[hpsdr] OpenHPSDR mRx Noise Reduction JT65 Effect??

[Erik Skovgaard]

Hi John,

It is generally not a good idea to use NR with digital modes - at least
that is what I have found with a couple of SDRs and my K3.  I have had
similar experiences to yours and I also found degraded decode performance
when I switched NR on.

73 de ve7mdl/mm,         ....Erik.
 On Sep 5, 2013 8:46 AM, "John" <radio at mediacombb.net> wrote:

> ***** High Performance Software Defined Radio Discussion List *****
>
>
>
> Greetings,
>
> I have been enjoying my Hermes and lately have been using it with
> OpenHPSDR mRx v 3.1.5 and Windows 7 Pro 64 bit.  To run JT65 and JT9 I am
> now using WSJT-X v. 1.1.
>
> Looking over some measurements posted recently, it seemed there was a
> benefit to the Noise Reduction (NR) feature of  mRx.  My experience with NR
> ON and using WSJT-X was unexpected.
>
> With NR OFF, the bandpass shown in the WSJT-X spectrum display looks nice
> and flat and noise seems to be distributed evenly across the pass band.
>  However, with NR ON the spectrum display in WSJT-X shows areas of very
> strong noise and the displayed passband has what I would describe is
> extreme ripple.  I live in a noisy location, but the display with NR ON has
> never been as bad as when I first tried NR today.  The spectrum display in
> mRx looks normal.
>
> Here is a screen shot showing both mRX and OpenHPSDR mRx.  You may need to
> scroll down to see the spectrum display of WSJT-X
>
>      http://www.n-connect.net/**radio/Ham_Pix/HPSDR/OpenHPSDR%**
> 20NR%20ON.PNG<http://www.n-connect.net/radio/Ham_Pix/HPSDR/OpenHPSDR%20NR%20ON.PNG>
>
> I wonder if others are observing the same effect.  Perhaps some program I
> use is effecting these programs or, maybe, the NR feature is not meant for
> JT9 - JT65.
>
> Best regards,
>
> John  WoGN
>
>
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