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<DIV><FONT face=Arial size=2>I flew the Dx7 on Thursday and it felt pretty
good. It was in a Dog House Extreme with marginal servos but still had a
very nice feel. I took it way up and out so we could barely see it and had
no problems.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Today I ran a few tests. Following are some
results and my comments:</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>1) The update rate, that is, the rate at which the
servos get new information was about 45 Hz or every 22 milleseconds. This
is a little slower than most modern day systems.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>2) The resolution less the servo, that is, the
minimum change in the pulse width to the servo, was 1.0 microsecond. This
is better than any system I have measured. When I connected one of my
elevators with a good JR digital servo it was extremely accurate and neutralized
perfectly as far as I could see. This was confirmed by measuring the pulse
width on a scope scaled to one microsecond per cm. This also says the
mechanics of the transmitter gimbal are not creating an error in commanding
neutral.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>3) The change in pulse width per click of the
digital trim was 3 to 4 microseconds which is not good. The basic system
is a 1024, 1024 steps from lock to lock, but you can only trim it as if it
were a 256. To me it is setting the trim that requires the best
resolution. We could fly with a 256 system as long as we could trim to 1
in 1024. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>4) An interesting thing was the dither on the pulse
width of .4 to .8 microseconds. I assume this was done on purpose because
there should be no pulse jitter in a digital system. I'm wondering if this
can contribute to the good feel when flying. Any opinions out
there?</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>This system looks like a very good value and the
big boys better get a spread spectrum system out if they want to sell systems in
this price range.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Jim O</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
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