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NR vs NRL on 4.1.3

VE7ATJ_Don
VE7ATJ_Don Member ✭✭✭✭
in SmartSDR+

It was very interesting to try the new NR (Legacy) mode vs. the NR that I normally use in the new 4.3.1 firmware.

It was my first time really 'back on the air' since the update and I thought I'd give the new noise reduction mode a try. (Don't use the ANF much, so can't speak to those new modes).

Overall, I was impressed. On the upper bands (it was mid-afternoon on the west coast and most of the activity was on 20 thru 10m). The NRL was effective and reduced the background noise pretty well. Signals came through clearer, but with a distinctively 'mechanical' sound — similar to what I've heard on 'legacy radios', like the Kenwood TS series, my Yaesu FT-991 and some of the ICOMs from the last 10 years. Very different from the slightly noiser, but more natural sounding NR mode. I have both a vertical and EFHW antenna and the effect was pretty much the same on both.

Haven't decided which mode I prefer (for one to save on the Global Profile), but it's great to have the choice available.

Comments

  • KD0RC
    KD0RC Member, Super Elmer Moderator

    Hi Don, I tried the NRL on my 6400 and found it far superior to the old NR. NRL did impart a watery sound to the noise, but that was much easier to listen to than the remaining noise from the NR filter.

    The new NRS filter on the 8000 series takes noise reduction to a whole new level. With it, I just leave it on. If I am not on a signal, I have to check to be sure that the slice is not muted! The increased horsepower of the 8000 series really makes a difference.

    So to me, it is a win whether you have a 6000 or 8000 series radio.

  • VE7ATJ_Don
    VE7ATJ_Don Member ✭✭✭✭

    yea… if only they had an 8-slice version of the 8600 with the 2m capability, I'd trade in the 6700 in a heartbeat. I might even consider it without the 2m capablity.

    Maybe a future version of SmartSDR… have to wait and see….

  • KD0RC
    KD0RC Member, Super Elmer Moderator

    The 8 slices may yet happen, you never know…

    I am using a cheap Ukrainian transverter, but to keep it legal, I had to use a 2 meter bandpass filter. Still, a pretty good deal with reasonable performance. I really enjoy having the whole Flex environment on 2 meters. If I did more with VHF and/or UHF, I would spend the money for a set of Q5 transverters.

  • Bill AB7AA
    Bill AB7AA Member ✭✭✭

    I wouldn't be too quick to ditch the 6700 just to get better noise reduction. I'm sure that some knowledgeable ham will develop a dedicated noise mitigation program that will run on a recent I5 or I7 processor that will rival or better one running on a radio processor. Sooner or later.

    This would have widespread appeal across the entire amateur market.

    73,

    Bill AB7AA

  • Trucker
    Trucker Member ✭✭✭✭

    I have used different noise reduction plug-ins with different programs connected through DAX in the past. Some worked well. And others, no matter what I tried, introduced latency in the received audio. The best one was RM Noise that sent audio over the internet to a remote server for processing. As long as there wasn't many users online at the same time, it worked well. I had asked the developer if he would consider creating a standalone application that didn't depend on using an off site server to process the audio. His response was that he didn't have any intention of doing that at the moment. Disappointing, but understandable. There are several DSP plug-ins with source code on Github that someone could modify to use the VITA 49 audio stream that the Flex radios send to the pc. But, it would take some work to get it going right.

    James

    WD5GWY

  • Stan VA7NF
    Stan VA7NF Member ✭✭✭

    Probably mistaken but I thought NR and NRL were both supposed to remove non-correlated noise. For reference on my 6700.

    Pre V4 NR was disappointing because it mostly reduced the received audio bandwidth thereby reducing the noticeable "noise". It sounded like just an audio HF filter. Always changed the AGC-T to recover levels.

    Post V4 NR still did the same thing, just a little better by reducing more static pops, but still eliminating most of the higher audio frequency correlated signal. Both better and worse.

    Now NRL even more severely removes higher audio frequency correlated signals. It is much more difficult to hear all the transmitted signal but overall the signals come out of the noise slightly better.

    Question for Flex - Is it actually possible to ONLY remove non-correlated noise yet maintain the transmitted audio spectrum?

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