At 04:07 PM 12/30/99 +0100, Lars Harlin wrote:
>
>Now the linearity and measurement page at www.pocab.se/amp/g2daf.htm
>is updated with setup for measurement, more plots and curves, complete
tube data
>from manufacturer and description of measurement by SM3PXO. Just follow
the link to
>"linearity and measurements".
>
>Happy New 2000!
>
>Lars/SM3BDZ
Hi Lars,
I looked at the additional test data on the web page. All I saw was the
same test repeated on different bands. I still have trouble with your test
data. Please understand, I am not saying your conclusions are incorrect,
just that you cannot prove them with the data presented.
Over the past 35 years or so, I have spent literally hundreds of hours with
my face stuck in the front of spectrum analyzers, and I can say with no
doubt at all: If the data looks too good to be true, then it is certainly
not true!
One thing I don't like is that I see no trash from the exciter. If you
cannot measure the IMD from the exciter, then how can you measure the amps
contribution? That Kenwood is not perfect, where's the trash?
Another clue is the shape of the spectrum. If the setup was correct, with
peak hold, sufficient sample time, and multiple tone modulation, (nasty
voice or better, music) the displayed spectrum should approximate the
filter response of the exciter. Show me the filter response.
Assuming no analyzer front end overload, then the setup that produces the
worst data is probably true. The one that produces the best data is
certainly not.
Thanks Lars, keep the info coming.
73 and Happy New Year,
Larry - W7IUV
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