Here is a link to my recording. With such distortion and sharp edges (or crossover, or whatever others call it) it is no wonder that the WNB was catching impulses and pumping.
This is a ridiculous signal....
But it made me wonder. Is there a way to define the WNB so that it samples a more limited bandwidth of signals in order to do its work so that I can exclude such nasty out of band signals from the WNB's calculations?
Ken - NM9P
I have also seen this on the upper end of 40m band around 7.160 - 7.200. In Europe we often see some very strong international broadcast stations above 7.2. This renders the WNB almost unusable on 40m, and to an extent 80m SSB DX segment as well. So yes please, a more definable "passband" for the WNB should be very very effective.
Also, I feel that as it could be configured to just process say the current panadapor visible range then we might actually see more dynamic noise reduction because it can be better focused on the noise we are currently experiencing, not the much wider bandwidth we don't really care about.
Looking forward to the WNB focus slider...
73 de Steve G1XOW
In addition, I have added these comments into a program change request (technical a feature request) as item #3807 in our bug tracker
Ken, thanks a heap for tracking down the cause of the pumping. I’ve noticed similar behavior many times but never took the time to investigate further. If WNB can be improved in such cases by giving the user the option of narrowing the range that WNB searches (maybe even down to the slice receiver range?) then I’m all for it. Great idea!
Personally I don't find much need for WNB at my quiet country location but others may need this facility to work without the overload pumping action when AM broadcasters are around.
73 de Steve G1XOW
As I said in my post, personally I don't need WNB so it's not an issue for me. The few experiments I did proved it was pointless as it was impossible to make the massive AM broadcast signals low enough relative to the signal we are interested in. Being up to 10 times louder than the miniscule DX in the noise I am trying to receive.
There is no facility for "spot-attenuation", and a sig 10 times louder that is just out of the 20m band cannot be reduced by filters to any large degree without badly affecting performance of the desired in-band signal too. I use the well respected Heros Filter (external to the F6k) which makes no difference with such close-in sigs.
I also tried adjusting the slider downward (it was set at about 40 in the video to ensure the demonstration). Once the slider drops below about 20 there is no benefit anyway. Also, I have notice the same pumping affect at the top end of 40m (7.170) even with the slider set at 0 and WNB turned on.
I feel there is a fundamental design flaw in the math/sampling scheme. The massive AM broadcast signals being sampled versus the tiny desired signals will never lead to happy math (weighted averaging) and thus the blanking will be ineffective when any big sigs are present. I suspect the same would be true in any big contest such as WPX SSB too.
To work really well, some tweaking is required (or the ability to notch-out the AM broadcast bands QRM prior to averaging), Otherwise its function will only be useful in a small number of cases (those without big AM BC QRM), and hence why some claim WNB is a gift from god, yet others think the opposite.
In a nutshell, it needs more work based around real-life environmental situations to be a really useful facility.
73 de Steve G1XOW
Not really a problem for me now that I know to shut them off. Thanks again for the hints. Much appreciated.