[NLRS] 222 ???

[Gerald]

On Wed, 2005-09-14 at 11:37 -0500, John P. Toscano wrote:
> 
> Gerald wrote:
> 
> >
> >On Wed, 2005-09-14 at 09:44 -0500, John P. Toscano wrote:
> >
> >>Gerald wrote:
> >>
> >>
> ><SNIP>
> >

> >
> Oh, absolutely.  I just meant to say that the DEMI transverter has more
> than sufficient Rx gain available so that even with some attenuation
> between the IF rig and the transverter, it is still possible to adjust
> the Rx gain so that signals are where they belong.  IIRC, At maximum
> Rx gain, the noise floor on my IF rig from the 222 transverter is
> around S6 - S8 or thereabouts, so I have turned the Rx gain down quite
> a bit to bring the noise floor down to where it belongs.  I believe
> that the adjustment range is approximately 25 dB, and there is even an
> option to add one more stage of gain if the path from the transverter
> Rx to the IF radio Rx has too much loss, but the DEMI folks are quick
> to point out that it is very rare to need (or want) it.
> 
> John (W0JT)
> _______________________________________________
And I just want to make the point that the noise level rise when
connecting the receive converter to the IF is not the magic value to
optimum system performance. MDS (minimum detectable signal) is harder to
measure than NF so I advocate that NF should be measured for the system
(and the HP NF meter isn't useful unless it can be run in a manual mode)
and the converter gain set for the minimum gain that will still give the
best NF. Any gain above that level increases the receiver overload
signals.

-- 
73, Jerry, K0CQ
Dr. Gerald N. Johnson, electrical engineer
All content copyright, Dr. Gerald N. Johnson