Strange behavior on 160 and 17 meters using WNB

Burch - K4QXX

I tried out the WNB on 160 meters last night.  I always have a very high noise level.  I had the AGC-T set between 5-10 and when I would move the WNB control close to 100, the panadapter screen noise level would rise and I got spikes all over the panadapter.  When I would move the slider back down to around 80, the problem went away but the WNB was not effective at this level.  I hooked up my Flex 5000 to 160 meters and the NB took out about 2 S units of noise.

Also, if I set the slider to 100 on 17 meters, the panadator noise level would disappear.  If I moved the slider back to about halfway, the screen came back.

The good news for me was the WNB worked pretty good on my power line noise on 6 meters.

Anyone else seen strange behavior if you move the WNB slider close to 100?  I start getting weird noise on the panadator on 160 meters once the slider gets above 80.  It goes crazy on 160 if I move it to 100.  I'll try to take a picture tonight after work.  I am using a Flex 6500 and SSDR 1.5.

Bill -VA3WTB

For most I have read so far the WNB is amazing. There is a proper way to use it, I believe it is discussed in the release notes. The AGC-T must be set correctly, read about how to do that, the WNB and AGC-T work together.

Burch - K4QXX

I have had Flex radios from the beginning (SDR-1000) and am very familiar with adjusting the AGC-T.   Regardless of the AGC-T setting, I still had the issue.  I usually only run the AGC-T at 5 or 10 on 160 meters because of the noise.  You can't really go much lower than that.  I even had it set at 0 for testing and still had the spikes and artifacts on 160 with WNB running.  AGC-T setting had no affect on the panadator screen when the WNB was activated.

The other thing that is weird is after the WNB slider gets around 80, I start hearing weak broadcast stations on 160.  I could see them in the waterfall and you can hear the broadcast if you tune to them.

Bill -VA3WTB

this may be of help, i don't know
https://www.youtube.com/watch?v=Hwm6rszuMis

SteveM

Burch,

I had the exact same issue when I tried WBN - weird intermod spikes all over the place. I was hoping it would reduce with the band noise on 80 and/or 160m. It caused all sorts of harm and no help for me.

Burch - K4QXX

Ok, glad it's not just me.  I was really hoping it would help on 160 meters.  I guess I will keep using the Flex 5000 on the low bands for the time being.

SteveM

I suspect some of us who have strong broadcast signal reception cause math overflow in the DSP algorithm for the WNB feature.

Do you have strong BCB signal reception?

WA2SQQ

I've noted the same behavior on 160. I've actually connected an external filter (via the looping in / out connection) that offers -60db of attenuation from 530-1700 khz. Switching the filter in and out makes no difference, though this condition only occurs at a setting of "100" - a very extreme condition. I'm not seeing this as a flaw. I had hoped that WNB would get rid of some hash generated by a local light dimmer - it does not. Time to go to Home Depot and buy a new dimmer!

Burch - K4QXX

It starts occurring to me when it gets over 80 and then is extremely bad when at 100.  I have to set the slider to 100 on 6 meters for the WNB to have any affect.  It actually works pretty good so far on 6 meters but does nothing on 160 because of this behavior.  When I use the NB on the Flex 5000, it reduces my noise 1-2 S units on 160.

Burch - K4QXX

Not sure on the broadcast signal. I know about 5 miles away from me is a broadcast tower but I don't know exactly what it broadcast.  I have never heard/seen any broadcast stations on 160 meters before until now when I turn on WNB.

Steve G1XOW

Me too. Generally low noise environment. But turn up above about 80% and it implodes with nasty stuff all over the display and the whole panadaptor trace bouncing up and down by 20-30db. Sumat not right!

SteveM

Burch,

Bob's test suggests it's not related to BCB. What does your noise floor from 160-80m look like? If I zoom out so that I can look across the bottom ~10MHz spectrum, there is a mountain of noise that starts at 160m band, peaks right in the middle of the 80m band (s6-s7 level), and tapers off toward the 40m band. The 80m band is where WNB flaked-out the worst for me.

Burch - K4QXX

Hopefully this is just something that needs to be "tweaked" in a future maintenance release.  6 meters was dead last night but the WNB seemed to work well on my limited power-line noise.  It took two S units of noise from the audio and panadater so that is promising.  Definitely a step in the right direction.

Sergey R5AU

Have the same behavior, however it can be an WNB algorithm with noise recognition

Burch - K4QXX

I will check again tonight but my noise level wasn't to bad on 80 meters last night.  I don't remember all the nasty spikes and noise using WNB on 80. 

My noise floor on 160 is almost S9 and on my Flex 5000 the NB will usually take out between 1 and 2 S units of noise.  With the WNB on the 6500, the screen just goes crazy when you put the slider much past 80%.  It I put the slide slightly above 80, I start to get a little noise in the panadapter and that is when I get the broadcast stations coming in. Move it a bit more and things go crazy on the screen.  I will try and post some pictures tonight when I get home from work.

Gerald-K5SDR

On 160m, make sure that you are not in WIDE mode.  If you are in WIDE, the 160m BPF is disabled.  The left side of the panadapter should not go below 1.8 MHz and the right should not be above 2 MHz to keep the BPF engaged.  

