Wideband Noise Blanking

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  • Updated 4 years ago
  • (Edited)
This may be more of an FYI than a question. I enter this as I did a full search on all 19 occurrences of WNB in the users guide to find what a blinking WNB means.  

When the WNB detects a significant change in signal level or bandwidth, it attempts to normalize the slider value. During this time, blanking will be momentarily bypassed, and the WNB indicator in the Panadapter will be highlighted.
So, if I read this correctly, when it is highlighted, like the +20dB or +10dB, it is actually not blanking anything.

Actually, I am going to make this an idea, as I find the blinking WNB to be both confusing and distracting. It seems to work opposite of the 'highlighted' RF Gain figure just to it's right. The fact it is 'blinking' is a distraction and, for one, I don't appreciate that distinction so ... perhaps...it is a distraction with little to no value?

ANF and APF don't have similar flags on the panadapter. Further 

Given the wideband nature of this feature, the threshold slider in the GUI controls an entire SCU, which may have several Panadapters and/or Slice receivers attached to it. For convenience, the slider control is available in each Slice and each Panadapter.
I opened a second panadapter and it did not show the WNB flag next to the RF Gain, nor did it show the WNF as on in the slice. In the 6500 there is only the one SCU, correct, and where it's on in the first open pan, shouldn't it show open in the subsequent panadapters?

So the idea part of this is, if the value of displaying whether or not the WNB is blanking anything adds little to no value, should that 'flag' next to the RF Gain (which has great value there) be removed? Second, if it applies to the entire SCU shouldn't all slices on the SCU show the control enabled with identical slider indicators?

On a separate note, the NB now is awesome!
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Walt - KZ1F

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Posted 4 years ago

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Lee, Elmer

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When  WNB is grayed out the NB is "on" but creating (for want of a better word) the blanking mask.  When WNB is lit blanking is occurring.  For a dramatic amount of blanking, say 15 dbm the condition is obvious but for a virtually noise free band the condition is not obvious necessarily.  The annunciator tells you the state of the noise blanker dynamically.  It is also useful if you want to tune the minimum amount  of blanking, but I haven't found the blanker to really need tuning.  I would prefer this feature be left alone.

73  W9OY
(Edited)
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Terry Tankersley

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It works great. I am waiting to hear from my power company to fix a problem pole and my noise is a s8. The new WNB takes it out so I can now use my new 6500. Thank you Flex
Terry  K7NY
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Tim - W4TME, Customer Experience Manager

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WNB works differently from NR so you really can't compare the two.  NR is a narrow bandwidth process that once converged, doesn't usually require re-convergence.  

With WNB, since the bandwidth it operates on is very wide, signals in other parts of the band away from your signal of interest may adversely affect the aggravate signal levels requiring frequent re-training.

In our alpha testing, we received feedback that there was no visual indication that WNB was temporarily disabled while it re-trained  after a significant change in signal level and the WNB indicator.  It seemed that WNB was "broken" (not blanking) when it was actually re-training.  If you want to propose a change, make it an idea post and allow public feedback on the merit of it.

Second, while WNB does operate at the SCU level, it can be applied on a per panadapter basis.  If WNB is not applied to a particular panadapter, we decided there was no need to display the blanking state of WNB.  And all slices within the same panadapter do show the same WNB enabled/disabled state.
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Walt - KZ1F

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Tim, I merely added the nb call out so people wouldn't think I was being negative. I like it way more than in 1.4.

It IS an idea.

I don't understand your first sentence in last paragraph. I'll accept it but it strikes me as counter intuitive.
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Tim - W4TME, Customer Experience Manager

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To do wide band noise blanking we do it at a very low level in the radio architecture; in the FPGA to all of the data coming from SCU.  Panadapters are derived from the SCU data, so noise blanking can be applied (or not) on a per panadapter basis.

Example.  Wide band noise is wiping out 160-40m.  I have a panadapter on 60m and another one on 10m.  I do not need noise blanking applied on 10m so I do not apply it to that panadapter.  I want it on 60m, so I apply it to that panadapter.
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Walt - KZ1F

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Let me repeat back how I understand what you just said. Lee used the term 'mask', that actually helped. So the mask is determined based on the entire SCU. It may or may not be applied to any given panadapter. OK, assuming that accurately reflects what you said. Now, following your example, if 10m was noisy and the op selected WNF there, it would be the same mask? Or would a compromise mask be rebuilt?

Thanks for helping me understand. I am sure it is helpful to others as well.
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Tim - W4TME, Customer Experience Manager

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There is no compromise; the blanking (mask) just isn't applied to a panadapter when it is not enabled.
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Walt - KZ1F

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Thank you Tim.
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Tim - W4TME, Customer Experience Manager

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The pleasure is all mine, Walt.
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Walt - KZ1F

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When I said NB, I meant NR.
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WX7Y

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I did notice that if you move the slider up above half way it starts to introduce artifacts and if it's near 100% (not that I'll ever have it that high) I hear all kinds of crap like a bunch of Broadcast stations jammed into a very small bandwidth window at least on my radio (6700) in the PM on 40 Meters.

Bret
WX7Y
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Tim - W4TME, Customer Experience Manager

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If it hurts, don't do it.  We have to accommodate all sorts of noise levels and signatures, which call for a wide setting range.  There there is not any periodic nose to blank, running up the gain will result in some adverse affects.

So the "Spinal Tap" method of setting everything to 11 is not applicable for this control.  ;-)  As we noted in the release announcement, this is a completely new way of mitigating periodic (pulse) noise so the method of how it is applied is a little different than with traditional very narrow bandwidth noise blankers.  Use only as much blanking as you need without distorting the signal. 
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Bill -VA3WTB

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It takes a while for us to grasp this wide band technology Tim.....
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Burch - K4QXX

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I am getting this issue on 160 meters.  Once I move the slider to around 75-80 on 160 meters, I start getting broadcast stations (weak) and lots of artifacts.  I just posted a message about this so I guess I'm not the only one.

On 6 meters, the WNB does nothing until I move the slider to 100% or close to 100% but it works pretty good on that band and I don't get the artifacts.
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Sergey, R5AU

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Just published video with WNB at my location into the other post also: "Strange behavior...."
https://youtu.be/w88Zfhs-SpI