K3 NR (was making K3 RX audio like K2)
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K3 NR (was making K3 RX audio like K2)
 
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I agree on the observation of the NR. Up till now I have not been able to find a setting that gives me a real improvement. The NB is very good, but I find the NR disappointing. Any advice from list members is appriciated, or is the solution in improving the NR algorithms? Arie PA3A -----Oorspronkelijk bericht----- Van: [hidden email] [mailto:[hidden email]] Namens J Fox Verzonden: donderdag 20 november 2008 3:31 Aan: [hidden email] Onderwerp: Re: [Elecraft] Making K3 RX audio like K2 I'm glad I'm not the only one that has been disappointed in the "sound" of the K3. Coming from a Yaesu FT990 with a Heil Clear Speech speaker, the sound was smoother and less fatiguing. Moving the shift to a value of FC= 1.2 or so might help. I'm also hoping that more work will be done on the Noise Reduction. In each of the four groups of NR the 1 and 2 settings just seem to lower the signal and noise together while settings 3 and 4 do a much better job of reducing noise but with an adverse effect of a tunnel and echo sound. Is it just my radio or do others have the same problem? -- _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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Not sure what mode is being referred to here, but I will assume CW as this is the mode most suited to NR.
I find RX EQ settings have a significant effect on NR; I have boosted the 400-800Hz channels a few dB and that causes the cw note to appear to 'jump out at you' under NR along with reduction in the noise. Can't remember NR settings but it's not extreme and I aim for least echoing and character softening... I also had an FT990 before the K3. It was a great radio but I don't find myself hankering after it's hifi audio while listening to my K3; I'm sure the overall audio quality was no worse than the K3 but as with the K3 I only ever used the internal speaker - one less potential rfi path for one thing. Can't do an A/B comparison because I eventually sold it to finance the purchase of a KRX3, which incidentally is scheduled for delivery today(!) Wish me luck because I plan to fit asap and have it all running for cqww......... Stewart Rolfe, GW0ETF (K3 #145)
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In reply to this post by Arie Kleingeld PA3A-2
You may simply be expecting too much of NR. It cannot overcome the basic physics of noise bandwidth. If you're already at a narrow CW bandwidth, it will do very little except confuse you. N.B. #6 below. http://www.zerobeat.net/mediawiki/index.php/K3_DSP NR explained by Lyle Johnson I think there is a fundamental misunderstanding of what NR is and how it works, at least in the context of the K3. 1) NR is better named SE (signal enhancer). 2) It is a "short" FIR filter whose coefficients are continuously being recalculated. 3) It defaults to suppressing everything. 4) When it senses that there is something that correlates (i.e., has a pattern that doesn't seem to be entirely random), it attempts to build a filter around those frequencies that seem less random. 5) Because the FIR filter that is being implemented is short, the filter being built is less selective than the normal DSP filters in the radio. 6) NR is rarely useful if the bandwidth is narrow. If you set your CW width to 400 Hz or less, for example, there is no point in running NR *unless* you want to use it as a sort-of "smart squelch." 7) The narrower you set your WIDTH, the more that noise appears like a signal, and the worse the NR will perform. And the less noise there is anyway, assuming there is a signal present. NR cannot compete with a narrow filter, and was not designed to. 8) I find NR most useful during CW operation with the 2.8 kHz roofing filter NORM'ed so the Rx bandwidth is wide. Assuming band activity is low, the Rx is quiet. If a CW station comes on within the Rx passband, a filter will be built around the station and I can hear it. 9) Similarly, I find NR in SSB is mostly useful as a sort of squelch when tuning around, or monitoring a frequency you are expecting a call on (probably a net or a sked). I use NR1-1 or NR1-2 for this. Mild suppression, not too much impact on fidelity, and lets me hear weak signals, too. I hope this is helpful in better understanding how NR is implemented in the K3. |
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In reply to this post by GW0ETF
GW0ETF wrote:
