Henry M.Y.
Second Officer
Flight distance : 11548839 ft
Hong Kong
Offline
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Hi Richard,
Comparing the FCC compliance test report of the Mavic Pro with that of the Inspire 1, we can see that radio transmission technology employing by the Mavic Pro is very differnt. It consists of 3 different modes:-
1) the 20 MHz mode (having 63 channels, from Channel 1 @ 2,410.5MHz to Channel 63 @ 2,472.5MHz, i.e. with 1MHz channel separation),
2) the 10MHz mode (having 73 channels, from Channel 1 @ 2,405.5MHz to Channel 73 @ 2,477.5MHz, i.e. with 1MHz channel separation), &
3) the 1.4MHz mode (having 38 channels, from Channel 1 @ 2,403.5MHz to Chanel 38 @ 2,477.5MHz, i.e. with 2MHz channel seperation).
The duty cycles for the 3 different transmission modes are 85.15%, 84.16% & 10.4% for the 20MHz mode, the 10MHz mode, and the 1.4MHz mode respectively.
Unlike the Inspire 1 which can only employ 1.2MHz narrow band transmission mode (having 39 channels, from Channel 1 @ 2,404MHz to Channel 39 @ 2,480MHz, with 2MHz channel separation), the Mavic Pro will, subject to initial channel noise scanning result, under Auto Selection automatically choose any of the 3 different modes with the order of priority starting from the 20MHz mode, the 10MHz mode, to the lowest priority 1.4MHz mode; and then automatically switch channels within the chosen mode whenever possible, should channel interference is encountered. It is the wide bandwidth spread spectrum transmission technology in the 20MHz mode (and to a certain extent the 10MHz modes) combining with the high duty cycle of signal modulation on radio carrier frequencies in the transmission that give the Mavic Pro excellent video downlink performance.
These all imply that in Custom Selection, we should as far as possible choose 20MHz mode if there exists sufficiently wide low-noise radio frequency ranges and slide the rectangular box to sit in any of one of the ranges. If there isn't any wide low-noise range but exists narrower low-noise range, choose 10MHz mode and slide the narrower rectangular box to sit in any of the narrower ranges. If the low-noise ranges exists but are discrete, we had better switch back to Auto Selection and let the Mavic Pro automatically choose amongst the 1.4MHz mode, let the Mavic Pro subsequently choose the 10MHz mode, or the 20MHz modes if circumstances allow it later.
Hope my interpretations are correct, and are of help. And hope knowledgeable Fellow Member correct me if any of my understanding is not correct.
Henry |
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