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Re: More Re: [TenTec] Orion redefines the meaning of ... AGC OFF

To: tentec@contesting.com
Subject: Re: More Re: [TenTec] Orion redefines the meaning of ... AGC OFF
From: K3BU@aol.com
Reply-to: tentec@contesting.com
Date: Sat, 7 Feb 2004 21:24:54 EST
List-post: <mailto:tentec@contesting.com>
In a message dated 2/7/04 6:12:46 PM Eastern Standard Time, n1eu@yahoo.com 
writes:

Not meaning any disrespect, but I'll offer a prize to
anyone who can repeat K6SE's weak signal reception
test results with proper adjustment of the Orion AGC.


What's the prize?
Can somebody prove K6SE wrong?

You can try this. You can simulate very weak signal in the noise. Turn your 
antenna switch to ground, shorting out you antenna feedline. There will be most 
likely some feed through, some weak signals leaking through. Or switch Orion 
ANT selector to Ant 2 with nothing on it. Then tune weak station just barely 
breaking through the noise. If you had one of the rigs that K6SE found to be 
better, you would see the difference in inteligibility. Now if you want to see 
how your AGC, NR, DSP, etc works, switch it on, try different settings and see 
what you get. This is again is simulating weak signal reception on the 
threshold of noise "gate" of Orion. If you apply signals from the antenna with 
higher 
level of band background noise, of course, this overrides the noise threshold 
of Orion and it is different situation.
The point is to see the sensitivity of the RX at the threshold of the 
circuits ahead of filters. If there is internal noise generated it will mask 
those 
weak signals, and you can have all DSP in the world, it will not take them out. 
(Well computer DSP might get few dB below that threshold, but we are talking 
human interface, ears.)
>From what I gather about K6SE tests, he in direct comparisson of two radios 
at the same time, under same situation, demonstrated that some radios heard the 
weak signal and some did not. You can argue about the test method and 
scientificity of it, but it is real life test. Just like someone might argue 
about 
ICOM CW filter characteristics (they are OK) and you stick that filter in IC706 
and you get horrible blow by and hear guys 4 kHz away. Filter looks OK on 
spectrum analyzer, works great in IC781, but sucks in 706. Can't be? try it.

Yuri
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