Trying to suppress this noise...Any ideas?

[Skydawg]

This noise is pervasive and seems to exist in SDR Console as opposed to SDRuno. To me sounds like "water waves breaking on a beach". Seems to be across all bands. Hoping it will be a setting I am missing somewhere. Any help would be appreciated. I tried to attach wav files to this post but get a wrong format message. What sound format can be attached?

Thanks,
John

[G0OFE]

Your best bet is to attach a screenshot (generated by Console) of when you have the noise, showing on the waterfall. Someone may be able to offer an idea.

[Max]

Hi John

Sounds to me like you might have one of the Noise Reduction settings selected in error in the RX DSP panel. It' a possibility anyway. See attached pic. If any on, try all off.

Best

Max

[Skydawg]

Max, it appears what I hear is related to the noise reduction settings. If however, I turn all off, it is difficult to suppress the background noise. If I check the noise blanker on, I get no response from that control. Changing sliders has no effect. The NR1 gives the best suppression but I get the result I referenced. Do you have suggestion for best noise reduction settings?
John

Noise2.mp3

(551.43 KiB) Downloaded 117 times

Noise1.mp3

(515.51 KiB) Downloaded 140 times

[Max]

Hi John

Difficult one. Screenshots always help and receiver (hardware) details, antenna, location etc etc. I guess you have a high noise level where you are? Although, to be honest HF is always noisy to some degree, is it not?

Of all the NRs on SDRC I personally find the most effective with the least "waterfall" effect is NR3 at around 6-8 dB but others differ and everyone has their personal favourite. For HF personally I just tend to put up with the noise, but I guess I hail from the era when there was no such thing as noise reduction so I guess I just got used to it over 40+ years of listening!

Noise blanker is not for suppression of general noise. It's designed for suppression of impulse noise like static crashes, car ignition etc. I would not expect any effect at all on atmospheric white noise:
https://en.wikipedia.org/wiki/Noise_blanker

More information about your setup would be useful and may get other responses. And don't forget that screenshot, unedited as generated by the screenshot button within SDRC:
https://www.sdr-radio.com/screenshot

Best

Max

[Skydawg]

I am listening on an SDRPlay RSP1A. The antenna is a MyAntenna EFHW8010 in inverted V over the tree about 40ft high, fed to the receiver with 12ft of RG8/u. I am in rural Missouri on 8 acres. Nearest neighbor at least 100yds away through the woods. Attached screed shot. Can you shed any light on the AGC hang and decay sliders? How they might effect the signal.

John

[Max]

Actually John your noise situation looks pretty good. You seem to have a basic background noise around S2-S3 (though gain settings and meaningful S point readings can be tricky with SDR Play receivers). But overall it looks good. Here in the UK many people in urban areas complain of S8++ constant noise from every type of annoying source!

Regarding AGC settings, I find the defaults work very well. I don't think I ever changed them much. Hang is the time after signal stops that the decay begins, and decay is the time it takes to decay AGC back to "normal" level of gain (crank the gain back up to "full").

I probably leave mine on MED most of the time. Here are my own settings. They are very "mild". (See attachment).

73

Max

[Max]

Nice AGC explanation from Joanne on the old Forum:

https://sdr-radio.groups.io/g/main/message/58859

73

Max

[Skydawg]

Thanks for the replies. I am old to the world, but new to hf listening. Based on your comments, I'm learning not to expect noise to be reduced just because there is a control there for suppression and since I have no relative experience to compare, crystal clear background is probably not going to happen. From listening to the comments of ham operators, this is a particularly noisy time, and the "bands" tend to change daily if not hourly.
John

[Max]

Hi John

I think most of us that work on HF accept that even in a rural location on an average day you would expect natural background noise at around S3 to S5 signal strength, especially on the lower frequencies (80m,60m 40m bands). Many cope with far higher man-made interference if they have near neighbours in town/city location.

Yes, even the natural noise varies considerably according to solar activity and other factors.

Maybe take a read of this. It has some interesting information:
http://rsgb.org/main/files/2018/01/1801 ... ue-2.3.pdf

Best

Max