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[TenTec] Orion NR on SSB

To: "'Discussion of Ten-Tec Equipment'" <tentec@contesting.com>
Subject: [TenTec] Orion NR on SSB
From: "Grant Youngman" <nq5t@comcast.net>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Sat, 11 Jun 2005 11:41:26 -0500
List-post: <mailto:tentec@contesting.com>
I may well be the last guy on the block to have this particular epiphany ...

One of the things that the Orion NR does on voice modes is produce an
extremely bassy output (to my poor ears, anyway).  No highs, and a
substantial loss of speech articulation.  My solution was always to tilt the
RX EQ to a high negative value to restore balance, which sort of helped, but
was still unsatisfactory.  The noise may have been reduced but I still found
the resulting audio muffled and unpleasant.  I'm sure this effect is the
result of the way the Orion NR builds filters around the speech frequencies,
and the fact that the typical male voice has a great deal of low frequency
energy.  The nut of it is that I rarely used the Orion NR on SSB.

While checked in to a MARS voice net this morning on a very noisy 7.3 Mhz
frequency, I got to fiddling with the radio to see what else could be done.
An external audio NR had a more balanced audio output spectrum, but I
generally consider those things unsatisfactory in most cases for other
reasons.  And I can only listen to their typical "watery" output for so long
before throwing in the towel.

I found that by simply using PBT to kill the low audio frequencies in the
received signal spectrum (set to 200-300Hz) that the result was superb.
Good articulation, no bassy audio.  Not FI, but if you have to use NR, FI
becomes a non-issue anyway.  In fact, the whole NR result was much better,
possibly due to the fact that the energy in the low frequency speech
spectrum wasn't hitting the AGC.  It was a real pleasure to have really good
sounding signals popping up out of the quiet.

I'm just surprised it took me 2 1/2 years to discover this simple and
obvious tweak :-)


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