> I find RX EQ settings have a significant effect on NR; I have boosted the > 400-800Hz channels a few dB and that causes the cw note to appear to 'jump > out at you' under NR along with reduction in the noise. Can't remember NR > settings but it's not extreme and I aim for least echoing and character > softening... This is not the best approach because of the following: when the 50 and 100 Hz DSP filters are enabled the RX EQ is disabled (I forgot the reason for this, but Lyle explained it to me). So the effect of narrowing the bandwidth is that the signal suddenly drops several dB! If you want to use the RX EQ for this the best way to do it is to leave the desired bands at 0 dB and *reduce* all others by the amount of 'boost' that you prefer. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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Vic,
You probably won't be using NR at these narrow bandwidths anyway; it's been explained before by Lyle and quoted in the message in this thread from Bill W4ZV: "NR is rarely useful if the bandwidth is narrow. If you set your CW width to 400 Hz or less, for example, there is no point in running NR *unless* you want to use it as a sort-of "smart squelch."...." Thinking about it I never feel the need to use NR when the bandwidth is cranked right down so it sort of makes sense.... 73, Stewart Rolfe, GW0ETF
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Re: K3 NR (was making K3 RX audio like K2)
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Down in the valley where the less-than-DXCC serfs eke out their lives hoping to make another new-one, I for one just enjoy the capability to adjust the receiver to new filters or shifting the cut-off better than the YaeKenCom radio I was used to using. If I were to re-read the K3 operator manual (and a fine manual it is) I would simply add more trivia to my brain as to what the capabilities are. But what I'd really enjoy sitting down with is a K3 for Dummies guide to using the enhanced receiver capabilities of the K3 over the lower class of radios. I'm stepping up from a FT-897D to the K3. I can tell the difference. It's obvious. But, I'm sure I'm missing out on more -- and that's entirely my own project to find out. I am looking forward to it! Here's the other proof of the difference. I'm getting for the first time comments about the audio quality on the K3 -- before they even know what rig it is. Never heard a word like that on the FT-897. I never operated the big$ rigs like 7#00 or pro{123}, or ft/ts-2000 to compare. -jeff -- Jeff Wandling DE W7BRS K3 #2105 http://w7brs.com/k3 [hidden email] On Thu, 20 Nov 2008, GW0ETF wrote: > > Vic, > > You probably won't be using NR at these narrow bandwidths anyway; it's been > explained before by Lyle and quoted in the message in this thread from Bill > W4ZV: > > "NR is rarely useful if the bandwidth is narrow. If you set your CW width > to 400 Hz or less, for example, there is no point in running NR *unless* you > want to use it as a sort-of "smart squelch."...." > > Thinking about it I never feel the need to use NR when the bandwidth is > cranked right down so it sort of makes sense.... > > 73, > > Stewart Rolfe, GW0ETF > > > Vic K2VCO wrote: >> >> GW0ETF wrote: >> >>> I find RX EQ settings have a significant effect on NR; I have boosted the >>> 400-800Hz channels a few dB and that causes the cw note to appear to >>> 'jump >>> out at you' under NR along with reduction in the noise. Can't remember NR >>> settings but it's not extreme and I aim for least echoing and character >>> softening... >> >> This is not the best approach because of the following: when the 50 and >> 100 Hz DSP filters are enabled the RX EQ is disabled (I forgot the >> reason for this, but Lyle explained it to me). >> >> > > -- > View this message in context: http://n2.nabble.com/K3-NR-%28was-making-K3-RX-audio-like-K2%29-tp1556080p1557856.html > Sent from the Elecraft mailing list archive at Nabble.com. > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > 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: [hidden email] 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 |
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In reply to this post by GW0ETF
GW0ETF wrote:
> Vic, > > You probably won't be using NR at these narrow bandwidths anyway; it's been > explained before by Lyle and quoted in the message in this thread from Bill > W4ZV: > > "NR is rarely useful if the bandwidth is narrow. If you set your CW width > to 400 Hz or less, for example, there is no point in running NR *unless* you > want to use it as a sort-of "smart squelch."...." > > Thinking about it I never feel the need to use NR when the bandwidth is > cranked right down so it sort of makes sense.... No, you won't want to use NR at narrow bandwidths. The problem is that if you set up the RX EQ to boost these ranges, then the narrowest filters will *always* show a steep drop in gain whether NR is on or off. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco _______________________________________________ Elecraft mailing list Post to: [hidden email] 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: K3 NR (was making K3 RX audio like K2)
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In reply to this post by Bill W4ZV
When I was commenting on the NR, I did not have CW in mind particularly.
