Grant, your comments on the Orion I's NR behavior were quite
illuminating. I have complained about the increased noise issue on
several occasions. I have to admit that the problem was erratic, and I
never could pin down what combination of conditions and settings
resulted in increased noise. When increased noise was evident, I had
tried changing the RF gain and threshold with little or no practical
improvement. The bottom line is that whatever the reason for its
behavior, the NR was basically useless here. (BTW, it seemed to get
noticeably worse with firmware 1.372.)
I haven't used the NR much since installing 2.054, but my impression
after a quick check or two is that it's much improved.
73, Joe
Grant Youngman wrote:
>
>
>
>>1) The average power output on SSB seems unusually low.
>>
>>
>
>Maybe you're voice characteristic? Too far from the mic? Turn up audio
>gain a bit for a little more ALC action? I haven't seen this as an issue.
>
>
>
>>2) "NR" at any setting produces significant distortion at
>>narrow bandwidths.
>>
>>
>
>This has been discussed and reported to T-T. I agree with you, that at
>narrow bandwidths there seems to me at least to be too much distortion --
>sounds like something is clipping slightly. It's also noticeable on SSB if
>you listen critically.
>
>
>
>>Using NR does not appear to enhance
>>reception during noisy conditions.
>>
>>
>
>In the Orion I, activating NR automatically reduced AGC THRESHOLD to a low
>value no matter where it had been manually set. This frequently led to
>complaints (misinterpreted) as "NR increases noise". It was done to ensure
>that the DSP algorithms had enough signal to work with to be able to adapt.
>NR effectively builds a narrow filter around the signal, so it needs some
>(unknown) critical signal level to work effectively. I'm not 100% sure, but
>I don't think THRESHOLD is automatically lowered in the II, but if you have
>RF gain reduced,and thus THRESHOLD raised since they are linked, and turn on
>NR, you may not have enough signal to give NR something to work with and the
>signal just sort of disappears in the mud. I've found it works much better
>if you run a high RF gain level (and low THRESHOLD value) in those
>circumstances.
>
>YMMV ... Grant/NQ5T
>
>
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