You are right about that Lin. From what I can hear using the NR (2.032)
Downward Expansion is an effective feature that makes CW easier to copy if
the threshold is set just below the desired signal. The way to test it
would be to measure the difference between the noise levels with the tone
turned off, as it would be between dits and dahs.
Ron N6AHA
----- Original Message -----
From: "Lin Davis" <linbdavis@earthlink.net>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Sunday, March 26, 2006 9:44 AM
Subject: Re: [TenTec] Orion II NR Performance Measurements
Hi Grant,
Just a thought- I assume you made these measurements with a steady state
signal.
Well that will be the worst case for a downward expanding type of NR.
However, if the carrier was modulated (like in Sinisa test with continuous
dits), and the RF gain adjusted so that the difference between the signal
plus
noise level and the noise level with no signal is maximized, the average
SNNR
would be at it's best (by definition). Seems to me, this test is more
applicable; more "real-world".
Wouldn't that be a better test? Let me know what you think.
Almost forgot-I'm assuming a narrow bandwidth, since you have shown quite
nicely
that, by itself, the v2.xxxx NR doesn't do much in this regard.
Lin
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