Burch - K4QXX

I was at the low end of 160 last night so I might have been in WIDE mode.  I will check tonight.  Thanks Gerald.

Sergey R5AU

Just make a video with WNB at my setup on silent 20m band - visible modulation from the strong broadcasting station
https://youtu.be/w88Zfhs-SpI

Simon Lewis

same issue here .. same behaviour - certainly not as dramatic as lee W9OY's video ... I set the knee using the meter or ear and I get the same behaviour with artefacts etc. Having said that .... there is little effect on plasma TV's or network router interference. Maybe because they are not regular pulse type emissions ... if it was a powerline it might have the better response. Needs more investigation but I don't see the amazing results from Lee's video and I do see artefacts at high settings on WNB Cheers

Simon ZL4PLM

Burch - K4QXX

I did check and I am not in WIDE mode.  I start seeing the broadcast in the 160 meter band when the slider gets to about 68-70 the WNB.  Really strange.

WA2SQQ

With or without WNB enabled I'm now seeing images from two AM broadcast stations that I never had before. I am definitely NOT in wide mode. v1.5 seems to have lost some image rejection on 160. Seriously thinking about falling back to 1.4.16

Tim - W4TME

Let me know immediately if you do not see the images with 1.4.16.  COntact me directly (firstname@flexradio.com)

WA2SQQ

Any chance I can call you? I have some info that might be useful now. I'll revert back to 1.4.16 this weekend

Burch - K4QXX

Tim

I have not reverted back but I never saw images/broadcast in the past in SSDR.  I only seem to see them when the WNB is selected and I am on 160M but I will double check tonight.

WA2SQQ

Like many of you, after installing v1.5 I started seeing some broadcast stations leaking through on 160, more so when WNB was enabled. I was convinced that the fault was with v1.5 Reverting back to 1.4.16 over the weekend did not clear up the two BCB blips at 1.900 and 1.820

At this point, since I live about 2 miles from WABC (770) I knew, somehow they had to be a component of the problem. Using my 160 sloper WABC booms in at -11dbm. Some quick math revealed that the 1.820 signal was 770 khz mixing with another local station on 1050 khz. The 1.900 signal was 770 khz mixing with WBBR on 1130 khz. The revealing discovery was that my BCB filter that offers about -70db of attenuation did not do anything to improve the situation. This convinced me that the problem was not within the 6500.

While watching the signal I saw and heard the signal come and go with a scratchy noise that sounded like a loose connection. Last night it started raining and the two blips are gone. I now believe that I have some bi-metalic mixing taking place somewhere in the neighborhood which is being powered by WABC’s booming signal. Noise hunting to follow as soon as the rain stops!  My apologies to the Flex team for possibly raising some concerns.

Now, while the noise is gone, I’ve also noticed that running WNB to the max produces very little if any additional artifacts.

Tim - W4TME

No apologies are necessary.  This happens more often that you would think.  We have seen corroded bolts on a tower, bad coax to connector shield connections and a partially blown lightning arrestor rectify strong signals to produce "images" on a 6000.

Your troubleshooting approach was solid and ended up providing the correct answer.  That is the positive takeaway.

SteveM

Yes Bob, why apologize? There are still several others in this thread who have reported the issue with WNB. Sergey even provided a video.

I was listening to one of the 40m late-nets on Monday when I decided to enable WNB. With AGC-T adjusted and the WNB slider set to 20 I was still seeing artifacts. The bouncing noise-floor from 80m was also replicated into the 40m band.

WA2SQQ

I know what it's like to be at the other end of a user forum like this. Many are quick to complain, but a far fewer number of people inform the help desk guys that what they initially reported may not be, as it was explained. Noise is like ice cream - it comes in many flavors so I can't expect WNB to be a universal cure all.  So while WNB is doing a great job on pulse type noise like ignition noise, in my case I had hoped that it would destroy the buzz caused by a light dimmer in the living room. It has no effect on it. A trip to Home Depot fixed that problem!

One suggestion that Flex should consider is to  create a noise blanker that can be expanded to allow the user to select profiles for different types of noise. These profiles can be created and added over time.

We just have to realize that it's impossible to satisfy everyone.

SteveM

Maybe your confusing this thread with some other thread re WNB. I haven't seen anyone here clamoring for satisfaction nor using this issue as an excuse to bash or complain about some subjective comparison of WNB to 'Brand X - NB'.

So far, all here are reporting a problem with WNB and the problem is that WNB can act as a noise generator (apparently, under certain conditions). I don't think this thread would exist if the net effect of enabling WNB is, simply, NULL. I know I would not have posted here if that were the case.

I also know that if I was one of the developers of WNB, I would be very interested to hear about real problems reported back from the field.

Ken - NM9P

WA2SSK...
It just goes to show that noise, static, "Intermod," spurs and other interference often have multiple causes.  Sometimes they are frustratingly mysterious and difficult to trace.  Every report, especially when there is a followup post like yours, helps enlighten the whole community.  Thanks for the followup.

BTW... my electric fence noise disappeared about two weeks ago... I guess the guy trimmed a branch, cut the hay, or tightened a rusty turnbuckle.  I bet it will return again......