|02-13-2007, 08:45 PM||#1|
RCC Supreme Contributor
I am: Wayne MIller
Join Date: Aug 2004
Location: Kitchener/Drumbo, On
Radio of choice:
Hitec A9 JR 9303
# of RCs: 19
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Understanding DX-7 Frequency Select and Model Matching
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The KWFD (Kitchener Waterloo Flying Dutchmen) just recently had a general meeting, and during the discussion the setting up of the frequency board to accomodate the DX-7 system came up. Very quickly it became apparent that there is a lot of confusion surrounding how this system works.
When I got home I searched the web for "simple" explainations that I could understand, as a result I put together a very basic explaination below that may help others.
Please review and if you have any other comments or corrections, please let me know.
I hope this helps others in understanding DX-7.
Spread Spectrum and DX-7 Explained
DX-7 system is new and is capable of automatically selecting a “free” frequency and also prevents selecting/flying a wrong model on your transmitter by “model matching”. A good explanation of the systems and its functions can be found at the web site below. Scroll down the opening page to the orange buttons for video explanations, be sure to click on “BINDING” and “MODEL MATCH” as a minimum.
Basically, each transmitter has a special code unique only to it. When you install a receiver, you match that receive, and model name, to your unique transmitter code with a “binding” process. This process requires a one time special receiver harness to be plugged in, and a button to be pushed, on the transmitter when that model is selected on the transmitter. Once this is done (binding), the receiver will only work with “your” transmitter and only when that correct model name is selected in the transmitter (this is called “model matching”). Now, when you go to the field, and turn on your transmitter, it will search for a free frequency in the 2.4GHz band (80 available). Once it finds a “free” frequency, and you have the correct model selected, the transmitter will communicate to the model’s receiver the frequency to be used for this flight. This is a very basic description, but I hope this helps clear up some confusion about this new technology and how it works. The site with the explanation videos can be located here: http://www.spektrumrc.com/Products/D...ProdID=SPM2710
|02-13-2007, 11:18 PM||#2|
RCC Pro Contributor
I am: wayne b
Join Date: Nov 2006
Location: Sh. Park, Ab
Feedback: 0 / 0%
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There are some resource material on the maac web site as well:
People may be making it more complicated than it is because, although the technology is a couple of years old, the application to regular RC aircraft is new.
There aren't enough days in the weekend. -- Steven Wright
|02-14-2007, 11:42 AM||#3|
RCC Junior Contributor
Join Date: Jan 2006
Location: Vancouver, BC
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2.4 GHZ spread spectrum radios are approved for use in Canada by Industry Canada and MAAC.
Modified Vario flybarless AV ship
Vario Silence AP ship
Easystar FPV/AP plank
|02-14-2007, 01:38 PM||#4|
RCC Master Contributor
I am: Eric T
Join Date: Jan 2004
Location: Mississauga, Ont
Feedback: 1 / 100%
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Let me answer your question:
The DX technology uses a type of frequency hopping. The radio will change its (crystal) frequency on its own in an attempt to always stay on or look for clear channels. So you can not post a regular frequency board for 2.4Ghz, there is no "channel" to go by.
The system is more about how many radios should be "on" at the same time. So a 2.4Ghz board should be more about showing who is actively "on" at any given time.
For example, allow for 5 available slots you put your tag in the first available slot and the 6th person will have to wait for someone to finish flying. This has nothing to do with the theoretical RF limit for Spektrum and more to do with establishing a courtious system for everyone to work within.
At this time, it should work similar to the 72Mhz system to keep everyone in the habbit of using the board before flying.
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