Originally Posted by RVDriver
Title says it all, I am new and just bought a Delta Ray (Hobby Zone) complete with everything RTF. But what is "spread spectrum" how does it work?
PS: Hope I posted in the right "Forum"
Wow, did you open a can of worms!
As one of my college professors replied to a question on how a superhetrodyne receiver works, his response was "Very Well". He went on further in the class to cover it all.
As for spread spectrum, that actually goes back to World War II, where the spread spectrum used frequency hopping all over the radio frequencies they used back then.
Advance to the present day, now we are using those 2.4 Ghz (That's 2400 Megahertz, just above the cellphone frequencies) radio frequencies. One big advantage of those high frequencies, is not much in the model airplane can interfere with them.
However, that 2.4 Ghz radio frequency is pretty heavily used, requiring some fancy mathematical gyrations to keep your radio system from getting hit by someones home cordless telephone.
Again, Futaba uses the Frequency Hopping type of spread spectrum that goes back to WWII. Spektrum uses a Direct Sequence Spread Spectrum system that is far far more complex than that Frequency Hopping system.
Frequency hopping is a bunch of very narrow band radio frequency transmissions whose frequencies is jumping all over the place.
DSSS is a wide band radio frequency transmission where the original servo pulse modulation signal is modulated again by a very high frequency digital modulation process. This modulation is sort of an electronic combination key that can only be decoded by a receiver programmed with the same "Key". Any other receivers picking up that signal see this signal as just plain electronic noise, and ignore it. It takes a lot of knowledge in electronic and mathematical theory to make sense of it all.
Now, Spektrum has their DSMX system, which is a combination of both DSSS and frequency hopping. They did this so people could travel to those giant fun fly meets where there could be hundreds of pilots.
I ran a poll in wattflyer that shows Spektrum/JR has over 50% of the market, Futaba has 15%, and the other MFG's account for the rest.
Spektrum has a very good feature called "Model Match" where if your transmitter's designated model doesn't match your model on the ground, the model on the ground won't move. That pretty much eliminates taking off with the wrong model in the transmitter, and a pretty certain crash.
For what it's worth, if you have a full range receiver, the line of sight range of the transmitter and receiver is over two miles. We have come a long way with these Radio Control systems, as compared to what we had 20 years ago. And, I go back 50 years in this stuff.
Hope that helps.