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| 2.4 Ghz Spread Spectrum Technology Discuss Spektrum, Futaba FASST, and all of the exciting 2.4 transmitter/receiver technology here! |
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| | #1 (permalink) |
| Help - I like helicopters ![]() Join Date: Jan 2006 Location: Elk Horn, IA Age: 37
Posts: 606
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Just a scenario I thought of: cross country flying - someone far far away from the field turns on his Spektrum radio and start flying back to the home field. The frequency "channels" on this plane/radio are set. ..... Say someone at the home field is flying a plane with a Spektrum setup and it has chosen the exact same 2 channel combination (out of 80 I believe.) As the cross country pilot gets back to his field, the radios are set & can't choose a new channel. Would both planes go into the preset lockout?.... and shoot each other down? This is probably a very unlikely situation, but it seems like the possiblility is there. I love the new technology - but was wondering if there's a slight chance this could happen. Thanks Terry |
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| | #2 (permalink) |
| Uber Contributer ![]() Join Date: Jun 2006 Location: PA Age: 35
Posts: 175
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As with everything if you say it can't it will... There is only one thing that is 100% sure we will all die at some point LOL..... That is it... Like you said i am sure it possible but i dont think it is likely...
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| | #4 (permalink) |
| Independent Thinkers Guild ![]() Join Date: Jun 2006 Location: OCOEE
Posts: 1,506
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I agree - very unlikely - Each transmitter has its own unique signal -that is why you first bind the two together. Read again: http://www.spektrumrc.com/DSM/Technology.aspx Unlike current narrow band 27 and 75MHz systems, Direct Sequencing Spread Spectrum or DSSS generates a wide signal on a single frequency, and information is encoded with its own Globally Unique Identification number (called GUID) such that the receiver only recognizes the information from its specific transmitter. And with over 4.2 billion available GUID codes, it is virtually impossible for a receiver to be controlled by anything other than its mating transmitter. Spektrum calls this optimized form of modulation DSM-Digital Spectrum Modulation. Each individual module is factory programmed with its own unique serial code called GUID (Globally Unique Identification code). Once a receiver is programmed to a specific module (called binding) the receiver will only recognize that module ignoring signals from any other sources. And with over 4 billion possible GUID codes, it's virtually impossible for a receiver to listen to anything other than its bound transmitter. BINDING Each module has it own unique code (called GUID). The receiver must be programmed to a specific module so that the receiver will only recognize that module, ignoring signals from any other sources. This process called binding is push-button-easy and takes only about 30 seconds. "LoBatt" is the main enemy |
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| | #5 (permalink) |
| Bad-ass Super Contributer! ![]() | What he said but he beat me to it.NO, the rx and the transmitter is constantly changing "channels" within the 2.4ghz system, and it searches for that open channels that it changes to. So unless some other radio just happens to search the same channels (2channels) and switches over at the same time, it won't happen. you have a better chance winning the lottery.BUT if you fly behind an opstackle the spectrum will go into fail safe, because the transmitter is on such a high resolution the messege sent will not go around obstackles. I don't know if you will be having that problem or not. Hope that helps.
__________________ Jamie Hicks Special Thanks To: Hacker Brushless Motors Team 2DogRC/Dualsky USA Mercury Adhesives Higher Plane Productions Florida Freestyle Aerobatic Association |
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| | #6 (permalink) |
| Help - I like helicopters ![]() Join Date: Jan 2006 Location: Elk Horn, IA Age: 37
Posts: 606
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The 4.2 billion possibilities makes it sound pretty safe. I thought I had heard that there were 80 different possible "channels" that the Spektrum chould choose 2 from - making a maximium amount of fliers in the air 40. I didn't know about the GUID part of it.
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| | #7 (permalink) |
| Its the 4th bell BIOTCH!!! ![]() Join Date: Nov 2006 Location: cortland ohio
Posts: 560
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There are 80 diffrent frequencies in th 2.4 band but spektrum uses all of them at split second intervals to make a super solid connection. i did the math and there would have to be 4000 people with the same code all across the country to cause even a slight bit of stray RF. just FYI since the 2.4 band has such a high frequency its band width is low as compared to a 72 mhz that is why they use two and four short antennas opposed to one long one. basiclly the low bandwidth doesn't permit the wave to go around certain metallic and dense objects. the short antennas solve the dillema by covering the craft with full XYZ penetration so you almost always pointing directly at an antenna with your transmitter. i hope all that made sense. there is no reason to worry about another person turning on and taking you out.
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| | #9 (permalink) |
| Major League Dead Beat ![]() Join Date: Jan 2006 Location: Munster, Indiana
Posts: 877
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From what I have seen the new ones will shoot down themselves.
__________________ "This plane has no limits as to performance with this engine except vertical" |
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| | #10 (permalink) |
| Bad-ass Super Contributer! ![]() Join Date: Jan 2006 Location: murray utah
Posts: 1,377
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How many of you have the DX7 ? My own experience is this: The radio if everything is operating as specified - has a almost zero chance of being the cause of a control loss. There are a bunch of guys using this system with small electric models and these guys could, in many instances , bust an anvil with a rubber mallet. Causing the rx to drop below operating voltage is an easily proven occurance --and NO fault of the radio. The errors I have seen with setups on the electric models are too numerous to mention. Personally, I am switching all my models to DX7- The statistical chance of a RF failure of ANY cause is far less than my present type system - which by the way has not failed in over twenty years . I do update tx/rx all the time and all my equipment is in good operating condition plus I use latest quality NiMh batts throughout. In one step -I have elliminated the chance of a dufus "turning on" my frequency Also any loose ignition wire will not shoot me down Further a loose pipe-rubbing on a header is of no concern and I have seen this stop the most expensive new system on the market - COLD. Last edited by dick hanson; 01-05-2007 at 11:32 PM. |
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| | #11 (permalink) |
| Stiiiiiiil Huckin'! |
Interesting "what if", but speaking to the nebulous term "GUID". Not to be like the explaining acronym guy, but we use the same bit pattern in internet communications, and software development all the time for uniquely, or "globally unique identification" all the time. From this perspective, you will never collide. The 80 channel limit is actually, I believe 160 channels but during the design process they played it very safe. I don't claim any of my statements to be accurate or true - that's a 6 newcastles talking. carry on
__________________ Sponsored by Visa, American Express, SLEEPYC, and SnapaSaurus.Facebook: Maxon Duncan |
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| | #12 (permalink) | ||||||||||||||||||
| Independent Thinkers Guild ![]() Join Date: Jun 2006 Location: OCOEE
Posts: 1,506
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My JR 700 & 600 series receivers failed to operate their ST125MG smoothly. ( Long story sending all Chit back and all no problem for them tho ). I connected the 'problem elevator' servos extension to the AR700 - and Wha-La!! Smoooooooth operator!!! I don't understand, and I don't want to say I don't care - but It is a good thing all the same. That is why the second receiver will be added to my hanger. $100.00 for receiver alone. I will finally madein this bird after 9 mos of it just leaning around!! Man, do I need to say I'm JaZZed about that?!! Last edited by jaguar bone; 01-06-2007 at 09:47 AM. | ||||||||||||||||||
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