Op 02/04/13, Rick - DJ0IP / NJ0IP <Rick@DJ0IP.de> schreef:
> You guys are forgetting one very important point. Radios behave different
> in the real world, on the air, than they do in the lab with just two signals
> injected.
>
*snip*
> What we saw in that demonstration was a single carrier
>
*snip*
>
> What I'm trying to say is, although our lab tests use two signals and we
> take a measurement, in the real world there can be tens of signals which
> affect how the radio behaves.
>
*more snip*
Fully agree with all above.
I do confirm that benchmark testing is not the same as the on the air result.
I still not understand why everyone compares ***dead carriers***.
Try modulating the signal source(es) for a change and look how completely
different some DSPs repsond.
I could dial in some extra 8dB on the attenuator for the K2 compared to the
IC746Pro (=756Pro) before the signal could not be read anymore. Something I had
noticed before on two different IC756PRoIII (one with Inrad roofer), while
detecting weak signals on 50Mhz. This story started on SSB with tiny garble on
the 756Pro3 vs Q4 copy on the K2. So it's not only CW where these difference in
RX performance appear. Months of additional testing and comparing with several
rigs confirmed this. Analog filtering (or analog filtershapes like the ORION)
is key.
See my hearing results:
http://pa5mw.blogspot.nl/2009/12/upgrade-current-vhf-station-iv-mds.html
And before that :
http://pa5mw.blogspot.nl/2009/12/upgrade-current-vhf-station-iii-mds.html
Today I use an ORION and an ORION II.
Have tried a TS590 for several months. It is a very good TRX. But nowhere close
to the TenTecs I use.
Again, anyone trying/comparing the receiver performance of any rig; please use
modulated signal(s) for a change.
73 Mark, PA5MW
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