Definitely not NR in a narrow CW-filter situation. Lyle's explanation of NR seems logical to me. What I expect the NR to do is: enhancing the copyablility of SSB signals that are in the local noise and barely understandable. Engaging the NR at the present situation, I can hear something happening to the audio at the different settings, but it does NOT make the signal sound better copyable. But if the NR is only for further de-noising already good signals... then I set my expectations are too high. Please tell me I'm wrong here. 73, Arie PA3A (using last version beta SW) -----Oorspronkelijk bericht----- Van: [hidden email] [mailto:[hidden email]] Namens Bill W4ZV Verzonden: donderdag 20 november 2008 12:42 Aan: [hidden email] Onderwerp: Re: [Elecraft] K3 NR (was making K3 RX audio like K2) Arie Kleingeld PA3A-2 wrote: > > > > I agree on the observation of the NR. > Up till now I have not been able to find a setting that gives me a > real improvement. The NB is very good, but I find the NR > disappointing. Any advice from list members is appriciated, or is the > solution in improving the NR algorithms? > You may simply be expecting too much of NR. It cannot overcome the basic physics of noise bandwidth. If you're already at a narrow CW bandwidth, it will do very little except confuse you. N.B. #6 below. _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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In reply to this post by Vic K2VCO
OK I've just checked this out and Vic is entirely correct.....boosting the cw tone frequencies certainly does cause a drop in signal when the dsp bandwidth crosses from 150 to 100Hz, NR or no NR. (and conversely cutting those frequencies leads to a sudden increase in signal at the crossing point - it's quite dramatic)
Glad I found this out before cqww but a little bemused as to why this 'feature' hasn't been better circulated; I've been using my K3 for a year now and have never seen mention of this. Thanks for the heads up Vic (I think that's the term...!) Stewart, GW0ETF
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Re: ***SPAM*** RE: K3 NR (was making K3 RX audio like K2)
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In reply to this post by Arie Kleingeld PA3A-2
On Thu, 20 Nov 2008 19:47:17 +0100, Arie Kleingeld PA3A wrote:
>But if the NR is only for further de-noising already good signals... >then I set my expectations are too high. Please tell me I'm wrong >here. Lyle's guidance is on the mark -- after all, he wrote the code, so he knows what it does! In CW mode, I'm nearly always working at bandwidths less than 400 Hz, and I've rarely found NR very useful In SSB mode, NR greatly reduces the noise when there's no signal, so it allows me to crank the gain higher when I'm just monitoring or tuning arond, without a lot of fatigue from the noise. That's a good thing, but I've not often found situations where NR improves the readability of a signal. On the other hand, I DO find that the Noise Blanker helps if I don't overdo it, and also find that it's easy to overdo it. :) 73, Jim K9YC _______________________________________________ Elecraft mailing list Post to: [hidden email] 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: K3 NR (was making K3 RX audio like K2)
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In reply to this post by Arie Kleingeld PA3A-2
Arie Kleingeld PA3A wrote:
> But if the NR is only for further de-noising already good signals... > then I set my expectations are too high. Please tell me I'm wrong here. If you could come up with a good algorithm for de-noising moderate to very noisy speech, you could make a fortune in the hearing aid industry. I suspect that is where most research has been done on the topic. In the limit, you are competing with a device that is already rather good at the job, the human brain. -- David Woolley "The Elecraft list is a forum for the discussion of topics related to Elecraft products and more general topics related ham radio" List Guidelines <http://www.elecraft.com/elecraft_list_guidelines.htm> _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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