. You should always keep some part of your passband at the CW pitch you are listening to (the sidetone pitch), otherwise the signal you wish to receive will be attenuated because it is outside the passband. The width simply narrows the passband - and it narrows it from both sides, so as you attempt to use more narrow widths, the setting of the shift control becomes more critical. That is about all there is to shift and width. Now, for SSB, you will find the shift and width more cumbersome to use while trying to maintain SSB intelligibility. The cure is to tap either the shift or width buttons so they become LO CUT and HI CUT instead. Set the LO CUT at 200 to 300 Hz and leave it there. Control the width of the SSB passband only with the HI CUT knob and you will maintain intelligibility as you narrow the passband. If the band is not crowded and you have no QRM on your desired SSB signal, reduce the LO CUT to 150 Hz, and increase the HI CUT to 3.00 kHz (or even 3.50) to achieve the best fidelity. If an interfering signal comes in on the (audio) high frequency side of the desired station, reduce the HI CUT to try to minimize the QRM - conversely, if the interfering signal is on the low frequency end, increase the frequency of the LO CUT to eliminate the QRM - one caution, go slowly with the LO CUT because if the low end of the passband is much above 350 Hz, you will sacrifice a lot of intelligibility for the desired station. I hope that is helpful. If you did not understand, please ask again. 73, Don W3FPR Jeff Hall (W6UX) wrote: Hi, I've been searching for some operating tips on how to strategically employ the following K3 controls: - NOTCH - NR - NB - WIDTH - SHIFT As good as the manual is, I still feel like I don't understand how these really work and when I should use them to get the best possible results. To date, I've been randomly turning them on and off, adjusting their various settings to see what they do. But I'm hoping some of the experts here can explain how and when they like to use each of these controls. __ 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
