Probably because there are differences in the RF and first IF circuits.
Those in the Corsair II use multiple transformer coupled feed back
(Ulrich Rohde's favorite circuit though patented by Anzac) and in the
Omni V uses Jfets in grounded gate in parallel. The dynamic range of the
transformer feedback circuit may be a bit better, quieter and harder to
overload. And while the synthesizer in the Omni V is fairly quiet, it
may not have as low phase noise as the PTO in the Corsair II which means
less reciprocal mixing of unwanted signals and noise. I don't know that
either has been tested for phase noise as much as more recent radios.
73, Jerry, K0CQ
On 4/25/2010 2:12 PM, Steve Berg wrote:
> I have been enjoying this thread quite a bit. One question that I have
> about receiver performance may bear a bit on what has been discussed so
> far. Since upgrading to extra several years ago, I have been having a
> lot of fun on the low end of 80 and 40 meters, working DX on CW. I have
> two Ten Tec rigs, a Corsair II and an Omni V.9. Both have the 500 Hz
> and 250 Hz filters in the IF string, and the Omni also has a 250 Hz
> filter in the first IF. What I have noticed is that the Corsair II is
> seemingly able to pull out really weak signals more clearly than does
> the Omni. I am reasonably familiar with both radios, and also have a
> pair of ears that have given their all to heavy weapons and artillery
> many years ago, and been further damaged by loud motorcycles, since
> then. Why might I seem to notice a difference in clarity from otherwise
> somewhat similar radios?
>
> Steve WA9JML
>
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>
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