WQ7X:
> So, I just hope that distortion of strong signals will be
> eliminated (doesn't exist in other DSP radios).
NQ5T:
I've read with interest all of the discussion of this issue. I have yet to
experience any case of a high level signal causing distorted output, at 9+35
or anywhere -- but of course I haven't found a signal around here that has
bent the S-meter yet, either, although on 75 meters at night there are some
VERY strong signals :-)
Grant, I believe the strong signal distortion problem
began with 1.372 when AGC Threshold (the DSP's digital IF gain)
was integrated with analog RF gain (previously set by RFGAIN).
"11/30/04 Version 1.372
- Enhanced RF GAIN control knob operation."
1.372's RFGAIN now controls both analog and digital AGC gain,
which makes Orion's AGC much easier to use, but apparently the code
which limits the input to the DSP has been corrupted. When any
DSP is over-driven, very bad distortion results. The Analog AGC loop is
supposed to protect the DSP stage from any
signals exceeding about S9+35, but that protection has
apparently been lost in 1.372, under certain conditions.
My unit does not distort consistently, but often enough
to be a bother. However, I like 1.372's integrated RFGAIN
so much that I am living with 1.372 until the problem is fixed.
One alternative to fix the distortion problem is to re-install
1.371, if you don't mind separately setting AGC Threshold and
RFGAIN as before. I'm sure this problem can be fixed once the
major revision (2.0) is completed.
BTW, the first report of this noted it was only when using
headphones (doesn't seem logical to me) but that could explain why
some have not noticed it (if they always use the speaker). I
never use anything but headphones so cannot comment.
http://dayton.akorn.net/pipermail/orion/2004-December/000504.html
73, Bill W4ZV
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