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Quote: Originally Posted by XJet |
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But just as JD refused to provide the parameters -- the guys from Boeing have been strangely silent about *how* they got it to hop. |
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This is what JD wrote last year with regards to the hopping.
http://www.rcgroups.com/forums/showp...80&postcount=4
This is what Bruff wrote as one of the witnesses to this top-secret test.
http://www.rcgroups.com/forums/showp...0&postcount=89
http://www.rcgroups.com/forums/showp...7&postcount=93
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Quote: |
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over a period of 11 seconds using a signal within +/- 15MHz of the XBeePro's center-operating frequency |
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This is just more crap. The reason that JD wrote that is purely to discredit Tyhoc and Kiwi’s tests.
The Xbeepro modules centre frequency range is 2.41Ghz to 2.465Ghz in 5Mhz steps page 38 of the user manual with regards to the CH command clearly points this out.
- First off 2.41GHz – 15Mhz is outside the 2.4Ghz ISM band and is outside the frequency that the Xbeepro can even go too.
- 15Mhz away is 3 channels away for the Xbeepro modules. What crackpot would get their system to go looking for signal degradation 3 channels away?
- The Xbeepro modules can only measure received signal strength. In order to be able to get any signal strength readings 3 channels away they would have to change channels and in so doing it would take a relatively long time during which there is no controlling signal being sent to the aircraft during the hop (channel changing) sequence.
- Frequently channel hopping around on a DSSS system is an idiotic stupid thing to do as the constant changing of channels will crash your aircraft and that is why the Spektrum system and Assan systems don’t even try to hop once they are locked onto a channel(s). Remember the Xbeepro modules are DSSS just the same as Spektrum and Assan.
Let me also make it very clear people that changing channels does not make up for lack of antenna diversity. That is why when you look at JD’s XPS install in his own turbine jet he has the receiver mounted high up in the canopy on a pedestal to try and keep the antenna maintain a line of sight to the transmitter and not get this blocked by that large turbine jet engine.
http://www.rcgroups.com/forums/showp...6&postcount=32
Just to make it clear the XPS system is the same as Assan X8 and Spektrum DX6 DSM (not the DX6i DSM2) park flyer systems.