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What's wrong with using 2.4 Ghz airplane radio with a boat?
  • Hey,

    I'm no lawyer,  Just an AMA member.

    I'd RATHER use my existing AIRPLANE radio, a Futaba FASST 2.4 Ghz
    6 channel for my boat/hovercraft project than a ground radio...

    GROUND radio is supposed to be required for boats/hovercraft. 
    Just a LEEEGULL problem or a technical one ?
    brew2u

  • Well, both. My hunch is that the goal is to reduce the chance of interference between air and land RC users. That is also how the old (PPM, PCM) radio frequencies were set up.

    Carlos
  • I have never heard of a Futaba 2.4ghz boat/marine radio.  The car guys use a different kind of 2.4 radio.. pistol grip.

    At our pond everbody uses their Futaba/ Spektrum/Hitec 2.4ghz aircraft radios for both planes and sailboats.

  • That's interesting. I know that by ground radio they seem to be referring to the pistol grip radios. They seem to be popular with the boat folks, too.

    Curiosity has gotten the better of me. I'm going to do a little bit of digging to see what I can find out.

    Carlos
  • Sailboats use regular two stick aircraft radios,  the power boat guys may use pistol grip(not sure).
  • Yeah. That's what I saw.

    Carlos
  • 2.4ghz doesnt care whether its land craft or aircraft. The reason Futaba FASST and Spektrum radios separate their air from their land systems is strictly $$. Will they make the same if a guy runs a boat on their air 2.4ghz radio? No.

    I like XPS 2.4ghz modules in my futaba radios as they use the same high performance Rx's in either car or aircraft, Its silly in todays age that a aircraft rx wont bind to the same company land radio and vice versa.
  • Hmmm. I cannot imagine that the number of folks that do both RC airplanes and RC boats is large. I'm much more inclined to believe that the incompatibility between the air and land systems is an attempt to avoid unexpected interference.

    Carlos
  • Hey Carlos im buying ya brew once i finally get back to town for good so ya know bud!

    Look at Futaba with their top feature FASST aircraft Rx's which wont work with their cheaper lesser channel aircraft Tx's. FASST and their own own beginner bind n fly system SFHSS wont talk or mix BUT the new flagship 18MZ FASST Futaba will run both modulation systems.....NO MODULES in spektrum or futaba means your married to this convoluted mix of tech with expensive rx's. you seen the prices for outdated 72mhz stuff new?? rediculous!
  • Hi, Garland. Glad to see you are getting back into the swing of things with RC.

    Carlos
  • Update: I built my hover craft with two fans, img src="file:///C:/@@@/
    image
    ">escs and batteries, see picture. 
    Both ESCs have battery eliminators going to the Futaba FASST 4 channel receiver and I have to plug and unplug the batteries to make them both work. 

    I am needing to know which color wire to cut on one of the ESC to Receiver cables so I don't burn something. 

    One ESC is an Electrifly C-25 w/BEC and the other is a "Red Brick" 20A w/UBEC.
    Please answer and thanks if you do.
  • The "separation" goes back just a few years to when there were distinct different frequency sets for land and air use. Land RC (cars, boats, etc) operated on 27mHz (with only 6 frequencies) and 75mHz (with, iir, 30 frequencies). Aircraft operated on 72mHz and (I think) 35 and 40-something, all with a fairly limited number of frequencies. The separation was because the user picked a distinct frequency with a crystal set (or, toward the end, dialed in with a synthesized system), and since aircraft and land craft COULD be operating at close but not in communication venues each could operate without fear that other users would inadvertently be on their channel as long as everyone was playing by the rules.

    2.4gHz has changed this. I believe the Futaba system is similar, but I'm pretty sure the Spektrum system has 80 distinct frequencies that the TRANMITTER automatically selects after sampling the airwaves to make certain the frequency/frequencies it is selecting are clearl, much as your cell phone does when it communicates with a tower. The ground systems use a single frequency, so the theory is that the 81st transmitter to turn on won't lock on to a frequency and, thus, won't transmit. The aircraft systems would use two frequencies for redundancy sake, so the 41st transmitter in that case. There have been some changes in the Spektrum system with the new DSM-X (making it, I understand, more similar to the Futaba FAST system in operation) but I believe the basics remain the same. The automatic frequency selecting performed by the 2.4 systems makes the need to separate ground and air frequencies obsolete.
  • What you are saying makes sense.

    Carlos

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