The new audio clips comparing the two receivers is currently posted on my
site at www.n6ie.com. The clips are about 1 MB each, so if you have
dial-up, it could take some time.
BTW...my website has no ads, no music, no annoying 'dancing graphics', etc.!
Ron Castro
Chief Technical Officer
Results Radio, LLC
N6IE
www.N6IE.com
(Formerly N6AHA)
----- Original Message -----
From: "Ron Castro" <ronc@sonic.net>
To: "Ten Tec List" <tentec@contesting.com>
Sent: Wednesday, January 24, 2007 10:04 PM
Subject: [TenTec] O2 AM Distortion FIXED!
I got a nice e-mail from Jack Burchfield at Ten Tec about the AM distortion
problem. He listened to my recording and agreed that the Orion II didn't
sound as good as it should, and explained that the dual-loop AGC system
with the new adjustable hang time has to be slowed down to sound good in
AM. He suggested using a hang of 3 to 4 seconds.
I increased the hang time to 4 seconds and that cured the distortion! I
didn't realize that the two AGC loops were so independent and I had been
thinking that a slow decay time coupled with a hang time of more like .5
seconds would eliminate AGC distortion from the equation. It does take a
very long hang to clean up the sound. The short hang time is apparently
what was causing the clipping and the "crunched" sound due to severe loss
of dynamic range.
I made a new recording that I will place on my website later that
demonstrates how AM sounds when the settings are changed. I recorded a 40
meter short-wave broadcast station on both receivers simultaneously with
the 870 in the left channel and the O2 in the right. I split the channels
and made separate MP3 files of each radio. I also backed off the
bandwidth of 870 and matched the O2 so the -3 dB points were at the exact
same frequency. Both receivers were fed from a T connector to the same
antenna. The results were outstanding! The only noticeable difference is
the AGC action, and that the O2 handled the really deep fades better than
the 870.
Good work TT! I'll mark that off the 'fix' list...
Ron N6IE
www.N6IE.com
(Formerly N6AHA)
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