[NSRCA-discussion] SPECKTRUM Modules for Futaba and JR

[John Pavlick]

Actually there is a difference between the Spektrum and the Futaba FASST. The Spektrum chooses its channel(frequency) when you turn it on and stays there as long as you keep it powered up. The next time you turn it back on it may select a different frequency. The Futaba system constantly changes (every 2 milliseconds I believe). As Jon pointed out, you don't really care what it chooses. There are advantages / disadvantages to both systems - as I'm sure we'll soon find out. Keep in mind there's now a LOT of stuff in the 2.4GHz band. Toy airplanes aren't the only thing. In theory this should all work great, but...

John Pavlick
http://www.idseng.com

BTW - I have written code for some Freescale MCUs that are running hardware on the 2.4 GHz band (using Freescale's SMAC). If you think this is a magic, foolproof transport medium, boy have I got some stories for you... <LOL>
  ----- Original Message ----- 
  From: JonLowe at aol.com 
  To: nsrca-discussion at lists.nsrca.org 
  Sent: Thursday, February 22, 2007 10:26 PM
  Subject: Re: [NSRCA-discussion] SPECKTRUM Modules for Futaba and JR


  In a message dated 2/22/2007 6:52:04 PM Central Standard Time, patterndude at tx.rr.com writes:
    What does Spectral capacity - 40 systems mean?  Is this the number of tranmitters that can operate in range of each other, or is this 40 channels or what?
    --Lance

  This is grossly simplified, but the 2.4 ghz band has about 80 frequencies.  Each Spektrum unit picks two unused frequencies and transmits on both.  80/2=40 transmitters that can operate at once.  It is a requirement of the FCC that things on this band don't interfere with each other, and transmitter power is strictly regulated, therefore anything using the band has to check before transmitting.  You have no idea which two frequencies you are on (nor do you care), as they change each time the transmitter turns on.

  I've flown my Dad's Arresti III with the DX7 extensively.  Absolutely solid link, with no fear of getting shot down.  I have been waiting for something like the modules so I could use a decent transmitter for things like throttle curves, conditional mixes, etc.

  I don't want to be at a field that has 40 airplanes in the air at once!

  Jon Lowe





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