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Author Topic: Are any external audio noise filtering devices helpful with the dx/Uno?  (Read 307 times)

KK4GMU

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On the RSPdx/SDRuno combo, has anyone found supplemental external audio noise reducers, such as West Mountain CLR/DSP 58407-949Speaker Amplifier with ClearSpeech® Adaptive DSP Noise Reduction for Voice  and CW or others to be useful?

Here is one example:https://www.hamradio.com/detail.cfm?pid=H0-009030

Please describe your experience. Are there any other specific noise filtering settings on the uno that filter out atmospheric static as well as something like the West Mountain or other dedicated dsp devices do?

Being fairly new to this, and not having experimented with all the noise filtering options on the uno, I'm wondering what those more experienced than I am have done.

I've tried various RF noise reduction measures - still have a high noise floor in my fairly dense suburb. What I have is more atmospheric and distant sources.  So my next focus is to address the audio output side of things.
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KD6VXI

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Re: Are any external audio noise filtering devices helpful with the dx/Uno?
« Reply #1 on: December 24, 2021, 07:04:44 AM »

I piped audio through a virtual jack to the RTX voice enhancer / noise reduction on my pc.  Made a pretty dramatic difference.

You have to have some decent horsepower under the hood of your pc in respect to the video card though.  Especially if using the Simon brown sdr package.  His sdr software takes advantage of the RTX hardware.....  As does the RTX noise reduction.

I used a RTX980 and it was able to support it.  A 1650 did and a 1660 as well.  A 950 did NOT.

--Shane
WP2ASS / ex KD6VXI
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KD7RDZI2

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Re: Are any external audio noise filtering devices helpful with the dx/Uno?
« Reply #2 on: December 24, 2021, 01:25:00 PM »

On the RSPdx/SDRuno combo, has anyone found supplemental external audio noise reducers, such as West Mountain CLR/DSP 58407-949Speaker Amplifier with ClearSpeech® Adaptive DSP Noise Reduction for Voice  and CW or others to be useful?

Here is one example:https://www.hamradio.com/detail.cfm?pid=H0-009030

Please describe your experience. Are there any other specific noise filtering settings on the uno that filter out atmospheric static as well as something like the West Mountain or other dedicated dsp devices do?

Being fairly new to this, and not having experimented with all the noise filtering options on the uno, I'm wondering what those more experienced than I am have done.

I've tried various RF noise reduction measures - still have a high noise floor in my fairly dense suburb. What I have is more atmospheric and distant sources.  So my next focus is to address the audio output side of things.

I use Softrock SDRs. I have had an ancestral DSP made by JPS, model NTR1 made in 1994. It works better than expected.  The Notch removes quickly automatically tones and CW. It has almost no latency. Noise reduction was better as well than the PC. To get better results I changed the value of AGC in the PC software to the fastest. It is not a must, but I think it may be useful. To avoid ground loops the cable between the soundcard and the external DSP unit has an audio 1:1 transformer.
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VK6HP

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Re: Are any external audi o noise filtering devices helpful with the dx/Uno?
« Reply #3 on: December 25, 2021, 02:25:40 AM »

I have an RSPdx and run it mainly with SDRuno, largely because the combination is the only one that gives access to the low-band hardware filters.  SDRuno is a bit clunky but, interestingly, I find that, properly adjusted, its noise reduction algorithm is actually pretty good - better than many ham transceivers.  I also have a West Mountain CLRdsp unit able to be allocated to any audio stream, including the RSPdx/PC.  I'm not a gushing fan of that unit: it's OK and, with careful setting, helps a bit with classic radios in the presence of some types of noise.  I'm not disgruntled with it by any means - just not fully gruntled, either. There are some great DSP algorithms around, including the well-known Apache labs variations but these boxes are a long way from those: as you'd expect, of course, given the baseband domain in which they operate and the lack of programmability.  I suspect that a lot of the favourable impression one gets on first try is just from the low-pass and spectrum shaping effects.  Depending on the type of noise you're dealing with, you may or may not find a particular external audio processor useful.  In my case, I've not found that the addition of the CLRdsp box adds much worthwhile to the SDRuno implementation.  Any way you could arrange a trial of your favoured external box?

73, Peter.
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KK4GMU

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Re: Are any external audi o noise filtering devices helpful with the dx/Uno?
« Reply #4 on: December 25, 2021, 03:51:51 PM »

I suspect that a lot of the favourable impression one gets on first try is just from the low-pass and spectrum shaping effects.  Depending on the type of noise you're dealing with, you may or may not find a particular external audio processor useful.  In my case, I've not found that the addition of the CLRdsp box adds much worthwhile to the SDRuno implementation.  Any way you could arrange a trial of your favoured external box?

73, Peter.
Now that I've become a bit familiar with the uno EX Control Panel and played with a few settings, your experience may have saved me an extra $180 or so.  Where would you like me to mail the check?

Seriously, thanks for your feedback.

I like new gadgets that might make some improvement, but the West Mountain box sounds excessively iffy. Probably not worth trying out.  I can't imagine it doing any more than the combination of uno settings and my Behringer EQ.  The primary potential benefit might be more immediately accessible tweaking via "knob" vs an extra window and sliders.

On the other hand, I have noted that when I go too far to the left with the noise blanker slider on the uno, its take some several seconds for the loud hash noise to settle back to normal after its moved back to the right.  But I understand from a video of testing the CLRdsp that it also takes a few seconds for noise to settle down between new frequencies.  I don't know...still a bit torn.  Sorry for the obvious indecisiveness.

Merry Christmas evening.
« Last Edit: December 25, 2021, 04:07:01 PM by KK4GMU »
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KK4GMU

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Re: Are any external audio noise filtering devices helpful with the dx/Uno?
« Reply #5 on: December 28, 2021, 09:54:43 AM »

Here is additional feedback I received:

From West Mountain Radio:  Probably won't make any significant improvement.  But try it.  You can always return it.

From the place with the cheapest price, but a 15% restocking fee, HRO: We don't recommend you try it.  Likely won't do any better than your SDRuno.

So, I best hone my
* uno noise blanker, notch filter, and noise reduction skills
* antenna placement and tuning skills
* noise reduction expectations
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K7JQ

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Re: Are any external audio noise filtering devices helpful with the dx/Uno?
« Reply #6 on: December 28, 2021, 10:17:18 AM »

I don't know anything about the SDRuno, but yes, the CLRdsp adaptive NR algorithm does take a little for the hash noise to settle down when going from transmit to receive. It has to sample the noise and step it down. In some exterme cases, up to 15 seconds.

BUT, WMR recently did a firmware update to help lessen the time frame to "settle down" the hash. I sent in both of my CLRdsp's for the upgrade, and it did help. You have the choice for that mode or the original algorithm (depending on operating mode and conditions) by turning the Filter control clockwise to the end, and then backing it off. That feature is not in the online manual yet. Whether it will be a major improvement over the SDRuno, I don't know.
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