Some interesting comments by Rob Sherwood
after reviewing ARRL's ETR for the 9000 here:
http://groups.yahoo.com/group/FTdx-9000/message/619
A few excerpts:
As one would expect, once one is inside the 3 kHz roofing filter, the
dynamic range is 70 dB, like any FT-1000 series.
The Orion blows it out of the water in close-in dynamic range.
The inband IMD on receive is terrible with strong signals. 30% IMD
distortion at S9 +60 dB.
5% inband IMD distortion at S9 +40. Inband IMD should be 1% or less.
My S-Line started out about this level of inband IMD, regardless of signal
level, but after modifying the Collins circuit, I got it down to 1%.
The Collins sound great now, but sounded like garbage when the IMD was up in
the 10% to 20% range.
Microtune front end has 6 to 8 dB insertion loss.
Where is the bandwidth data on the microtune front end?
Some of the tables have strange blocks that are blank.
In respect to close-in dynamic range (DR3), the radio performs as one would
expect give the 3 kHz bandwidth roofing filter.
Only one measurement is made of close-in DR3 at 1 and 2 kHz, and that with
the preamp on.
Strange looking transmit IMD in class A. Wide-spaced it is clean, but lots
of close in "sticks" on the spectrum analyzer plot that should not be there.
Just a note, at 2 kHz the DR3 of the 9000 is 4 dB better than a 30 year old
Sherwood modified R-4C.
At 1 kHz the 9000 DR3 is 10 dB worse than a Sherwood modified R-4C.
Rob also has a new paper on receiver performance
that I have not seen before:
http://www.sherweng.com/images/MeasurementAccuracy&SampleVariation.pdf
73, Bill W4ZV
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