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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